4.3.1

fix SMP server stats (#612 )
* fix SMP server stats * add server stats test * fix test
2026-08-30 22:48:26 +00:00 · 2023-01-18 11:21:45 +00:00 · 2023-01-18 11:07:25 +00:00 · 2023-01-17 12:24:05 +00:00 · 2023-01-16 12:00:37 +00:00 · 2023-01-15 18:14:20 +00:00
122 changed files with 16894 additions and 3324 deletions
@@ -11,34 +11,51 @@ on:

 jobs:
  build:
-    runs-on: ubuntu-20.04
+    name: build-${{ matrix.os }}
+    runs-on: ${{ matrix.os }}
+    strategy:
+      fail-fast: false
+      matrix:
+        include:
+          - os: ubuntu-18.04
+          - os: ubuntu-20.04
    steps:
      - name: Clone project
        uses: actions/checkout@v2

-      - name: Setup Stack
+      - name: Setup Haskell
        uses: haskell/actions/setup@v1
        with:
-          ghc-version: '8.10.7'
-          enable-stack: true
-          stack-version: 'latest'
+          ghc-version: "8.10.7"
+          cabal-version: "latest"

      - name: Cache dependencies
        uses: actions/cache@v2
        with:
-          path: ~/.stack
-          key: ${{ hashFiles('stack.yaml') }}
+          path: |
+            ~/.cabal/store
+            dist-newstyle
+          key: ${{ matrix.os }}-${{ hashFiles('cabal.project', 'simplexmq.cabal') }}

-      - name: Build & test
-        id: build_test
+      - name: Build
+        shell: bash
+        run: cabal build --enable-tests
+
+      - name: Test
+        if: matrix.os == 'ubuntu-18.04'
+        timeout-minutes: 30
+        shell: bash
+        run: cabal test --test-show-details=direct
+
+      - name: Prepare binaries
+        if: startsWith(github.ref, 'refs/tags/v') && matrix.os == 'ubuntu-20.04'
        shell: bash
        run: |
-          stack build --test --force-dirty
-          install_root=$(stack path --local-install-root)
-          mv ${install_root}/bin/smp-server smp-server-ubuntu-20_04-x86-64
+          mv $(cabal list-bin smp-server) smp-server-ubuntu-20_04-x86-64
+          mv $(cabal list-bin ntf-server) ntf-server-ubuntu-20_04-x86-64

      - name: Build changelog
-        if: startsWith(github.ref, 'refs/tags/v')
+        if: startsWith(github.ref, 'refs/tags/v') && matrix.os == 'ubuntu-20.04'
        id: build_changelog
        uses: mikepenz/release-changelog-builder-action@v1
        with:
@@ -49,19 +66,8 @@ jobs:
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}

-      - name: Extract release candidate
-        if: startsWith(github.ref, 'refs/tags/v')
-        id: extract_release_candidate
-        shell: bash
-        run: |
-          if [[ ${GITHUB_REF} == *rc* ]]; then
-            echo "::set-output name=release_candidate::true"
-          else
-            echo "::set-output name=release_candidate::false"
-          fi
-
      - name: Create release
-        if: startsWith(github.ref, 'refs/tags/v')
+        if: startsWith(github.ref, 'refs/tags/v') && matrix.os == 'ubuntu-20.04'
        uses: softprops/action-gh-release@v1
        with:
          body: |
@@ -69,10 +75,11 @@ jobs:

            Commits:
            ${{ steps.build_changelog.outputs.changelog }}
-          prerelease: ${{ steps.extract_release_candidate.outputs.release_candidate }}
+          prerelease: true
          files: |
            LICENSE
            smp-server-ubuntu-20_04-x86-64
+            ntf-server-ubuntu-20_04-x86-64
          fail_on_unmatched_files: true
        env:
          GITHUB_TOKEN: ${{ secrets.GITHUB_TOKEN }}
@@ -4,3 +4,6 @@
 *.session.sql
 tests/tmp
 dist-newstyle/
+
+cabal.project.local
+cabal.project.local~
@@ -1,9 +1,201 @@
+# 4.3.0
+
+SMP server:
+
+- additional server usage statistics.
+
+SMP agent:
+
+- increase retry interval when sending messages after ERR QUOTA.
+
+# 4.2.0
+
+SMP agent and server:
+
+- reduce sender traffic in cases when queue quota is exceeded:
+  - server sends quota exceeded message to the recipient when sender receives ERR QUOTA.
+  - recipient sends QCONT message to the send once the queue is drained (via reply queue).
+  - sender retry delays are increased, reducing traffic, but sender instantly resumes delivery where QCONT is received.
+
+SMP server:
+
+- increase internal queue sizes.
+
+SMP agent:
+
+- deduplicate connection IDs in connect/disconnect responses.
+- unit tests for Crypto.hs.
+- fix connection switch to another queue: correctly set primary send queue.
+
+Notification server (v1.3.0):
+
+- check token status when sending verification notificaiton.
+
+# 4.1.0
+
+SMP agent and server:
+
+- option to toggle TLS handshake error logs (disabled by default).
+
+SMP agent:
+
+- include server address in BROKER error.
+- api to get hash of double ratchet associated data (for connection verification).
+- api to get agent statistics.
+
+# 4.0.0
+
+SMP server:
+
+- Basic authentication. The server address can now include an optional password that is required to create messaging queues, so the contacts who message you will not be able to receive messages via your server, unless you share with them the address with the password. It is recommended to enable basic authentication on all private servers by adding `create_password` parameter into AUTH section of server INI file (the previously deployed servers do not have this section, you need to add it).
+- Disable creating new queues completely with `new_queues: off` parameter in AUTH section of INI file - it can be used to simplify migrating the exising connections to another server.
+- Updated server CLI with changed defaults:
+  - interactive server initialization, use -y flag to initalize the server non-interactively.
+  - store log is now enabled by default, so messaging queues and messages are restored when the server is restarted (to restore undelivered messages the server needs to be stopped with SIGINT signal).
+  - a random password is now generated by default during the server initialization.
+
+SMP agent:
+
+- API to test SMP servers. It connects to the server, creates and deletes a messaging queue. The new SimpleX Chat client uses this API to allow you to test that you have the correct server address, with the valid certificate fingerprint and pasword, before enabling the new server.
+
+# 3.4.0
+
+SMP agent:
+
+- increase concurrency with connection-level locks
+- fix issues identified in security assessment (see the announcement: https://github.com/simplex-chat/simplex-chat/blob/stable/blog/20221108-simplex-chat-v4.2-security-audit-new-website.md)
+- manual connection queue rotation
+- optional client data in connection requests links
+
+SMP server:
+
+- specialize monad stack to improve performance
+- log slow commands
+
+# 3.3.0
+
+SMP server:
+
+- allow repeated KEY command with the same key (to avoid failures on retries)
+
+SMP agent:
+
+- enable/disable connection notifications
+- asynchronous commands that retry on network error
+- use SQLCipher
+
+# 3.2.0
+
+SMP agent:
+
+- Support multiple server hostnames (including onion hostnames) in server addresses.
+- Network configuration options.
+- Options to define rules to choose server hostname.
+
+# 3.1.0
+
+SMP server and agent:
+
+- SMP protocol v4: batching multiple server commands/responses in a transport block.
+
+# 3.0.0
+
+SMP server:
+
+- restore undeliverd messages when the server is restarted.
+- SMP protocol v3 to support push notification:
+  - updated SEND and MSG to add message flags (for notification flag that contros whether the notification is sent and for any future extensions) and to move message meta-data sent to the recipient into the encrypted envelope.
+  - update NKEY and NID to add e2e encryption keys (for the notification meta-data encryption between SMP server and the client), and update NMSG to include this meta-data.
+  - update ACK command to include message ID (to avoid acknowledging unprocessed message).
+  - add NDEL commands to remove notification subscription credentials from SMP queue.
+  - add GET command to receive messages without subscription - to be used in iOS notification service extension to receive messages without terminating app subscriptions.
+
+SMP agent:
+
+- new protocol for duplex connection handshake reducing traffic and connection time.
+- support for SMP notifications server and managing device token.
+- remove redundant FQDN validation from TLS handshake to prepare for access via Tor.
+- support for fully stopping agent and for termporary suspending agent operations.
+- improve management of duplicate message delivery.
+
+SMP notifications server v1.0:
+
+- SMP notifications protocol with version negotiation during handshake.
+- device token registration and verification (via background notification).
+- SMP notification subscriptions and push notifications via APNS.
+- restoring notification subscriptions when the server is restarted.
+
+# 2.3.0
+
+SMP server:
+
+- Save and restore undelivered messages, to avoid losing them. To save messages the server has to be stopped with SIGINT signal, if it is stopped with SIGTERM undelivered messages would not be saved.
+
+# 2.2.0
+
+SMP server:
+
+- Fix sockets/threads/memory leak
+
+SMP agent:
+
+- Support stopping and resuming agent with `disconnectAgentClient` / `resumeAgentClient`
+
+# 2.1.1
+
+SMP server:
+
+- gracefully close sockets on client disconnection
+- CLI warning when deleting server configuration
+
+# 2.1.0
+
+SMP server:
+
+- configuration to expire inactive clients in ini file, increased TTL and check interval for client expiration
+
+# 2.0.0
+
+Push notifications server (beta):
+
+- supports APNS
+- manage device tokens verification via notification delivery
+- sending periodic background notification to check messages (not more frequent than every 20 min)
+
+SMP server:
+
+- disconnect inactive clients after some period
+- remove undelivered messages after 30 days
+- log aggregate usage daily stats: only the number of queues created/secured/deleted/used and messages sent/delivered is logged, as one line per day, so we can plan server capacity and diagnose any problems.
+
+SMP agent:
+
+- manage device tokens and notification server connection
+- DOWN/UP events to the agent user about server disconnections/reconnections are now sent once per server
+
+# 1.1.0
+
+SMP server:
+
+- message TTL and periodic deletion of old messages
+- configuration to prevent creation of the new queues
+
+SMP agent:
+
+- asynchronous connection handshake
+- configurable SMP servers at run-time
+- use TCP keep-alive for connection stability
+- improve stability of connection subscriptions
+- auto-vacuum DB to remove deleted records
+
 # 1.0.3

 SMP server:
+
 - Reduce server message queue quota to 128 messages.

 SMP agent:
+
 - Add "yes to migrations" option.
 - Make new SMP client attempt to reconnect on network error.
 - Reduce connection handshake expiration to 2 days.
@@ -13,24 +205,29 @@ JSON encoding of types used in simplex-chat, some other minor adjustments.
 # 1.0.2

 General:
+
 - Enable TLS 1.3 parameters for TLS handshake (server and client).
 - Switch from hs-tls fork to original repo now that it supports getFinished and getPeerFinished APIs for both TLS 1.2 and TLS 1.3.

 SMP server:
+
 - Perform TLS handshake in a separate thread per-connection.

 SMP agent:
+
 - Cease attempts to send HELLO after one week timeout.
 - Coalesce requests to connect to SMP servers, to have 1 connection per server.

 # 1.0.1

 SMP server:
+
 - Explicitly set line buffering in stdout/stderr to log each line when output is redirected to files.

 # 1.0.0

 Security and privacy improvements:
+
 - Faster and more secure 2-layer E2E encryption with additional encryption layer between servers and recipients:
  - application messages in each duplex connection (managed by SMP agents - see [overview](https://github.com/simplex-chat/simplexmq/blob/master/protocol/overview-tjr.md)) are encrypted using [double-ratchet algorithm](https://www.signal.org/docs/specifications/doubleratchet/), providing forward secrecy and break-in recovery. This layer uses two Curve448 keys per client for [X3DH key agreement](https://www.signal.org/docs/specifications/x3dh/), SHA512 based HKDFs and AES-GCM AEAD encryption.
  - SMP client messages are additionally E2E encrypted in each SMP queue to avoid cipher-text correlation of messages sent via multiple redundant queues (that will be supported soon). This and the next layer use [NaCl crypto_box algorithm](https://nacl.cr.yp.to/index.html) with XSalsa20Poly1305 cipher and Curve25519 keys for DH key agreement.
@@ -43,13 +240,16 @@ Security and privacy improvements:
 - Server identity verification via server offline certificate fingerprints included in SMP server addresses.

 New functionality:
+
 - Support for notification servers with new SMP commands: `NKEY`/`NID`, `NSUB`/`NMSG`.

 Efficiency improvements:
+
 - Binary protocol encodings to reduce overhead from circa 15% to approximately 3.7% of transmitted application message size, with only 2.2% overhead for SMP protocol messages.
 - More performant cryptographic algorithms.

 For more information about SimpleX:
+
 - [SimpleX overview](https://github.com/simplex-chat/simplexmq/blob/master/protocol/overview-tjr.md).
 - [SimpleX chat v1 announcement](https://github.com/simplex-chat/simplex-chat/blob/master/blog/20220112-simplex-chat-v1-released.md).

@@ -11,7 +11,7 @@ If you have a server deployed please deploy a new server to a new host and retir

 ## Message broker for unidirectional (simplex) queues

-SimpleXMQ is a message broker for managing message queues and sending messages over public network. It consists of SMP server, SMP client library and SMP agent that implement [SMP protocol](https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md) for client-server communication and [SMP agent protocol](https://github.com/simplex-chat/simplexmq/blob/master/protocol/agent-protocol.md) to manage duplex connections via simplex queues on multiple SMP servers.
+SimpleXMQ is a message broker for managing message queues and sending messages over public network. It consists of SMP server, SMP client library and SMP agent that implement [SMP protocol](./protocol/simplex-messaging.md) for client-server communication and [SMP agent protocol](./protocol/agent-protocol.md) to manage duplex connections via simplex queues on multiple SMP servers.

 SMP protocol is inspired by [Redis serialization protocol](https://redis.io/topics/protocol), but it is much simpler - it currently has only 10 client commands and 8 server responses.

@@ -27,17 +27,19 @@ SimpleXMQ is implemented in Haskell - it benefits from robust software transacti

 ### SMP server

-[SMP server](https://github.com/simplex-chat/simplexmq/blob/master/apps/smp-server/Main.hs) can be run on any Linux distribution without any dependencies, including low power/low memory devices.
+[SMP server](./apps/smp-server/Main.hs) can be run on any Linux distribution, including low power/low memory devices. OpenSSL library is required for initialization.

-To initialize the server use `smp-server init` command - it will generate keys and certificates for TLS transport. The fingerprint of offline certificate is used as part of the server address to protect client/server connection against man-in-the-middle attacks: `smp://<fingerprint>@<hostname>[:5223]`.
+To initialize the server use `smp-server init -n <fqdn>` (or `smp-server init --ip <ip>` for IP based address) command - it will generate keys and certificates for TLS transport. The fingerprint of offline certificate is used as part of the server address to protect client/server connection against man-in-the-middle attacks: `smp://<fingerprint>@<hostname>[:5223]`.

 SMP server uses in-memory persistence with an optional append-only log of created queues that allows to re-start the server without losing the connections. This log is compacted on every server restart, permanently removing suspended and removed queues.

 To enable store log, initialize server using `smp-server -l` command, or modify `smp-server.ini` created during initialization (uncomment `enable: on` option in the store log section). Use `smp-server --help` for other usage tips.

+Starting from version 2.3.0, when store log is enabled, the server would also enable saving undelivered messages on exit and restoring them on start. This can be disabled via a separate setting `restore_messages` in `smp-server.ini` file. Saving messages would only work if the server is stopped with SIGINT signal (keyboard interrupt), if it is stopped with SIGTERM signal the messages would not be saved.
+
 > **Please note:** On initialization SMP server creates a chain of two certificates: a self-signed CA certificate ("offline") and a server certificate used for TLS handshake ("online"). **You should store CA certificate private key securely and delete it from the server. If server TLS credential is compromised this key can be used to sign a new one, keeping the same server identity and established connections.** CA private key location by default is `/etc/opt/simplex/ca.key`.

-SMP server implements [SMP protocol](https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md).
+SMP server implements [SMP protocol](./protocol/simplex-messaging.md).

 #### Running SMP server on MacOS

@@ -60,20 +62,21 @@ Now `openssl version` should be saying "OpenSSL". You can now run `smp-server in

 ### SMP client library

-[SMP client](https://github.com/simplex-chat/simplexmq/blob/master/src/Simplex/Messaging/Client.hs) is a Haskell library to connect to SMP servers that allows to:
+[SMP client](./src/Simplex/Messaging/Client.hs) is a Haskell library to connect to SMP servers that allows to:
+
 - execute commands with a functional API.
 - receive messages and other notifications via STM queue.
 - automatically send keep-alive commands.

 ### SMP agent

-[SMP agent library](https://github.com/simplex-chat/simplexmq/blob/master/src/Simplex/Messaging/Agent.hs) can be used to run SMP agent as part of another application and to communicate with the agent via STM queues, without serializing and parsing commands and responses.
+[SMP agent library](./src/Simplex/Messaging/Agent.hs) can be used to run SMP agent as part of another application and to communicate with the agent via STM queues, without serializing and parsing commands and responses.

-Haskell type [ACommand](https://github.com/simplex-chat/simplexmq/blob/master/src/Simplex/Messaging/Agent/Protocol.hs) represents SMP agent protocol to communicate via STM queues.
+Haskell type [ACommand](./src/Simplex/Messaging/Agent/Protocol.hs) represents SMP agent protocol to communicate via STM queues.

 See [simplex-chat](https://github.com/simplex-chat/simplex-chat) terminal UI for the example of integrating SMP agent into another application.

-[SMP agent executable](https://github.com/simplex-chat/simplexmq/blob/master/apps/smp-agent/Main.hs) can be used to run a standalone SMP agent process that implements plaintext [SMP agent protocol](https://github.com/simplex-chat/simplexmq/blob/master/protocol/agent-protocol.md) via TCP port 5224, so it can be used via telnet. It can be deployed in private networks to share access to the connections between multiple applications and services.
+[SMP agent executable](./apps/smp-agent/Main.hs) can be used to run a standalone SMP agent process that implements plaintext [SMP agent protocol](./protocol/agent-protocol.md) via TCP port 5224, so it can be used via telnet. It can be deployed in private networks to share access to the connections between multiple applications and services.

 ## Using SMP server and SMP agent

@@ -87,7 +90,111 @@ You can either run your own SMP server locally or deploy using [Linode StackScri

 It's the easiest to try SMP agent via a prototype [simplex-chat](https://github.com/simplex-chat/simplex-chat) terminal UI.

-[<img alt="Linode" src="https://raw.githubusercontent.com/simplex-chat/simplexmq/master/img/linode.svg" align="right" width="200">](https://cloud.linode.com/stackscripts/748014)
+## Deploy SMP server on Linux
+
+You can run your SMP server as a Linux process, optionally using a service manager for booting and restarts.
+
+Notice that `smp-server` requires `openssl` as run-time dependency (it is used to generate server certificates during initialization). Install it with your packet manager:
+
+```sh
+# For Ubuntu
+apt update && apt install openssl
+```
+
+### Install binaries
+
+#### Using Docker
+
+On Linux, you can deploy smp server using Docker. This will download image from [Docker Hub](https://hub.docker.com/r/simplexchat/simplexmq).
+
+1. Create `config` and `logs` directories:
+
+   ```sh
+   mkdir -p ~/simplex/{config,logs}
+   ```
+
+2. Run your Docker container. You must change **your_ip_or_domain**. `-e pass="password"` is optional variable to password-protect your `smp` server:
+   ```sh
+   docker run -d \
+       -e addr="your_ip_or_domain" \
+       -e pass="password" \
+       -p 5223:5223 \
+       -v $HOME/simplex/config:/etc/opt/simplex:z \
+       -v $HOME/simplex/logs:/var/opt/simplex:z \
+       simplexchat/simplexmq
+   ```
+
+#### Ubuntu
+
+For Ubuntu you can download a binary from [the latest release](https://github.com/simplex-chat/simplexmq/releases).
+
+### Build from source
+
+#### Using Docker
+
+> **Please note:** to build the app use source code from [stable branch](https://github.com/simplex-chat/simplexmq/tree/stable).
+
+On Linux, you can build smp server using Docker.
+
+1. Build your `smp-server` image:
+
+   ```sh
+   git clone https://github.com/simplex-chat/simplexmq
+   cd simplexmq
+   git checkout stable
+   DOCKER_BUILDKIT=1 docker build -t smp-server -f ./build.Dockerfile .
+   ```
+
+2. Create `config` and `logs` directories:
+
+   ```sh
+   mkdir -p ~/simplex/{config,logs}
+   ```
+
+3. Run your Docker container. You must change **your_ip_or_domain**. `-e pass="password"` is optional variable to password-protect your `smp` server::
+   ```sh
+   docker run -d \
+       -e addr="your_ip_or_domain" \
+       -e pass="password" \
+       -p 5223:5223 \
+       -v $HOME/simplex/config:/etc/opt/simplex:z \
+       -v $HOME/simplex/logs:/var/opt/simplex:z \
+       smp-server
+   ```
+
+#### Using your distribution
+
+1. Install [Haskell GHCup](https://www.haskell.org/ghcup/), GHC 8.10.7 and cabal:
+
+   ```sh
+   curl --proto '=https' --tlsv1.2 -sSf https://get-ghcup.haskell.org | sh
+   ghcup install ghc 8.10.7
+   ghcup install cabal
+   ghcup set ghc 8.10.7
+   ghcup set cabal
+   ```
+
+2. Build the project:
+
+   ```sh
+   git clone https://github.com/simplex-chat/simplexmq
+   cd simplexmq
+   git checkout stable
+   # On Ubuntu. Depending on your distribution, use your package manager to determine package names.
+   apt-get update && apt-get install -y build-essential libgmp3-dev zlib1g-dev
+   cabal update
+   cabal install
+   ```
+
+- Initialize SMP server with `smp-server init [-l] -n <fqdn>` or `smp-server init [-l] --ip <ip>` - depending on how you initialize it, either FQDN or IP will be used for server's address.
+
+- Run `smp-server start` to start SMP server, or you can configure a service manager to run it as a service.
+
+- Optionally, `smp-server` can be setup for having an onion address in `tor` network. See: [`scripts/tor`](./scripts/tor/). In this case, the server address can have both public and onion hostname pointing to the same server, to allow two people connect when only one of them is using Tor. The server address would be: `smp://<fingerprint>@<public_hostname>,<onion_hostname>`
+
+See [this section](#smp-server) for more information. Run `smp-server -h` and `smp-server init -h` for explanation of commands and options.
+
+[<img alt="Linode" src="./img/linode.svg" align="right" width="200">](https://cloud.linode.com/stackscripts/748014)

 ## Deploy SMP server on Linode

@@ -98,11 +205,11 @@ Deployment on Linode is performed via StackScripts, which serve as recipes for L
 - Create a Linode account or login with an already existing one.
 - Open [SMP server StackScript](https://cloud.linode.com/stackscripts/748014) and click "Deploy New Linode".
 - You can optionally configure the following parameters:
-    - SMP Server store log flag for queue persistence on server restart, recommended.
-    - [Linode API token](https://www.linode.com/docs/guides/getting-started-with-the-linode-api#get-an-access-token) to attach server address etc. as tags to Linode and to add A record to your 2nd level domain (e.g. `example.com` [domain should be created](https://cloud.linode.com/domains/create) in your account prior to deployment). The API token access scopes:
-      - read/write for "linodes"
-      - read/write for "domains"
-    - Domain name to use instead of Linode IP address, e.g. `smp1.example.com`.
+  - SMP Server store log flag for queue persistence on server restart, recommended.
+  - [Linode API token](https://www.linode.com/docs/guides/getting-started-with-the-linode-api#get-an-access-token) to attach server address etc. as tags to Linode and to add A record to your 2nd level domain (e.g. `example.com` [domain should be created](https://cloud.linode.com/domains/create) in your account prior to deployment). The API token access scopes:
+    - read/write for "linodes"
+    - read/write for "domains"
+  - Domain name to use instead of Linode IP address, e.g. `smp1.example.com`.
 - Choose the region and plan, Shared CPU Nanode with 1Gb is sufficient.
 - Provide ssh key to be able to connect to your Linode via ssh. If you haven't provided a Linode API token this step is required to login to your Linode and get the server's fingerprint either from the welcome message or from the file `/etc/opt/simplex/fingerprint` after server starts. See [Linode's guide on ssh](https://www.linode.com/docs/guides/use-public-key-authentication-with-ssh/) .
 - Deploy your Linode. After it starts wait for SMP server to start and for tags to appear (if a Linode API token was provided). It may take up to 5 minutes depending on the connection speed on the Linode. Connecting Linode IP address to provided domain name may take some additional time.
@@ -111,7 +218,7 @@ Deployment on Linode is performed via StackScripts, which serve as recipes for L

 Please submit an [issue](https://github.com/simplex-chat/simplexmq/issues) if any problems occur.

-[<img alt="DigitalOcean" src="https://raw.githubusercontent.com/simplex-chat/simplexmq/master/img/digitalocean.png" align="right" width="300">](https://marketplace.digitalocean.com/apps/simplex-server)
+[<img alt="DigitalOcean" src="/img/digitalocean.png" align="right" width="300">](https://marketplace.digitalocean.com/apps/simplex-server)

 ## Deploy SMP server on DigitalOcean

@@ -139,12 +246,12 @@ smp-server init [-l] -n <fqdn>

 ## SMP server design

-![SMP server design](https://raw.githubusercontent.com/simplex-chat/simplexmq/master/design/server.svg)
+![SMP server design](./design/server.svg)

 ## SMP agent design

-![SMP agent design](https://raw.githubusercontent.com/simplex-chat/simplexmq/master/design/agent2.svg)
+![SMP agent design](./design/agent2.svg)

 ## License

-[AGPL v3](https://github.com/simplex-chat/simplexmq/blob/master/LICENSE)
+[AGPL v3](./LICENSE)
@@ -0,0 +1,18 @@
+module Main where
+
+import Control.Logger.Simple
+import Simplex.Messaging.Notifications.Server.Main
+
+cfgPath :: FilePath
+cfgPath = "/etc/opt/simplex-notifications"
+
+logPath :: FilePath
+logPath = "/var/opt/simplex-notifications"
+
+logCfg :: LogConfig
+logCfg = LogConfig {lc_file = Nothing, lc_stderr = True}
+
+main :: IO ()
+main = do
+  setLogLevel LogDebug -- change to LogError in production
+  withGlobalLogging logCfg $ ntfServerCLI cfgPath logPath
@@ -1,4 +1,5 @@
 {-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE NumericUnderscores #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE TypeApplications #-}

@@ -8,10 +9,19 @@ import Control.Logger.Simple
 import qualified Data.List.NonEmpty as L
 import Simplex.Messaging.Agent.Env.SQLite
 import Simplex.Messaging.Agent.Server (runSMPAgent)
+import Simplex.Messaging.Client (defaultNetworkConfig)
 import Simplex.Messaging.Transport (TLS, Transport (..))

 cfg :: AgentConfig
-cfg = defaultAgentConfig {initialSMPServers = L.fromList ["smp://bU0K-bRg24xWW__lS0umO1Zdw_SXqpJNtm1_RrPLViE=@localhost:5223"]}
+cfg = defaultAgentConfig
+
+servers :: InitialAgentServers
+servers =
+  InitialAgentServers
+    { smp = L.fromList ["smp://bU0K-bRg24xWW__lS0umO1Zdw_SXqpJNtm1_RrPLViE=@localhost:5223"],
+      ntf = [],
+      netCfg = defaultNetworkConfig
+    }

 logCfg :: LogConfig
 logCfg = LogConfig {lc_file = Nothing, lc_stderr = True}
@@ -20,4 +30,4 @@ main :: IO ()
 main = do
  putStrLn $ "SMP agent listening on port " ++ tcpPort (cfg :: AgentConfig)
  setLogLevel LogInfo -- LogError
-  withGlobalLogging logCfg $ runSMPAgent (transport @TLS) cfg
+  withGlobalLogging logCfg $ runSMPAgent (transport @TLS) cfg servers
@@ -1,319 +1,18 @@
-{-# LANGUAGE DataKinds #-}
-{-# LANGUAGE DuplicateRecordFields #-}
-{-# LANGUAGE GADTs #-}
-{-# LANGUAGE LambdaCase #-}
-{-# LANGUAGE NamedFieldPuns #-}
-{-# LANGUAGE OverloadedStrings #-}
-{-# LANGUAGE TypeApplications #-}
-
 module Main where

-import Control.Monad.Except
-import Data.ByteString.Char8 (ByteString)
-import qualified Data.ByteString.Char8 as B
-import Data.Either (fromRight)
-import Data.Ini (Ini, lookupValue, readIniFile)
-import Data.Maybe (fromMaybe)
-import qualified Data.Text as T
-import Data.X509.Validation (Fingerprint (..))
-import Network.Socket (HostName, ServiceName)
-import Options.Applicative
-import Simplex.Messaging.Encoding.String
-import Simplex.Messaging.Server (runSMPServer)
-import Simplex.Messaging.Server.Env.STM
-import Simplex.Messaging.Server.StoreLog (StoreLog, openReadStoreLog, storeLogFilePath)
-import Simplex.Messaging.Transport (ATransport (..), TLS, Transport (..), simplexMQVersion)
-import Simplex.Messaging.Transport.Server (loadFingerprint)
-import Simplex.Messaging.Transport.WebSockets (WS)
-import System.Directory (createDirectoryIfMissing, doesDirectoryExist, doesFileExist, removeDirectoryRecursive)
-import System.Exit (exitFailure)
-import System.FilePath (combine)
-import System.IO (BufferMode (..), IOMode (..), hGetLine, hSetBuffering, stderr, stdout, withFile)
-import System.Process (readCreateProcess, shell)
-import Text.Read (readMaybe)
+import Control.Logger.Simple
+import Simplex.Messaging.Server.Main

-cfgDir :: FilePath
-cfgDir = "/etc/opt/simplex"
+cfgPath :: FilePath
+cfgPath = "/etc/opt/simplex"

-logDir :: FilePath
-logDir = "/var/opt/simplex"
+logPath :: FilePath
+logPath = "/var/opt/simplex"

-iniFile :: FilePath
-iniFile = combine cfgDir "smp-server.ini"
-
-storeLogFile :: FilePath
-storeLogFile = combine logDir "smp-server-store.log"
-
-caKeyFile :: FilePath
-caKeyFile = combine cfgDir "ca.key"
-
-caCrtFile :: FilePath
-caCrtFile = combine cfgDir "ca.crt"
-
-serverKeyFile :: FilePath
-serverKeyFile = combine cfgDir "server.key"
-
-serverCrtFile :: FilePath
-serverCrtFile = combine cfgDir "server.crt"
-
-fingerprintFile :: FilePath
-fingerprintFile = combine cfgDir "fingerprint"
+logCfg :: LogConfig
+logCfg = LogConfig {lc_file = Nothing, lc_stderr = True}

 main :: IO ()
 main = do
-  getCliCommand >>= \case
-    Init opts ->
-      doesFileExist iniFile >>= \case
-        True -> exitError $ "Error: server is already initialized (" <> iniFile <> " exists).\nRun `smp-server start`."
-        _ -> initializeServer opts
-    Start ->
-      doesFileExist iniFile >>= \case
-        True -> readIniFile iniFile >>= either exitError (runServer . mkIniOptions)
-        _ -> exitError $ "Error: server is not initialized (" <> iniFile <> " does not exist).\nRun `smp-server init`."
-    Delete -> cleanup >> putStrLn "Deleted configuration and log files"
-
-exitError :: String -> IO ()
-exitError msg = putStrLn msg >> exitFailure
-
-data CliCommand
-  = Init InitOptions
-  | Start
-  | Delete
-
-data InitOptions = InitOptions
-  { enableStoreLog :: Bool,
-    signAlgorithm :: SignAlgorithm,
-    ip :: HostName,
-    fqdn :: Maybe HostName
-  }
-  deriving (Show)
-
-data SignAlgorithm = ED448 | ED25519
-  deriving (Read, Show)
-
-getCliCommand :: IO CliCommand
-getCliCommand =
-  customExecParser
-    (prefs showHelpOnEmpty)
-    ( info
-        (helper <*> versionOption <*> cliCommandP)
-        (header version <> fullDesc)
-    )
-  where
-    versionOption = infoOption version (long "version" <> short 'v' <> help "Show version")
-
-cliCommandP :: Parser CliCommand
-cliCommandP =
-  hsubparser
-    ( command "init" (info initP (progDesc $ "Initialize server - creates " <> cfgDir <> " and " <> logDir <> " directories and configuration files"))
-        <> command "start" (info (pure Start) (progDesc $ "Start server (configuration: " <> iniFile <> ")"))
-        <> command "delete" (info (pure Delete) (progDesc "Delete configuration and log files"))
-    )
-  where
-    initP :: Parser CliCommand
-    initP =
-      Init
-        <$> ( InitOptions
-                <$> switch
-                  ( long "store-log"
-                      <> short 'l'
-                      <> help "Enable store log for SMP queues persistence"
-                  )
-                <*> option
-                  (maybeReader readMaybe)
-                  ( long "sign-algorithm"
-                      <> short 'a'
-                      <> help "Signature algorithm used for TLS certificates: ED25519, ED448"
-                      <> value ED448
-                      <> showDefault
-                      <> metavar "ALG"
-                  )
-                <*> strOption
-                  ( long "ip"
-                      <> help
-                        "Server IP address used as Subject Alternative Name for TLS online certificate, \
-                        \also used as Common Name if FQDN is not supplied"
-                      <> value "127.0.0.1"
-                      <> showDefault
-                      <> metavar "IP"
-                  )
-                <*> (optional . strOption)
-                  ( long "fqdn"
-                      <> short 'n'
-                      <> help "Server FQDN used as Common Name and Subject Alternative Name for TLS online certificate"
-                      <> showDefault
-                      <> metavar "FQDN"
-                  )
-            )
-
-initializeServer :: InitOptions -> IO ()
-initializeServer InitOptions {enableStoreLog, signAlgorithm, ip, fqdn} = do
-  cleanup
-  createDirectoryIfMissing True cfgDir
-  createDirectoryIfMissing True logDir
-  createX509
-  fp <- saveFingerprint
-  createIni
-  putStrLn $ "Server initialized, you can modify configuration in " <> iniFile <> ".\nRun `smp-server start` to start server."
-  printServiceInfo fp
-  warnCAPrivateKeyFile
-  where
-    createX509 = do
-      createOpensslCaConf
-      createOpensslServerConf
-      -- CA certificate (identity/offline)
-      run $ "openssl genpkey -algorithm " <> show signAlgorithm <> " -out " <> caKeyFile
-      run $ "openssl req -new -x509 -days 999999 -config " <> opensslCaConfFile <> " -extensions v3 -key " <> caKeyFile <> " -out " <> caCrtFile
-      -- server certificate (online)
-      run $ "openssl genpkey -algorithm " <> show signAlgorithm <> " -out " <> serverKeyFile
-      run $ "openssl req -new -config " <> opensslServerConfFile <> " -reqexts v3 -key " <> serverKeyFile <> " -out " <> serverCsrFile
-      run $ "openssl x509 -req -days 999999 -extfile " <> opensslServerConfFile <> " -extensions v3 -in " <> serverCsrFile <> " -CA " <> caCrtFile <> " -CAkey " <> caKeyFile <> " -CAcreateserial -out " <> serverCrtFile
-      where
-        run cmd = void $ readCreateProcess (shell cmd) ""
-        opensslCaConfFile = combine cfgDir "openssl_ca.conf"
-        opensslServerConfFile = combine cfgDir "openssl_server.conf"
-        serverCsrFile = combine cfgDir "server.csr"
-        createOpensslCaConf =
-          writeFile
-            opensslCaConfFile
-            "[req]\n\
-            \distinguished_name = req_distinguished_name\n\
-            \prompt = no\n\n\
-            \[req_distinguished_name]\n\
-            \CN = SMP server CA\n\
-            \O = SimpleX\n\n\
-            \[v3]\n\
-            \subjectKeyIdentifier = hash\n\
-            \authorityKeyIdentifier = keyid:always\n\
-            \basicConstraints = critical,CA:true\n"
-        -- TODO revise https://www.rfc-editor.org/rfc/rfc5280#section-4.2.1.3, https://www.rfc-editor.org/rfc/rfc3279#section-2.3.5
-        -- IP and FQDN can't both be used as server address interchangeably even if IP is added
-        -- as Subject Alternative Name, unless the following validation hook is disabled:
-        -- https://hackage.haskell.org/package/x509-validation-1.6.10/docs/src/Data-X509-Validation.html#validateCertificateName
-        createOpensslServerConf =
-          writeFile
-            opensslServerConfFile
-            ( "[req]\n\
-              \distinguished_name = req_distinguished_name\n\
-              \prompt = no\n\n\
-              \[req_distinguished_name]\n"
-                <> ("CN = " <> cn <> "\n\n")
-                <> "[v3]\n\
-                   \basicConstraints = CA:FALSE\n\
-                   \keyUsage = digitalSignature, nonRepudiation, keyAgreement\n\
-                   \extendedKeyUsage = serverAuth\n"
-            )
-          where
-            cn = fromMaybe ip fqdn
-
-    saveFingerprint = do
-      Fingerprint fp <- loadFingerprint caCrtFile
-      withFile fingerprintFile WriteMode (`B.hPutStrLn` strEncode fp)
-      pure fp
-
-    createIni = do
-      writeFile iniFile $
-        "[STORE_LOG]\n\
-        \# The server uses STM memory to store SMP queues and messages,\n\
-        \# that will be lost on restart (e.g., as with redis).\n\
-        \# This option enables saving SMP queues to append only log,\n\
-        \# and restoring them when the server is started.\n\
-        \# Log is compacted on start (deleted queues are removed).\n\
-        \# The messages in the queues are not logged.\n"
-          <> ("enable: " <> (if enableStoreLog then "on" else "off  # on") <> "\n\n")
-          <> "[TRANSPORT]\n\
-             \port: 5223\n\
-             \websockets: off\n"
-
-    warnCAPrivateKeyFile =
-      putStrLn $
-        "----------\n\
-        \You should store CA private key securely and delete it from the server.\n\
-        \If server TLS credential is compromised this key can be used to sign a new one, \
-        \keeping the same server identity and established connections.\n\
-        \CA private key location:\n"
-          <> caKeyFile
-          <> "\n----------"
-
-data IniOptions = IniOptions
-  { enableStoreLog :: Bool,
-    port :: ServiceName,
-    enableWebsockets :: Bool
-  }
-
-- TODO ? properly parse ini as a whole
-mkIniOptions :: Ini -> IniOptions
-mkIniOptions ini =
-  IniOptions
-    { enableStoreLog = (== "on") $ strict "STORE_LOG" "enable",
-      port = T.unpack $ strict "TRANSPORT" "port",
-      enableWebsockets = (== "on") $ strict "TRANSPORT" "websockets"
-    }
-  where
-    strict :: String -> String -> T.Text
-    strict section key =
-      fromRight (error ("no key " <> key <> " in section " <> section)) $
-        lookupValue (T.pack section) (T.pack key) ini
-
-runServer :: IniOptions -> IO ()
-runServer IniOptions {enableStoreLog, port, enableWebsockets} = do
-  hSetBuffering stdout LineBuffering
-  hSetBuffering stderr LineBuffering
-  fp <- checkSavedFingerprint
-  printServiceInfo fp
-  storeLog <- openStoreLog
-  let cfg = mkServerConfig storeLog
-  printServerConfig cfg
-  runSMPServer cfg
-  where
-    checkSavedFingerprint = do
-      savedFingerprint <- loadSavedFingerprint
-      Fingerprint fp <- loadFingerprint caCrtFile
-      when (B.pack savedFingerprint /= strEncode fp) $
-        exitError "Stored fingerprint is invalid."
-      pure fp
-
-    mkServerConfig storeLog =
-      ServerConfig
-        { transports = (port, transport @TLS) : [("80", transport @WS) | enableWebsockets],
-          tbqSize = 16,
-          serverTbqSize = 64,
-          msgQueueQuota = 128,
-          queueIdBytes = 24,
-          msgIdBytes = 24, -- must be at least 24 bytes, it is used as 192-bit nonce for XSalsa20
-          caCertificateFile = caCrtFile,
-          privateKeyFile = serverKeyFile,
-          certificateFile = serverCrtFile,
-          storeLog
-        }
-
-    openStoreLog :: IO (Maybe (StoreLog 'ReadMode))
-    openStoreLog =
-      if enableStoreLog
-        then Just <$> openReadStoreLog storeLogFile
-        else pure Nothing
-
-    printServerConfig ServerConfig {storeLog, transports} = do
-      putStrLn $ case storeLog of
-        Just s -> "Store log: " <> storeLogFilePath s
-        Nothing -> "Store log disabled."
-      forM_ transports $ \(p, ATransport t) ->
-        putStrLn $ "Listening on port " <> p <> " (" <> transportName t <> ")..."
-
-cleanup :: IO ()
-cleanup = do
-  deleteDirIfExists cfgDir
-  deleteDirIfExists logDir
-  where
-    deleteDirIfExists path = doesDirectoryExist path >>= (`when` removeDirectoryRecursive path)
-
-printServiceInfo :: ByteString -> IO ()
-printServiceInfo fpStr = do
-  putStrLn version
-  B.putStrLn $ "Fingerprint: " <> strEncode fpStr
-
-version :: String
-version = "SMP server v" <> simplexMQVersion
-
-loadSavedFingerprint :: IO String
-loadSavedFingerprint = withFile fingerprintFile ReadMode hGetLine
+  setLogLevel LogDebug
+  withGlobalLogging logCfg $ smpServerCLI cfgPath logPath
@@ -0,0 +1,51 @@
+FROM ubuntu:focal AS final
+FROM ubuntu:focal AS build
+
+### Build stage
+
+# Install curl and git and smp-related dependencies
+RUN apt-get update && apt-get install -y curl git build-essential libgmp3-dev zlib1g-dev
+
+# Install ghcup
+RUN curl https://downloads.haskell.org/~ghcup/x86_64-linux-ghcup -o /usr/bin/ghcup && \
+    chmod +x /usr/bin/ghcup
+
+# Install ghc
+RUN ghcup install ghc 8.10.7
+# Install cabal
+RUN ghcup install cabal
+# Set both as default
+RUN ghcup set ghc 8.10.7 && \
+    ghcup set cabal
+
+COPY . /project
+WORKDIR /project
+
+# Adjust PATH
+ENV PATH="/root/.cabal/bin:/root/.ghcup/bin:$PATH"
+
+# Compile smp-server
+RUN cabal update
+RUN cabal install
+
+### Final stage
+
+FROM final
+
+# Install OpenSSL dependency
+RUN apt-get update && apt-get install -y openssl
+
+# Copy compiled smp-server from build stage
+COPY --from=build /root/.cabal/bin/smp-server /usr/bin/smp-server
+
+# Copy our helper script
+COPY ./scripts/docker/entrypoint /usr/bin/entrypoint
+
+# Open smp-server listening port
+EXPOSE 5223
+
+# SimpleX requires using SIGINT to correctly preserve undelivered messages and restore them on restart
+STOPSIGNAL SIGINT
+
+# Finally, execute helper script
+ENTRYPOINT [ "/usr/bin/entrypoint" ]
@@ -1,6 +1,17 @@
 packages: .
+-- packages: . ../direct-sqlcipher ../sqlcipher-simple

 source-repository-package
    type: git
-    location: git://github.com/simplex-chat/aeson.git
+    location: https://github.com/simplex-chat/aeson.git
    tag: 3eb66f9a68f103b5f1489382aad89f5712a64db7
+
+source-repository-package
+    type: git
+    location: https://github.com/simplex-chat/direct-sqlcipher.git
+    tag: 34309410eb2069b029b8fc1872deb1e0db123294
+
+source-repository-package
+    type: git
+    location: https://github.com/simplex-chat/sqlcipher-simple.git
+    tag: 5e154a2aeccc33ead6c243ec07195ab673137221
@@ -0,0 +1,20 @@
+FROM ubuntu:focal
+
+# Install curl
+RUN apt-get update && apt-get install -y curl
+
+# Download latest smp-server release and assign executable permission
+RUN curl -L https://github.com/simplex-chat/simplexmq/releases/latest/download/smp-server-ubuntu-20_04-x86-64 -o /usr/bin/smp-server && \
+	chmod +x /usr/bin/smp-server
+
+# Copy our helper script
+COPY ./scripts/docker/entrypoint /usr/bin/entrypoint
+
+# Open smp-server listening port
+EXPOSE 5223
+
+# SimpleX requires using SIGINT to correctly preserve undelivered messages and restore them on restart
+STOPSIGNAL SIGINT
+
+# Finally, execute helper script
+ENTRYPOINT [ "/usr/bin/entrypoint" ]
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@@ -1,7 +1,7 @@
 name: simplexmq
-version: 1.0.3
+version: 4.3.1
 synopsis: SimpleXMQ message broker
-description:  |
+description: |
  This package includes <./docs/Simplex-Messaging-Server.html server>,
  <./docs/Simplex-Messaging-Client.html client> and
  <./docs/Simplex-Messaging-Agent.html agent> for SMP protocols:
@@ -28,34 +28,42 @@ dependencies:
  - asn1-types == 0.3.*
  - async == 2.2.*
  - attoparsec == 0.14.*
-  - base >= 4.7 && < 5
+  - base >= 4.14 && < 5
  - base64-bytestring >= 1.0 && < 1.3
  - bytestring == 0.10.*
+  - case-insensitive == 1.2.*
  - composition == 1.0.*
  - constraints >= 0.12 && < 0.14
  - containers == 0.6.*
  - cryptonite >= 0.27 && < 0.30
  - cryptostore == 0.2.*
  - data-default == 0.7.*
-  - direct-sqlite == 2.3.*
+  - direct-sqlcipher == 2.3.*
  - directory == 1.3.*
  - filepath == 1.4.*
  - http-types == 0.12.*
+  - http2 == 3.0.*
  - generic-random >= 1.3 && < 1.5
+  - ini == 0.4.1
  - iso8601-time == 0.1.*
  - memory == 0.15.*
  - mtl == 2.2.*
-  - network == 3.1.*
-  - network-transport == 0.5.*
+  - network >= 3.1.2.7 && < 3.2
+  - network-transport == 0.5.4
+  - optparse-applicative >= 0.15 && < 0.17
  - QuickCheck == 2.14.*
+  - process == 1.6.*
  - random >= 1.1 && < 1.3
  - simple-logger == 0.1.*
-  - sqlite-simple == 0.4.*
+  - socks == 0.6.*
+  - sqlcipher-simple == 0.4.*
  - stm == 2.5.*
  - template-haskell == 2.16.*
  - text == 1.2.*
  - time == 1.9.*
-  - tls >= 1.5.7 && < 1.6
+  - time-compat == 1.9.*
+  - time-manager == 0.0.*
+  - tls >= 1.6.0 && < 1.7
  - transformers == 0.5.*
  - unliftio == 0.2.*
  - unliftio-core == 0.2.*
@@ -64,6 +72,17 @@ dependencies:
  - x509-store == 1.6.*
  - x509-validation == 1.6.*

+flags:
+  swift:
+    description: Enable swift JSON format
+    manual: True
+    default: False
+
+when:
+  - condition: flag(swift)
+    cpp-options:
+      - -DswiftJSON
+
 library:
  source-dirs: src

@@ -72,9 +91,14 @@ executables:
    source-dirs: apps/smp-server
    main: Main.hs
    dependencies:
-      - ini == 0.4.*
-      - optparse-applicative >= 0.15 && < 0.17
-      - process == 1.6.*
+      - simplexmq
+    ghc-options:
+      - -threaded
+
+  ntf-server:
+    source-dirs: apps/ntf-server
+    main: Main.hs
+    dependencies:
      - simplexmq
    ghc-options:
      - -threaded
@@ -97,6 +121,8 @@ tests:
      - hspec-core == 2.7.*
      - HUnit == 1.6.*
      - QuickCheck == 2.14.*
+      - silently == 1.2.*
+      - main-tester == 0.2.*
      - timeit == 2.0.*

 ghc-options:
@@ -0,0 +1,71 @@
+sequenceDiagram
+  participant A as Alice
+  participant AA as Alice's<br>agent
+  participant AS as Alice's<br>server
+  participant BS as Bob's<br>server
+  participant BA as Bob's<br>agent
+  participant B as Bob
+
+  note over AA, BA: status (receive/send): NONE/NONE
+
+  note over A, AA: 1. request connection<br>from agent
+  A ->> AA: NEW: create<br>duplex connection
+ 
+  note over AA, AS: 2. create Alice's SMP queue
+  AA ->> AS: NEW: create SMP queue
+  AS ->> AA: IDS: SMP queue IDs
+  note over AA: status: NEW/NONE
+
+  AA ->> A: INV: invitation<br>to connect
+
+  note over A, B: 3. out-of-band invitation
+  A ->> B: OOB: invitation to connect
+
+  note over BA, B: 4. accept connection
+  B ->> BA: JOIN:<br>via invitation info
+  note over BA: status: NONE/NEW
+
+  note over BA, BS: 5. create Bob's SMP queue
+  BA ->> BS: NEW: create SMP queue
+  BS ->> BA: IDS: SMP queue IDs
+  note over BA: status: NEW/NEW
+
+  note over BA, AA: 6. establish Alice's SMP queue
+  BA ->> AS: SEND: Bob's info and sender server key (SMP confirmation with reply queues)
+  note over BA: status: NEW/CONFIRMED
+
+  AS ->> AA: MSG: Bob's info and<br>sender server key
+  note over AA: status: CONFIRMED/NONE
+  AA ->> AS: ACK: confirm message
+  AA ->> A: CONF: connection request ID<br>and Bob's info
+  A ->> AA: LET: accept connection request,<br>send Alice's info
+  AA ->> AS: KEY: secure queue
+  note over AA: status: SECURED/NONE
+
+  AA ->> BS: SEND: Alice's info and sender's server key (SMP confirmation without reply queues)
+  note over AA: status: SECURED/CONFIRMED
+
+  BS ->> BA: MSG: Alice's info and<br>sender's server key
+  note over BA: status: CONFIRMED/CONFIRMED
+  BA ->> B: INFO: Alice's info
+  BA ->> BS: ACK: confirm message
+  BA ->> BS: KEY: secure queue
+  note over BA: status: SECURED/CONFIRMED
+
+  BA ->> AS: SEND: HELLO: only needs to be sent once in v2
+
+  note over BA: status: SECURED/ACTIVE
+  note over BA, B: 7a. notify Bob<br>about connection success
+  BA ->> B: CON: connected
+
+  AS ->> AA: MSG: HELLO: Alice's agent<br>knows Bob can send
+  note over AA: status: SECURED/ACTIVE
+  AA ->> AS: ACK: confirm message
+  note over A, AA: 7a. notify Alice<br>about connection success
+  AA ->> A: CON: connected
+
+  AA ->> BS: SEND: HELLO: only needs to be sent once in v2
+  note over AA: status: ACTIVE/ACTIVE
+  BS ->> BA: MSG: HELLO: Bob's agent<br>knows Alice can send
+  note over BA: status: ACTIVE/ACTIVE
+  BA ->> BS: ACK: confirm message
@@ -33,8 +33,8 @@ sequenceDiagram
  AS ->> AA: MSG: Bob's info and<br>sender server key
  note over AA: status: CONFIRMED/NONE
  AA ->> AS: ACK: confirm message
-  AA ->> A: REQ: connection request ID<br>and Bob's info
-  A ->> AA: ACPT: accept connection request,<br>send Alice's info
+  AA ->> A: CONF: connection request ID<br>and Bob's info
+  A ->> AA: LET: accept connection request,<br>send Alice's info
  AA ->> AS: KEY: secure queue
  note over AA: status: SECURED/NONE

@@ -0,0 +1,30 @@
+sequenceDiagram
+  participant M as mobile app
+  participant C as chat core
+  participant A as agent
+  participant P as push server
+  participant APN as APN
+
+  note over M, APN: get device token
+  M ->> APN: registerForRemoteNotifications()
+  APN ->> M: device token
+
+  note over M, P: register device token with push server
+  M ->> C: /_ntf register <token>
+  C ->> A: registerNtfToken(<token>)
+  A ->> P: TNEW
+  P ->> A: ID (tokenId)
+  A ->> C: registered
+  C ->> M: registered
+
+  note over M, APN: verify device token
+  P ->> APN: E2E encrypted code<br>in background<br>notification
+  APN ->> M: deliver background notification with e2ee verification token
+  M ->> C: /_ntf verify <e2ee code>
+  C ->> A: verifyNtfToken(<e2ee code>)
+  A ->> P: TVFY code
+  P ->> A: OK / ERR
+  A ->> C: verified
+  C ->> M: verified
+
+  note over M, APN: now token ID can be used
@@ -0,0 +1,40 @@
+sequenceDiagram
+  participant M as mobile app
+  participant C as chat core
+  participant A as agent
+  participant S as SMP server
+  participant N as NTF server
+  participant APN as APN
+
+  note over M, APN: register subscription
+
+  alt register existing
+    M -->> A: on /_ntf register, for subscribed queues
+  else create new connection
+    A -->> S: NEW / JOIN
+    note over A, S: ...<br>Connection handshake<br>...
+    S -->> A: CON
+  end
+  A ->> S: NKEY nKey
+  S ->> A: NID nId
+  A ->> N: SNEW tknId dhKey (smpServer, nId, nKey)
+  N ->> A: ID subId dhKey
+  N ->> S: NSUB nId
+  S ->> N: OK [/ NMSG]
+
+  note over M, APN: notify about message
+
+  S ->> N: NMSG
+  N ->> APN: APNSMutableContent<br>ntfQueue, nonce
+  APN ->> M: UNMutableNotificationContent
+  note over M, S: ...<br>Client awaken, message is received<br>...
+  S ->> M: message
+  note over M: mutate notification
+
+  note over M, APN: change APN token
+
+  APN ->> M: new device token
+  M -->> C: /_ntf_sub update tkn
+  C -->> A: updateNtfToken()
+  A -->> N: TUPD tknId newDeviceToken
+  note over M, N: ...<br>Verify token<br>...
@@ -24,6 +24,7 @@
    - [Subscribe to queue](#subscribe-to-queue)
    - [Secure queue command](#secure-queue-command)
    - [Enable notifications command](#enable-notifications-command)
+    - [Disable notifications command](#disable-notifications-command)
    - [Acknowledge message delivery](#acknowledge-message-delivery)
    - [Suspend queue](#suspend-queue)
    - [Delete queue](#delete-queue)
@@ -50,6 +51,8 @@ It's designed with the focus on communication security and integrity, under the

 It is designed as a low level protocol for other application protocols to solve the problem of secure and private message transmission, making [MITM attack][1] very difficult at any part of the message transmission system.

+This document describes SMP protocol versions 3 and 4, the previous versions are discontinued.
+
 ## Introduction

 The objective of Simplex Messaging Protocol (SMP) is to facilitate the secure and private unidirectional transfer of messages from senders to recipients via persistent simplex queues managed by the message broker (server).
@@ -146,61 +149,61 @@ To create and start using a simplex queue Alice and Bob follow these steps:

 1. Alice creates a simplex queue on the server:

-    1. Decides which SMP server to use (can be the same or different server that Alice uses for other queues) and opens secure encrypted transport connection to the chosen SMP server (see [Appendix A](#appendix-a)).
+   1. Decides which SMP server to use (can be the same or different server that Alice uses for other queues) and opens secure encrypted transport connection to the chosen SMP server (see [Appendix A](#appendix-a)).

-    2. Generates a new random public/private key pair (encryption key - `EK`) that she did not use before for Bob to encrypt the messages.
+   2. Generates a new random public/private key pair (encryption key - `EK`) that she did not use before for Bob to encrypt the messages.

-    3. Generates another new random public/private key pair (recipient key - `RK`) that she did not use before for her to sign commands and to decrypt the transmissions received from the server.
+   3. Generates another new random public/private key pair (recipient key - `RK`) that she did not use before for her to sign commands and to decrypt the transmissions received from the server.

-    4. Generates one more random key pair (recipient DH key - `RDHK`) to negotiate symmetric key that will be used by the server to encrypt message bodies delivered to Alice (to avoid shared cipher-text inside transport connection).
+   4. Generates one more random key pair (recipient DH key - `RDHK`) to negotiate symmetric key that will be used by the server to encrypt message bodies delivered to Alice (to avoid shared cipher-text inside transport connection).

-    5. Sends `"NEW"` command to the server to create a simplex queue (see `create` in [Create queue command](#create-queue-command)). This command contains previously generated unique "public" keys `RK` and `RDHK`. `RK` will be used to verify the following commands related to the same queue signed by its private counterpart, for example to subscribe to the messages received to this queue or to update the queue, e.g. by setting the key required to send the messages (initially Alice creates the queue that accepts unsigned messages, so anybody could send the message via this queue if they knew the queue sender's ID and server address).
+   5. Sends `"NEW"` command to the server to create a simplex queue (see `create` in [Create queue command](#create-queue-command)). This command contains previously generated unique "public" keys `RK` and `RDHK`. `RK` will be used to verify the following commands related to the same queue signed by its private counterpart, for example to subscribe to the messages received to this queue or to update the queue, e.g. by setting the key required to send the messages (initially Alice creates the queue that accepts unsigned messages, so anybody could send the message via this queue if they knew the queue sender's ID and server address).

-    6. The server sends `"IDS"` response with queue IDs (`queueIds`):
+   6. The server sends `"IDS"` response with queue IDs (`queueIds`):

-        - Recipient ID `RID` for Alice to manage the queue and to receive the messages.
+      - Recipient ID `RID` for Alice to manage the queue and to receive the messages.

-        - Sender ID `SID` for Bob to send messages to the queue.
+      - Sender ID `SID` for Bob to send messages to the queue.

-        - Server public DH key (`SDHK`) to negotiate a shared secret for message body encryption, that Alice uses to derive a shared secret with the server `SS`.
+      - Server public DH key (`SDHK`) to negotiate a shared secret for message body encryption, that Alice uses to derive a shared secret with the server `SS`.

 2. Alice sends an out-of-band message to Bob via the alternative channel that both Alice and Bob trust (see [protocol abstract](#simplex-messaging-protocol-abstract)). The message must include:

-    - Unique "public" key (`EK`) that Bob must use for E2E key agreement.
+   - Unique "public" key (`EK`) that Bob must use for E2E key agreement.

-    - SMP server hostname and information to open secure encrypted transport connection (see [Appendix A](#appendix-a)).
+   - SMP server hostname and information to open secure encrypted transport connection (see [Appendix A](#appendix-a)).

-    - Sender queue ID `SID` for Bob to use.
+   - Sender queue ID `SID` for Bob to use.

 3. Bob, having received the out-of-band message from Alice, connects to the queue:

-    1. Generates a new random public/private key pair (sender key - `SK`) that he did not use before for him to sign messages sent to Alice's server.
+   1. Generates a new random public/private key pair (sender key - `SK`) that he did not use before for him to sign messages sent to Alice's server.

-    2. Prepares the confirmation message for Alice to secure the queue. This message includes:
+   2. Prepares the confirmation message for Alice to secure the queue. This message includes:

-        - Previously generated "public" key `SK` that will be used by Alice's server to authenticate Bob's messages, once the queue is secured.
+      - Previously generated "public" key `SK` that will be used by Alice's server to authenticate Bob's messages, once the queue is secured.

-        - Optionally, any additional information (application specific, e.g. Bob's profile name and details).
+      - Optionally, any additional information (application specific, e.g. Bob's profile name and details).

-    3. Encrypts the confirmation body with the "public" key `EK` (that Alice provided via the out-of-band message).
+   3. Encrypts the confirmation body with the "public" key `EK` (that Alice provided via the out-of-band message).

-    4. Sends the encrypted message to the server with queue ID `SID` (see `send` in [Send message](#send-message)). This initial message to the queue must not be signed - signed messages will be rejected until Alice secures the queue (below).
+   4. Sends the encrypted message to the server with queue ID `SID` (see `send` in [Send message](#send-message)). This initial message to the queue must not be signed - signed messages will be rejected until Alice secures the queue (below).

 4. Alice receives Bob's message from the server using recipient queue ID `RID` (possibly, via the same transport connection she already has opened - see `message` in [Deliver queue message](#deliver-queue-message)):

-    1. She decrypts received message body using the secret `SS`.
+   1. She decrypts received message body using the secret `SS`.

-    2. She decrypts received message with [key agreed with sender using] "private" key `EK`.
+   2. She decrypts received message with [key agreed with sender using] "private" key `EK`.

-    3. Even though anybody could have sent the message to the queue with ID `SID` before it is secured (e.g. if communication is compromised), Alice would ignore all messages until the decryption succeeds (i.e. the result contains the expected message format). Optionally, in the client application, she also may identify Bob using the information provided, but it is out of scope of SMP protocol.
+   3. Even though anybody could have sent the message to the queue with ID `SID` before it is secured (e.g. if communication is compromised), Alice would ignore all messages until the decryption succeeds (i.e. the result contains the expected message format). Optionally, in the client application, she also may identify Bob using the information provided, but it is out of scope of SMP protocol.

 5. Alice secures the queue `RID` with `"KEY"` command so only Bob can send messages to it (see [Secure queue command](#secure-queue-command)):

-    1. She sends the `KEY` command with `RID` signed with "private" key `RK` to update the queue to only accept requests signed by "private" key `SK` provided by Bob. This command contains unique "public" key `SK` previously generated by Bob.
+   1. She sends the `KEY` command with `RID` signed with "private" key `RK` to update the queue to only accept requests signed by "private" key `SK` provided by Bob. This command contains unique "public" key `SK` previously generated by Bob.

-    2. From this moment the server will accept only signed commands to `SID`, so only Bob will be able to send messages to the queue `SID` (corresponding to `RID` that Alice has).
+   2. From this moment the server will accept only signed commands to `SID`, so only Bob will be able to send messages to the queue `SID` (corresponding to `RID` that Alice has).

-    3. Once queue is secured, Alice deletes `SID` and `SK` - even if Alice's client is compromised in the future, the attacker would not be able to send messages pretending to be Bob.
+   3. Once queue is secured, Alice deletes `SID` and `SK` - even if Alice's client is compromised in the future, the attacker would not be able to send messages pretending to be Bob.

 6. The simplex queue `RID` is now ready to be used.

@@ -214,21 +217,21 @@ Bob now can securely send messages to Alice:

 1. Bob sends the message:

-    1. He encrypts the message to Alice with "public" key `EK` (provided by Alice, only known to Bob, used only for one simplex queue).
+   1. He encrypts the message to Alice with "public" key `EK` (provided by Alice, only known to Bob, used only for one simplex queue).

-    2. He signs `"SEND"` command to the server queue `SID` using the "private" key `SK` (that only he knows, used only for this queue).
+   2. He signs `"SEND"` command to the server queue `SID` using the "private" key `SK` (that only he knows, used only for this queue).

-    3. He sends the command to the server (see `send` in [Send message](#send-message)), that the server will authenticate using the "public" key `SK` (that Alice earlier received from Bob and provided to the server via `"KEY"` command).
+   3. He sends the command to the server (see `send` in [Send message](#send-message)), that the server will authenticate using the "public" key `SK` (that Alice earlier received from Bob and provided to the server via `"KEY"` command).

 2. Alice receives the message(s):

-    1. She signs `"SUB"` command to the server to subscribe to the queue `RID` with the "private" key `RK` (see `subscribe` in [Subscribe to queue](#subscribe-to-queue)).
+   1. She signs `"SUB"` command to the server to subscribe to the queue `RID` with the "private" key `RK` (see `subscribe` in [Subscribe to queue](#subscribe-to-queue)).

-    2. The server, having authenticated Alice's command with the "public" key `RK` that she provided, delivers Bob's message(s) (see `message` in [Deliver queue message](#deliver-queue-message)).
+   2. The server, having authenticated Alice's command with the "public" key `RK` that she provided, delivers Bob's message(s) (see `message` in [Deliver queue message](#deliver-queue-message)).

-    3. She decrypts Bob's message(s) with the "private" key `EK` (that only she has).
+   3. She decrypts Bob's message(s) with the "private" key `EK` (that only she has).

-    4. She acknowledges the message reception to the server with `"ACK"` so that the server can delete the message and deliver the next messages.
+   4. She acknowledges the message reception to the server with `"ACK"` so that the server can delete the message and deliver the next messages.

 This flow is show on sequence diagram below.

@@ -355,18 +358,22 @@ To protect the privacy of the recipients, there are several commands in SMP prot
 The clients can optionally instruct a dedicated push notification server to subscribe to notifications and deliver push notifications to the device, which can then retrieve the messages in the background and send local notifications to the user - this is out of scope of SMP protocol. The commands that SMP protocol provides to allow it:

 - `enableNotifications` (`"NKEY"`) with `notifierId` (`"NID"`) response - see [Enable notifications command](#enable-notifications-command).
+- `disableNotifications` (`"NDEL"`) - see [Disable notifications command](#disable-notifications-command).
 - `subscribeNotifications` (`"NSUB"`) - see [Subscribe to queue notifications](#subscribe-to-queue-notifications).
 - `messageNotification` (`"NMSG"`) - see [Deliver message notification](#deliver-message-notification).

-## SMP Transmission structure
+[`SEND` command](#send-message) includes the notification flag to instruct SMP server whether to send the notification - this flag is forwarded to the recepient inside encrypted envelope, together with the timestamp and the message body, so even if TLS is compromised this flag cannot be used for traffic correlation.
+
+## SMP Transmission andtransport block structure

 Each transport block (SMP transmission) has a fixed size of 16384 bytes for traffic uniformity.

+From SMP version 4 each block can contain multiple transmissions, version 3 blocks have 1 transmission.
 Some parts of SMP transmission are padded to a fixed size; this padding is uniformly added as a word16 encoded in network byte order - see `paddedString` syntax.

 In places where some part of the transmission should be padded, the syntax for `paddedNotation` is used:

-```
+```abnf
 paddedString = originalLength string pad
 originalLength = 2*2 OCTET
 pad = N*N"#" ; where N = paddedLength - originalLength - 2
@@ -376,9 +383,9 @@ paddedNotation = <padded(string, paddedLength)>
 ; paddedLength - required length after padding, including 2 bytes for originalLength
 ```

-Each transmission between the client and the server must have this format/syntax:
+Each transmission/block for SMP v3 between the client and the server must have this format/syntax:

-```
+```abnf
 paddedTransmission = <padded(transmission), 16384>
 transmission = [signature] SP signed
 signed = sessionIdentifier SP [corrId] SP [queueId] SP smpCommand
@@ -395,13 +402,23 @@ encoded = <base64 encoded binary>

 `base64` encoding should be used with padding, as defined in section 4 of [RFC 4648][9]

+Transport block for SMP v4 has this syntax:
+
+```abnf
+paddedTransportBlock = <padded(transportBlock), 16384>
+transportBlock = transmissionCount transmissions
+transmissionCount = 1*1 OCTET ; equal or greater than 1
+transmissions = transmissionLength transmission [transmissions]
+transmissionLength = 2*2 OCTET ; word16 encoded in network byte order
+```
+
 ## SMP commands

 Commands syntax below is provided using [ABNF][8] with [case-sensitive strings extension][8a].

 ```abnf
 smpCommand = ping / recipientCmd / send / subscribeNotifications / serverMsg
-recipientCmd = create / subscribe / secure / enableNotifications /
+recipientCmd = create / subscribe / secure / enableNotifications / disableNotifications /
               acknowledge / suspend / delete
 serverMsg = queueIds / message / notifierId / messageNotification /
            unsubscribed / ok / error
@@ -502,22 +519,42 @@ Once the queue is secured only signed messages can be sent to it.
 This command is sent by the recipient to the server to add notifier's key to the queue, to allow push notifications server to receive notifications when the message arrives, via a separate queue ID, without receiving message content.

 ```abnf
-enableNotifications = %s"NKEY " notifierKey
+enableNotifications = %s"NKEY " notifierKey recipientNotificationDhPublicKey
 notifierKey = length x509encoded
 ; the notifier's Ed25519 or Ed448 public key public key to verify NSUB command for this queue
+
+recipientNotificationDhPublicKey = length x509encoded
+; the recipient's Curve25519 key for DH exchange to derive the secret
+; that the server will use to encrypt notification metadata (encryptedNMsgMeta in NMSG)
+; using [NaCl crypto_box][16] encryption scheme (curve25519xsalsa20poly1305).
 ```

 The server will respond with `notifierId` response if notifications were enabled and the notifier's key was successfully added to the queue:

 ```abnf
-notifierId = %s"NID " notifierId
+notifierId = %s"NID " notifierId srvNotificationDhPublicKey
 notifierId = length *OCTET ; 16-24 bytes
+srvNotificationDhPublicKey = length x509encoded
+; the server's Curve25519 key for DH exchange to derive the secret
+; that the server will use to encrypt notification metadata to the recipient (encryptedNMsgMeta in NMSG)
 ```

 This response is sent with the recipient's queue ID (the third part of the transmission).

 To receive the message notifications, `subscribeNotifications` command ("NSUB") must be sent signed with the notifier's key.

+#### Disable notifications command
+
+This command is sent by the recipient to the server to remove notifier's credentials from the queue:
+
+```abnf
+disableNotifications = %s"NDEL"
+```
+
+The server must respond `ok` to this command if it was successful.
+
+Once notifier's credentials are removed server will no longer send "NMSG" for this queue to notifier.
+
 #### Acknowledge message delivery

 The recipient should send the acknowledgement of message delivery once the message was stored in the client, to notify the server that the message should be deleted:
@@ -565,7 +602,9 @@ Currently SMP defines only one command that can be used by senders - `send` mess
 This command is sent to the server by the sender both to confirm the queue after the sender received out-of-band message from the recipient and to send messages after the queue is secured:

 ```abnf
-send = %s"SEND " smpEncMessage
+send = %s"SEND " msgFlags SP smpEncMessage
+msgFlags = notificationFlag reserved
+notificationFlag = %s"T" / %s"F"
 smpEncMessage = smpPubHeader sentMsgBody ; message up to 16088 bytes
 smpPubHeader = smpClientVersion ("1" senderPublicDhKey / "0")
 smpClientVersion = word16
@@ -707,9 +746,11 @@ See its syntax in [Create queue command](#create-queue-command)
 The server must deliver messages to all subscribed simplex queues on the currently open transport connection. The syntax for the message delivery is:

 ```abnf
-message = %s"MSG " msgId SP timestamp SP encryptedMsgBody
+message = %s"MSG " msgId encryptedRcvMsgBody
 encryptedMsgBody = <encrypt paddedSentMsgBody> ; server-encrypted padded sent msgBody
 paddedSentMsgBody = <padded(sentMsgBody, maxMessageLength + 2)> ; maxMessageLength = 16088
+encryptedRcvMsgBody = <encrypt rcvMsgBody> ; server-encrypted meta-data and padded sent msgBody
+rcvMsgBody = timestamp msgFlags SP paddedSentMsgBody
 msgId = length 24*24OCTET
 timestamp = 8*8OCTET
 ```
@@ -735,10 +776,19 @@ See its syntax in [Enable notifications command](#enable-notifications-command)
 The server must deliver message notifications to all simplex queues that were subscribed with `subscribeNotifications` command ("NSUB") on the currently open transport connection. The syntax for the message notification delivery is:

 ```abnf
-messageNotification = %s"NMSG"
+messageNotification = %s"NMSG " nmsgNonce encryptedNMsgMeta
+
+encryptedNMsgMeta = <encrypted message metadata passed in notification>
+; metadata E2E encrypted between server and recipient containing server's message ID and timestamp (allows extension),
+; to be passed to the recipient by the notifier for them to decrypt
+; with key negotiated in NKEY and NID commands using nmsgNonce
+
+nmsgNonce = <nonce used in NaCl crypto_box encryption scheme>
+; nonce used by the server for encryption of message metadata, to be passed to the recipient by the notifier
+; for them to use in decryption of E2E encrypted metadata
 ```

-Message notification does not contain any message data or meta-data, it only notifies that the message is available.
+Message notification does not contain any message data or non E2E encrypted metadata.

 #### Subscription END notification

@@ -770,7 +820,7 @@ The syntax for error responses:
 ```abnf
 error = %s"ERR " errorType
 errorType = %s"BLOCK" / %s"SESSION" / %s"CMD " cmdError / %s"AUTH" / %s"LARGE_MSG" /%s"INTERNAL"
-cmdError = %s"SYNTAX" / %s"PROHIBITED" / %s"NO_AUTH" / %s"HAS_AUTH" / %s"NO_QUEUE"
+cmdError = %s"SYNTAX" / %s"PROHIBITED" / %s"NO_AUTH" / %s"HAS_AUTH" / %s"NO_ENTITY"
 ```

 Server implementations must aim to respond within the same time for each command in all cases when `"ERR AUTH"` response is required to prevent timing attacks (e.g., the server should perform signature verification even when the queue does not exist on the server or the signature of different size is sent, using any RSA key with the same size as the signature size).
@@ -792,6 +842,7 @@ ok = %s"OK"
 Both the recipient and the sender can use TCP or some other, possibly higher level, transport protocol to communicate with the server. The default TCP port for SMP server is 5223.

 For scenarios when meta-data privacy is critical, it is recommended that clients:
+
 - communicating over Tor network,
 - establish a separate connection for each SMP queue,
 - send noise traffic (using PING command).
@@ -799,12 +850,14 @@ For scenarios when meta-data privacy is critical, it is recommended that clients
 In addition to that, the servers can be deployed as Tor onion services.

 The transport protocol should provide the following:
+
 - server authentication (by matching server certificate hash with `serverIdentity`),
 - forward secrecy (by encrypting the traffic using ephemeral keys agreed during transport handshake),
 - integrity (preventing data modification by the attacker without detection),
 - unique channel binding (`sessionIdentifier`) to include in the signed part of SMP transmissions.

 By default, the client and server communicate using [TLS 1.3 protocol][13] restricted to:
+
 - TLS_CHACHA20_POLY1305_SHA256 cipher suite (for better performance on mobile devices),
 - ed25519 and ed448 EdDSA algorithms for signatures,
 - x25519 and x448 ECDHE groups for key exchange.
@@ -13,6 +13,6 @@ Change controller: Evgeny Poberezkin <ep@simplex.chat>

 References:
 The syntax for connection requests in the latest version of SimpleX Agent Protocol:
-https://github.com/simplex-chat/simplexmq/blob/v5/protocol/agent-protocol.md#connection-request
+https://github.com/simplex-chat/simplexmq/blob/master/protocol/agent-protocol.md#connection-request
 SimpleX Messaging Protocol:
-https://github.com/simplex-chat/simplexmq/blob/v5/protocol/simplex-messaging.md
+https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md
@@ -13,4 +13,4 @@ Change controller: Evgeny Poberezkin <ep@simplex.chat>

 References:
 The syntax for message queue URIs in the latest version of SimpleX Messaging Protocol:
-https://github.com/simplex-chat/simplexmq/blob/v5/protocol/simplex-messaging.md#smp-queue-uri
+https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md#smp-queue-uri
@@ -0,0 +1,21 @@
+# SMP confirmation timeout recovery
+
+## Problem
+
+When sending an SMP confirmation a network timeout can lead to the following race condition:
+- server receives the confirmation while the joining party fails to receive the server's response;
+- joining party deletes the connection together with credentials sent in the confirmation for securing the queue;
+- initiating party will receive the confirmation from the server and secure the queue;
+- on subsequent attempt to join via the same invitation link initiating party will generate new credentials and fail authorization.
+
+This renders the joining party permanently unable to join via that invitation link and complete the connection.
+
+## Solution
+
+A possible solution is to keep and try to reuse same credentials on subsequent attempts:
+- joining party has to remember invitation link when saving the connection;
+- if SMP confirmation fails due to network timeout joining party doesn't delete the connection and keeps the credentials;
+- when joining, joining party checks whether such invitation link was already used for a connection, if yes:
+  - joining party tries to send SMP confirmation with the same credentials;
+  - if this SMP confirmation fails with authorization error (for example it can happen due to race condition explained above) joining party tries to send HELLO message;
+  - if HELLO message fails with authorization error (it can happen if connection was deleted or secured with different credentials), the recovery is no longer possible and connection can be deleted.
@@ -0,0 +1,161 @@
+# SimpleX File Transfer protocol
+
+## Problem
+
+Sending files as currently implemented in SimpleX Chat is inefficient for these reasons:
+
+1. Slow: message delivery requires acknowledgement for each message before the server sends the next message.
+2. Not fully asynchronous:
+   a. SMP queue size is limited, so the whole file cannot be sent/stored in server memory.
+   b. Recipient needs to accept the file before it is sent.
+3. No broadcast: sending the same file to multiple recipients requires sending it multiple times.
+
+## Possible solutions
+
+These problems could be solved within SMP protocol:
+
+- streaming messages without waiting for acknowledgements.
+- bigger queue sizes stored on hard drive and accepting large files without waiting for the recipient confirmation.
+- adding broadcast to SMP servers.
+
+These solution are complex and they do not scale well.
+
+Another approach would be adopting some open-source file storage, possibly S3-compatible, to host files while "in transit". The downsides are:
+
+1. Missing features. S3-compatible file servers require a service layer that we would need to develop to manage user accounts and permissions. There are solutions that allow self-registering users and uploading files without service layer, but they are not flexible enough in managing policies for these files.
+2. Limited meta-data protection, both on the application and on transport layer: same address for sending and receiving a file, file size is known to the server, etc.
+3. More difficult to self-host for the users when the server has 2 components (a 3rd party solution with our service component).
+
+We are not considering P2P solutions because of their bad meta-data privacy and requirement of having a single network - the same reason why P2P design is not used for SimpleX messaging network.
+
+A proposed solution is to develop a file hosting service (SimpleX File Transfer service) that would have better meta-data protection and functionality than the alternatives, using the ideas from SMP protocol design.
+
+The parameters of the solution would be:
+
+1. The server does not have knowledge of the users and actual files – only anonymously uploaded fixed-size chunks (considered 8Mb, maybe we should allow 2 sizes, e.g. 1Mb and 8Mb).
+2. The server should allow broadcast, so that a chunk can be downloaded by multiple recipients.
+3. There should be no identifiers and ciphertext in common inside TLS between sender and recipient traffic, and between the traffic of different recipients of the same file. This approach can be extended to support public chunks that have persistent identifiers.
+4. The server should prevent multiple uploads of the same chunk. This can be extended to allow multiple downloads from the same persistent address.
+5. Clients can send the chunks from the same file via multiple servers, both by splitting chunks between them and for redundancy.
+
+## Design approach
+
+File transfer servers will be chosen by file senders. The servers will allow senders to anonymously upload fixed-size file chunks.
+
+### Transport protocol
+
+- binary-encoded commands sent as fixed-size padded block in the body of HTTP2 POST request, similar to SMP and notifications server protocol transmission encodings.
+- HTTP2 POST with a fixed size padded block body for file upload and download.
+
+Block size - 4096 bytes (it would fit ~120 Ed25519 recipient keys).
+
+The reasons to use HTTP2:
+
+- avoid the need to have two hostnames (or two different ports) for commands and file uploads.
+- compatibility with the existing HTTP2 client libraries.
+
+The reason not to use JSON bodies:
+
+- bigger request size, so fewer recipient keys would fit in a single request
+- signature over command has to be outside of JSON anyway.
+
+The reason not to use URI segments / HTTP verbs / REST semantics is to have consistent request size.
+
+### Required server commands:
+
+- File sender:
+  - create file chunk record.
+    - Parameters:
+      - Ed25519 key for subsequent sender commands and Ed25519 keys for commands of each recipient.
+      - chunk size.
+    - Response:
+      - chunk ID for the sender and different IDs for all recipients.
+  - add recipients to file chunk
+    - Parameters:
+      - sender's chunk ID
+      - Ed25519 keys for commands of each recipient.
+    - Response:
+      - chunk IDs for new recipients.
+  - upload file chunk.
+  - delete file chunk (invalidates all recipient IDs).
+- File recipient:
+  - download file chunk:
+    - chunk ID
+    - DH key for additional encryption of the chunk.
+    - command should be signed with the key passed by the sender when creating chunk record.
+  - delete file chunk ID (only for one recipient): signed with the same key.
+
+### Storage model
+
+Same as for SMP and notifications server - in-memory storage of the records, with adding to append-only log, restored and compacted on server restart.
+
+### Sending file
+
+To send the file, the sender will:
+
+- compute SHA512 digest
+- pad the file to match the whole number of chunks in size,
+- encrypt it with a randomly chosen symmetric key and IV (e.g., using NaCL crypto_secretbox),
+- split into fixed size chunks
+- upload each chunk to a randomly chosen server.
+
+The sending client should generate more per-recipient keys than the actual number of recipients, possibly rounding up to a power of 2, to conceal the actual number of intended recipients.
+
+Then the sending client will combine addresses of all chunks and other information into "file description", different for each file recipient, that will include:
+
+- an encryption key that was used to encrypt the file (the same for all recipients).
+- file SHA512 digest
+- list of chunk descriptions; information for each chunk:
+  - private Ed25519 key to sign commands for file transfer server.
+  - chunk address (server host and chunk ID).
+  - chunk sha512 digest
+
+To reduce the size, chunk descriptions will be grouped by the server host.
+
+This "file description" itself will be sent as a small file over an authenticated channel, to prevent file description modification. To estimate its size:
+
+- each chunk \* redundancy per chunk, assuming chunks are grouped per server:
+  - 1-based chunk number in the file - 8 bytes (including any overhead)
+  - Ed25519 key (different for each recipient / chunk combination) - 32 bytes \* 4/3 (base64, assuming text encoding)
+  - chunk ID (different for each recipient) - 64 bytes \* 4/3
+  - optional (only in the first chunk occurence) chunk sha512 digests - 64 bytes \* 4/3
+- server addresses - say, 128 bytes per server
+- sha512 digest - 64 bytes \* 4/3
+- encryption key - 32 bytes \* 4/3
+- IV - 32 bytes \* 4/3
+- encoding overhead - say, 256 bytes
+
+For 1gb file, sent via 4 different servers, in 8Mb chunks, with redundancy 2, the size of "file description", assuming text encoding, will be ~45kb (`128 * (8 + 32 + 64) * 2 * 4/3 + 128 * 64 * 4/3 + 128 * 4 + (64 + 32 + 32) * 4/3 + 256`).
+
+File description format (yml):
+
+```
+name: file.ext
+size: 33200000
+chunk: 8Mb
+hash: abc=
+key: abc=
+iv: abc=
+part_hashes: [def=, def=, def=, def=]
+parts:
+  - server: xftp://abc=@example1.com
+    chunks: [1:abc=:def=:ghi=, 3:abc=:def=:ghi=]
+  - server: xftp://abc=@example2.com
+    chunks: [2:abc=:def=:ghi=, 4:abc=:def=:ghi=]
+  - server: xftp://abc=@example3.com
+    chunks: [1:abc=:def=, 4:abc=:def=]
+  - server: xftp://abc=@example4.com
+    chunks: [2:abc=:def=, 3:abc=:def=]
+```
+
+This file description is sent to all recipients via normal messages, split to 15780 byte chunks if needed.
+
+### Receiving file
+
+Having received the description, the recipient will:
+
+- download all chunks falling back to secondary servers, if needed
+- combine the chunks into a file
+- decrypt the file
+- un-pad it
+- validate file digest
@@ -0,0 +1,20 @@
+# SMP and SMP agent protocol extensions to manage queue quotas
+
+## Problem
+
+SMP servers define a limit on the number of messages that can be stored on the server. When the sender reaches this limit, they continue trying to send the message with exponential back off, until the server allows it. To reduce the traffic we added expiration on unsent messages of 2 days that:
+
+- adds its own set of problems because of expired control messages - e.g., group fragmentation.
+- doesn't solve problem of traffic in active groups with many inactive members - there are still too many retries in queues that reached capacity.
+
+## Solution
+
+Sending agent permanently stops trying to send messages having received `ERR QUOTA` (or, for the period of clients migration, increases TTL much more than in cases of network errors).
+
+Add SMP server event that means "quota reached" (e.g. `QTA` or `MSG QUOTA`) - it will be delivered to the recipient once all messages are retrieved at the same point in message stream where the sender received `ERR QUOTA`. Alternatively, it could be a message flag that is set on the last message in the queue at a point the sender received `ERR QUOTA`.
+
+Add SMP agent message that means "quota available, resume sending" (e.g. `A_QTA` or `A_RESUME`) – the receiving agent will send it via the reply queue to the sending agent that will resume sending messages at this point.
+
+Possibly, increase TTL for local messages to 30 days. That might require separately addressing the problem of permanently failing servers.
+
+We discussed a possible solution of merging all messages to one server into one delivery queue, so that having multiple failing queues on this server will not result in multiple connection attempts, and this proposal also answers the question what to do with the messages when quota is exceeded - the whole queue can be marked as suspended, and processed separately from others - TBD.
@@ -0,0 +1,91 @@
+# Notification server
+
+## Background and motivation
+
+SimpleX Chat clients should receive message notifications when not being online and/or subscribed to SMP servers.
+
+To avoid revealing identities of clients directly to SMP servers via any kind of push notification tokens, a new party called SimpleX Notification Server is introduced to act as a service for subscribing to SMP server queue notifications on behalf of clients and sending push notifications to them.
+
+## Proposal
+
+TCP service using the same TLS transport as SMP server, with the fixed size blocks (256 bytes?) and the following set of commands:
+
+### Protocol
+
+#### Create subscription
+
+Command:
+
+`%s"CREATE " ntfSmpQueueURI ntfPrivateKey token subPublicKey`
+
+Response:
+
+`s%"OK"`
+
+#### Check subscription status
+
+Command:
+
+`%s"CHECK " ntfSmpQueueURI`
+
+Response:
+
+```abnf
+statusResp = %s"STAT " status
+status = %s"ERR AUTH" / "ERR SMP AUTH" / %s"ERR SMP TIMEOUT" / %s"ACTIVE" / %s"PENDING"
+```
+
+#### Update subscription device token
+
+Command:
+
+`%s"TOKEN " ntfSmpQueueURI token`
+
+Response:
+
+`s%"OK" / %s"ERR"`
+
+#### Delete subscription (e.g. when deleting the queue or moving to another notification server)
+
+Command:
+
+`%s"DELETE " SP ntfSmpQueueURI`
+
+Response:
+
+`s%"OK" / %s"ERR"`
+
+### Agent schema changes
+
+See [migration](../src/Simplex/Messaging/Agent/Store/SQLite/Migrations/M20220322_notifications.hs)
+
+### Agent code
+
+```haskell
+data NtfOptions = NtfOptions
+  { ntfServer :: Server, -- same type as for SMP servers, probably will be renamed
+    ntfToken :: ByteString,
+    ntfInitialCheckDelay :: Int, -- initial check delay after subscription is created, seconds
+    ntfPeriodicCheckInterval :: Int -- subscription check interval, seconds
+  }
+
+data AgentConfig = AgentConfig {
+  -- ...
+  initialNtfOpts :: Maybe NtfOptions
+  -- ...
+  }
+
+data AgentClient = AgentClient {
+  -- ...
+  ntfOpts :: TVar (Maybe NtfOptions)
+  -- ...
+  }
+```
+
+A configuration parameter `initialNtfOpts :: Maybe NtfOptions` - if it is set or changes the agent would automatically manage subscriptions as SMP queues are subscribed/created/deleted and as the token or server changes.
+
+There will be a method to update notifications configuration in case token or server changes.
+
+All subscriptions will be managed in a separate subscription management loop, that would always take the earliest un-updated subscription that requires some action (ntf_sub_action column) and perform this action - the table of subscription would serve both as the table of existing subscriptions and required actions.
+
+E.g. if the queue is subscribed and there is no notification subscription, it will be created in the table with "create" action, and the loop would create it and schedule "check" action on it.
@@ -0,0 +1,34 @@
+# SMP protocol changes to support push notifications on iOS
+
+## Problem
+
+There are already commands/responses to allow subscriptions to message notifications - NKEY/NID, NSUB/NMSG. These commands will be used by SMP agent (NKEY/NID) and by notification server (NSUB/NMSG) to have message notifications delivered to notification server, so it can forward them to APNS server using device token.
+
+There are two remaining problems that these commands do not solve.
+
+1. Receiving the message when notification arrives.
+
+iOS requires creating a bundled notification service extension (NSE) that runs in isolated container and, if we were to use the existing commands, would have SMP subscription to the same SMP servers as the main app, triggering resubscriptions every time the message reception switches between the app and NSE. That would cause a substantial increase in traffic and battery consumption to the users.
+
+2. Showing notifications for service messages.
+
+Users do not expect to see notifications for every single SMP messages - e.g., we currently do not show notifications when messages are edited and deleted, and users do not expect them. NSE requires that for every received push notification there should be some notification shown to the users. So only we would have to show a notification for message deletes and updates, we would have to show it for all service messages - e.g. user accepted file invitation, or file transmission has started, contact profile updates and so on.
+
+We considered differentiating whether notifications are sent per queue, from the recipient side, so we do not send notifications for file queues. But it seems insufficient, particularly if we add such features as message receipts, status updates, etc.
+
+## Proposal
+
+1. To retrieve messages when push notifications arrive, we will add 2 SMP commands:
+
+- GET: retrieve one message from the connection. Resonse could be either MSG (the same as when MSG is delivered, but with the correlation id) or GMSG (to simplify processing) – TBC during implementation. If message is not available, the response could be ERR NO_MSG
+- ACK or GACK: acknowledge that the message was processed by the client and can be removed - TBC which one is better. The response is OK or ERR NO_MSG if there was nothing to acknowledge (same as with ACK now)
+
+This would allow receiving a single message from the queue without subscription, this way avoiding that the main app is unsubscribed from the queue.
+
+2. The only way to avoid showing unnecessary notifications (status updates, service messages, etc.) is to avoid sending them. That requires instructing SMP server whether notification should be sent both per queue, from the recipient side, and per message - from the sender side. So the notification would only be sent if the queue has them enabled (via NKEY command) and the sender includes an additional flag in SEND command. The same flag should be included into MSG, so when the message is retrieved with GET command, the client knows, on the agent or chat level (or both), whether this message should have notification shown to the user, and if not - retrieve the next one(s) as well.
+
+This is a substantial change to SMP protocol, that would require client and server upgrade for notifications to be supported.
+
+We should consider whether to increase the SMP protocol version number to 2, so that the new clients can connect to the old clients but without notifications, or we could keep the old commands in the protocol and instead of adding flags to the existing commands, create new commands.
+
+We can also consider making commands extensible so that the new flags can be added (and ignored by parsers if not supported) to at least some existing commands.
@@ -0,0 +1,75 @@
+# DB access and processing messages for iOS notification service extension
+
+## Problem
+
+The only way to receive/process notificaitons is via a separate NSE process that requires a concurrent DB and network access.
+
+SQLite concurenncy does not work, so we need to sync database access.
+
+The problem is complex, as we do not directly control db access from the app, it can be triggered by the message arriving and it may fail to complete in case the app is suspended in the background.
+
+So we need to prevent db access from starting when we know the app is about to be suspended.
+
+The last problem is how to receive and process messages in NSE - should it use recently added GET command or should it subscribe to the connections that receive messages and process messages normally.
+
+To summarize, 2 problems need to be solved:
+
+1. sync db access between 2 (or more, if we add share extension) processes
+
+2. prevent access from starting when the process is due to suspend, only complete operations.
+
+3. Receiveing and processing agent messages in NSE
+
+## Proposed solution
+
+For problem 1, we can use Posix semaphores from our core code, in the same bracket that manages database connection - it would wait for semaphore to be free and unlock it once the db operation is complete.
+
+For problem 2, we need to communicate from the app when it goes to the background to prevent database access starting and completing before the suspension. This would set some `aboutToSuspend` STM flag (or the opposite) that would prevent operations from progressing (using STM retry, that would block until the flag has the value allowing operation to progress).
+
+Several possibilities can be considered:
+
+- use this flag in the bracket that provides DB connections. While simple, it may lock some operations in the middle and may also lead to the situation when network operation succeeds but database access was blocked, and the database is not updated.
+- use this flag to stop network operations that would require database updates - like sending messages, subscriptions and ACK - all these operations would require database access once they succeed.
+- use two flags, for both cases above, but set them at different times since going to background - block new network operations as soon as the app goes to the background and block database access once the app is about to be suspended.
+
+The last option seems more robust. To do it, there will be an api allowing the app to communicat its phase:
+
+- app going to the background would trigger blocking new network operations and start a new background task - `background` phase.
+- background task receiving completion warning, or, maybe, some time after it is started - probably 20 seconds - or whatever happens earlier - would trigger call blocking db access - `suspended` phase.
+- app becoming active would trigger unblocking both flags - `active` phase.
+
+`/_app phase <phase>` where `phase` can be one of the above values.
+
+NSE would also use the same phases:
+
+- sending `active` when it is started (the process starts as active, but it is possible that the new notification arrives to the same process, after the previous one sent background/suspension)
+- sending `background + suspended` (or `suspended` should set both flags) once it is finished processing the notification, provided no new notification arrived and started processing - this should be tracked in NSE.
+
+For problem 3, NSE can do one of the following:
+
+- use SUB and process messages normally - the downside is that the app will have to resubscribe and it has to be tracked.
+- use GET and process messages by pushing them through the processing function - the downside it that a rewiring of message processing is needed.
+- use GET but deliver messages through the same queue as when they arrive normally (in which case getMessage agent function should not return the message, but will return a flag showing whether the message was received, or, possibly, or, possibly will return a message but the message would also be sent to the queue?).
+- process messages in agent manually and in chat via the queue.
+
+One of the downside of GET is that it requires calling GET again after ACK. We could have two variants of ACK (or additional ACK parameter) - one that never delivers a new message, and another one that does. In this case, if get needs to process the next message (when the current one has no notification flag), it can call ACK that delivers the next message. But, it is probably a premature optimization, and having general support of batched commands would add more value.
+
+Additional problem is concurrency in NSE - if the new notification from the same queue arrives before the current one finishes processing in the same process one of the following can happen:
+
+- the 2nd notification naively call GET and receives the same message.
+- the 2nd notification waits until the first finished processing, in which case it can run out of time.
+
+The problem is that the app won't know it's the same queue, as nId is encrypted, so the agent should handle this scenario when the new call to getMessage is made before the previous one finished processing, and differentiate between calls made for additional messages (possibly, getMessage should include previous message ID, if it is available) and the first call.
+
+EDIT: GETs have to be sent from UI to chat and from chat to agent as function calls, but the agent will have to queue get calls to make sure they return different messages. GET call would return message flags (incl. notification flag), so that the UI can send the next GET if needed without waiting.
+
+Considered alternative: include notification content in the message and have NSE only perform decryption, without any network IO. In this case notification content would be in SEND and in NMSG, e2e encrypted.
+
+While promising, as it solves network coordination issues and makes GET unnecessary, it creates mutliple other problems, so it was rejected:
+
+- message content is exposed to centralized ntf and apns servers, creating additional attack vector.
+- it adds complexity in security critical parts of the stack - double ratchet encryption, as it requires either storing message keys and using different IVs for notifications, or initializing completely separate ratchet for notifications content.
+- it reduces the size of the message.
+- it makes user experience worse, as:
+  - it would not accelerate handshake for new contacts and for file delivery - this approach only works for content messages.
+  - it would open the app without the new messages - the users would have to wait until the messages are received. It is also bad for "security optics" - the users might think that the message content was exposed to notifications.
@@ -0,0 +1,61 @@
+sequenceDiagram
+  participant M as iOS message<br>notification
+  participant S as iOS system
+  participant N as iOS NSE
+  participant U as iOS UI
+  participant C as Core chat
+  participant A as Core agent
+
+  M ->> N: notification
+  S ->> N: get app pref
+  note over N: ignore,<br>app is active
+
+  note over M, A: app going to background
+  S ->> U: phase: background<br>(possibly, "will" method)
+  U ->> S: set app pref "pausing"
+  U ->> C: /_app phase paused, result CRCmdOk
+  C ->> A: pauseAgent<br>(no new network IO)
+  M ->> N: notification
+  S ->> N: get app pref
+  note over N: wait/poll for<br>"paused"/"suspending"/"suspended"<br>event/pref
+  A ->> C: event "IO paused"<br>(after in-flight op completed)<br>PHASE PAUSED
+  C ->> U: event "IO paused" (CRAppPaused)
+  U ->> S: set shared pref "paused"
+
+  note over M, A: process notification
+  M ->> N: notification
+  S ->> N: get app pref<br>continue if<br>"paused"/"suspending"/"suspended"
+  N ->> S: set NSE pref "active"
+  N ->> C: /_get message
+  C ->> A: getMessage
+  A ->> C: msg flags
+  C ->> N: msg flags
+  note over N: get messages<br>until notification flag set
+  A ->> C: MSG/CONF/INFO
+  C ->> N: some event
+  N ->> S: set NSE pref "completed"
+  N ->> S: show notification
+
+  note over M, A: app about to be suspended<br>(or 15-20 sec after background)
+  S ->> U: background task notice
+  U ->> S: set app pref "suspending"
+  U ->> C: /_app phase suspended, response ok
+  C ->> A: suspendAgent<br>(no new DB)
+  A ->> C: event "DB paused"<br>(after in-flight op completed)<br>PHASE SUSPENDED
+  C ->> U: event "DB paused" (CRAppSuspended)
+  U ->> S: set app pref "suspended"
+
+  note over M, A: app about to be activated
+  S ->> U: phase: active<br>(or inactive?)<br><br>(possibly, "will" method)
+  S ->> U: get NSE pref
+  U ->> S: set app pref "activating"
+  alt nse active?
+    U ->> C: /_app phase inactive
+    note over U: poll/wait till NSE pref is "completed"
+  end
+
+  U ->> C: /_app phase active (response result)
+  C ->> A: activateAgent<br>(allow IO/DB)
+  A ->> C: result ()
+  C ->> U: CRCmdOk
+  U ->> S: set app pref "active"
@@ -0,0 +1,26 @@
+# Accessing SMP servers via Tor
+
+## Problem
+
+While SMP protocol is focussed on minimizing application-level meta-data by using pair-wise identifiers instead of user profile identifiers, it is important for many users to protect their IP addresses.
+
+Further, even if IP addresses are hidden by onion routing, clients should be able to choose to use a separate TCP connection to subscribe to each queue, even though it increases traffic and battery consumption, as otherwise the servers can observe multiple queues accessed by the same client.
+
+## Solution and requirements
+
+While some users may want to access SMP servers via tor, some other users (even their contacts) may want the opposite - e.g., if they use the network when accessing Tor would be suspicious (or blocked).
+
+Therefore we need to support the connections when one of the user accesses the same server via Tor (and, possibly, via onion address), while another user accesses this server without Tor.
+
+At the same time the user accessing the server via Tor may not want that their contacts access this server without Tor, and it also may be possible that the server is not available under a normal (not .onion) address.
+
+The proposed options for connecting via Tor are:
+
+1. Access servers via Socks proxy: no/yes (specify port?)
+2. Use .onion addresses: no/when available/warn/always
+3. Require senders to use .onion addresses: yes/no
+4. Use separate TCP connection for each queue
+
+While it should be possible for SMP servers to have two addresses (with and without Tor), the queues should only use one server address - if the queue started being accessed via .onion address it should not be possible to access it via a normal address. Queue addresses in connection invitations should support dual server addresses (when senders are not required ot use .onion address).
+
+At the same time, the queue with the normal addresses can be accessed with and without Tor, depending on the current device settings.
@@ -0,0 +1,53 @@
+# SMP queue rotation and redundancy
+
+## Problem
+
+1. Long term usage of the queue allows the servers to analyze long term traffic patterns.
+
+2. If the user changes the configured SMP server(s), the previously created contacts do not migrate to the new server(s).
+
+3. Server can lose messages.
+
+## Solution
+
+Additional messages exchanged by SMP agents to negotiate addition and removal of queues to the connection.
+
+This approach allows for both rotation and redundancy, as changing queue will be done be adding a queue and then removing the existing queue.
+
+The reason for this approach is that otherwise it's non-trivial to switch from one queue to another without losing messages or delivering them out of order, it's easier to have messages delivered via both queues during the switch, however short or long time it is.
+
+### Messages
+
+Additional agent messages required for the protocol:
+
+    QADD_ -> "QA"
+    QKEY_ -> "QK"
+    QUSE_ -> "QU"
+    QTEST_ -> "QT"
+
+`QADD`: add the new queue address(es), the same format as `REPLY` message, encoded as `QA`.
+
+`QKEY`: pass sender's key via existing connection (SMP confirmation message will not be used, to avoid the same "race" of the initial key exchange that would create the risk of intercepting the queue for the attacker), encoded as `QK`.
+
+`QUSE`: instruct the sender to use the new queue with sender's queue ID as parameter, encoded as `QU`.
+
+`QTEST`: send test message to the new connection, encoded as `QT`. Any other message can be sent if available to continue rotation, the absence of this message is not an error. Once this message is successfully sent the sender will stop using the old queue. Once this message (or any other message in the new queue) is received, the recipient will stop using the old queue and delete it.
+
+### Protocol
+
+```
+participant A as Alice
+participant B as Bob
+participant R as Server that has A's receive queue
+participant S as Server that has A's send queue (B's receive queue)
+participant R' as Server that hosts the new A's receive queue
+
+A ->> R': create new queue
+A ->> S ->> B: QADD (R'): snd address of the new queue(s)
+B ->> S(R) ->> A: QKEY (R'): sender's key for the new queue(s) (to avoid the race of SMP confirmation for the initial exchange)
+A ->> S(R'): secure new queue
+A ->> S ->> B: QUSE (R'): instruction to use new queue(s)
+B ->> S(R') ->> A: QTEST
+A ->> S(R): DEL: delete the old queue
+B ->> S(R') ->> A: send all new messages to the new queue
+```
@@ -0,0 +1,27 @@
+# SMP Basic Auth
+
+## Problem
+
+Users who host their own servers do not want unknown people to be able to create messaging queues on their servers after discovering server address in groups or after making a connection. As the number of self-hosted servers is growing it became more important than it was when we excluded it from the original design.
+
+## Solution
+
+Single access password that can be optionally included in server address that is passed to app configuration. It will not be allowed in the existing contexts (and parsing will fail), to avoid accidentally leaking it. Server address with password will look this way: `smp://fingerprint:password@hosts`
+
+## Implementation plan
+
+1. A separate type to include server and password, so it can only be used where allowed.
+
+2. Server password to create queues will be configured in TRANSPORT section of INI file, as `create_password` parameter.
+
+3. The password will only be required in server configuration/address to create queues only, it won't be required for other receiving queue operations on already existing queues.
+
+4. If new command is attempted in the session that does not allow creating queues, the server will send `ERR AUTH` response
+
+5. Passing password to the server can be done in one of the several ways, we need to decide:
+
+  - as a parameter of NEW command. Pros: a local change, that only needs checking when queue is created. Cons: protocol version change.
+  - as a separate command AUTH. Pros: allows to include additional parameters and potentially be extended beyond basic auth. Cons: more complex to manage server state, can be more difficult syntax in the future, if extended.
+  - as part of handshake (we currently ignore the unparsed part of handshake block, so it can be extended). Pros: probably, the simplest, and independent of the commands protocol – establishes create permission for the current session. Cons: the client won't know about whether it is able to create the queue until it tries (same as in case 1).
+
+  My preference is the last option. As a variant of the last option, we can add a server response/message that includes permission to create queues - it will only be sent to the clients who pass credential in handshake - that might simplify testing server connection (we currently do not do it). It might be unnecessary, as we could simply create and delete queue in case credential is passed as part of testing connection (and even sending a message to it).
@@ -0,0 +1,29 @@
+#!/usr/bin/env sh
+confd="/etc/opt/simplex"
+logd="/var/opt/simplex/"
+
+# Check if server has been initialized
+if [ ! -f "$confd/smp-server.ini" ]; then
+  # If not, determine ip or domain
+  case $addr in
+    '') printf "Please specify \$addr environment variable.\n"; exit 1 ;;
+    *[a-zA-Z]*) set -- -n $addr ;;
+    *) set -- --ip $addr ;;
+  esac
+
+  case $pass in
+    '') set -- "$@" --no-password ;;
+    *) set -- "$@" --password $pass ;;
+  esac
+
+  smp-server init -y -l "$@"
+fi
+
+# backup store log
+[ -f "$logd/smp-server-store.log" ] && cp "$logd"/smp-server-store.log "$logd"/smp-server-store.log.bak
+# rotate server log
+[ -f "$logd/smp-server.log" ] && mv "$logd"/smp-server.log "$logd"/smp-server-"$(date +'%FT%T')".log
+
+# Finally, run smp-sever. Notice that "exec" here is important:
+# smp-server replaces our helper script, so that it can catch INT signal
+exec smp-server start > "$logd"/smp-server.log 2>&1
@@ -0,0 +1,178 @@
+#!/bin/bash
+
+# <UDF name="enable_store_log" label="Store log - persist notification subscriptions to append only log and restore them upon server restart." default="on" oneof="on, off" />
+# <UDF name="api_token" label="Linode API token - enable Linode to create tags with server address, fingerprint and version. Note: minimal permissions token should have are read/write access to `linodes` (to create tags) and `domains` (to add A record for the third level domain if FQDN is provided)." default="" />
+# <UDF name="fqdn" label="FQDN (Fully Qualified Domain Name) - provide third level domain name (e.g. ntf.example.com). If provided use `ntf://fingerprint@FQDN` as server address in the client. If FQDN is not provided use `ntf://fingerprint@IP` instead." default="" />
+# <UDF name="apns_key_id" label="APNS key ID." default="" />
+
+# Log all stdout output to stackscript.log
+exec &> >(tee -i /var/log/stackscript.log)
+
+# Uncomment next line to enable debugging features
+# set -xeo pipefail
+
+cd $HOME
+
+# https://superuser.com/questions/1638779/automatic-yess-to-linux-update-upgrade
+# https://superuser.com/questions/1412054/non-interactive-apt-upgrade
+sudo DEBIAN_FRONTEND=noninteractive \
+  apt-get \
+  -o Dpkg::Options::=--force-confold \
+  -o Dpkg::Options::=--force-confdef \
+  -y --allow-downgrades --allow-remove-essential --allow-change-held-packages \
+  update
+
+sudo DEBIAN_FRONTEND=noninteractive \
+  apt-get \
+  -o Dpkg::Options::=--force-confold \
+  -o Dpkg::Options::=--force-confdef \
+  -y --allow-downgrades --allow-remove-essential --allow-change-held-packages \
+  dist-upgrade
+
+# TODO install unattended-upgrades
+sudo DEBIAN_FRONTEND=noninteractive \
+  apt-get \
+  -o Dpkg::Options::=--force-confold \
+  -o Dpkg::Options::=--force-confdef \
+  -y --allow-downgrades --allow-remove-essential --allow-change-held-packages \
+  install jq
+
+# Add firewall
+echo "y" | ufw enable
+
+# Open ports
+ufw allow ssh
+ufw allow https
+ufw allow 5223
+
+# Increase file descriptors limit
+echo 'fs.file-max = 1000000' >> /etc/sysctl.conf
+echo 'fs.inode-max = 1000000' >> /etc/sysctl.conf
+echo 'root soft nofile unlimited' >> /etc/security/limits.conf
+echo 'root hard nofile unlimited' >> /etc/security/limits.conf
+
+# Download latest release
+bin_dir="/opt/simplex-notifications/bin"
+binary="$bin_dir/ntf-server"
+mkdir -p $bin_dir
+curl -L -o $binary https://github.com/simplex-chat/simplexmq/releases/latest/download/ntf-server-ubuntu-20_04-x86-64
+chmod +x $binary
+
+# / Add to PATH
+cat > /etc/profile.d/simplex.sh << EOF
+#!/bin/bash
+
+export PATH="$PATH:$bin_dir"
+
+EOF
+# Add to PATH /
+
+# Source and test PATH
+source /etc/profile.d/simplex.sh
+ntf-server --version
+
+# Initialize server
+init_opts=()
+
+[[ $ENABLE_STORE_LOG == "on" ]] && init_opts+=(-l)
+
+ip_address=$(curl ifconfig.me)
+init_opts+=(--ip $ip_address)
+
+[[ -n "$FQDN" ]] && init_opts+=(-n $FQDN)
+
+ntf-server init "${init_opts[@]}"
+
+# Server fingerprint
+fingerprint=$(cat /etc/opt/simplex-notifications/fingerprint)
+
+# Determine server address to specify in welcome script and Linode tag
+if [[ -n "$FQDN" ]]; then
+  server_address=$FQDN
+else
+  server_address=$ip_address
+fi
+
+# Set up welcome script
+on_login_script="/opt/simplex-notifications/on_login.sh"
+
+# / Welcome script
+cat > $on_login_script << EOF
+#!/bin/bash
+
+fingerprint=\$1
+server_address=\$2
+
+cat << EOF2
+********************************************************************************
+
+SimpleX notifications server address: ntf://\$fingerprint@\$server_address
+Check server status with: systemctl status ntf-server
+
+To keep this server secure, the UFW firewall is enabled.
+All ports are BLOCKED except 22 (SSH), 443 (HTTPS), 5223 (notifications server).
+
+********************************************************************************
+To stop seeing this message delete line - bash /opt/simplex-notifications/on_login.sh - from /root/.bashrc
+EOF2
+
+EOF
+# Welcome script /
+
+chmod +x $on_login_script
+echo "bash $on_login_script $fingerprint $server_address" >> /root/.bashrc
+
+# Create A record and update Linode's tags
+if [[ -n "$API_TOKEN" ]]; then
+  if [[ -n "$FQDN" ]]; then
+    domain_address=$(echo $FQDN | rev | cut -d "." -f 1,2 | rev)
+    domain_id=$(curl -H "Authorization: Bearer $API_TOKEN" https://api.linode.com/v4/domains \
+    | jq --arg da "$domain_address" '.data[] | select( .domain == $da ) | .id')
+    if [[ -n $domain_id ]]; then
+      curl \
+        -s -H "Content-Type: application/json" \
+        -H "Authorization: Bearer $API_TOKEN" \
+        -X POST -d "{\"type\":\"A\",\"name\":\"$FQDN\",\"target\":\"$ip_address\"}" \
+        https://api.linode.com/v4/domains/${domain_id}/records
+    fi
+  fi
+
+  version=$(ntf-server --version | cut -d ' ' -f 3-)
+
+  curl \
+    -s -H "Content-Type: application/json" \
+    -H "Authorization: Bearer $API_TOKEN" \
+    -X PUT -d "{\"tags\":[\"$server_address\",\"$fingerprint\",\"$version\"]}" \
+    https://api.linode.com/v4/linode/instances/$LINODE_ID
+fi
+
+# / Create systemd service
+cat > /etc/systemd/system/ntf-server.service << EOF
+[Unit]
+Description=SimpleX notifications server
+
+[Service]
+Environment="APNS_KEY_FILE=/etc/opt/simplex-notifications/AuthKey.p8"
+Environment="APNS_KEY_ID=$APNS_KEY_ID"
+Type=simple
+ExecStart=/bin/sh -c "exec $binary start >> /var/opt/simplex-notifications/ntf-server.log 2>&1"
+KillSignal=SIGINT
+Restart=always
+RestartSec=10
+LimitNOFILE=1000000
+LimitNOFILESoft=1000000
+
+[Install]
+WantedBy=multi-user.target
+
+EOF
+# Create systemd service /
+
+# Start systemd service
+chmod 644 /etc/systemd/system/ntf-server.service
+sudo systemctl enable ntf-server
+# ! APNS key file and certificate have to be copied manually
+# sudo systemctl start ntf-server
+
+# Reboot Linode to apply upgrades
+# sudo reboot
@@ -86,10 +86,6 @@ smp-server init "${init_opts[@]}"
 fingerprint=$(cat /etc/opt/simplex/fingerprint)

 # Determine server address to specify in welcome script and Linode tag
-# ! If FQDN was provided and used as part of server initialization, server's certificate will not pass validation at client
-# ! if client tries to connect by server's IP address, so we have to specify FQDN as server address in Linode tag and
-# ! in welcome script regardless of creation of A record in Linode
-# ! https://hackage.haskell.org/package/x509-validation-1.6.10/docs/src/Data-X509-Validation.html#validateCertificateName
 if [[ -n "$FQDN" ]]; then
  server_address=$FQDN
 else
@@ -157,6 +153,8 @@ Description=SMP server
 [Service]
 Type=simple
 ExecStart=/bin/sh -c "exec $binary start >> /var/opt/simplex/smp-server.log 2>&1"
+KillSignal=SIGINT
+TimeoutStopSec=infinity
 Restart=always
 RestartSec=10
 LimitNOFILE=1000000
@@ -0,0 +1,37 @@
+1. Install `tor` following [official guide](https://community.torproject.org/onion-services/setup/install/).
+
+2. Modify `/etc/tor/torrc` configuration file:
+
+```sh
+...
+# Disable anonymous mode for better connectivity
+## Needed for HiddenServiceNonAnonymousMode
+SOCKSPort 0
+## Needed for HiddenServiceSingleHopMode
+HiddenServiceNonAnonymousMode 1
+## Flag to disable anonymous mode
+## This option reduces the latency of server connection, but it makes server itself not anonymous,
+## it only protects the anonymity of the users connecting to the server.
+## In case your server address has both public and onion hostnames it is not anonymous anyway,
+## so this is what you want.
+HiddenServiceSingleHopMode 1
+
+# Specify folder for smp-tor
+## Folder for keys, address, etc.
+HiddenServiceDir /var/lib/tor/simplex-smp/
+## Map smp port (5223) to tor
+HiddenServicePort 5223 localhost:5223
+...
+```
+
+3. Restart `tor` system service:
+
+```
+sudo systemctl restart tor
+```
+
+4. Onion address can be obtained from following file:
+
+```sh
+sudo cat /var/lib/tor/simplex-smp/hostname
+```
@@ -0,0 +1,12 @@
+#!/bin/bash
+
+# systemd has to be configured to use SIGINT to save and restore undelivered messages after restart.
+# Add this to [Service] section:
+# KillSignal=SIGINT
+curl -L -o /opt/simplex/bin/smp-server-new https://github.com/simplex-chat/simplexmq/releases/latest/download/smp-server-ubuntu-20_04-x86-64
+systemctl stop smp-server
+cp /var/opt/simplex/smp-server-store.log /var/opt/simplex/smp-server-store.log.bak
+mv /opt/simplex/bin/smp-server /opt/simplex/bin/smp-server-old
+mv /opt/simplex/bin/smp-server-new /opt/simplex/bin/smp-server
+chmod +x /opt/simplex/bin/smp-server
+systemctl start smp-server
@@ -1,11 +1,11 @@
 cabal-version: 1.12

-- This file has been generated from package.yaml by hpack version 0.34.4.
+-- This file has been generated from package.yaml by hpack version 0.35.0.
 --
 -- see: https://github.com/sol/hpack

 name:           simplexmq
-version:        1.0.3
+version:        4.3.1
 synopsis:       SimpleXMQ message broker
 description:    This package includes <./docs/Simplex-Messaging-Server.html server>,
                <./docs/Simplex-Messaging-Client.html client> and
@@ -27,11 +27,18 @@ extra-source-files:
    README.md
    CHANGELOG.md

+flag swift
+  description: Enable swift JSON format
+  manual: True
+  default: False
+
 library
  exposed-modules:
      Simplex.Messaging.Agent
      Simplex.Messaging.Agent.Client
      Simplex.Messaging.Agent.Env.SQLite
+      Simplex.Messaging.Agent.Lock
+      Simplex.Messaging.Agent.NtfSubSupervisor
      Simplex.Messaging.Agent.Protocol
      Simplex.Messaging.Agent.QueryString
      Simplex.Messaging.Agent.RetryInterval
@@ -41,23 +48,51 @@ library
      Simplex.Messaging.Agent.Store.SQLite.Migrations
      Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220101_initial
      Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220301_snd_queue_keys
-      Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220320_server_ips
+      Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220322_notifications
+      Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220608_v2
+      Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220625_v2_ntf_mode
+      Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220811_onion_hosts
+      Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220817_connection_ntfs
+      Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220905_commands
+      Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220915_connection_queues
+      Simplex.Messaging.Agent.TRcvQueues
      Simplex.Messaging.Client
+      Simplex.Messaging.Client.Agent
      Simplex.Messaging.Crypto
      Simplex.Messaging.Crypto.Ratchet
      Simplex.Messaging.Encoding
      Simplex.Messaging.Encoding.String
+      Simplex.Messaging.Notifications.Client
+      Simplex.Messaging.Notifications.Protocol
+      Simplex.Messaging.Notifications.Server
+      Simplex.Messaging.Notifications.Server.Env
+      Simplex.Messaging.Notifications.Server.Main
+      Simplex.Messaging.Notifications.Server.Push.APNS
+      Simplex.Messaging.Notifications.Server.Stats
+      Simplex.Messaging.Notifications.Server.Store
+      Simplex.Messaging.Notifications.Server.StoreLog
+      Simplex.Messaging.Notifications.Transport
+      Simplex.Messaging.Notifications.Types
      Simplex.Messaging.Parsers
      Simplex.Messaging.Protocol
      Simplex.Messaging.Server
+      Simplex.Messaging.Server.CLI
      Simplex.Messaging.Server.Env.STM
+      Simplex.Messaging.Server.Expiration
+      Simplex.Messaging.Server.Main
      Simplex.Messaging.Server.MsgStore
      Simplex.Messaging.Server.MsgStore.STM
      Simplex.Messaging.Server.QueueStore
      Simplex.Messaging.Server.QueueStore.STM
+      Simplex.Messaging.Server.Stats
      Simplex.Messaging.Server.StoreLog
+      Simplex.Messaging.TMap
      Simplex.Messaging.Transport
      Simplex.Messaging.Transport.Client
+      Simplex.Messaging.Transport.HTTP2
+      Simplex.Messaging.Transport.HTTP2.Client
+      Simplex.Messaging.Transport.HTTP2.Server
+      Simplex.Messaging.Transport.KeepAlive
      Simplex.Messaging.Transport.Server
      Simplex.Messaging.Transport.WebSockets
      Simplex.Messaging.Util
@@ -75,33 +110,41 @@ library
    , asn1-types ==0.3.*
    , async ==2.2.*
    , attoparsec ==0.14.*
-    , base >=4.7 && <5
+    , base >=4.14 && <5
    , base64-bytestring >=1.0 && <1.3
    , bytestring ==0.10.*
+    , case-insensitive ==1.2.*
    , composition ==1.0.*
    , constraints >=0.12 && <0.14
    , containers ==0.6.*
    , cryptonite >=0.27 && <0.30
    , cryptostore ==0.2.*
    , data-default ==0.7.*
-    , direct-sqlite ==2.3.*
+    , direct-sqlcipher ==2.3.*
    , directory ==1.3.*
    , filepath ==1.4.*
    , generic-random >=1.3 && <1.5
    , http-types ==0.12.*
+    , http2 ==3.0.*
+    , ini ==0.4.1
    , iso8601-time ==0.1.*
    , memory ==0.15.*
    , mtl ==2.2.*
-    , network ==3.1.*
-    , network-transport ==0.5.*
+    , network >=3.1.2.7 && <3.2
+    , network-transport ==0.5.4
+    , optparse-applicative >=0.15 && <0.17
+    , process ==1.6.*
    , random >=1.1 && <1.3
    , simple-logger ==0.1.*
-    , sqlite-simple ==0.4.*
+    , socks ==0.6.*
+    , sqlcipher-simple ==0.4.*
    , stm ==2.5.*
    , template-haskell ==2.16.*
    , text ==1.2.*
    , time ==1.9.*
-    , tls >=1.5.7 && <1.6
+    , time-compat ==1.9.*
+    , time-manager ==0.0.*
+    , tls >=1.6.0 && <1.7
    , transformers ==0.5.*
    , unliftio ==0.2.*
    , unliftio-core ==0.2.*
@@ -110,6 +153,70 @@ library
    , x509-store ==1.6.*
    , x509-validation ==1.6.*
  default-language: Haskell2010
+  if flag(swift)
+    cpp-options: -DswiftJSON
+
+executable ntf-server
+  main-is: Main.hs
+  other-modules:
+      Paths_simplexmq
+  hs-source-dirs:
+      apps/ntf-server
+  ghc-options: -Wall -Wcompat -Werror=incomplete-patterns -Wredundant-constraints -Wincomplete-record-updates -Wincomplete-uni-patterns -Wunused-type-patterns -threaded
+  build-depends:
+      QuickCheck ==2.14.*
+    , aeson ==2.0.*
+    , ansi-terminal >=0.10 && <0.12
+    , asn1-encoding ==0.9.*
+    , asn1-types ==0.3.*
+    , async ==2.2.*
+    , attoparsec ==0.14.*
+    , base >=4.14 && <5
+    , base64-bytestring >=1.0 && <1.3
+    , bytestring ==0.10.*
+    , case-insensitive ==1.2.*
+    , composition ==1.0.*
+    , constraints >=0.12 && <0.14
+    , containers ==0.6.*
+    , cryptonite >=0.27 && <0.30
+    , cryptostore ==0.2.*
+    , data-default ==0.7.*
+    , direct-sqlcipher ==2.3.*
+    , directory ==1.3.*
+    , filepath ==1.4.*
+    , generic-random >=1.3 && <1.5
+    , http-types ==0.12.*
+    , http2 ==3.0.*
+    , ini ==0.4.1
+    , iso8601-time ==0.1.*
+    , memory ==0.15.*
+    , mtl ==2.2.*
+    , network >=3.1.2.7 && <3.2
+    , network-transport ==0.5.4
+    , optparse-applicative >=0.15 && <0.17
+    , process ==1.6.*
+    , random >=1.1 && <1.3
+    , simple-logger ==0.1.*
+    , simplexmq
+    , socks ==0.6.*
+    , sqlcipher-simple ==0.4.*
+    , stm ==2.5.*
+    , template-haskell ==2.16.*
+    , text ==1.2.*
+    , time ==1.9.*
+    , time-compat ==1.9.*
+    , time-manager ==0.0.*
+    , tls >=1.6.0 && <1.7
+    , transformers ==0.5.*
+    , unliftio ==0.2.*
+    , unliftio-core ==0.2.*
+    , websockets ==0.12.*
+    , x509 ==1.7.*
+    , x509-store ==1.6.*
+    , x509-validation ==1.6.*
+  default-language: Haskell2010
+  if flag(swift)
+    cpp-options: -DswiftJSON

 executable smp-agent
  main-is: Main.hs
@@ -126,34 +233,42 @@ executable smp-agent
    , asn1-types ==0.3.*
    , async ==2.2.*
    , attoparsec ==0.14.*
-    , base >=4.7 && <5
+    , base >=4.14 && <5
    , base64-bytestring >=1.0 && <1.3
    , bytestring ==0.10.*
+    , case-insensitive ==1.2.*
    , composition ==1.0.*
    , constraints >=0.12 && <0.14
    , containers ==0.6.*
    , cryptonite >=0.27 && <0.30
    , cryptostore ==0.2.*
    , data-default ==0.7.*
-    , direct-sqlite ==2.3.*
+    , direct-sqlcipher ==2.3.*
    , directory ==1.3.*
    , filepath ==1.4.*
    , generic-random >=1.3 && <1.5
    , http-types ==0.12.*
+    , http2 ==3.0.*
+    , ini ==0.4.1
    , iso8601-time ==0.1.*
    , memory ==0.15.*
    , mtl ==2.2.*
-    , network ==3.1.*
-    , network-transport ==0.5.*
+    , network >=3.1.2.7 && <3.2
+    , network-transport ==0.5.4
+    , optparse-applicative >=0.15 && <0.17
+    , process ==1.6.*
    , random >=1.1 && <1.3
    , simple-logger ==0.1.*
    , simplexmq
-    , sqlite-simple ==0.4.*
+    , socks ==0.6.*
+    , sqlcipher-simple ==0.4.*
    , stm ==2.5.*
    , template-haskell ==2.16.*
    , text ==1.2.*
    , time ==1.9.*
-    , tls >=1.5.7 && <1.6
+    , time-compat ==1.9.*
+    , time-manager ==0.0.*
+    , tls >=1.6.0 && <1.7
    , transformers ==0.5.*
    , unliftio ==0.2.*
    , unliftio-core ==0.2.*
@@ -162,6 +277,8 @@ executable smp-agent
    , x509-store ==1.6.*
    , x509-validation ==1.6.*
  default-language: Haskell2010
+  if flag(swift)
+    cpp-options: -DswiftJSON

 executable smp-server
  main-is: Main.hs
@@ -178,37 +295,42 @@ executable smp-server
    , asn1-types ==0.3.*
    , async ==2.2.*
    , attoparsec ==0.14.*
-    , base >=4.7 && <5
+    , base >=4.14 && <5
    , base64-bytestring >=1.0 && <1.3
    , bytestring ==0.10.*
+    , case-insensitive ==1.2.*
    , composition ==1.0.*
    , constraints >=0.12 && <0.14
    , containers ==0.6.*
    , cryptonite >=0.27 && <0.30
    , cryptostore ==0.2.*
    , data-default ==0.7.*
-    , direct-sqlite ==2.3.*
+    , direct-sqlcipher ==2.3.*
    , directory ==1.3.*
    , filepath ==1.4.*
    , generic-random >=1.3 && <1.5
    , http-types ==0.12.*
-    , ini ==0.4.*
+    , http2 ==3.0.*
+    , ini ==0.4.1
    , iso8601-time ==0.1.*
    , memory ==0.15.*
    , mtl ==2.2.*
-    , network ==3.1.*
-    , network-transport ==0.5.*
+    , network >=3.1.2.7 && <3.2
+    , network-transport ==0.5.4
    , optparse-applicative >=0.15 && <0.17
    , process ==1.6.*
    , random >=1.1 && <1.3
    , simple-logger ==0.1.*
    , simplexmq
-    , sqlite-simple ==0.4.*
+    , socks ==0.6.*
+    , sqlcipher-simple ==0.4.*
    , stm ==2.5.*
    , template-haskell ==2.16.*
    , text ==1.2.*
    , time ==1.9.*
-    , tls >=1.5.7 && <1.6
+    , time-compat ==1.9.*
+    , time-manager ==0.0.*
+    , tls >=1.6.0 && <1.7
    , transformers ==0.5.*
    , unliftio ==0.2.*
    , unliftio-core ==0.2.*
@@ -217,6 +339,8 @@ executable smp-server
    , x509-store ==1.6.*
    , x509-validation ==1.6.*
  default-language: Haskell2010
+  if flag(swift)
+    cpp-options: -DswiftJSON

 test-suite smp-server-test
  type: exitcode-stdio-1.0
@@ -226,10 +350,17 @@ test-suite smp-server-test
      AgentTests.ConnectionRequestTests
      AgentTests.DoubleRatchetTests
      AgentTests.FunctionalAPITests
+      AgentTests.NotificationTests
+      AgentTests.SchemaDump
      AgentTests.SQLiteTests
+      CLITests
+      CoreTests.CryptoTests
      CoreTests.EncodingTests
      CoreTests.ProtocolErrorTests
+      CoreTests.RetryIntervalTests
      CoreTests.VersionRangeTests
+      NtfClient
+      NtfServerTests
      ServerTests
      SMPAgentClient
      SMPClient
@@ -246,37 +377,47 @@ test-suite smp-server-test
    , asn1-types ==0.3.*
    , async ==2.2.*
    , attoparsec ==0.14.*
-    , base >=4.7 && <5
+    , base >=4.14 && <5
    , base64-bytestring >=1.0 && <1.3
    , bytestring ==0.10.*
+    , case-insensitive ==1.2.*
    , composition ==1.0.*
    , constraints >=0.12 && <0.14
    , containers ==0.6.*
    , cryptonite >=0.27 && <0.30
    , cryptostore ==0.2.*
    , data-default ==0.7.*
-    , direct-sqlite ==2.3.*
+    , direct-sqlcipher ==2.3.*
    , directory ==1.3.*
    , filepath ==1.4.*
    , generic-random >=1.3 && <1.5
    , hspec ==2.7.*
    , hspec-core ==2.7.*
    , http-types ==0.12.*
+    , http2 ==3.0.*
+    , ini ==0.4.1
    , iso8601-time ==0.1.*
+    , main-tester ==0.2.*
    , memory ==0.15.*
    , mtl ==2.2.*
-    , network ==3.1.*
-    , network-transport ==0.5.*
+    , network >=3.1.2.7 && <3.2
+    , network-transport ==0.5.4
+    , optparse-applicative >=0.15 && <0.17
+    , process ==1.6.*
    , random >=1.1 && <1.3
+    , silently ==1.2.*
    , simple-logger ==0.1.*
    , simplexmq
-    , sqlite-simple ==0.4.*
+    , socks ==0.6.*
+    , sqlcipher-simple ==0.4.*
    , stm ==2.5.*
    , template-haskell ==2.16.*
    , text ==1.2.*
    , time ==1.9.*
+    , time-compat ==1.9.*
+    , time-manager ==0.0.*
    , timeit ==2.0.*
-    , tls >=1.5.7 && <1.6
+    , tls >=1.6.0 && <1.7
    , transformers ==0.5.*
    , unliftio ==0.2.*
    , unliftio-core ==0.2.*
@@ -285,3 +426,5 @@ test-suite smp-server-test
    , x509-store ==1.6.*
    , x509-validation ==1.6.*
  default-language: Haskell2010
+  if flag(swift)
+    cpp-options: -DswiftJSON
@@ -1,89 +1,201 @@
+{-# LANGUAGE ConstraintKinds #-}
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE NumericUnderscores #-}
+{-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE TypeApplications #-}
 {-# OPTIONS_GHC -fno-warn-unticked-promoted-constructors #-}

 module Simplex.Messaging.Agent.Env.SQLite
-  ( AgentConfig (..),
+  ( AgentMonad,
+    AgentConfig (..),
+    AgentDatabase (..),
+    databaseFile,
+    InitialAgentServers (..),
+    NetworkConfig (..),
    defaultAgentConfig,
+    defaultReconnectInterval,
    Env (..),
    newSMPAgentEnv,
+    createAgentStore,
+    NtfSupervisor (..),
+    NtfSupervisorCommand (..),
  )
 where

+import Control.Monad.Except
 import Control.Monad.IO.Unlift
+import Control.Monad.Reader
 import Crypto.Random
 import Data.List.NonEmpty (NonEmpty)
 import Data.Time.Clock (NominalDiffTime, nominalDay)
+import Data.Word (Word16)
 import Network.Socket
 import Numeric.Natural
-import Simplex.Messaging.Agent.Protocol (SMPServer)
+import Simplex.Messaging.Agent.Protocol
 import Simplex.Messaging.Agent.RetryInterval
 import Simplex.Messaging.Agent.Store.SQLite
 import qualified Simplex.Messaging.Agent.Store.SQLite.Migrations as Migrations
 import Simplex.Messaging.Client
+import Simplex.Messaging.Client.Agent ()
 import qualified Simplex.Messaging.Crypto as C
+import Simplex.Messaging.Crypto.Ratchet (supportedE2EEncryptVRange)
+import Simplex.Messaging.Notifications.Types
+import Simplex.Messaging.Protocol (NtfServer, supportedSMPClientVRange)
+import Simplex.Messaging.TMap (TMap)
+import qualified Simplex.Messaging.TMap as TM
+import Simplex.Messaging.Transport (TLS, Transport (..))
+import Simplex.Messaging.Transport.Client (defaultSMPPort)
+import Simplex.Messaging.Version
 import System.Random (StdGen, newStdGen)
+import UnliftIO (Async)
 import UnliftIO.STM

+-- | Agent monad with MonadReader Env and MonadError AgentErrorType
+type AgentMonad m = (MonadUnliftIO m, MonadReader Env m, MonadError AgentErrorType m)
+
+data InitialAgentServers = InitialAgentServers
+  { smp :: NonEmpty SMPServerWithAuth,
+    ntf :: [NtfServer],
+    netCfg :: NetworkConfig
+  }
+
+data AgentDatabase
+  = AgentDB SQLiteStore
+  | AgentDBFile {dbFile :: FilePath, dbKey :: String}
+
+databaseFile :: AgentDatabase -> FilePath
+databaseFile = \case
+  AgentDB SQLiteStore {dbFilePath} -> dbFilePath
+  AgentDBFile {dbFile} -> dbFile
+
 data AgentConfig = AgentConfig
  { tcpPort :: ServiceName,
-    initialSMPServers :: NonEmpty SMPServer,
    cmdSignAlg :: C.SignAlg,
    connIdBytes :: Int,
    tbqSize :: Natural,
-    dbFile :: FilePath,
-    dbPoolSize :: Int,
+    database :: AgentDatabase,
    yesToMigrations :: Bool,
-    smpCfg :: SMPClientConfig,
+    smpCfg :: ProtocolClientConfig,
+    ntfCfg :: ProtocolClientConfig,
    reconnectInterval :: RetryInterval,
+    messageRetryInterval :: RetryInterval2,
+    messageTimeout :: NominalDiffTime,
    helloTimeout :: NominalDiffTime,
+    ntfCron :: Word16,
+    ntfWorkerDelay :: Int,
+    ntfSMPWorkerDelay :: Int,
+    ntfSubCheckInterval :: NominalDiffTime,
+    ntfMaxMessages :: Int,
    caCertificateFile :: FilePath,
    privateKeyFile :: FilePath,
-    certificateFile :: FilePath
+    certificateFile :: FilePath,
+    e2eEncryptVRange :: VersionRange,
+    smpAgentVRange :: VersionRange,
+    smpClientVRange :: VersionRange,
+    initialClientId :: Int
  }

+defaultReconnectInterval :: RetryInterval
+defaultReconnectInterval =
+  RetryInterval
+    { initialInterval = 2_000000,
+      increaseAfter = 10_000000,
+      maxInterval = 180_000000
+    }
+
+defaultMessageRetryInterval :: RetryInterval2
+defaultMessageRetryInterval =
+  RetryInterval2
+    { riFast =
+        RetryInterval
+          { initialInterval = 1_000000,
+            increaseAfter = 10_000000,
+            maxInterval = 60_000000
+          },
+      riSlow =
+        -- TODO: these timeouts can be increased in v4.6 once most clients are updated
+        -- to resume sending on QCONT messages.
+        -- After that local message expiration period should be also increased.
+        RetryInterval
+          { initialInterval = 30_000000,
+            increaseAfter = 30_000000,
+            maxInterval = 600_000000
+          }
+    }
+
 defaultAgentConfig :: AgentConfig
 defaultAgentConfig =
  AgentConfig
    { tcpPort = "5224",
-      initialSMPServers = undefined, -- TODO move it elsewhere?
      cmdSignAlg = C.SignAlg C.SEd448,
      connIdBytes = 12,
      tbqSize = 64,
-      dbFile = "smp-agent.db",
-      dbPoolSize = 4,
+      database = AgentDBFile {dbFile = "smp-agent.db", dbKey = ""},
      yesToMigrations = False,
-      smpCfg = smpDefaultConfig,
-      reconnectInterval =
-        RetryInterval
-          { initialInterval = second,
-            increaseAfter = 10 * second,
-            maxInterval = 10 * second
-          },
+      smpCfg = defaultClientConfig {defaultTransport = (show defaultSMPPort, transport @TLS)},
+      ntfCfg = defaultClientConfig {defaultTransport = ("443", transport @TLS)},
+      reconnectInterval = defaultReconnectInterval,
+      messageRetryInterval = defaultMessageRetryInterval,
+      messageTimeout = 2 * nominalDay,
      helloTimeout = 2 * nominalDay,
+      ntfCron = 20, -- minutes
+      ntfWorkerDelay = 100000, -- microseconds
+      ntfSMPWorkerDelay = 500000, -- microseconds
+      ntfSubCheckInterval = nominalDay,
+      ntfMaxMessages = 4,
      -- CA certificate private key is not needed for initialization
      -- ! we do not generate these
      caCertificateFile = "/etc/opt/simplex-agent/ca.crt",
      privateKeyFile = "/etc/opt/simplex-agent/agent.key",
-      certificateFile = "/etc/opt/simplex-agent/agent.crt"
+      certificateFile = "/etc/opt/simplex-agent/agent.crt",
+      e2eEncryptVRange = supportedE2EEncryptVRange,
+      smpAgentVRange = supportedSMPAgentVRange,
+      smpClientVRange = supportedSMPClientVRange,
+      initialClientId = 0
    }
-  where
-    second = 1_000_000

 data Env = Env
  { config :: AgentConfig,
    store :: SQLiteStore,
    idsDrg :: TVar ChaChaDRG,
    clientCounter :: TVar Int,
-    randomServer :: TVar StdGen
+    randomServer :: TVar StdGen,
+    ntfSupervisor :: NtfSupervisor
  }

 newSMPAgentEnv :: (MonadUnliftIO m, MonadRandom m) => AgentConfig -> m Env
-newSMPAgentEnv config@AgentConfig {dbFile, dbPoolSize, yesToMigrations} = do
+newSMPAgentEnv config@AgentConfig {database, yesToMigrations, initialClientId} = do
  idsDrg <- newTVarIO =<< drgNew
-  store <- liftIO $ createSQLiteStore dbFile dbPoolSize Migrations.app yesToMigrations
-  clientCounter <- newTVarIO 0
+  store <- case database of
+    AgentDB st -> pure st
+    AgentDBFile {dbFile, dbKey} -> liftIO $ createAgentStore dbFile dbKey yesToMigrations
+  clientCounter <- newTVarIO initialClientId
  randomServer <- newTVarIO =<< liftIO newStdGen
-  return Env {config, store, idsDrg, clientCounter, randomServer}
+  ntfSupervisor <- atomically . newNtfSubSupervisor $ tbqSize config
+  return Env {config, store, idsDrg, clientCounter, randomServer, ntfSupervisor}
+
+createAgentStore :: FilePath -> String -> Bool -> IO SQLiteStore
+createAgentStore dbFilePath dbKey = createSQLiteStore dbFilePath dbKey Migrations.app
+
+data NtfSupervisor = NtfSupervisor
+  { ntfTkn :: TVar (Maybe NtfToken),
+    ntfSubQ :: TBQueue (ConnId, NtfSupervisorCommand),
+    ntfWorkers :: TMap NtfServer (TMVar (), Async ()),
+    ntfSMPWorkers :: TMap SMPServer (TMVar (), Async ())
+  }
+
+data NtfSupervisorCommand = NSCCreate | NSCDelete | NSCSmpDelete | NSCNtfWorker NtfServer | NSCNtfSMPWorker SMPServer
+  deriving (Show)
+
+newNtfSubSupervisor :: Natural -> STM NtfSupervisor
+newNtfSubSupervisor qSize = do
+  ntfTkn <- newTVar Nothing
+  ntfSubQ <- newTBQueue qSize
+  ntfWorkers <- TM.empty
+  ntfSMPWorkers <- TM.empty
+  pure NtfSupervisor {ntfTkn, ntfSubQ, ntfWorkers, ntfSMPWorkers}
@@ -0,0 +1,24 @@
+{-# LANGUAGE NamedFieldPuns #-}
+
+module Simplex.Messaging.Agent.Lock where
+
+import Control.Monad (void)
+import Control.Monad.IO.Unlift
+import Data.Functor (($>))
+import qualified UnliftIO.Exception as E
+import UnliftIO.STM
+
+type Lock = TMVar String
+
+withLock :: MonadUnliftIO m => TMVar String -> String -> m a -> m a
+withLock lock name =
+  E.bracket_
+    (atomically $ putTMVar lock name)
+    (void . atomically $ takeTMVar lock)
+
+withGetLock :: MonadUnliftIO m => STM Lock -> String -> m a -> m a
+withGetLock getLock name a =
+  E.bracket
+    (atomically $ getLock >>= \l -> putTMVar l name $> l)
+    (atomically . takeTMVar)
+    (const a)
@@ -0,0 +1,371 @@
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE TupleSections #-}
+
+module Simplex.Messaging.Agent.NtfSubSupervisor
+  ( runNtfSupervisor,
+    nsUpdateToken,
+    nsRemoveNtfToken,
+    sendNtfSubCommand,
+    instantNotifications,
+    closeNtfSupervisor,
+    getNtfServer,
+  )
+where
+
+import Control.Concurrent.Async (Async, uninterruptibleCancel)
+import Control.Concurrent.STM (stateTVar)
+import Control.Logger.Simple (logError, logInfo)
+import Control.Monad
+import Control.Monad.Except
+import Control.Monad.IO.Unlift (MonadUnliftIO)
+import Control.Monad.Reader
+import Data.Bifunctor (first)
+import Data.Fixed (Fixed (MkFixed), Pico)
+import qualified Data.Map.Strict as M
+import Data.Text (Text)
+import Data.Time (UTCTime, addUTCTime, diffUTCTime, getCurrentTime, nominalDiffTimeToSeconds)
+import Simplex.Messaging.Agent.Client
+import Simplex.Messaging.Agent.Env.SQLite
+import Simplex.Messaging.Agent.Protocol (AgentErrorType (..), BrokerErrorType (..), ConnId, NotificationsMode (..))
+import qualified Simplex.Messaging.Agent.Protocol as AP
+import Simplex.Messaging.Agent.RetryInterval
+import Simplex.Messaging.Agent.Store
+import Simplex.Messaging.Agent.Store.SQLite
+import Simplex.Messaging.Client.Agent ()
+import qualified Simplex.Messaging.Crypto as C
+import Simplex.Messaging.Notifications.Protocol (NtfSubStatus (..), NtfTknStatus (..), SMPQueueNtf (..))
+import Simplex.Messaging.Notifications.Types
+import Simplex.Messaging.Protocol
+import Simplex.Messaging.TMap (TMap)
+import qualified Simplex.Messaging.TMap as TM
+import Simplex.Messaging.Util (tshow, unlessM)
+import System.Random (randomR)
+import UnliftIO (async)
+import UnliftIO.Concurrent (forkIO, threadDelay)
+import qualified UnliftIO.Exception as E
+import UnliftIO.STM
+
+runNtfSupervisor :: forall m. (MonadUnliftIO m, MonadReader Env m) => AgentClient -> m ()
+runNtfSupervisor c = do
+  ns <- asks ntfSupervisor
+  forever $ do
+    cmd@(connId, _) <- atomically . readTBQueue $ ntfSubQ ns
+    handleError connId . agentOperationBracket c AONtfNetwork waitUntilActive $
+      runExceptT (processNtfSub c cmd) >>= \case
+        Left e -> notifyErr connId e
+        Right _ -> return ()
+  where
+    handleError :: ConnId -> m () -> m ()
+    handleError connId = E.handle $ \(e :: E.SomeException) -> do
+      logError $ "runNtfSupervisor error " <> tshow e
+      notifyErr connId e
+    notifyErr connId e = notifyInternalError c connId $ "runNtfSupervisor error " <> show e
+
+processNtfSub :: forall m. AgentMonad m => AgentClient -> (ConnId, NtfSupervisorCommand) -> m ()
+processNtfSub c (connId, cmd) = do
+  logInfo $ "processNtfSub - connId = " <> tshow connId <> " - cmd = " <> tshow cmd
+  case cmd of
+    NSCCreate -> do
+      (a, RcvQueue {server = smpServer, clientNtfCreds}) <- withStore c $ \db -> runExceptT $ do
+        a <- liftIO $ getNtfSubscription db connId
+        q <- ExceptT $ getPrimaryRcvQueue db connId
+        pure (a, q)
+      logInfo $ "processNtfSub, NSCCreate - a = " <> tshow a
+      case a of
+        Nothing -> do
+          withNtfServer c $ \ntfServer -> do
+            case clientNtfCreds of
+              Just ClientNtfCreds {notifierId} -> do
+                let newSub = newNtfSubscription connId smpServer (Just notifierId) ntfServer NASKey
+                withStore' c $ \db -> createNtfSubscription db newSub $ NtfSubNTFAction NSACreate
+                addNtfNTFWorker ntfServer
+              Nothing -> do
+                let newSub = newNtfSubscription connId smpServer Nothing ntfServer NASNew
+                withStore' c $ \db -> createNtfSubscription db newSub $ NtfSubSMPAction NSASmpKey
+                addNtfSMPWorker smpServer
+        (Just (sub@NtfSubscription {ntfSubStatus, ntfServer = subNtfServer, smpServer = smpServer', ntfQueueId}, action_)) -> do
+          case (clientNtfCreds, ntfQueueId) of
+            (Just ClientNtfCreds {notifierId}, Just ntfQueueId')
+              | sameSrvAddr smpServer smpServer' && notifierId == ntfQueueId' -> create
+              | otherwise -> rotate
+            (Nothing, Nothing) -> create
+            _ -> rotate
+          where
+            create :: m ()
+            create = case action_ of
+              -- action was set to NULL after worker internal error
+              Nothing -> resetSubscription
+              Just (action, _)
+                -- subscription was marked for deletion / is being deleted
+                | isDeleteNtfSubAction action -> do
+                  if ntfSubStatus == NASNew || ntfSubStatus == NASOff || ntfSubStatus == NASDeleted
+                    then resetSubscription
+                    else withNtfServer c $ \ntfServer -> do
+                      withStore' c $ \db -> supervisorUpdateNtfSub db sub {ntfServer} (NtfSubNTFAction NSACreate)
+                      addNtfNTFWorker ntfServer
+                | otherwise -> case action of
+                  NtfSubNTFAction _ -> addNtfNTFWorker subNtfServer
+                  NtfSubSMPAction _ -> addNtfSMPWorker smpServer
+            rotate :: m ()
+            rotate = do
+              withStore' c $ \db -> supervisorUpdateNtfSub db sub (NtfSubNTFAction NSARotate)
+              addNtfNTFWorker subNtfServer
+            resetSubscription :: m ()
+            resetSubscription =
+              withNtfServer c $ \ntfServer -> do
+                let sub' = sub {ntfQueueId = Nothing, ntfServer, ntfSubId = Nothing, ntfSubStatus = NASNew}
+                withStore' c $ \db -> supervisorUpdateNtfSub db sub' (NtfSubSMPAction NSASmpKey)
+                addNtfSMPWorker smpServer
+    NSCDelete -> do
+      sub_ <- withStore' c $ \db -> do
+        supervisorUpdateNtfAction db connId (NtfSubNTFAction NSADelete)
+        getNtfSubscription db connId
+      logInfo $ "processNtfSub, NSCDelete - sub_ = " <> tshow sub_
+      case sub_ of
+        (Just (NtfSubscription {ntfServer}, _)) -> addNtfNTFWorker ntfServer
+        _ -> pure () -- err "NSCDelete - no subscription"
+    NSCSmpDelete -> do
+      withStore' c (`getPrimaryRcvQueue` connId) >>= \case
+        Right rq@RcvQueue {server = smpServer} -> do
+          logInfo $ "processNtfSub, NSCSmpDelete - rq = " <> tshow rq
+          withStore' c $ \db -> supervisorUpdateNtfAction db connId (NtfSubSMPAction NSASmpDelete)
+          addNtfSMPWorker smpServer
+        _ -> notifyInternalError c connId "NSCSmpDelete - no rcv queue"
+    NSCNtfWorker ntfServer -> addNtfNTFWorker ntfServer
+    NSCNtfSMPWorker smpServer -> addNtfSMPWorker smpServer
+  where
+    addNtfNTFWorker = addWorker ntfWorkers runNtfWorker
+    addNtfSMPWorker = addWorker ntfSMPWorkers runNtfSMPWorker
+    addWorker ::
+      (NtfSupervisor -> TMap (ProtocolServer s) (TMVar (), Async ())) ->
+      (AgentClient -> ProtocolServer s -> TMVar () -> m ()) ->
+      ProtocolServer s ->
+      m ()
+    addWorker wsSel runWorker srv = do
+      ws <- asks $ wsSel . ntfSupervisor
+      atomically (TM.lookup srv ws) >>= \case
+        Nothing -> do
+          doWork <- newTMVarIO ()
+          worker <- async $ runWorker c srv doWork `E.finally` atomically (TM.delete srv ws)
+          atomically $ TM.insert srv (doWork, worker) ws
+        Just (doWork, _) ->
+          void . atomically $ tryPutTMVar doWork ()
+
+withNtfServer :: AgentMonad m => AgentClient -> (NtfServer -> m ()) -> m ()
+withNtfServer c action = getNtfServer c >>= mapM_ action
+
+runNtfWorker :: forall m. AgentMonad m => AgentClient -> NtfServer -> TMVar () -> m ()
+runNtfWorker c srv doWork = do
+  delay <- asks $ ntfWorkerDelay . config
+  forever $ do
+    void . atomically $ readTMVar doWork
+    agentOperationBracket c AONtfNetwork throwWhenInactive runNtfOperation
+    threadDelay delay
+  where
+    runNtfOperation :: m ()
+    runNtfOperation = do
+      nextSub_ <- withStore' c (`getNextNtfSubNTFAction` srv)
+      logInfo $ "runNtfWorker, nextSub_ " <> tshow nextSub_
+      case nextSub_ of
+        Nothing -> noWorkToDo
+        Just a@(NtfSubscription {connId}, _, _) -> do
+          ri <- asks $ reconnectInterval . config
+          withRetryInterval ri $ \loop ->
+            processAction a
+              `catchError` retryOnError c "NtfWorker" loop (workerInternalError c connId . show)
+    noWorkToDo = void . atomically $ tryTakeTMVar doWork
+    processAction :: (NtfSubscription, NtfSubNTFAction, NtfActionTs) -> m ()
+    processAction (sub@NtfSubscription {connId, smpServer, ntfSubId}, action, actionTs) = do
+      ts <- liftIO getCurrentTime
+      unlessM (rescheduleAction doWork ts actionTs) $
+        case action of
+          NSACreate ->
+            getNtfToken >>= \case
+              Just tkn@NtfToken {ntfTokenId = Just tknId, ntfTknStatus = NTActive, ntfMode = NMInstant} -> do
+                RcvQueue {clientNtfCreds} <- withStore c (`getPrimaryRcvQueue` connId)
+                case clientNtfCreds of
+                  Just ClientNtfCreds {ntfPrivateKey, notifierId} -> do
+                    nSubId <- agentNtfCreateSubscription c tknId tkn (SMPQueueNtf smpServer notifierId) ntfPrivateKey
+                    -- possible improvement: smaller retry until Active, less frequently (daily?) once Active
+                    let actionTs' = addUTCTime 30 ts
+                    withStore' c $ \db ->
+                      updateNtfSubscription db sub {ntfSubId = Just nSubId, ntfSubStatus = NASCreated NSNew} (NtfSubNTFAction NSACheck) actionTs'
+                  _ -> workerInternalError c connId "NSACreate - no notifier queue credentials"
+              _ -> workerInternalError c connId "NSACreate - no active token"
+          NSACheck ->
+            getNtfToken >>= \case
+              Just tkn ->
+                case ntfSubId of
+                  Just nSubId ->
+                    agentNtfCheckSubscription c nSubId tkn >>= \case
+                      NSAuth -> do
+                        getNtfServer c >>= \case
+                          Just ntfServer -> do
+                            withStore' c $ \db ->
+                              updateNtfSubscription db sub {ntfServer, ntfQueueId = Nothing, ntfSubId = Nothing, ntfSubStatus = NASNew} (NtfSubSMPAction NSASmpKey) ts
+                            ns <- asks ntfSupervisor
+                            atomically $ writeTBQueue (ntfSubQ ns) (connId, NSCNtfSMPWorker smpServer)
+                          _ -> workerInternalError c connId "NSACheck - failed to reset subscription, notification server not configured"
+                      status -> updateSubNextCheck ts status
+                  Nothing -> workerInternalError c connId "NSACheck - no subscription ID"
+              _ -> workerInternalError c connId "NSACheck - no active token"
+          NSADelete -> case ntfSubId of
+            Just nSubId ->
+              (getNtfToken >>= mapM_ (agentNtfDeleteSubscription c nSubId))
+                `E.finally` continueDeletion
+            _ -> continueDeletion
+            where
+              continueDeletion = do
+                let sub' = sub {ntfSubId = Nothing, ntfSubStatus = NASOff}
+                withStore' c $ \db -> updateNtfSubscription db sub' (NtfSubSMPAction NSASmpDelete) ts
+                ns <- asks ntfSupervisor
+                atomically $ writeTBQueue (ntfSubQ ns) (connId, NSCNtfSMPWorker smpServer)
+          NSARotate -> case ntfSubId of
+            Just nSubId ->
+              (getNtfToken >>= mapM_ (agentNtfDeleteSubscription c nSubId))
+                `E.finally` deleteCreate
+            _ -> deleteCreate
+            where
+              deleteCreate = do
+                withStore' c $ \db -> deleteNtfSubscription db connId
+                ns <- asks ntfSupervisor
+                atomically $ writeTBQueue (ntfSubQ ns) (connId, NSCCreate)
+      where
+        updateSubNextCheck ts toStatus = do
+          checkInterval <- asks $ ntfSubCheckInterval . config
+          let nextCheckTs = addUTCTime checkInterval ts
+          updateSub (NASCreated toStatus) (NtfSubNTFAction NSACheck) nextCheckTs
+        updateSub toStatus toAction actionTs' =
+          withStore' c $ \db ->
+            updateNtfSubscription db sub {ntfSubStatus = toStatus} toAction actionTs'
+
+runNtfSMPWorker :: forall m. AgentMonad m => AgentClient -> SMPServer -> TMVar () -> m ()
+runNtfSMPWorker c srv doWork = do
+  delay <- asks $ ntfSMPWorkerDelay . config
+  forever $ do
+    void . atomically $ readTMVar doWork
+    agentOperationBracket c AONtfNetwork throwWhenInactive runNtfSMPOperation
+    threadDelay delay
+  where
+    runNtfSMPOperation = do
+      nextSub_ <- withStore' c (`getNextNtfSubSMPAction` srv)
+      logInfo $ "runNtfSMPWorker, nextSub_ " <> tshow nextSub_
+      case nextSub_ of
+        Nothing -> noWorkToDo
+        Just a@(NtfSubscription {connId}, _, _) -> do
+          ri <- asks $ reconnectInterval . config
+          withRetryInterval ri $ \loop ->
+            processAction a
+              `catchError` retryOnError c "NtfSMPWorker" loop (workerInternalError c connId . show)
+    noWorkToDo = void . atomically $ tryTakeTMVar doWork
+    processAction :: (NtfSubscription, NtfSubSMPAction, NtfActionTs) -> m ()
+    processAction (sub@NtfSubscription {connId, ntfServer}, smpAction, actionTs) = do
+      ts <- liftIO getCurrentTime
+      unlessM (rescheduleAction doWork ts actionTs) $
+        case smpAction of
+          NSASmpKey ->
+            getNtfToken >>= \case
+              Just NtfToken {ntfTknStatus = NTActive, ntfMode = NMInstant} -> do
+                rq <- withStore c (`getPrimaryRcvQueue` connId)
+                C.SignAlg a <- asks (cmdSignAlg . config)
+                (ntfPublicKey, ntfPrivateKey) <- liftIO $ C.generateSignatureKeyPair a
+                (rcvNtfPubDhKey, rcvNtfPrivDhKey) <- liftIO C.generateKeyPair'
+                (notifierId, rcvNtfSrvPubDhKey) <- enableQueueNotifications c rq ntfPublicKey rcvNtfPubDhKey
+                let rcvNtfDhSecret = C.dh' rcvNtfSrvPubDhKey rcvNtfPrivDhKey
+                withStore' c $ \db -> do
+                  setRcvQueueNtfCreds db connId $ Just ClientNtfCreds {ntfPublicKey, ntfPrivateKey, notifierId, rcvNtfDhSecret}
+                  updateNtfSubscription db sub {ntfQueueId = Just notifierId, ntfSubStatus = NASKey} (NtfSubNTFAction NSACreate) ts
+                ns <- asks ntfSupervisor
+                atomically $ sendNtfSubCommand ns (connId, NSCNtfWorker ntfServer)
+              _ -> workerInternalError c connId "NSASmpKey - no active token"
+          NSASmpDelete -> do
+            rq_ <- withStore' c $ \db -> do
+              setRcvQueueNtfCreds db connId Nothing
+              getPrimaryRcvQueue db connId
+            mapM_ (disableQueueNotifications c) rq_
+            withStore' c $ \db -> deleteNtfSubscription db connId
+
+rescheduleAction :: AgentMonad m => TMVar () -> UTCTime -> UTCTime -> m Bool
+rescheduleAction doWork ts actionTs
+  | actionTs <= ts = pure False
+  | otherwise = do
+    void . atomically $ tryTakeTMVar doWork
+    void . forkIO $ do
+      threadDelay $ diffInMicros actionTs ts
+      void . atomically $ tryPutTMVar doWork ()
+    pure True
+
+fromPico :: Pico -> Integer
+fromPico (MkFixed i) = i
+
+diffInMicros :: UTCTime -> UTCTime -> Int
+diffInMicros a b = (`div` 1000000) . fromInteger . fromPico . nominalDiffTimeToSeconds $ diffUTCTime a b
+
+retryOnError :: AgentMonad m => AgentClient -> Text -> m () -> (AgentErrorType -> m ()) -> AgentErrorType -> m ()
+retryOnError c name loop done e = do
+  logError $ name <> " error: " <> tshow e
+  case e of
+    BROKER _ NETWORK -> retryLoop
+    BROKER _ TIMEOUT -> retryLoop
+    _ -> done e
+  where
+    retryLoop = do
+      atomically $ endAgentOperation c AONtfNetwork
+      atomically $ throwWhenInactive c
+      atomically $ beginAgentOperation c AONtfNetwork
+      loop
+
+workerInternalError :: AgentMonad m => AgentClient -> ConnId -> String -> m ()
+workerInternalError c connId internalErrStr = do
+  withStore' c $ \db -> setNullNtfSubscriptionAction db connId
+  notifyInternalError c connId internalErrStr
+
+notifyInternalError :: (MonadUnliftIO m) => AgentClient -> ConnId -> String -> m ()
+notifyInternalError AgentClient {subQ} connId internalErrStr = atomically $ writeTBQueue subQ ("", connId, AP.ERR $ AP.INTERNAL internalErrStr)
+
+getNtfToken :: AgentMonad m => m (Maybe NtfToken)
+getNtfToken = do
+  tkn <- asks $ ntfTkn . ntfSupervisor
+  readTVarIO tkn
+
+nsUpdateToken :: NtfSupervisor -> NtfToken -> STM ()
+nsUpdateToken ns tkn = writeTVar (ntfTkn ns) $ Just tkn
+
+nsRemoveNtfToken :: NtfSupervisor -> STM ()
+nsRemoveNtfToken ns = writeTVar (ntfTkn ns) Nothing
+
+sendNtfSubCommand :: NtfSupervisor -> (ConnId, NtfSupervisorCommand) -> STM ()
+sendNtfSubCommand ns cmd = do
+  tkn <- readTVar (ntfTkn ns)
+  when (instantNotifications tkn) $ writeTBQueue (ntfSubQ ns) cmd
+
+instantNotifications :: Maybe NtfToken -> Bool
+instantNotifications = \case
+  Just NtfToken {ntfTknStatus = NTActive, ntfMode = NMInstant} -> True
+  _ -> False
+
+closeNtfSupervisor :: NtfSupervisor -> IO ()
+closeNtfSupervisor ns = do
+  cancelNtfWorkers_ $ ntfWorkers ns
+  cancelNtfWorkers_ $ ntfSMPWorkers ns
+
+cancelNtfWorkers_ :: TMap (ProtocolServer s) (TMVar (), Async ()) -> IO ()
+cancelNtfWorkers_ wsVar = do
+  ws <- atomically $ stateTVar wsVar (,M.empty)
+  mapM_ (uninterruptibleCancel . snd) ws
+
+getNtfServer :: AgentMonad m => AgentClient -> m (Maybe NtfServer)
+getNtfServer c = do
+  ntfServers <- readTVarIO $ ntfServers c
+  case ntfServers of
+    [] -> pure Nothing
+    [srv] -> pure $ Just srv
+    servers -> do
+      gen <- asks randomServer
+      atomically . stateTVar gen $
+        first (Just . (servers !!)) . randomR (0, length servers - 1)
@@ -24,7 +24,16 @@ instance StrEncoding QueryStringParams where
  strP = QSP QEscape . Q.parseSimpleQuery <$> A.takeTill (\c -> c == ' ' || c == '\n')

 queryParam :: StrEncoding a => ByteString -> QueryStringParams -> Parser a
-queryParam name (QSP _ q) =
-  case find ((== name) . fst) q of
-    Just (_, p) -> either fail pure $ parseAll strP p
+queryParam name q =
+  case queryParamStr name q of
+    Just p -> either fail pure $ parseAll strP p
    _ -> fail $ "no qs param " <> B.unpack name
+
+queryParam_ :: StrEncoding a => ByteString -> QueryStringParams -> Parser (Maybe a)
+queryParam_ name q =
+  case queryParamStr name q of
+    Just p -> either fail pure $ parseAll strP p
+    _ -> pure Nothing
+
+queryParamStr :: ByteString -> QueryStringParams -> Maybe ByteString
+queryParamStr name (QSP _ q) = snd <$> find ((== name) . fst) q
@@ -1,10 +1,21 @@
+{-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE ScopedTypeVariables #-}

-module Simplex.Messaging.Agent.RetryInterval where
+module Simplex.Messaging.Agent.RetryInterval
+  ( RetryInterval (..),
+    RetryInterval2 (..),
+    RetryIntervalMode (..),
+    withRetryInterval,
+    withRetryLock2,
+  )
+where

-import Control.Concurrent (threadDelay)
+import Control.Concurrent (forkIO, threadDelay)
+import Control.Monad (void)
 import Control.Monad.IO.Class (MonadIO, liftIO)
+import Simplex.Messaging.Util (whenM)
+import UnliftIO.STM

 data RetryInterval = RetryInterval
  { initialInterval :: Int,
@@ -12,17 +23,51 @@ data RetryInterval = RetryInterval
    maxInterval :: Int
  }

+data RetryInterval2 = RetryInterval2
+  { riSlow :: RetryInterval,
+    riFast :: RetryInterval
+  }
+
+data RetryIntervalMode = RISlow | RIFast
+  deriving (Eq)
+
 withRetryInterval :: forall m. MonadIO m => RetryInterval -> (m () -> m ()) -> m ()
-withRetryInterval RetryInterval {initialInterval, increaseAfter, maxInterval} action =
-  callAction 0 initialInterval
+withRetryInterval ri action = callAction 0 $ initialInterval ri
  where
    callAction :: Int -> Int -> m ()
-    callAction elapsedTime delay = action loop
+    callAction elapsed delay = action loop
      where
        loop = do
-          let newDelay =
-                if elapsedTime < increaseAfter || delay == maxInterval
-                  then delay
-                  else min (delay * 3 `div` 2) maxInterval
          liftIO $ threadDelay delay
-          callAction (elapsedTime + delay) newDelay
+          let elapsed' = elapsed + delay
+          callAction elapsed' $ nextDelay elapsed' delay ri
+
+-- This function allows action to toggle between slow and fast retry intervals.
+withRetryLock2 :: forall m. MonadIO m => RetryInterval2 -> TMVar () -> ((RetryIntervalMode -> m ()) -> m ()) -> m ()
+withRetryLock2 RetryInterval2 {riSlow, riFast} lock action =
+  callAction (0, initialInterval riSlow) (0, initialInterval riFast)
+  where
+    callAction :: (Int, Int) -> (Int, Int) -> m ()
+    callAction slow fast = action loop
+      where
+        loop = \case
+          RISlow -> run slow riSlow (`callAction` fast)
+          RIFast -> run fast riFast (callAction slow)
+        run (elapsed, delay) ri call = do
+          wait delay
+          let elapsed' = elapsed + delay
+          call (elapsed', nextDelay elapsed' delay ri)
+        wait delay = do
+          waiting <- newTVarIO True
+          _ <- liftIO . forkIO $ do
+            threadDelay delay
+            atomically $ whenM (readTVar waiting) $ void $ tryPutTMVar lock ()
+          atomically $ do
+            takeTMVar lock
+            writeTVar waiting False
+
+nextDelay :: Int -> Int -> RetryInterval -> Int
+nextDelay elapsed delay RetryInterval {increaseAfter, maxInterval} =
+  if elapsed < increaseAfter || delay == maxInterval
+    then delay
+    else min (delay * 3 `div` 2) maxInterval
@@ -31,26 +31,26 @@ import UnliftIO.STM
 -- | Runs an SMP agent as a TCP service using passed configuration.
 --
 -- See a full agent executable here: https://github.com/simplex-chat/simplexmq/blob/master/apps/smp-agent/Main.hs
-runSMPAgent :: (MonadRandom m, MonadUnliftIO m) => ATransport -> AgentConfig -> m ()
-runSMPAgent t cfg = do
+runSMPAgent :: (MonadRandom m, MonadUnliftIO m) => ATransport -> AgentConfig -> InitialAgentServers -> m ()
+runSMPAgent t cfg initServers = do
  started <- newEmptyTMVarIO
-  runSMPAgentBlocking t started cfg
+  runSMPAgentBlocking t started cfg initServers

 -- | Runs an SMP agent as a TCP service using passed configuration with signalling.
 --
 -- This function uses passed TMVar to signal when the server is ready to accept TCP requests (True)
 -- and when it is disconnected from the TCP socket once the server thread is killed (False).
-runSMPAgentBlocking :: (MonadRandom m, MonadUnliftIO m) => ATransport -> TMVar Bool -> AgentConfig -> m ()
-runSMPAgentBlocking (ATransport t) started cfg@AgentConfig {tcpPort, caCertificateFile, certificateFile, privateKeyFile} = do
+runSMPAgentBlocking :: (MonadRandom m, MonadUnliftIO m) => ATransport -> TMVar Bool -> AgentConfig -> InitialAgentServers -> m ()
+runSMPAgentBlocking (ATransport t) started cfg@AgentConfig {tcpPort, caCertificateFile, certificateFile, privateKeyFile} initServers = do
  runReaderT (smpAgent t) =<< newSMPAgentEnv cfg
  where
    smpAgent :: forall c m'. (Transport c, MonadUnliftIO m', MonadReader Env m') => TProxy c -> m' ()
    smpAgent _ = do
      -- tlsServerParams is not in Env to avoid breaking functional API w/t key and certificate generation
      tlsServerParams <- liftIO $ loadTLSServerParams caCertificateFile certificateFile privateKeyFile
-      runTransportServer started tcpPort tlsServerParams $ \(h :: c) -> do
+      runTransportServer started tcpPort tlsServerParams True $ \(h :: c) -> do
        liftIO . putLn h $ "Welcome to SMP agent v" <> B.pack simplexMQVersion
-        c <- getAgentClient
+        c <- getAgentClient initServers
        logConnection c True
        race_ (connectClient h c) (runAgentClient c)
          `E.finally` disconnectAgentClient c
@@ -3,83 +3,52 @@
 {-# LANGUAGE DuplicateRecordFields #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE KindSignatures #-}
+{-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE StandaloneDeriving #-}
 {-# OPTIONS_GHC -fno-warn-unticked-promoted-constructors #-}

 module Simplex.Messaging.Agent.Store where

-import Control.Concurrent.STM (TVar)
 import Control.Exception (Exception)
-import Crypto.Random (ChaChaDRG)
+import qualified Data.Attoparsec.ByteString.Char8 as A
 import Data.ByteString.Char8 (ByteString)
 import Data.Int (Int64)
 import Data.Kind (Type)
+import Data.List (find)
+import Data.List.NonEmpty (NonEmpty)
+import qualified Data.List.NonEmpty as L
 import Data.Time (UTCTime)
 import Data.Type.Equality
 import Simplex.Messaging.Agent.Protocol
 import qualified Simplex.Messaging.Crypto as C
-import Simplex.Messaging.Crypto.Ratchet (RatchetX448, SkippedMsgDiff, SkippedMsgKeys)
+import Simplex.Messaging.Crypto.Ratchet (RatchetX448)
+import Simplex.Messaging.Encoding.String
 import Simplex.Messaging.Protocol
  ( MsgBody,
+    MsgFlags,
    MsgId,
+    NotifierId,
+    NtfPrivateSignKey,
+    NtfPublicVerifyKey,
    RcvDhSecret,
+    RcvNtfDhSecret,
    RcvPrivateSignKey,
    SndPrivateSignKey,
  )
 import qualified Simplex.Messaging.Protocol as SMP
-
-- * Store management
-
-- | Store class type. Defines store access methods for implementations.
-class Monad m => MonadAgentStore s m where
-  -- Queue and Connection management
-  createRcvConn :: s -> TVar ChaChaDRG -> ConnData -> RcvQueue -> SConnectionMode c -> m ConnId
-  createSndConn :: s -> TVar ChaChaDRG -> ConnData -> SndQueue -> m ConnId
-  getConn :: s -> ConnId -> m SomeConn
-  getRcvConn :: s -> SMPServer -> SMP.RecipientId -> m SomeConn
-  deleteConn :: s -> ConnId -> m ()
-  upgradeRcvConnToDuplex :: s -> ConnId -> SndQueue -> m ()
-  upgradeSndConnToDuplex :: s -> ConnId -> RcvQueue -> m ()
-  setRcvQueueStatus :: s -> RcvQueue -> QueueStatus -> m ()
-  setRcvQueueConfirmedE2E :: s -> RcvQueue -> C.DhSecretX25519 -> m ()
-  setSndQueueStatus :: s -> SndQueue -> QueueStatus -> m ()
-
-  -- Confirmations
-  createConfirmation :: s -> TVar ChaChaDRG -> NewConfirmation -> m ConfirmationId
-  acceptConfirmation :: s -> ConfirmationId -> ConnInfo -> m AcceptedConfirmation
-  getAcceptedConfirmation :: s -> ConnId -> m AcceptedConfirmation
-  removeConfirmations :: s -> ConnId -> m ()
-
-  -- Invitations - sent via Contact connections
-  createInvitation :: s -> TVar ChaChaDRG -> NewInvitation -> m InvitationId
-  getInvitation :: s -> InvitationId -> m Invitation
-  acceptInvitation :: s -> InvitationId -> ConnInfo -> m ()
-  deleteInvitation :: s -> ConnId -> InvitationId -> m ()
-
-  -- Msg management
-  updateRcvIds :: s -> ConnId -> m (InternalId, InternalRcvId, PrevExternalSndId, PrevRcvMsgHash)
-  createRcvMsg :: s -> ConnId -> RcvMsgData -> m ()
-  updateSndIds :: s -> ConnId -> m (InternalId, InternalSndId, PrevSndMsgHash)
-  createSndMsg :: s -> ConnId -> SndMsgData -> m ()
-  getPendingMsgData :: s -> ConnId -> InternalId -> m (Maybe RcvQueue, (AgentMessageType, MsgBody, InternalTs))
-  getPendingMsgs :: s -> ConnId -> m [InternalId]
-  checkRcvMsg :: s -> ConnId -> InternalId -> m ()
-  deleteMsg :: s -> ConnId -> InternalId -> m ()
-
-  -- Double ratchet persistence
-  createRatchetX3dhKeys :: s -> ConnId -> C.PrivateKeyX448 -> C.PrivateKeyX448 -> m ()
-  getRatchetX3dhKeys :: s -> ConnId -> m (C.PrivateKeyX448, C.PrivateKeyX448)
-  createRatchet :: s -> ConnId -> RatchetX448 -> m ()
-  getRatchet :: s -> ConnId -> m RatchetX448
-  getSkippedMsgKeys :: s -> ConnId -> m SkippedMsgKeys
-  updateRatchet :: s -> ConnId -> RatchetX448 -> SkippedMsgDiff -> m ()
+import Simplex.Messaging.Util ((<$?>))
+import Simplex.Messaging.Version

 -- * Queue types

 -- | A receive queue. SMP queue through which the agent receives messages from a sender.
 data RcvQueue = RcvQueue
-  { server :: SMPServer,
+  { connId :: ConnId,
+    server :: SMPServer,
    -- | recipient queue ID
    rcvId :: SMP.RecipientId,
    -- | key used by the recipient to sign transmissions
@@ -91,15 +60,37 @@ data RcvQueue = RcvQueue
    -- | public sender's DH key and agreed shared DH secret for simple per-queue e2e
    e2eDhSecret :: Maybe C.DhSecretX25519,
    -- | sender queue ID
-    sndId :: Maybe SMP.SenderId,
+    sndId :: SMP.SenderId,
    -- | queue status
-    status :: QueueStatus
+    status :: QueueStatus,
+    -- | database queue ID (within connection), can be Nothing for old queues
+    dbQueueId :: Int64,
+    -- | True for a primary or a next primary queue of the connection (next if dbReplaceQueueId is set)
+    primary :: Bool,
+    -- | database queue ID to replace, Nothing if this queue is not replacing another, `Just Nothing` is used for replacing old queues
+    dbReplaceQueueId :: Maybe Int64,
+    -- | SMP client version
+    smpClientVersion :: Version,
+    -- | credentials used in context of notifications
+    clientNtfCreds :: Maybe ClientNtfCreds
+  }
+  deriving (Eq, Show)
+
+data ClientNtfCreds = ClientNtfCreds
+  { -- | key pair to be used by the notification server to sign transmissions
+    ntfPublicKey :: NtfPublicVerifyKey,
+    ntfPrivateKey :: NtfPrivateSignKey,
+    -- | queue ID to be used by the notification server for NSUB command
+    notifierId :: NotifierId,
+    -- | shared DH secret used to encrypt/decrypt notification metadata (NMsgMeta) from server to recipient
+    rcvNtfDhSecret :: RcvNtfDhSecret
  }
  deriving (Eq, Show)

 -- | A send queue. SMP queue through which the agent sends messages to a recipient.
 data SndQueue = SndQueue
-  { server :: SMPServer,
+  { connId :: ConnId,
+    server :: SMPServer,
    -- | sender queue ID
    sndId :: SMP.SenderId,
    -- | key pair used by the sender to sign transmissions
@@ -110,14 +101,59 @@ data SndQueue = SndQueue
    -- | shared DH secret agreed for simple per-queue e2e encryption
    e2eDhSecret :: C.DhSecretX25519,
    -- | queue status
-    status :: QueueStatus
+    status :: QueueStatus,
+    -- | database queue ID (within connection), can be Nothing for old queues
+    dbQueueId :: Int64,
+    -- | True for a primary or a next primary queue of the connection (next if dbReplaceQueueId is set)
+    primary :: Bool,
+    -- | ID of the queue this one is replacing
+    dbReplaceQueueId :: Maybe Int64,
+    -- | SMP client version
+    smpClientVersion :: Version
  }
  deriving (Eq, Show)

+instance SMPQueue RcvQueue where
+  qServer RcvQueue {server} = server
+  {-# INLINE qServer #-}
+  qAddress RcvQueue {server, rcvId} = (server, rcvId)
+  {-# INLINE qAddress #-}
+  sameQueue addr q = sameQAddress addr (qAddress q)
+  {-# INLINE sameQueue #-}
+
+instance SMPQueue SndQueue where
+  qServer SndQueue {server} = server
+  {-# INLINE qServer #-}
+  qAddress SndQueue {server, sndId} = (server, sndId)
+  {-# INLINE qAddress #-}
+  sameQueue addr q = sameQAddress addr (qAddress q)
+  {-# INLINE sameQueue #-}
+
+findQ :: SMPQueue q => (SMPServer, SMP.QueueId) -> NonEmpty q -> Maybe q
+findQ = find . sameQueue
+{-# INLINE findQ #-}
+
+removeQ :: SMPQueue q => (SMPServer, SMP.QueueId) -> NonEmpty q -> Maybe (q, [q])
+removeQ = removeQP . sameQueue
+{-# INLINE removeQ #-}
+
+removeQP :: (q -> Bool) -> NonEmpty q -> Maybe (q, [q])
+removeQP p qs = case L.break p qs of
+  (_, []) -> Nothing
+  (qs1, q : qs2) -> Just (q, qs1 <> qs2)
+
+sndAddress :: RcvQueue -> (SMPServer, SMP.SenderId)
+sndAddress RcvQueue {server, sndId} = (server, sndId)
+{-# INLINE sndAddress #-}
+
+findRQ :: (SMPServer, SMP.SenderId) -> NonEmpty RcvQueue -> Maybe RcvQueue
+findRQ sAddr = find $ sameQAddress sAddr . sndAddress
+{-# INLINE findRQ #-}
+
 -- * Connection types

 -- | Type of a connection.
-data ConnType = CRcv | CSnd | CDuplex | CContact deriving (Eq, Show)
+data ConnType = CNew | CRcv | CSnd | CDuplex | CContact deriving (Eq, Show)

 -- | Connection of a specific type.
 --
@@ -130,22 +166,33 @@ data ConnType = CRcv | CSnd | CDuplex | CContact deriving (Eq, Show)
 -- - DuplexConnection is a connection that has both receive and send queues set up,
 --   typically created by upgrading a receive or a send connection with a missing queue.
 data Connection (d :: ConnType) where
+  NewConnection :: ConnData -> Connection CNew
  RcvConnection :: ConnData -> RcvQueue -> Connection CRcv
  SndConnection :: ConnData -> SndQueue -> Connection CSnd
-  DuplexConnection :: ConnData -> RcvQueue -> SndQueue -> Connection CDuplex
+  DuplexConnection :: ConnData -> NonEmpty RcvQueue -> NonEmpty SndQueue -> Connection CDuplex
  ContactConnection :: ConnData -> RcvQueue -> Connection CContact

 deriving instance Eq (Connection d)

 deriving instance Show (Connection d)

+connData :: Connection d -> ConnData
+connData = \case
+  NewConnection cData -> cData
+  RcvConnection cData _ -> cData
+  SndConnection cData _ -> cData
+  DuplexConnection cData _ _ -> cData
+  ContactConnection cData _ -> cData
+
 data SConnType :: ConnType -> Type where
+  SCNew :: SConnType CNew
  SCRcv :: SConnType CRcv
  SCSnd :: SConnType CSnd
  SCDuplex :: SConnType CDuplex
  SCContact :: SConnType CContact

 connType :: SConnType c -> ConnType
+connType SCNew = CNew
 connType SCRcv = CRcv
 connType SCSnd = CSnd
 connType SCDuplex = CDuplex
@@ -173,9 +220,127 @@ instance Eq SomeConn where

 deriving instance Show SomeConn

-newtype ConnData = ConnData {connId :: ConnId}
+data ConnData = ConnData
+  { connId :: ConnId,
+    connAgentVersion :: Version,
+    enableNtfs :: Bool,
+    duplexHandshake :: Maybe Bool, -- added in agent protocol v2
+    deleted :: Bool
+  }
  deriving (Eq, Show)

+data AgentCmdType = ACClient | ACInternal
+
+instance StrEncoding AgentCmdType where
+  strEncode = \case
+    ACClient -> "CLIENT"
+    ACInternal -> "INTERNAL"
+  strP =
+    A.takeTill (== ' ') >>= \case
+      "CLIENT" -> pure ACClient
+      "INTERNAL" -> pure ACInternal
+      _ -> fail "bad AgentCmdType"
+
+data AgentCommand
+  = AClientCommand (ACommand 'Client)
+  | AInternalCommand InternalCommand
+
+instance StrEncoding AgentCommand where
+  strEncode = \case
+    AClientCommand cmd -> strEncode (ACClient, Str $ serializeCommand cmd)
+    AInternalCommand cmd -> strEncode (ACInternal, cmd)
+  strP =
+    strP_ >>= \case
+      ACClient -> AClientCommand <$> ((\(ACmd _ cmd) -> checkParty cmd) <$?> dbCommandP)
+      ACInternal -> AInternalCommand <$> strP
+
+data AgentCommandTag
+  = AClientCommandTag (ACommandTag 'Client)
+  | AInternalCommandTag InternalCommandTag
+  deriving (Show)
+
+instance StrEncoding AgentCommandTag where
+  strEncode = \case
+    AClientCommandTag t -> strEncode (ACClient, t)
+    AInternalCommandTag t -> strEncode (ACInternal, t)
+  strP =
+    strP_ >>= \case
+      ACClient -> AClientCommandTag <$> strP
+      ACInternal -> AInternalCommandTag <$> strP
+
+data InternalCommand
+  = ICAck SMP.RecipientId MsgId
+  | ICAckDel SMP.RecipientId MsgId InternalId
+  | ICAllowSecure SMP.RecipientId SMP.SndPublicVerifyKey
+  | ICDuplexSecure SMP.RecipientId SMP.SndPublicVerifyKey
+  | ICDeleteConn
+  | ICQSecure SMP.RecipientId SMP.SndPublicVerifyKey
+  | ICQDelete SMP.RecipientId
+
+data InternalCommandTag
+  = ICAck_
+  | ICAckDel_
+  | ICAllowSecure_
+  | ICDuplexSecure_
+  | ICDeleteConn_
+  | ICQSecure_
+  | ICQDelete_
+  deriving (Show)
+
+instance StrEncoding InternalCommand where
+  strEncode = \case
+    ICAck rId srvMsgId -> strEncode (ICAck_, rId, srvMsgId)
+    ICAckDel rId srvMsgId mId -> strEncode (ICAckDel_, rId, srvMsgId, mId)
+    ICAllowSecure rId sndKey -> strEncode (ICAllowSecure_, rId, sndKey)
+    ICDuplexSecure rId sndKey -> strEncode (ICDuplexSecure_, rId, sndKey)
+    ICDeleteConn -> strEncode ICDeleteConn_
+    ICQSecure rId senderKey -> strEncode (ICQSecure_, rId, senderKey)
+    ICQDelete rId -> strEncode (ICQDelete_, rId)
+  strP =
+    strP >>= \case
+      ICAck_ -> ICAck <$> _strP <*> _strP
+      ICAckDel_ -> ICAckDel <$> _strP <*> _strP <*> _strP
+      ICAllowSecure_ -> ICAllowSecure <$> _strP <*> _strP
+      ICDuplexSecure_ -> ICDuplexSecure <$> _strP <*> _strP
+      ICDeleteConn_ -> pure ICDeleteConn
+      ICQSecure_ -> ICQSecure <$> _strP <*> _strP
+      ICQDelete_ -> ICQDelete <$> _strP
+
+instance StrEncoding InternalCommandTag where
+  strEncode = \case
+    ICAck_ -> "ACK"
+    ICAckDel_ -> "ACK_DEL"
+    ICAllowSecure_ -> "ALLOW_SECURE"
+    ICDuplexSecure_ -> "DUPLEX_SECURE"
+    ICDeleteConn_ -> "DELETE_CONN"
+    ICQSecure_ -> "QSECURE"
+    ICQDelete_ -> "QDELETE"
+  strP =
+    A.takeTill (== ' ') >>= \case
+      "ACK" -> pure ICAck_
+      "ACK_DEL" -> pure ICAckDel_
+      "ALLOW_SECURE" -> pure ICAllowSecure_
+      "DUPLEX_SECURE" -> pure ICDuplexSecure_
+      "DELETE_CONN" -> pure ICDeleteConn_
+      "QSECURE" -> pure ICQSecure_
+      "QDELETE" -> pure ICQDelete_
+      _ -> fail "bad InternalCommandTag"
+
+agentCommandTag :: AgentCommand -> AgentCommandTag
+agentCommandTag = \case
+  AClientCommand cmd -> AClientCommandTag $ aCommandTag cmd
+  AInternalCommand cmd -> AInternalCommandTag $ internalCmdTag cmd
+
+internalCmdTag :: InternalCommand -> InternalCommandTag
+internalCmdTag = \case
+  ICAck {} -> ICAck_
+  ICAckDel {} -> ICAckDel_
+  ICAllowSecure {} -> ICAllowSecure_
+  ICDuplexSecure {} -> ICDuplexSecure_
+  ICDeleteConn -> ICDeleteConn_
+  ICQSecure {} -> ICQSecure_
+  ICQDelete _ -> ICQDelete_
+
 -- * Confirmation types

 data NewConfirmation = NewConfirmation
@@ -220,30 +385,42 @@ type PrevRcvMsgHash = MsgHash
 -- | Corresponds to `last_snd_msg_hash` in `connections` table
 type PrevSndMsgHash = MsgHash

-- * Message data containers - used on Msg creation to reduce number of parameters
+-- * Message data containers

 data RcvMsgData = RcvMsgData
  { msgMeta :: MsgMeta,
    msgType :: AgentMessageType,
+    msgFlags :: MsgFlags,
    msgBody :: MsgBody,
    internalRcvId :: InternalRcvId,
    internalHash :: MsgHash,
    externalPrevSndHash :: MsgHash
  }

+data RcvMsg = RcvMsg
+  { internalId :: InternalId,
+    msgMeta :: MsgMeta,
+    msgBody :: MsgBody,
+    userAck :: Bool
+  }
+
 data SndMsgData = SndMsgData
  { internalId :: InternalId,
    internalSndId :: InternalSndId,
    internalTs :: InternalTs,
    msgType :: AgentMessageType,
+    msgFlags :: MsgFlags,
    msgBody :: MsgBody,
    internalHash :: MsgHash,
    prevMsgHash :: MsgHash
  }

-data PendingMsg = PendingMsg
-  { connId :: ConnId,
-    msgId :: InternalId
+data PendingMsgData = PendingMsgData
+  { msgId :: InternalId,
+    msgType :: AgentMessageType,
+    msgFlags :: MsgFlags,
+    msgBody :: MsgBody,
+    internalTs :: InternalTs
  }
  deriving (Show)

@@ -278,8 +455,14 @@ data MsgBase = MsgBase

 newtype InternalId = InternalId {unId :: Int64} deriving (Eq, Show)

+instance StrEncoding InternalId where
+  strEncode = strEncode . unId
+  strP = InternalId <$> strP
+
 type InternalTs = UTCTime

+type AsyncCmdId = Int64
+
 -- * Store errors

 -- | Agent store error.
@@ -301,6 +484,8 @@ data StoreError
    SEInvitationNotFound
  | -- | Message not found
    SEMsgNotFound
+  | -- | Command not found
+    SECmdNotFound
  | -- | Currently not used. The intention was to pass current expected queue status in methods,
    -- as we always know what it should be at any stage of the protocol,
    -- and in case it does not match use this error.
@@ -309,6 +494,6 @@ data StoreError
    SERatchetNotFound
  | -- | connection does not have associated x3dh keys
    SEX3dhKeysNotFound
-  | -- | Used in `getMsg` that is not implemented/used. TODO remove.
-    SENotImplemented
+  | -- | Used to wrap agent errors inside store operations to avoid race conditions
+    SEAgentError AgentErrorType
  deriving (Eq, Show, Exception)
@@ -1,5 +1,6 @@
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedLists #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE QuasiQuotes #-}
 {-# LANGUAGE ScopedTypeVariables #-}
@@ -15,18 +16,29 @@ module Simplex.Messaging.Agent.Store.SQLite.Migrations
  )
 where

-import Control.Monad (forM_)
-import Data.Function (on)
-import Data.List (intercalate, sortBy)
+import Control.Monad (forM_, when)
+import Data.List (intercalate, sortOn)
+import Data.List.NonEmpty (NonEmpty)
+import qualified Data.Map as M
 import Data.Text (Text)
+import Data.Text.Encoding (decodeLatin1)
 import Data.Time.Clock (getCurrentTime)
 import Database.SQLite.Simple (Connection, Only (..), Query (..))
 import qualified Database.SQLite.Simple as DB
 import Database.SQLite.Simple.QQ (sql)
 import qualified Database.SQLite3 as SQLite3
+import Simplex.Messaging.Agent.Protocol (extraSMPServerHosts)
 import Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220101_initial
 import Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220301_snd_queue_keys
-import Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220320_server_ips
+import Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220322_notifications
+import Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220608_v2
+import Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220625_v2_ntf_mode
+import Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220811_onion_hosts
+import Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220817_connection_ntfs
+import Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220905_commands
+import Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220915_connection_queues
+import Simplex.Messaging.Encoding.String
+import Simplex.Messaging.Transport.Client (TransportHost)

 data Migration = Migration {name :: String, up :: Text}
  deriving (Show)
@@ -35,12 +47,18 @@ schemaMigrations :: [(String, Query)]
 schemaMigrations =
  [ ("20220101_initial", m20220101_initial),
    ("20220301_snd_queue_keys", m20220301_snd_queue_keys),
-    ("20220320_server_ips", m20220320_server_ips)
+    ("20220322_notifications", m20220322_notifications),
+    ("20220607_v2", m20220608_v2),
+    ("m20220625_v2_ntf_mode", m20220625_v2_ntf_mode),
+    ("m20220811_onion_hosts", m20220811_onion_hosts),
+    ("m20220817_connection_ntfs", m20220817_connection_ntfs),
+    ("m20220905_commands", m20220905_commands),
+    ("m20220915_connection_queues", m20220915_connection_queues)
  ]

 -- | The list of migrations in ascending order by date
 app :: [Migration]
-app = sortBy (compare `on` name) $ map migration schemaMigrations
+app = sortOn name $ map migration schemaMigrations
  where
    migration (name, query) = Migration {name = name, up = fromQuery query}

@@ -50,11 +68,16 @@ get conn migrations =
    <$> DB.query_ conn "SELECT name FROM migrations ORDER BY name ASC;"

 run :: Connection -> [Migration] -> IO ()
-run conn ms = DB.withImmediateTransaction conn . forM_ ms $
-  \Migration {name, up} -> insert name >> execSQL up
+run conn ms = forM_ ms $ \Migration {name, up} -> do
+  when (name == "m20220811_onion_hosts") updateServers
+  DB.withImmediateTransaction conn $ insert name >> execSQL up
  where
    insert name = DB.execute conn "INSERT INTO migrations (name, ts) VALUES (?, ?);" . (name,) =<< getCurrentTime
    execSQL = SQLite3.exec $ DB.connectionHandle conn
+    updateServers = forM_ (M.assocs extraSMPServerHosts) $ \(h, h') ->
+      DB.withImmediateTransaction conn $
+        let hs = decodeLatin1 . strEncode $ ([h, h'] :: NonEmpty TransportHost)
+         in DB.execute conn "UPDATE servers SET host = ? WHERE host = ?" (hs, decodeLatin1 $ strEncode h)

 initialize :: Connection -> IO ()
 initialize conn =
@@ -107,8 +107,8 @@ CREATE TABLE snd_messages (
 CREATE TABLE conn_confirmations (
  confirmation_id BLOB NOT NULL PRIMARY KEY,
  conn_id BLOB NOT NULL REFERENCES connections ON DELETE CASCADE,
-  e2e_snd_pub_key BLOB NOT NULL, -- TODO per-queue key. Split?
-  sender_key BLOB NOT NULL, -- TODO per-queue key. Split?
+  e2e_snd_pub_key BLOB NOT NULL,
+  sender_key BLOB NOT NULL,
  ratchet_state BLOB NOT NULL,
  sender_conn_info BLOB NOT NULL,
  accepted INTEGER NOT NULL,
@@ -1,14 +0,0 @@
-{-# LANGUAGE QuasiQuotes #-}
-
-module Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220320_server_ips where
-
-import Database.SQLite.Simple (Query)
-import Database.SQLite.Simple.QQ (sql)
-
-m20220320_server_ips :: Query
-m20220320_server_ips =
-  [sql|
-UPDATE servers SET host = '178.79.168.175' WHERE host = 'smp8.simplex.im';
-UPDATE servers SET host = '178.79.169.107' WHERE host = 'smp9.simplex.im';
-UPDATE servers SET host = '45.33.54.229' WHERE host = 'smp10.simplex.im';
-|]
@@ -0,0 +1,39 @@
+{-# LANGUAGE QuasiQuotes #-}
+
+module Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220322_notifications where
+
+import Database.SQLite.Simple (Query)
+import Database.SQLite.Simple.QQ (sql)
+
+m20220322_notifications :: Query
+m20220322_notifications =
+  [sql|
+CREATE TABLE ntf_servers (
+  ntf_host TEXT NOT NULL,
+  ntf_port TEXT NOT NULL,
+  ntf_key_hash BLOB NOT NULL,
+  created_at TEXT NOT NULL DEFAULT (datetime('now')),
+  updated_at TEXT NOT NULL DEFAULT (datetime('now')),
+  PRIMARY KEY (ntf_host, ntf_port)
+) WITHOUT ROWID;
+
+CREATE TABLE ntf_tokens (
+  provider TEXT NOT NULL, -- apns
+  device_token TEXT NOT NULL, -- ! this field is mislabeled and is actually saved as binary
+  ntf_host TEXT NOT NULL,
+  ntf_port TEXT NOT NULL,
+  tkn_id BLOB, -- token ID assigned by notifications server
+  tkn_pub_key BLOB NOT NULL, -- client's public key to verify token commands (used by server, for repeat registraions)
+  tkn_priv_key BLOB NOT NULL, -- client's private key to sign token commands
+  tkn_pub_dh_key BLOB NOT NULL, -- client's public DH key (for repeat registraions)
+  tkn_priv_dh_key BLOB NOT NULL, -- client's private DH key (for repeat registraions)
+  tkn_dh_secret BLOB, -- DH secret for e2e encryption of notifications
+  tkn_status TEXT NOT NULL,
+  tkn_action BLOB,
+  created_at TEXT NOT NULL DEFAULT (datetime('now')),
+  updated_at TEXT NOT NULL DEFAULT (datetime('now')), -- this is to check token status periodically to know when it was last checked
+  PRIMARY KEY (provider, device_token, ntf_host, ntf_port),
+  FOREIGN KEY (ntf_host, ntf_port) REFERENCES ntf_servers
+    ON DELETE RESTRICT ON UPDATE CASCADE
+) WITHOUT ROWID;
+|]
@@ -0,0 +1,50 @@
+{-# LANGUAGE QuasiQuotes #-}
+
+module Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220608_v2 where
+
+import Database.SQLite.Simple (Query)
+import Database.SQLite.Simple.QQ (sql)
+
+m20220608_v2 :: Query
+m20220608_v2 =
+  [sql|
+ALTER TABLE messages ADD COLUMN msg_flags TEXT NULL;
+
+ALTER TABLE conn_confirmations ADD COLUMN smp_reply_queues BLOB NULL;
+
+ALTER TABLE connections ADD COLUMN duplex_handshake INTEGER NULL DEFAULT 0;
+
+ALTER TABLE rcv_messages ADD COLUMN user_ack INTEGER NULL DEFAULT 0;
+
+ALTER TABLE rcv_queues ADD COLUMN ntf_public_key BLOB;
+
+ALTER TABLE rcv_queues ADD COLUMN ntf_private_key BLOB;
+
+ALTER TABLE rcv_queues ADD COLUMN ntf_id BLOB;
+
+ALTER TABLE rcv_queues ADD COLUMN rcv_ntf_dh_secret BLOB;
+
+CREATE UNIQUE INDEX idx_rcv_queues_ntf ON rcv_queues (host, port, ntf_id);
+
+CREATE TABLE ntf_subscriptions (
+  conn_id BLOB NOT NULL,
+  smp_host TEXT NULL,
+  smp_port TEXT NULL,
+  smp_ntf_id BLOB,
+  ntf_host TEXT NOT NULL,
+  ntf_port TEXT NOT NULL,
+  ntf_sub_id BLOB,
+  ntf_sub_status TEXT NOT NULL, -- see NtfAgentSubStatus
+  ntf_sub_action TEXT, -- if there is an action required on this subscription: NtfSubNTFAction
+  ntf_sub_smp_action TEXT, -- action with SMP server: NtfSubSMPAction; only one of this and ntf_sub_action can (should) be not null in same record
+  ntf_sub_action_ts TEXT, -- the earliest time for the action, e.g. checks can be scheduled every X hours
+  updated_by_supervisor INTEGER NOT NULL DEFAULT 0, -- to be checked on updates by workers to not overwrite supervisor command (state still should be updated)
+  created_at TEXT NOT NULL DEFAULT (datetime('now')),
+  updated_at TEXT NOT NULL DEFAULT (datetime('now')),
+  PRIMARY KEY (conn_id),
+  FOREIGN KEY (smp_host, smp_port) REFERENCES servers (host, port)
+    ON DELETE SET NULL ON UPDATE CASCADE,
+  FOREIGN KEY (ntf_host, ntf_port) REFERENCES ntf_servers
+    ON DELETE RESTRICT ON UPDATE CASCADE
+) WITHOUT ROWID;
+|]
@@ -0,0 +1,14 @@
+{-# LANGUAGE QuasiQuotes #-}
+
+module Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220625_v2_ntf_mode where
+
+import Database.SQLite.Simple (Query)
+import Database.SQLite.Simple.QQ (sql)
+
+m20220625_v2_ntf_mode :: Query
+m20220625_v2_ntf_mode =
+  [sql|
+ALTER TABLE ntf_tokens ADD COLUMN ntf_mode TEXT NULL;
+
+DELETE FROM ntf_tokens;
+|]
@@ -0,0 +1,16 @@
+{-# LANGUAGE QuasiQuotes #-}
+
+module Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220811_onion_hosts where
+
+import Database.SQLite.Simple (Query)
+import Database.SQLite.Simple.QQ (sql)
+
+m20220811_onion_hosts :: Query
+m20220811_onion_hosts =
+  [sql|
+ALTER TABLE conn_confirmations ADD COLUMN smp_client_version INTEGER;
+
+UPDATE ntf_servers
+SET ntf_host = 'ntf2.simplex.im,ntg7jdjy2i3qbib3sykiho3enekwiaqg3icctliqhtqcg6jmoh6cxiad.onion'
+WHERE ntf_host = 'ntf2.simplex.im';
+|]
@@ -0,0 +1,12 @@
+{-# LANGUAGE QuasiQuotes #-}
+
+module Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220817_connection_ntfs where
+
+import Database.SQLite.Simple (Query)
+import Database.SQLite.Simple.QQ (sql)
+
+m20220817_connection_ntfs :: Query
+m20220817_connection_ntfs =
+  [sql|
+ALTER TABLE connections ADD COLUMN enable_ntfs INTEGER;
+|]
@@ -0,0 +1,23 @@
+{-# LANGUAGE QuasiQuotes #-}
+
+module Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220905_commands where
+
+import Database.SQLite.Simple (Query)
+import Database.SQLite.Simple.QQ (sql)
+
+m20220905_commands :: Query
+m20220905_commands =
+  [sql|
+CREATE TABLE commands (
+  command_id INTEGER PRIMARY KEY,
+  conn_id BLOB NOT NULL REFERENCES connections ON DELETE CASCADE,
+  host TEXT,
+  port TEXT,
+  corr_id BLOB NOT NULL,
+  command_tag BLOB NOT NULL,
+  command BLOB NOT NULL,
+  agent_version INTEGER NOT NULL DEFAULT 1,
+  FOREIGN KEY (host, port) REFERENCES servers
+    ON DELETE RESTRICT ON UPDATE CASCADE
+);
+|]
@@ -0,0 +1,52 @@
+{-# LANGUAGE QuasiQuotes #-}
+
+module Simplex.Messaging.Agent.Store.SQLite.Migrations.M20220915_connection_queues where
+
+import Database.SQLite.Simple (Query)
+import Database.SQLite.Simple.QQ (sql)
+
+m20220915_connection_queues :: Query
+m20220915_connection_queues =
+  [sql|
+PRAGMA ignore_check_constraints=ON;
+
+-- rcv_queues
+ALTER TABLE rcv_queues ADD COLUMN rcv_queue_id INTEGER CHECK (rcv_queue_id NOT NULL);
+UPDATE rcv_queues SET rcv_queue_id = 1;
+CREATE UNIQUE INDEX idx_rcv_queue_id ON rcv_queues (conn_id, rcv_queue_id);
+
+ALTER TABLE rcv_queues ADD COLUMN rcv_primary INTEGER CHECK (rcv_primary NOT NULL);
+UPDATE rcv_queues SET rcv_primary = 1;
+
+ALTER TABLE rcv_queues ADD COLUMN replace_rcv_queue_id INTEGER NULL;
+
+-- snd_queues
+ALTER TABLE snd_queues ADD COLUMN snd_queue_id INTEGER CHECK (snd_queue_id NOT NULL);
+UPDATE snd_queues SET snd_queue_id = 1;
+CREATE UNIQUE INDEX idx_snd_queue_id ON snd_queues (conn_id, snd_queue_id);
+
+ALTER TABLE snd_queues ADD COLUMN snd_primary INTEGER CHECK (snd_primary NOT NULL);
+UPDATE snd_queues SET snd_primary = 1;
+
+ALTER TABLE snd_queues ADD COLUMN replace_snd_queue_id INTEGER NULL;
+
+-- connections
+ALTER TABLE connections ADD COLUMN deleted INTEGER DEFAULT 0 CHECK (deleted NOT NULL);
+UPDATE connections SET deleted = 0;
+
+-- messages
+CREATE TABLE snd_message_deliveries (
+  snd_message_delivery_id INTEGER PRIMARY KEY AUTOINCREMENT,
+  conn_id BLOB NOT NULL REFERENCES connections ON DELETE CASCADE,
+  snd_queue_id INTEGER NOT NULL,
+  internal_id INTEGER NOT NULL,
+  FOREIGN KEY (conn_id, internal_id) REFERENCES messages ON DELETE CASCADE DEFERRABLE INITIALLY DEFERRED
+);
+
+CREATE INDEX idx_snd_message_deliveries ON snd_message_deliveries (conn_id, snd_queue_id);
+
+ALTER TABLE rcv_messages ADD COLUMN rcv_queue_id INTEGER CHECK (rcv_queue_id NOT NULL);
+UPDATE rcv_messages SET rcv_queue_id = 1;
+
+PRAGMA ignore_check_constraints=OFF;
+|]
@@ -0,0 +1,230 @@
+CREATE TABLE migrations(
+  name TEXT NOT NULL,
+  ts TEXT NOT NULL,
+  PRIMARY KEY(name)
+);
+CREATE TABLE servers(
+  host TEXT NOT NULL,
+  port TEXT NOT NULL,
+  key_hash BLOB NOT NULL,
+  PRIMARY KEY(host, port)
+) WITHOUT ROWID;
+CREATE TABLE connections(
+  conn_id BLOB NOT NULL PRIMARY KEY,
+  conn_mode TEXT NOT NULL,
+  last_internal_msg_id INTEGER NOT NULL DEFAULT 0,
+  last_internal_rcv_msg_id INTEGER NOT NULL DEFAULT 0,
+  last_internal_snd_msg_id INTEGER NOT NULL DEFAULT 0,
+  last_external_snd_msg_id INTEGER NOT NULL DEFAULT 0,
+  last_rcv_msg_hash BLOB NOT NULL DEFAULT x'',
+  last_snd_msg_hash BLOB NOT NULL DEFAULT x'',
+  smp_agent_version INTEGER NOT NULL DEFAULT 1
+  ,
+  duplex_handshake INTEGER NULL DEFAULT 0,
+  enable_ntfs INTEGER,
+  deleted INTEGER DEFAULT 0 CHECK(deleted NOT NULL)
+) WITHOUT ROWID;
+CREATE TABLE rcv_queues(
+  host TEXT NOT NULL,
+  port TEXT NOT NULL,
+  rcv_id BLOB NOT NULL,
+  conn_id BLOB NOT NULL REFERENCES connections ON DELETE CASCADE,
+  rcv_private_key BLOB NOT NULL,
+  rcv_dh_secret BLOB NOT NULL,
+  e2e_priv_key BLOB NOT NULL,
+  e2e_dh_secret BLOB,
+  snd_id BLOB NOT NULL,
+  snd_key BLOB,
+  status TEXT NOT NULL,
+  smp_server_version INTEGER NOT NULL DEFAULT 1,
+  smp_client_version INTEGER,
+  ntf_public_key BLOB,
+  ntf_private_key BLOB,
+  ntf_id BLOB,
+  rcv_ntf_dh_secret BLOB,
+  rcv_queue_id INTEGER CHECK(rcv_queue_id NOT NULL),
+  rcv_primary INTEGER CHECK(rcv_primary NOT NULL),
+  replace_rcv_queue_id INTEGER NULL,
+  PRIMARY KEY(host, port, rcv_id),
+  FOREIGN KEY(host, port) REFERENCES servers
+  ON DELETE RESTRICT ON UPDATE CASCADE,
+  UNIQUE(host, port, snd_id)
+) WITHOUT ROWID;
+CREATE TABLE snd_queues(
+  host TEXT NOT NULL,
+  port TEXT NOT NULL,
+  snd_id BLOB NOT NULL,
+  conn_id BLOB NOT NULL REFERENCES connections ON DELETE CASCADE,
+  snd_private_key BLOB NOT NULL,
+  e2e_dh_secret BLOB NOT NULL,
+  status TEXT NOT NULL,
+  smp_server_version INTEGER NOT NULL DEFAULT 1,
+  smp_client_version INTEGER NOT NULL DEFAULT 1,
+  snd_public_key BLOB,
+  e2e_pub_key BLOB,
+  snd_queue_id INTEGER CHECK(snd_queue_id NOT NULL),
+  snd_primary INTEGER CHECK(snd_primary NOT NULL),
+  replace_snd_queue_id INTEGER NULL,
+  PRIMARY KEY(host, port, snd_id),
+  FOREIGN KEY(host, port) REFERENCES servers
+  ON DELETE RESTRICT ON UPDATE CASCADE
+) WITHOUT ROWID;
+CREATE TABLE messages(
+  conn_id BLOB NOT NULL REFERENCES connections(conn_id)
+  ON DELETE CASCADE,
+  internal_id INTEGER NOT NULL,
+  internal_ts TEXT NOT NULL,
+  internal_rcv_id INTEGER,
+  internal_snd_id INTEGER,
+  msg_type BLOB NOT NULL, --(H)ELLO,(R)EPLY,(D)ELETE. Should SMP confirmation be saved too?
+  msg_body BLOB NOT NULL DEFAULT x'',
+  msg_flags TEXT NULL,
+  PRIMARY KEY(conn_id, internal_id),
+  FOREIGN KEY(conn_id, internal_rcv_id) REFERENCES rcv_messages
+  ON DELETE CASCADE DEFERRABLE INITIALLY DEFERRED,
+  FOREIGN KEY(conn_id, internal_snd_id) REFERENCES snd_messages
+  ON DELETE CASCADE DEFERRABLE INITIALLY DEFERRED
+) WITHOUT ROWID;
+CREATE TABLE rcv_messages(
+  conn_id BLOB NOT NULL,
+  internal_rcv_id INTEGER NOT NULL,
+  internal_id INTEGER NOT NULL,
+  external_snd_id INTEGER NOT NULL,
+  broker_id BLOB NOT NULL,
+  broker_ts TEXT NOT NULL,
+  internal_hash BLOB NOT NULL,
+  external_prev_snd_hash BLOB NOT NULL,
+  integrity BLOB NOT NULL,
+  user_ack INTEGER NULL DEFAULT 0,
+  rcv_queue_id INTEGER CHECK(rcv_queue_id NOT NULL),
+  PRIMARY KEY(conn_id, internal_rcv_id),
+  FOREIGN KEY(conn_id, internal_id) REFERENCES messages
+  ON DELETE CASCADE
+) WITHOUT ROWID;
+CREATE TABLE snd_messages(
+  conn_id BLOB NOT NULL,
+  internal_snd_id INTEGER NOT NULL,
+  internal_id INTEGER NOT NULL,
+  internal_hash BLOB NOT NULL,
+  previous_msg_hash BLOB NOT NULL DEFAULT x'',
+  PRIMARY KEY(conn_id, internal_snd_id),
+  FOREIGN KEY(conn_id, internal_id) REFERENCES messages
+  ON DELETE CASCADE
+) WITHOUT ROWID;
+CREATE TABLE conn_confirmations(
+  confirmation_id BLOB NOT NULL PRIMARY KEY,
+  conn_id BLOB NOT NULL REFERENCES connections ON DELETE CASCADE,
+  e2e_snd_pub_key BLOB NOT NULL,
+  sender_key BLOB NOT NULL,
+  ratchet_state BLOB NOT NULL,
+  sender_conn_info BLOB NOT NULL,
+  accepted INTEGER NOT NULL,
+  own_conn_info BLOB,
+  created_at TEXT NOT NULL DEFAULT(datetime('now'))
+  ,
+  smp_reply_queues BLOB NULL,
+  smp_client_version INTEGER
+) WITHOUT ROWID;
+CREATE TABLE conn_invitations(
+  invitation_id BLOB NOT NULL PRIMARY KEY,
+  contact_conn_id BLOB NOT NULL REFERENCES connections ON DELETE CASCADE,
+  cr_invitation BLOB NOT NULL,
+  recipient_conn_info BLOB NOT NULL,
+  accepted INTEGER NOT NULL DEFAULT 0,
+  own_conn_info BLOB,
+  created_at TEXT NOT NULL DEFAULT(datetime('now'))
+) WITHOUT ROWID;
+CREATE TABLE ratchets(
+  conn_id BLOB NOT NULL PRIMARY KEY REFERENCES connections
+  ON DELETE CASCADE,
+  -- x3dh keys are not saved on the sending side(the side accepting the connection)
+  x3dh_priv_key_1 BLOB,
+  x3dh_priv_key_2 BLOB,
+  -- ratchet is initially empty on the receiving side(the side offering the connection)
+  ratchet_state BLOB,
+  e2e_version INTEGER NOT NULL DEFAULT 1
+) WITHOUT ROWID;
+CREATE TABLE skipped_messages(
+  skipped_message_id INTEGER PRIMARY KEY,
+  conn_id BLOB NOT NULL REFERENCES ratchets
+  ON DELETE CASCADE,
+  header_key BLOB NOT NULL,
+  msg_n INTEGER NOT NULL,
+  msg_key BLOB NOT NULL
+);
+CREATE TABLE ntf_servers(
+  ntf_host TEXT NOT NULL,
+  ntf_port TEXT NOT NULL,
+  ntf_key_hash BLOB NOT NULL,
+  created_at TEXT NOT NULL DEFAULT(datetime('now')),
+  updated_at TEXT NOT NULL DEFAULT(datetime('now')),
+  PRIMARY KEY(ntf_host, ntf_port)
+) WITHOUT ROWID;
+CREATE TABLE ntf_tokens(
+  provider TEXT NOT NULL, -- apns
+  device_token TEXT NOT NULL, -- ! this field is mislabeled and is actually saved as binary
+  ntf_host TEXT NOT NULL,
+  ntf_port TEXT NOT NULL,
+  tkn_id BLOB, -- token ID assigned by notifications server
+  tkn_pub_key BLOB NOT NULL, -- client's public key to verify token commands(used by server, for repeat registraions)
+tkn_priv_key BLOB NOT NULL, -- client's private key to sign token commands
+tkn_pub_dh_key BLOB NOT NULL, -- client's public DH key(for repeat registraions)
+tkn_priv_dh_key BLOB NOT NULL, -- client's private DH key(for repeat registraions)
+tkn_dh_secret BLOB, -- DH secret for e2e encryption of notifications
+  tkn_status TEXT NOT NULL,
+  tkn_action BLOB,
+  created_at TEXT NOT NULL DEFAULT(datetime('now')),
+  updated_at TEXT NOT NULL DEFAULT(datetime('now')),
+  ntf_mode TEXT NULL, -- this is to check token status periodically to know when it was last checked
+  PRIMARY KEY(provider, device_token, ntf_host, ntf_port),
+  FOREIGN KEY(ntf_host, ntf_port) REFERENCES ntf_servers
+  ON DELETE RESTRICT ON UPDATE CASCADE
+) WITHOUT ROWID;
+CREATE UNIQUE INDEX idx_rcv_queues_ntf ON rcv_queues(host, port, ntf_id);
+CREATE TABLE ntf_subscriptions(
+  conn_id BLOB NOT NULL,
+  smp_host TEXT NULL,
+  smp_port TEXT NULL,
+  smp_ntf_id BLOB,
+  ntf_host TEXT NOT NULL,
+  ntf_port TEXT NOT NULL,
+  ntf_sub_id BLOB,
+  ntf_sub_status TEXT NOT NULL, -- see NtfAgentSubStatus
+  ntf_sub_action TEXT, -- if there is an action required on this subscription: NtfSubNTFAction
+  ntf_sub_smp_action TEXT, -- action with SMP server: NtfSubSMPAction; only one of this and ntf_sub_action can(should) be not null in same record
+  ntf_sub_action_ts TEXT, -- the earliest time for the action, e.g. checks can be scheduled every X hours
+  updated_by_supervisor INTEGER NOT NULL DEFAULT 0, -- to be checked on updates by workers to not overwrite supervisor command(state still should be updated)
+  created_at TEXT NOT NULL DEFAULT(datetime('now')),
+  updated_at TEXT NOT NULL DEFAULT(datetime('now')),
+  PRIMARY KEY(conn_id),
+  FOREIGN KEY(smp_host, smp_port) REFERENCES servers(host, port)
+  ON DELETE SET NULL ON UPDATE CASCADE,
+  FOREIGN KEY(ntf_host, ntf_port) REFERENCES ntf_servers
+  ON DELETE RESTRICT ON UPDATE CASCADE
+) WITHOUT ROWID;
+CREATE TABLE commands(
+  command_id INTEGER PRIMARY KEY,
+  conn_id BLOB NOT NULL REFERENCES connections ON DELETE CASCADE,
+  host TEXT,
+  port TEXT,
+  corr_id BLOB NOT NULL,
+  command_tag BLOB NOT NULL,
+  command BLOB NOT NULL,
+  agent_version INTEGER NOT NULL DEFAULT 1,
+  FOREIGN KEY(host, port) REFERENCES servers
+  ON DELETE RESTRICT ON UPDATE CASCADE
+);
+CREATE UNIQUE INDEX idx_rcv_queue_id ON rcv_queues(conn_id, rcv_queue_id);
+CREATE UNIQUE INDEX idx_snd_queue_id ON snd_queues(conn_id, snd_queue_id);
+CREATE TABLE snd_message_deliveries(
+  snd_message_delivery_id INTEGER PRIMARY KEY AUTOINCREMENT,
+  conn_id BLOB NOT NULL REFERENCES connections ON DELETE CASCADE,
+  snd_queue_id INTEGER NOT NULL,
+  internal_id INTEGER NOT NULL,
+  FOREIGN KEY(conn_id, internal_id) REFERENCES messages ON DELETE CASCADE DEFERRABLE INITIALLY DEFERRED
+);
+CREATE TABLE sqlite_sequence(name,seq);
+CREATE INDEX idx_snd_message_deliveries ON snd_message_deliveries(
+  conn_id,
+  snd_queue_id
+);
@@ -0,0 +1,48 @@
+{-# LANGUAGE NamedFieldPuns #-}
+
+module Simplex.Messaging.Agent.TRcvQueues where
+
+import Control.Concurrent.STM
+import qualified Data.Map.Strict as M
+import Data.Set (Set)
+import qualified Data.Set as S
+import Simplex.Messaging.Agent.Protocol (ConnId)
+import Simplex.Messaging.Agent.Store (RcvQueue (..))
+import Simplex.Messaging.Protocol (RecipientId, SMPServer)
+import Simplex.Messaging.TMap (TMap)
+import qualified Simplex.Messaging.TMap as TM
+
+newtype TRcvQueues = TRcvQueues (TMap (SMPServer, RecipientId) RcvQueue)
+
+empty :: STM TRcvQueues
+empty = TRcvQueues <$> TM.empty
+
+clear :: TRcvQueues -> STM ()
+clear (TRcvQueues qs) = TM.clear qs
+
+deleteConn :: ConnId -> TRcvQueues -> STM ()
+deleteConn cId (TRcvQueues qs) = modifyTVar' qs $ M.filter (\rq -> cId /= connId rq)
+
+hasConn :: ConnId -> TRcvQueues -> STM Bool
+hasConn cId (TRcvQueues qs) = any (\rq -> cId == connId rq) <$> readTVar qs
+
+getConns :: TRcvQueues -> STM (Set ConnId)
+getConns (TRcvQueues qs) = M.foldr' (S.insert . connId) S.empty <$> readTVar qs
+
+addQueue :: RcvQueue -> TRcvQueues -> STM ()
+addQueue rq@RcvQueue {server, rcvId} (TRcvQueues qs) = TM.insert (server, rcvId) rq qs
+
+deleteQueue :: RcvQueue -> TRcvQueues -> STM ()
+deleteQueue RcvQueue {server, rcvId} (TRcvQueues qs) = TM.delete (server, rcvId) qs
+
+getSrvQueues :: SMPServer -> TRcvQueues -> STM [RcvQueue]
+getSrvQueues srv (TRcvQueues qs) = M.foldl' addQ [] <$> readTVar qs
+  where
+    addQ qs' rq@RcvQueue {server} = if srv == server then rq : qs' else qs'
+
+getDelSrvQueues :: SMPServer -> TRcvQueues -> STM ([RcvQueue], Set ConnId)
+getDelSrvQueues srv (TRcvQueues qs) = stateTVar qs $ M.foldl' addQ (([], S.empty), M.empty)
+  where
+    addQ (removed@(remQs, remConns), qs') rq@RcvQueue {connId, server, rcvId}
+      | srv == server = ((rq : remQs, S.insert connId remConns), qs')
+      | otherwise = (removed, M.insert (server, rcvId) rq qs')
@@ -1,10 +1,13 @@
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE DeriveAnyClass #-}
+{-# LANGUAGE DeriveGeneric #-}
 {-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE GADTs #-}
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE NumericUnderscores #-}
+{-# LANGUAGE OverloadedLists #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE TypeApplications #-}
@@ -23,27 +26,39 @@
 -- See https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md
 module Simplex.Messaging.Client
  ( -- * Connect (disconnect) client to (from) SMP server
+    ProtocolClient (thVersion, sessionId, sessionTs),
    SMPClient,
-    getSMPClient,
-    closeSMPClient,
+    getProtocolClient,
+    closeProtocolClient,
+    clientServer,
+    transportHost',

    -- * SMP protocol command functions
    createSMPQueue,
    subscribeSMPQueue,
+    subscribeSMPQueues,
+    getSMPMessage,
    subscribeSMPQueueNotifications,
    secureSMPQueue,
    enableSMPQueueNotifications,
+    disableSMPQueueNotifications,
+    enableSMPQueuesNtfs,
+    disableSMPQueuesNtfs,
    sendSMPMessage,
    ackSMPMessage,
    suspendSMPQueue,
    deleteSMPQueue,
-    sendSMPCommand,
+    sendProtocolCommand,

    -- * Supporting types and client configuration
-    SMPClientError (..),
-    SMPClientConfig (..),
-    smpDefaultConfig,
-    SMPServerTransmission,
+    ProtocolClientError (..),
+    ProtocolClientConfig (..),
+    NetworkConfig (..),
+    defaultClientConfig,
+    defaultNetworkConfig,
+    transportClientConfig,
+    chooseTransportHost,
+    ServerTransmission,
  )
 where

@@ -52,96 +67,199 @@ import Control.Concurrent.Async
 import Control.Concurrent.STM
 import Control.Exception
 import Control.Monad
-import Control.Monad.Trans.Class
+import Control.Monad.IO.Class (liftIO)
 import Control.Monad.Trans.Except
+import Data.Aeson (FromJSON (..), ToJSON (..))
+import qualified Data.Aeson as J
 import Data.ByteString.Char8 (ByteString)
 import qualified Data.ByteString.Char8 as B
-import Data.Map.Strict (Map)
-import qualified Data.Map.Strict as M
+import Data.Either (rights)
+import Data.Functor (($>))
+import Data.List (find)
+import Data.List.NonEmpty (NonEmpty)
+import qualified Data.List.NonEmpty as L
 import Data.Maybe (fromMaybe)
+import Data.Time.Clock (UTCTime, getCurrentTime)
+import GHC.Generics (Generic)
 import Network.Socket (ServiceName)
 import Numeric.Natural
 import qualified Simplex.Messaging.Crypto as C
-import Simplex.Messaging.Protocol
-import Simplex.Messaging.Transport (ATransport (..), THandle (..), TLS, TProxy, Transport (..), TransportError, clientHandshake)
-import Simplex.Messaging.Transport.Client (runTransportClient)
+import Simplex.Messaging.Encoding.String
+import Simplex.Messaging.Parsers (dropPrefix, enumJSON)
+import Simplex.Messaging.Protocol as SMP
+import Simplex.Messaging.TMap (TMap)
+import qualified Simplex.Messaging.TMap as TM
+import Simplex.Messaging.Transport
+import Simplex.Messaging.Transport.Client (SocksProxy, TransportClientConfig (..), TransportHost (..), runTransportClient)
+import Simplex.Messaging.Transport.KeepAlive
 import Simplex.Messaging.Transport.WebSockets (WS)
-import Simplex.Messaging.Util (bshow, liftError, raceAny_)
+import Simplex.Messaging.Util (bshow, raceAny_)
+import Simplex.Messaging.Version
 import System.Timeout (timeout)

 -- | 'SMPClient' is a handle used to send commands to a specific SMP server.
 --
-- The only exported selector is blockSize that is negotiated
-- with the server during the TCP transport handshake.
--
 -- Use 'getSMPClient' to connect to an SMP server and create a client handle.
-data SMPClient = SMPClient
-  { action :: Async (),
-    connected :: TVar Bool,
-    sessionId :: ByteString,
-    smpServer :: SMPServer,
+data ProtocolClient msg = ProtocolClient
+  { action :: Maybe (Async ()),
+    sessionId :: SessionId,
+    sessionTs :: UTCTime,
+    thVersion :: Version,
+    client_ :: PClient msg
+  }
+
+data PClient msg = PClient
+  { connected :: TVar Bool,
+    protocolServer :: ProtoServer msg,
+    transportHost :: TransportHost,
    tcpTimeout :: Int,
    clientCorrId :: TVar Natural,
-    sentCommands :: TVar (Map CorrId Request),
-    sndQ :: TBQueue SentRawTransmission,
-    rcvQ :: TBQueue (SignedTransmission BrokerMsg),
-    msgQ :: TBQueue SMPServerTransmission
+    sentCommands :: TMap CorrId (Request msg),
+    sndQ :: TBQueue (NonEmpty SentRawTransmission),
+    rcvQ :: TBQueue (NonEmpty (SignedTransmission msg)),
+    msgQ :: Maybe (TBQueue (ServerTransmission msg))
  }

+type SMPClient = ProtocolClient SMP.BrokerMsg
+
+-- | Type for client command data
+type ClientCommand msg = (Maybe C.APrivateSignKey, QueueId, ProtoCommand msg)
+
 -- | Type synonym for transmission from some SPM server queue.
-type SMPServerTransmission = (SMPServer, RecipientId, BrokerMsg)
+type ServerTransmission msg = (ProtoServer msg, Version, SessionId, QueueId, msg)

-- | SMP client configuration.
-data SMPClientConfig = SMPClientConfig
-  { -- | size of TBQueue to use for server commands and responses
-    qSize :: Natural,
-    -- | default SMP server port if port is not specified in SMPServer
-    defaultTransport :: (ServiceName, ATransport),
-    -- | timeout of TCP commands (microseconds)
+data HostMode
+  = -- | prefer (or require) onion hosts when connecting via SOCKS proxy
+    HMOnionViaSocks
+  | -- | prefer (or require) onion hosts
+    HMOnion
+  | -- | prefer (or require) public hosts
+    HMPublic
+  deriving (Eq, Show, Generic)
+
+instance FromJSON HostMode where
+  parseJSON = J.genericParseJSON . enumJSON $ dropPrefix "HM"
+
+instance ToJSON HostMode where
+  toJSON = J.genericToJSON . enumJSON $ dropPrefix "HM"
+  toEncoding = J.genericToEncoding . enumJSON $ dropPrefix "HM"
+
+-- | network configuration for the client
+data NetworkConfig = NetworkConfig
+  { -- | use SOCKS5 proxy
+    socksProxy :: Maybe SocksProxy,
+    -- | determines critera which host is chosen from the list
+    hostMode :: HostMode,
+    -- | if above criteria is not met, if the below setting is True return error, otherwise use the first host
+    requiredHostMode :: Bool,
+    -- | timeout for the initial client TCP/TLS connection (microseconds)
+    tcpConnectTimeout :: Int,
+    -- | timeout of protocol commands (microseconds)
    tcpTimeout :: Int,
+    -- | TCP keep-alive options, Nothing to skip enabling keep-alive
+    tcpKeepAlive :: Maybe KeepAliveOpts,
    -- | period for SMP ping commands (microseconds)
-    smpPing :: Int
+    smpPingInterval :: Int,
+    logTLSErrors :: Bool
  }
+  deriving (Eq, Show, Generic, FromJSON)

-- | Default SMP client configuration.
-smpDefaultConfig :: SMPClientConfig
-smpDefaultConfig =
-  SMPClientConfig
-    { qSize = 64,
-      defaultTransport = ("5223", transport @TLS),
-      tcpTimeout = 4_000_000,
-      smpPing = 30_000_000
+instance ToJSON NetworkConfig where
+  toJSON = J.genericToJSON J.defaultOptions {J.omitNothingFields = True}
+  toEncoding = J.genericToEncoding J.defaultOptions {J.omitNothingFields = True}
+
+defaultNetworkConfig :: NetworkConfig
+defaultNetworkConfig =
+  NetworkConfig
+    { socksProxy = Nothing,
+      hostMode = HMOnionViaSocks,
+      requiredHostMode = False,
+      tcpConnectTimeout = 7_500_000,
+      tcpTimeout = 5_000_000,
+      tcpKeepAlive = Just defaultKeepAliveOpts,
+      smpPingInterval = 600_000_000, -- 10min
+      logTLSErrors = False
    }

-data Request = Request
-  { queueId :: QueueId,
-    responseVar :: TMVar Response
+transportClientConfig :: NetworkConfig -> TransportClientConfig
+transportClientConfig NetworkConfig {socksProxy, tcpKeepAlive, logTLSErrors} =
+  TransportClientConfig {socksProxy, tcpKeepAlive, logTLSErrors}
+
+-- | protocol client configuration.
+data ProtocolClientConfig = ProtocolClientConfig
+  { -- | size of TBQueue to use for server commands and responses
+    qSize :: Natural,
+    -- | default server port if port is not specified in ProtocolServer
+    defaultTransport :: (ServiceName, ATransport),
+    -- | network configuration
+    networkConfig :: NetworkConfig,
+    -- | SMP client-server protocol version range
+    smpServerVRange :: VersionRange
  }

-type Response = Either SMPClientError BrokerMsg
+-- | Default protocol client configuration.
+defaultClientConfig :: ProtocolClientConfig
+defaultClientConfig =
+  ProtocolClientConfig
+    { qSize = 64,
+      defaultTransport = ("443", transport @TLS),
+      networkConfig = defaultNetworkConfig,
+      smpServerVRange = supportedSMPServerVRange
+    }

-- | Connects to 'SMPServer' using passed client configuration
+data Request msg = Request
+  { queueId :: QueueId,
+    responseVar :: TMVar (Response msg)
+  }
+
+type Response msg = Either ProtocolClientError msg
+
+chooseTransportHost :: NetworkConfig -> NonEmpty TransportHost -> Either ProtocolClientError TransportHost
+chooseTransportHost NetworkConfig {socksProxy, hostMode, requiredHostMode} hosts =
+  firstOrError $ case hostMode of
+    HMOnionViaSocks -> maybe publicHost (const onionHost) socksProxy
+    HMOnion -> onionHost
+    HMPublic -> publicHost
+  where
+    firstOrError
+      | requiredHostMode = maybe (Left PCEIncompatibleHost) Right
+      | otherwise = Right . fromMaybe (L.head hosts)
+    isOnionHost = \case THOnionHost _ -> True; _ -> False
+    onionHost = find isOnionHost hosts
+    publicHost = find (not . isOnionHost) hosts
+
+clientServer :: ProtocolTypeI (ProtoType msg) => ProtocolClient msg -> String
+clientServer = B.unpack . strEncode . protocolServer . client_
+
+transportHost' :: ProtocolClient msg -> TransportHost
+transportHost' = transportHost . client_
+
+-- | Connects to 'ProtocolServer' using passed client configuration
 -- and queue for messages and notifications.
 --
 -- A single queue can be used for multiple 'SMPClient' instances,
 -- as 'SMPServerTransmission' includes server information.
-getSMPClient :: SMPServer -> SMPClientConfig -> TBQueue SMPServerTransmission -> IO () -> IO (Either SMPClientError SMPClient)
-getSMPClient smpServer cfg@SMPClientConfig {qSize, tcpTimeout, smpPing} msgQ disconnected =
-  atomically mkSMPClient >>= runClient useTransport
+getProtocolClient :: forall msg. Protocol msg => ProtoServer msg -> ProtocolClientConfig -> Maybe (TBQueue (ServerTransmission msg)) -> (ProtocolClient msg -> IO ()) -> IO (Either ProtocolClientError (ProtocolClient msg))
+getProtocolClient protocolServer cfg@ProtocolClientConfig {qSize, networkConfig, smpServerVRange} msgQ disconnected = do
+  case chooseTransportHost networkConfig (host protocolServer) of
+    Right useHost ->
+      (atomically (mkProtocolClient useHost) >>= runClient useTransport useHost)
+        `catch` \(e :: IOException) -> pure . Left $ PCEIOError e
+    Left e -> pure $ Left e
  where
-    mkSMPClient :: STM SMPClient
-    mkSMPClient = do
+    NetworkConfig {tcpConnectTimeout, tcpTimeout, smpPingInterval} = networkConfig
+    mkProtocolClient :: TransportHost -> STM (PClient msg)
+    mkProtocolClient transportHost = do
      connected <- newTVar False
      clientCorrId <- newTVar 0
-      sentCommands <- newTVar M.empty
+      sentCommands <- TM.empty
      sndQ <- newTBQueue qSize
      rcvQ <- newTBQueue qSize
      return
-        SMPClient
-          { action = undefined,
-            sessionId = undefined,
-            connected,
-            smpServer,
+        PClient
+          { connected,
+            protocolServer,
+            transportHost,
            tcpTimeout,
            clientCorrId,
            sentCommands,
@@ -150,101 +268,108 @@ getSMPClient smpServer cfg@SMPClientConfig {qSize, tcpTimeout, smpPing} msgQ dis
            msgQ
          }

-    runClient :: (ServiceName, ATransport) -> SMPClient -> IO (Either SMPClientError SMPClient)
-    runClient (port', ATransport t) c = do
-      thVar <- newEmptyTMVarIO
+    runClient :: (ServiceName, ATransport) -> TransportHost -> PClient msg -> IO (Either ProtocolClientError (ProtocolClient msg))
+    runClient (port', ATransport t) useHost c = do
+      cVar <- newEmptyTMVarIO
+      let tcConfig = transportClientConfig networkConfig
      action <-
        async $
-          runTransportClient (host smpServer) port' (keyHash smpServer) (client t c thVar)
-            `finally` atomically (putTMVar thVar $ Left SMPNetworkError)
-      th_ <- tcpTimeout `timeout` atomically (takeTMVar thVar)
-      pure $ case th_ of
-        Just (Right THandle {sessionId}) -> Right c {action, sessionId}
+          runTransportClient tcConfig useHost port' (Just $ keyHash protocolServer) (client t c cVar)
+            `finally` atomically (putTMVar cVar $ Left PCENetworkError)
+      c_ <- tcpConnectTimeout `timeout` atomically (takeTMVar cVar)
+      pure $ case c_ of
+        Just (Right c') -> Right c' {action = Just action}
        Just (Left e) -> Left e
-        Nothing -> Left SMPNetworkError
+        Nothing -> Left PCENetworkError

    useTransport :: (ServiceName, ATransport)
-    useTransport = case port smpServer of
+    useTransport = case port protocolServer of
      "" -> defaultTransport cfg
      "80" -> ("80", transport @WS)
      p -> (p, transport @TLS)

-    client :: forall c. Transport c => TProxy c -> SMPClient -> TMVar (Either SMPClientError (THandle c)) -> c -> IO ()
-    client _ c thVar h =
-      runExceptT (clientHandshake h $ keyHash smpServer) >>= \case
-        Left e -> atomically . putTMVar thVar . Left $ SMPTransportError e
-        Right th@THandle {sessionId} -> do
+    client :: forall c. Transport c => TProxy c -> PClient msg -> TMVar (Either ProtocolClientError (ProtocolClient msg)) -> c -> IO ()
+    client _ c cVar h =
+      runExceptT (protocolClientHandshake @msg h (keyHash protocolServer) smpServerVRange) >>= \case
+        Left e -> atomically . putTMVar cVar . Left $ PCETransportError e
+        Right th@THandle {sessionId, thVersion} -> do
+          sessionTs <- getCurrentTime
+          let c' = ProtocolClient {action = Nothing, client_ = c, sessionId, thVersion, sessionTs}
          atomically $ do
            writeTVar (connected c) True
-            putTMVar thVar $ Right th
-          let c' = c {sessionId} :: SMPClient
-          raceAny_ [send c' th, process c', receive c' th, ping c']
-            `finally` disconnected
+            putTMVar cVar $ Right c'
+          raceAny_ ([send c' th, process c', receive c' th] <> [ping c' | smpPingInterval > 0])
+            `finally` disconnected c'

-    send :: Transport c => SMPClient -> THandle c -> IO ()
-    send SMPClient {sndQ} h = forever $ atomically (readTBQueue sndQ) >>= tPut h
+    send :: Transport c => ProtocolClient msg -> THandle c -> IO ()
+    send ProtocolClient {client_ = PClient {sndQ}} h = forever $ atomically (readTBQueue sndQ) >>= tPut h

-    receive :: Transport c => SMPClient -> THandle c -> IO ()
-    receive SMPClient {rcvQ} h = forever $ tGet h >>= atomically . writeTBQueue rcvQ
+    receive :: Transport c => ProtocolClient msg -> THandle c -> IO ()
+    receive ProtocolClient {client_ = PClient {rcvQ}} h = forever $ tGet h >>= atomically . writeTBQueue rcvQ

-    ping :: SMPClient -> IO ()
+    ping :: ProtocolClient msg -> IO ()
    ping c = forever $ do
-      threadDelay smpPing
-      runExceptT $ sendSMPCommand c Nothing "" PING
+      threadDelay smpPingInterval
+      runExceptT $ sendProtocolCommand c Nothing "" protocolPing

-    process :: SMPClient -> IO ()
-    process SMPClient {rcvQ, sentCommands} = forever $ do
-      (_, _, (corrId, qId, respOrErr)) <- atomically $ readTBQueue rcvQ
+    process :: ProtocolClient msg -> IO ()
+    process c = forever $ atomically (readTBQueue $ rcvQ $ client_ c) >>= mapM_ (processMsg c)
+
+    processMsg :: ProtocolClient msg -> SignedTransmission msg -> IO ()
+    processMsg c@ProtocolClient {client_ = PClient {sentCommands}} (_, _, (corrId, qId, respOrErr)) =
      if B.null $ bs corrId
-        then sendMsg qId respOrErr
+        then sendMsg respOrErr
        else do
-          cs <- readTVarIO sentCommands
-          case M.lookup corrId cs of
-            Nothing -> sendMsg qId respOrErr
+          atomically (TM.lookup corrId sentCommands) >>= \case
+            Nothing -> sendMsg respOrErr
            Just Request {queueId, responseVar} -> atomically $ do
-              modifyTVar sentCommands $ M.delete corrId
+              TM.delete corrId sentCommands
              putTMVar responseVar $
                if queueId == qId
                  then case respOrErr of
-                    Left e -> Left $ SMPResponseError e
-                    Right (ERR e) -> Left $ SMPServerError e
-                    Right r -> Right r
-                  else Left SMPUnexpectedResponse
+                    Left e -> Left $ PCEResponseError e
+                    Right r -> case protocolError r of
+                      Just e -> Left $ PCEProtocolError e
+                      _ -> Right r
+                  else Left . PCEUnexpectedResponse $ bshow respOrErr
+      where
+        sendMsg :: Either ErrorType msg -> IO ()
+        sendMsg = \case
+          Right msg -> atomically $ mapM_ (`writeTBQueue` serverTransmission c qId msg) msgQ
+          Left e -> putStrLn $ "SMP client error: " <> show e

-    sendMsg :: QueueId -> Either ErrorType BrokerMsg -> IO ()
-    sendMsg qId = \case
-      Right cmd -> atomically $ writeTBQueue msgQ (smpServer, qId, cmd)
-      -- TODO send everything else to errQ and log in agent
-      _ -> return ()
-
-- | Disconnects SMP client from the server and terminates client threads.
-closeSMPClient :: SMPClient -> IO ()
-closeSMPClient = uninterruptibleCancel . action
+-- | Disconnects client from the server and terminates client threads.
+closeProtocolClient :: ProtocolClient msg -> IO ()
+closeProtocolClient = mapM_ uninterruptibleCancel . action

 -- | SMP client error type.
-data SMPClientError
+data ProtocolClientError
  = -- | Correctly parsed SMP server ERR response.
    -- This error is forwarded to the agent client as `ERR SMP err`.
-    SMPServerError ErrorType
+    PCEProtocolError ErrorType
  | -- | Invalid server response that failed to parse.
    -- Forwarded to the agent client as `ERR BROKER RESPONSE`.
-    SMPResponseError ErrorType
+    PCEResponseError ErrorType
  | -- | Different response from what is expected to a certain SMP command,
    -- e.g. server should respond `IDS` or `ERR` to `NEW` command,
    -- other responses would result in this error.
    -- Forwarded to the agent client as `ERR BROKER UNEXPECTED`.
-    SMPUnexpectedResponse
+    PCEUnexpectedResponse ByteString
  | -- | Used for TCP connection and command response timeouts.
    -- Forwarded to the agent client as `ERR BROKER TIMEOUT`.
-    SMPResponseTimeout
+    PCEResponseTimeout
  | -- | Failure to establish TCP connection.
    -- Forwarded to the agent client as `ERR BROKER NETWORK`.
-    SMPNetworkError
+    PCENetworkError
+  | -- | No host compatible with network configuration
+    PCEIncompatibleHost
  | -- | TCP transport handshake or some other transport error.
    -- Forwarded to the agent client as `ERR BROKER TRANSPORT e`.
-    SMPTransportError TransportError
+    PCETransportError TransportError
  | -- | Error when cryptographically "signing" the command.
-    SMPSignatureError C.CryptoError
+    PCESignatureError C.CryptoError
+  | -- | IO Error
+    PCEIOError IOException
  deriving (Eq, Show, Exception)

 -- | Create a new SMP queue.
@@ -255,115 +380,178 @@ createSMPQueue ::
  RcvPrivateSignKey ->
  RcvPublicVerifyKey ->
  RcvPublicDhKey ->
-  ExceptT SMPClientError IO QueueIdsKeys
-createSMPQueue c rpKey rKey dhKey =
-  sendSMPCommand c (Just rpKey) "" (NEW rKey dhKey) >>= \case
+  Maybe BasicAuth ->
+  ExceptT ProtocolClientError IO QueueIdsKeys
+createSMPQueue c rpKey rKey dhKey auth =
+  sendSMPCommand c (Just rpKey) "" (NEW rKey dhKey auth) >>= \case
    IDS qik -> pure qik
-    _ -> throwE SMPUnexpectedResponse
+    r -> throwE . PCEUnexpectedResponse $ bshow r

 -- | Subscribe to the SMP queue.
 --
 -- https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md#subscribe-to-queue
-subscribeSMPQueue :: SMPClient -> RcvPrivateSignKey -> RecipientId -> ExceptT SMPClientError IO ()
-subscribeSMPQueue c@SMPClient {smpServer, msgQ} rpKey rId =
+subscribeSMPQueue :: SMPClient -> RcvPrivateSignKey -> RecipientId -> ExceptT ProtocolClientError IO ()
+subscribeSMPQueue c rpKey rId =
  sendSMPCommand c (Just rpKey) rId SUB >>= \case
    OK -> return ()
-    cmd@MSG {} ->
-      lift . atomically $ writeTBQueue msgQ (smpServer, rId, cmd)
-    _ -> throwE SMPUnexpectedResponse
+    cmd@MSG {} -> liftIO $ writeSMPMessage c rId cmd
+    r -> throwE . PCEUnexpectedResponse $ bshow r
+
+-- | Subscribe to multiple SMP queues batching commands if supported.
+subscribeSMPQueues :: SMPClient -> NonEmpty (RcvPrivateSignKey, RecipientId) -> IO (NonEmpty (Either ProtocolClientError ()))
+subscribeSMPQueues c qs = sendProtocolCommands c cs >>= mapM response . L.zip qs
+  where
+    cs = L.map (\(rpKey, rId) -> (Just rpKey, rId, Cmd SRecipient SUB)) qs
+    response ((_, rId), r) = case r of
+      Right OK -> pure $ Right ()
+      Right cmd@MSG {} -> writeSMPMessage c rId cmd $> Right ()
+      Right r' -> pure . Left . PCEUnexpectedResponse $ bshow r'
+      Left e -> pure $ Left e
+
+writeSMPMessage :: SMPClient -> RecipientId -> BrokerMsg -> IO ()
+writeSMPMessage c rId msg = atomically $ mapM_ (`writeTBQueue` serverTransmission c rId msg) (msgQ $ client_ c)
+
+serverTransmission :: ProtocolClient msg -> RecipientId -> msg -> ServerTransmission msg
+serverTransmission ProtocolClient {thVersion, sessionId, client_ = PClient {protocolServer}} entityId message =
+  (protocolServer, thVersion, sessionId, entityId, message)
+
+-- | Get message from SMP queue. The server returns ERR PROHIBITED if a client uses SUB and GET via the same transport connection for the same queue
+--
+-- https://github.covm/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md#receive-a-message-from-the-queue
+getSMPMessage :: SMPClient -> RcvPrivateSignKey -> RecipientId -> ExceptT ProtocolClientError IO (Maybe RcvMessage)
+getSMPMessage c rpKey rId =
+  sendSMPCommand c (Just rpKey) rId GET >>= \case
+    OK -> pure Nothing
+    cmd@(MSG msg) -> liftIO (writeSMPMessage c rId cmd) $> Just msg
+    r -> throwE . PCEUnexpectedResponse $ bshow r

 -- | Subscribe to the SMP queue notifications.
 --
 -- https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md#subscribe-to-queue-notifications
-subscribeSMPQueueNotifications :: SMPClient -> NtfPrivateSignKey -> NotifierId -> ExceptT SMPClientError IO ()
+subscribeSMPQueueNotifications :: SMPClient -> NtfPrivateSignKey -> NotifierId -> ExceptT ProtocolClientError IO ()
 subscribeSMPQueueNotifications = okSMPCommand NSUB

 -- | Secure the SMP queue by adding a sender public key.
 --
 -- https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md#secure-queue-command
-secureSMPQueue :: SMPClient -> RcvPrivateSignKey -> RecipientId -> SndPublicVerifyKey -> ExceptT SMPClientError IO ()
+secureSMPQueue :: SMPClient -> RcvPrivateSignKey -> RecipientId -> SndPublicVerifyKey -> ExceptT ProtocolClientError IO ()
 secureSMPQueue c rpKey rId senderKey = okSMPCommand (KEY senderKey) c rpKey rId

 -- | Enable notifications for the queue for push notifications server.
 --
 -- https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md#enable-notifications-command
-enableSMPQueueNotifications :: SMPClient -> RcvPrivateSignKey -> RecipientId -> NtfPublicVerifyKey -> ExceptT SMPClientError IO NotifierId
-enableSMPQueueNotifications c rpKey rId notifierKey =
-  sendSMPCommand c (Just rpKey) rId (NKEY notifierKey) >>= \case
-    NID nId -> pure nId
-    _ -> throwE SMPUnexpectedResponse
+enableSMPQueueNotifications :: SMPClient -> RcvPrivateSignKey -> RecipientId -> NtfPublicVerifyKey -> RcvNtfPublicDhKey -> ExceptT ProtocolClientError IO (NotifierId, RcvNtfPublicDhKey)
+enableSMPQueueNotifications c rpKey rId notifierKey rcvNtfPublicDhKey =
+  sendSMPCommand c (Just rpKey) rId (NKEY notifierKey rcvNtfPublicDhKey) >>= \case
+    NID nId rcvNtfSrvPublicDhKey -> pure (nId, rcvNtfSrvPublicDhKey)
+    r -> throwE . PCEUnexpectedResponse $ bshow r
+
+-- | Enable notifications for the multiple queues for push notifications server.
+enableSMPQueuesNtfs :: SMPClient -> NonEmpty (RcvPrivateSignKey, RecipientId, NtfPublicVerifyKey, RcvNtfPublicDhKey) -> IO (NonEmpty (Either ProtocolClientError (NotifierId, RcvNtfPublicDhKey)))
+enableSMPQueuesNtfs c qs = L.map response <$> sendProtocolCommands c cs
+  where
+    cs = L.map (\(rpKey, rId, notifierKey, rcvNtfPublicDhKey) -> (Just rpKey, rId, Cmd SRecipient $ NKEY notifierKey rcvNtfPublicDhKey)) qs
+    response = \case
+      Right (NID nId rcvNtfSrvPublicDhKey) -> Right (nId, rcvNtfSrvPublicDhKey)
+      Right r -> Left . PCEUnexpectedResponse $ bshow r
+      Left e -> Left e
+
+-- | Disable notifications for the queue for push notifications server.
+--
+-- https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md#disable-notifications-command
+disableSMPQueueNotifications :: SMPClient -> RcvPrivateSignKey -> RecipientId -> ExceptT ProtocolClientError IO ()
+disableSMPQueueNotifications = okSMPCommand NDEL
+
+-- | Disable notifications for multiple queues for push notifications server.
+disableSMPQueuesNtfs :: SMPClient -> NonEmpty (RcvPrivateSignKey, RecipientId) -> IO (NonEmpty (Either ProtocolClientError ()))
+disableSMPQueuesNtfs c qs = L.map response <$> sendProtocolCommands c cs
+  where
+    cs = L.map (\(rpKey, rId) -> (Just rpKey, rId, Cmd SRecipient NDEL)) qs
+    response = \case
+      Right OK -> Right ()
+      Right r -> Left . PCEUnexpectedResponse $ bshow r
+      Left e -> Left e

 -- | Send SMP message.
 --
 -- https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md#send-message
-sendSMPMessage :: SMPClient -> Maybe SndPrivateSignKey -> SenderId -> MsgBody -> ExceptT SMPClientError IO ()
-sendSMPMessage c spKey sId msg =
-  sendSMPCommand c spKey sId (SEND msg) >>= \case
+sendSMPMessage :: SMPClient -> Maybe SndPrivateSignKey -> SenderId -> MsgFlags -> MsgBody -> ExceptT ProtocolClientError IO ()
+sendSMPMessage c spKey sId flags msg =
+  sendSMPCommand c spKey sId (SEND flags msg) >>= \case
    OK -> pure ()
-    _ -> throwE SMPUnexpectedResponse
+    r -> throwE . PCEUnexpectedResponse $ bshow r

 -- | Acknowledge message delivery (server deletes the message).
 --
 -- https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md#acknowledge-message-delivery
-ackSMPMessage :: SMPClient -> RcvPrivateSignKey -> QueueId -> ExceptT SMPClientError IO ()
-ackSMPMessage c@SMPClient {smpServer, msgQ} rpKey rId =
-  sendSMPCommand c (Just rpKey) rId ACK >>= \case
+ackSMPMessage :: SMPClient -> RcvPrivateSignKey -> QueueId -> MsgId -> ExceptT ProtocolClientError IO ()
+ackSMPMessage c rpKey rId msgId =
+  sendSMPCommand c (Just rpKey) rId (ACK msgId) >>= \case
    OK -> return ()
-    cmd@MSG {} ->
-      lift . atomically $ writeTBQueue msgQ (smpServer, rId, cmd)
-    _ -> throwE SMPUnexpectedResponse
+    cmd@MSG {} -> liftIO $ writeSMPMessage c rId cmd
+    r -> throwE . PCEUnexpectedResponse $ bshow r

 -- | Irreversibly suspend SMP queue.
 -- The existing messages from the queue will still be delivered.
 --
 -- https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md#suspend-queue
-suspendSMPQueue :: SMPClient -> RcvPrivateSignKey -> QueueId -> ExceptT SMPClientError IO ()
+suspendSMPQueue :: SMPClient -> RcvPrivateSignKey -> QueueId -> ExceptT ProtocolClientError IO ()
 suspendSMPQueue = okSMPCommand OFF

 -- | Irreversibly delete SMP queue and all messages in it.
 --
 -- https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md#delete-queue
-deleteSMPQueue :: SMPClient -> RcvPrivateSignKey -> QueueId -> ExceptT SMPClientError IO ()
+deleteSMPQueue :: SMPClient -> RcvPrivateSignKey -> QueueId -> ExceptT ProtocolClientError IO ()
 deleteSMPQueue = okSMPCommand DEL

-okSMPCommand :: PartyI p => Command p -> SMPClient -> C.APrivateSignKey -> QueueId -> ExceptT SMPClientError IO ()
+okSMPCommand :: PartyI p => Command p -> SMPClient -> C.APrivateSignKey -> QueueId -> ExceptT ProtocolClientError IO ()
 okSMPCommand cmd c pKey qId =
  sendSMPCommand c (Just pKey) qId cmd >>= \case
    OK -> return ()
-    _ -> throwE SMPUnexpectedResponse
+    r -> throwE . PCEUnexpectedResponse $ bshow r

 -- | Send SMP command
-- TODO sign all requests (SEND of SMP confirmation would be signed with the same key that is passed to the recipient)
-sendSMPCommand :: PartyI p => SMPClient -> Maybe C.APrivateSignKey -> QueueId -> Command p -> ExceptT SMPClientError IO BrokerMsg
-sendSMPCommand SMPClient {sndQ, sentCommands, clientCorrId, sessionId, tcpTimeout} pKey qId cmd = do
-  corrId <- lift_ getNextCorrId
-  t <- signTransmission $ encodeTransmission sessionId (corrId, qId, cmd)
-  ExceptT $ sendRecv corrId t
-  where
-    lift_ :: STM a -> ExceptT SMPClientError IO a
-    lift_ action = ExceptT $ Right <$> atomically action
+sendSMPCommand :: PartyI p => SMPClient -> Maybe C.APrivateSignKey -> QueueId -> Command p -> ExceptT ProtocolClientError IO BrokerMsg
+sendSMPCommand c pKey qId cmd = sendProtocolCommand c pKey qId (Cmd sParty cmd)

+-- | Send multiple commands with batching and collect responses
+sendProtocolCommands :: forall msg. ProtocolEncoding (ProtoCommand msg) => ProtocolClient msg -> NonEmpty (ClientCommand msg) -> IO (NonEmpty (Either ProtocolClientError msg))
+sendProtocolCommands c@ProtocolClient {client_ = PClient {sndQ, tcpTimeout}} cs = do
+  ts <- mapM (runExceptT . mkTransmission c) cs
+  mapM_ (atomically . writeTBQueue sndQ . L.map fst) . L.nonEmpty . rights $ L.toList ts
+  forConcurrently ts $ \case
+    Right (_, r) -> withTimeout . atomically $ takeTMVar r
+    Left e -> pure $ Left e
+  where
+    withTimeout a = fromMaybe (Left PCEResponseTimeout) <$> timeout tcpTimeout a
+
+-- | Send Protocol command
+sendProtocolCommand :: forall msg. ProtocolEncoding (ProtoCommand msg) => ProtocolClient msg -> Maybe C.APrivateSignKey -> QueueId -> ProtoCommand msg -> ExceptT ProtocolClientError IO msg
+sendProtocolCommand c@ProtocolClient {client_ = PClient {sndQ, tcpTimeout}} pKey qId cmd = do
+  (t, r) <- mkTransmission c (pKey, qId, cmd)
+  ExceptT $ sendRecv t r
+  where
+    -- two separate "atomically" needed to avoid blocking
+    sendRecv :: SentRawTransmission -> TMVar (Response msg) -> IO (Response msg)
+    sendRecv t r = atomically (writeTBQueue sndQ [t]) >> withTimeout (atomically $ takeTMVar r)
+      where
+        withTimeout a = fromMaybe (Left PCEResponseTimeout) <$> timeout tcpTimeout a
+
+mkTransmission :: forall msg. ProtocolEncoding (ProtoCommand msg) => ProtocolClient msg -> ClientCommand msg -> ExceptT ProtocolClientError IO (SentRawTransmission, TMVar (Response msg))
+mkTransmission ProtocolClient {sessionId, thVersion, client_ = PClient {clientCorrId, sentCommands}} (pKey, qId, cmd) = do
+  corrId <- liftIO $ atomically getNextCorrId
+  let t = signTransmission $ encodeTransmission thVersion sessionId (corrId, qId, cmd)
+  r <- liftIO . atomically $ mkRequest corrId
+  pure (t, r)
+  where
    getNextCorrId :: STM CorrId
    getNextCorrId = do
      i <- stateTVar clientCorrId $ \i -> (i, i + 1)
      pure . CorrId $ bshow i
-
-    signTransmission :: ByteString -> ExceptT SMPClientError IO SentRawTransmission
-    signTransmission t = case pKey of
-      Nothing -> return (Nothing, t)
-      Just pk -> do
-        sig <- liftError SMPSignatureError $ C.sign pk t
-        return (Just sig, t)
-
-    -- two separate "atomically" needed to avoid blocking
-    sendRecv :: CorrId -> SentRawTransmission -> IO Response
-    sendRecv corrId t = atomically (send corrId t) >>= withTimeout . atomically . takeTMVar
-      where
-        withTimeout a = fromMaybe (Left SMPResponseTimeout) <$> timeout tcpTimeout a
-
-    send :: CorrId -> SentRawTransmission -> STM (TMVar Response)
-    send corrId t = do
+    signTransmission :: ByteString -> SentRawTransmission
+    signTransmission t = ((`C.sign` t) <$> pKey, t)
+    mkRequest :: CorrId -> STM (TMVar (Response msg))
+    mkRequest corrId = do
      r <- newEmptyTMVar
-      modifyTVar sentCommands . M.insert corrId $ Request qId r
-      writeTBQueue sndQ t
-      return r
+      TM.insert corrId (Request qId r) sentCommands
+      pure r
@@ -0,0 +1,304 @@
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE InstanceSigs #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE RankNTypes #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE TypeApplications #-}
+{-# OPTIONS_GHC -fno-warn-orphans #-}
+
+module Simplex.Messaging.Client.Agent where
+
+import Control.Concurrent (forkIO)
+import Control.Concurrent.Async (Async, uninterruptibleCancel)
+import Control.Logger.Simple
+import Control.Monad.Except
+import Control.Monad.IO.Unlift
+import Control.Monad.Trans.Except
+import Data.ByteString.Char8 (ByteString)
+import qualified Data.ByteString.Char8 as B
+import Data.Map.Strict (Map)
+import qualified Data.Map.Strict as M
+import Data.Set (Set)
+import Data.Text.Encoding
+import Numeric.Natural
+import Simplex.Messaging.Agent.RetryInterval
+import Simplex.Messaging.Client
+import qualified Simplex.Messaging.Crypto as C
+import Simplex.Messaging.Encoding.String
+import Simplex.Messaging.Protocol (BrokerMsg, ProtocolServer (..), QueueId, SMPServer)
+import Simplex.Messaging.TMap (TMap)
+import qualified Simplex.Messaging.TMap as TM
+import Simplex.Messaging.Transport
+import Simplex.Messaging.Util (catchAll_, tryE, unlessM, ($>>=))
+import System.Timeout (timeout)
+import UnliftIO (async, forConcurrently_)
+import UnliftIO.Exception (Exception)
+import qualified UnliftIO.Exception as E
+import UnliftIO.STM
+
+type SMPClientVar = TMVar (Either ProtocolClientError SMPClient)
+
+data SMPClientAgentEvent
+  = CAConnected SMPServer
+  | CADisconnected SMPServer (Set SMPSub)
+  | CAReconnected SMPServer
+  | CAResubscribed SMPServer SMPSub
+  | CASubError SMPServer SMPSub ProtocolClientError
+
+data SMPSubParty = SPRecipient | SPNotifier
+  deriving (Eq, Ord, Show)
+
+type SMPSub = (SMPSubParty, QueueId)
+
+-- type SMPServerSub = (SMPServer, SMPSub)
+
+data SMPClientAgentConfig = SMPClientAgentConfig
+  { smpCfg :: ProtocolClientConfig,
+    reconnectInterval :: RetryInterval,
+    msgQSize :: Natural,
+    agentQSize :: Natural
+  }
+
+defaultSMPClientAgentConfig :: SMPClientAgentConfig
+defaultSMPClientAgentConfig =
+  SMPClientAgentConfig
+    { smpCfg = defaultClientConfig {defaultTransport = ("5223", transport @TLS)},
+      reconnectInterval =
+        RetryInterval
+          { initialInterval = second,
+            increaseAfter = 10 * second,
+            maxInterval = 10 * second
+          },
+      msgQSize = 64,
+      agentQSize = 64
+    }
+  where
+    second = 1000000
+
+data SMPClientAgent = SMPClientAgent
+  { agentCfg :: SMPClientAgentConfig,
+    msgQ :: TBQueue (ServerTransmission BrokerMsg),
+    agentQ :: TBQueue SMPClientAgentEvent,
+    smpClients :: TMap SMPServer SMPClientVar,
+    srvSubs :: TMap SMPServer (TMap SMPSub C.APrivateSignKey),
+    pendingSrvSubs :: TMap SMPServer (TMap SMPSub C.APrivateSignKey),
+    reconnections :: TVar [Async ()],
+    asyncClients :: TVar [Async ()]
+  }
+
+newtype InternalException e = InternalException {unInternalException :: e}
+  deriving (Eq, Show)
+
+instance Exception e => Exception (InternalException e)
+
+instance (MonadUnliftIO m, Exception e) => MonadUnliftIO (ExceptT e m) where
+  withRunInIO :: ((forall a. ExceptT e m a -> IO a) -> IO b) -> ExceptT e m b
+  withRunInIO exceptToIO =
+    withExceptT unInternalException . ExceptT . E.try $
+      withRunInIO $ \run ->
+        exceptToIO $ run . (either (E.throwIO . InternalException) return <=< runExceptT)
+
+newSMPClientAgent :: SMPClientAgentConfig -> STM SMPClientAgent
+newSMPClientAgent agentCfg@SMPClientAgentConfig {msgQSize, agentQSize} = do
+  msgQ <- newTBQueue msgQSize
+  agentQ <- newTBQueue agentQSize
+  smpClients <- TM.empty
+  srvSubs <- TM.empty
+  pendingSrvSubs <- TM.empty
+  reconnections <- newTVar []
+  asyncClients <- newTVar []
+  pure SMPClientAgent {agentCfg, msgQ, agentQ, smpClients, srvSubs, pendingSrvSubs, reconnections, asyncClients}
+
+getSMPServerClient' :: SMPClientAgent -> SMPServer -> ExceptT ProtocolClientError IO SMPClient
+getSMPServerClient' ca@SMPClientAgent {agentCfg, smpClients, msgQ} srv =
+  atomically getClientVar >>= either newSMPClient waitForSMPClient
+  where
+    getClientVar :: STM (Either SMPClientVar SMPClientVar)
+    getClientVar = maybe (Left <$> newClientVar) (pure . Right) =<< TM.lookup srv smpClients
+
+    newClientVar :: STM SMPClientVar
+    newClientVar = do
+      smpVar <- newEmptyTMVar
+      TM.insert srv smpVar smpClients
+      pure smpVar
+
+    waitForSMPClient :: SMPClientVar -> ExceptT ProtocolClientError IO SMPClient
+    waitForSMPClient smpVar = do
+      let ProtocolClientConfig {networkConfig = NetworkConfig {tcpConnectTimeout}} = smpCfg agentCfg
+      smpClient_ <- liftIO $ tcpConnectTimeout `timeout` atomically (readTMVar smpVar)
+      liftEither $ case smpClient_ of
+        Just (Right smpClient) -> Right smpClient
+        Just (Left e) -> Left e
+        Nothing -> Left PCEResponseTimeout
+
+    newSMPClient :: SMPClientVar -> ExceptT ProtocolClientError IO SMPClient
+    newSMPClient smpVar = tryConnectClient pure tryConnectAsync
+      where
+        tryConnectClient :: (SMPClient -> ExceptT ProtocolClientError IO a) -> ExceptT ProtocolClientError IO () -> ExceptT ProtocolClientError IO a
+        tryConnectClient successAction retryAction =
+          tryE connectClient >>= \r -> case r of
+            Right smp -> do
+              logInfo . decodeUtf8 $ "Agent connected to " <> showServer srv
+              atomically $ putTMVar smpVar r
+              successAction smp
+            Left e -> do
+              if e == PCENetworkError || e == PCEResponseTimeout
+                then retryAction
+                else atomically $ do
+                  putTMVar smpVar (Left e)
+                  TM.delete srv smpClients
+              throwE e
+        tryConnectAsync :: ExceptT ProtocolClientError IO ()
+        tryConnectAsync = do
+          a <- async connectAsync
+          atomically $ modifyTVar' (asyncClients ca) (a :)
+        connectAsync :: ExceptT ProtocolClientError IO ()
+        connectAsync =
+          withRetryInterval (reconnectInterval agentCfg) $ \loop ->
+            void $ tryConnectClient (const reconnectClient) loop
+
+    connectClient :: ExceptT ProtocolClientError IO SMPClient
+    connectClient = ExceptT $ getProtocolClient srv (smpCfg agentCfg) (Just msgQ) clientDisconnected
+
+    clientDisconnected :: SMPClient -> IO ()
+    clientDisconnected _ = do
+      removeClientAndSubs >>= (`forM_` serverDown)
+      logInfo . decodeUtf8 $ "Agent disconnected from " <> showServer srv
+
+    removeClientAndSubs :: IO (Maybe (Map SMPSub C.APrivateSignKey))
+    removeClientAndSubs = atomically $ do
+      TM.delete srv smpClients
+      TM.lookupDelete srv (srvSubs ca) >>= mapM updateSubs
+      where
+        updateSubs sVar = do
+          ss <- readTVar sVar
+          addPendingSubs sVar ss
+          pure ss
+
+        addPendingSubs sVar ss = do
+          let ps = pendingSrvSubs ca
+          TM.lookup srv ps >>= \case
+            Just v -> TM.union ss v
+            _ -> TM.insert srv sVar ps
+
+    serverDown :: Map SMPSub C.APrivateSignKey -> IO ()
+    serverDown ss = unless (M.null ss) . void . runExceptT $ do
+      notify . CADisconnected srv $ M.keysSet ss
+      reconnectServer
+
+    reconnectServer :: ExceptT ProtocolClientError IO ()
+    reconnectServer = do
+      a <- async tryReconnectClient
+      atomically $ modifyTVar' (reconnections ca) (a :)
+
+    tryReconnectClient :: ExceptT ProtocolClientError IO ()
+    tryReconnectClient = do
+      withRetryInterval (reconnectInterval agentCfg) $ \loop ->
+        reconnectClient `catchE` const loop
+
+    reconnectClient :: ExceptT ProtocolClientError IO ()
+    reconnectClient = do
+      withSMP ca srv $ \smp -> do
+        notify $ CAReconnected srv
+        cs <- atomically $ mapM readTVar =<< TM.lookup srv (pendingSrvSubs ca)
+        forConcurrently_ (maybe [] M.assocs cs) $ \sub@(s, _) ->
+          unlessM (atomically $ hasSub (srvSubs ca) srv s) $
+            subscribe_ smp sub `catchE` handleError s
+      where
+        subscribe_ :: SMPClient -> (SMPSub, C.APrivateSignKey) -> ExceptT ProtocolClientError IO ()
+        subscribe_ smp sub@(s, _) = do
+          smpSubscribe smp sub
+          atomically $ addSubscription ca srv sub
+          notify $ CAResubscribed srv s
+
+        handleError :: SMPSub -> ProtocolClientError -> ExceptT ProtocolClientError IO ()
+        handleError s = \case
+          e@PCEResponseTimeout -> throwE e
+          e@PCENetworkError -> throwE e
+          e -> do
+            notify $ CASubError srv s e
+            atomically $ removePendingSubscription ca srv s
+
+    notify :: SMPClientAgentEvent -> ExceptT ProtocolClientError IO ()
+    notify evt = atomically $ writeTBQueue (agentQ ca) evt
+
+closeSMPClientAgent :: MonadUnliftIO m => SMPClientAgent -> m ()
+closeSMPClientAgent c = liftIO $ do
+  closeSMPServerClients c
+  cancelActions $ reconnections c
+  cancelActions $ asyncClients c
+
+closeSMPServerClients :: SMPClientAgent -> IO ()
+closeSMPServerClients c = readTVarIO (smpClients c) >>= mapM_ (forkIO . closeClient)
+  where
+    closeClient smpVar =
+      atomically (readTMVar smpVar) >>= \case
+        Right smp -> closeProtocolClient smp `catchAll_` pure ()
+        _ -> pure ()
+
+cancelActions :: Foldable f => TVar (f (Async ())) -> IO ()
+cancelActions as = readTVarIO as >>= mapM_ uninterruptibleCancel
+
+withSMP :: SMPClientAgent -> SMPServer -> (SMPClient -> ExceptT ProtocolClientError IO a) -> ExceptT ProtocolClientError IO a
+withSMP ca srv action = (getSMPServerClient' ca srv >>= action) `catchE` logSMPError
+  where
+    logSMPError :: ProtocolClientError -> ExceptT ProtocolClientError IO a
+    logSMPError e = do
+      liftIO $ putStrLn $ "SMP error (" <> show srv <> "): " <> show e
+      throwE e
+
+subscribeQueue :: SMPClientAgent -> SMPServer -> (SMPSub, C.APrivateSignKey) -> ExceptT ProtocolClientError IO ()
+subscribeQueue ca srv sub = do
+  atomically $ addPendingSubscription ca srv sub
+  withSMP ca srv $ \smp -> subscribe_ smp `catchE` handleError
+  where
+    subscribe_ smp = do
+      smpSubscribe smp sub
+      atomically $ addSubscription ca srv sub
+
+    handleError e = do
+      atomically . when (e /= PCENetworkError && e /= PCEResponseTimeout) $
+        removePendingSubscription ca srv $ fst sub
+      throwE e
+
+showServer :: SMPServer -> ByteString
+showServer ProtocolServer {host, port} =
+  strEncode host <> B.pack (if null port then "" else ':' : port)
+
+smpSubscribe :: SMPClient -> (SMPSub, C.APrivateSignKey) -> ExceptT ProtocolClientError IO ()
+smpSubscribe smp ((party, queueId), privKey) = subscribe_ smp privKey queueId
+  where
+    subscribe_ = case party of
+      SPRecipient -> subscribeSMPQueue
+      SPNotifier -> subscribeSMPQueueNotifications
+
+addSubscription :: SMPClientAgent -> SMPServer -> (SMPSub, C.APrivateSignKey) -> STM ()
+addSubscription ca srv sub = do
+  addSub_ (srvSubs ca) srv sub
+  removePendingSubscription ca srv $ fst sub
+
+addPendingSubscription :: SMPClientAgent -> SMPServer -> (SMPSub, C.APrivateSignKey) -> STM ()
+addPendingSubscription = addSub_ . pendingSrvSubs
+
+addSub_ :: TMap SMPServer (TMap SMPSub C.APrivateSignKey) -> SMPServer -> (SMPSub, C.APrivateSignKey) -> STM ()
+addSub_ subs srv (s, key) =
+  TM.lookup srv subs >>= \case
+    Just m -> TM.insert s key m
+    _ -> TM.singleton s key >>= \v -> TM.insert srv v subs
+
+removeSubscription :: SMPClientAgent -> SMPServer -> SMPSub -> STM ()
+removeSubscription = removeSub_ . srvSubs
+
+removePendingSubscription :: SMPClientAgent -> SMPServer -> SMPSub -> STM ()
+removePendingSubscription = removeSub_ . pendingSrvSubs
+
+removeSub_ :: TMap SMPServer (TMap SMPSub C.APrivateSignKey) -> SMPServer -> SMPSub -> STM ()
+removeSub_ subs srv s = TM.lookup srv subs >>= mapM_ (TM.delete s)
+
+getSubKey :: TMap SMPServer (TMap SMPSub C.APrivateSignKey) -> SMPServer -> SMPSub -> STM (Maybe C.APrivateSignKey)
+getSubKey subs srv s = TM.lookup srv subs $>>= TM.lookup s
+
+hasSub :: TMap SMPServer (TMap SMPSub C.APrivateSignKey) -> SMPServer -> SMPSub -> STM Bool
+hasSub subs srv s = maybe (pure False) (TM.member s) =<< TM.lookup srv subs
@@ -8,6 +8,7 @@
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE PatternSynonyms #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE StandaloneDeriving #-}
@@ -52,6 +53,7 @@ module Simplex.Messaging.Crypto
    CryptoPublicKey (..),
    CryptoPrivateKey (..),
    KeyPair,
+    ASignatureKeyPair,
    DhSecret (..),
    DhSecretX25519,
    ADhSecret (..),
@@ -65,7 +67,9 @@ module Simplex.Messaging.Crypto

    -- * key encoding/decoding
    encodePubKey,
+    decodePubKey,
    encodePrivKey,
+    decodePrivKey,
    pubKeyBytes,

    -- * sign/verify
@@ -100,9 +104,14 @@ module Simplex.Messaging.Crypto
    -- * NaCl crypto_box
    CbNonce (unCbNonce),
    cbEncrypt,
+    cbEncryptMaxLenBS,
    cbDecrypt,
    cbNonce,
    randomCbNonce,
+    pseudoRandomCbNonce,
+
+    -- * pseudo-random bytes
+    pseudoRandomBytes,

    -- * SHA256 hash
    sha256Hash,
@@ -113,9 +122,17 @@ module Simplex.Messaging.Crypto

    -- * Cryptography error type
    CryptoError (..),
+
+    -- * Limited size ByteStrings
+    MaxLenBS,
+    pattern MaxLenBS,
+    maxLenBS,
+    unsafeMaxLenBS,
+    appendMaxLenBS,
  )
 where

+import Control.Concurrent.STM
 import Control.Exception (Exception)
 import Control.Monad.Except
 import Control.Monad.Trans.Except
@@ -129,7 +146,7 @@ import qualified Crypto.PubKey.Curve25519 as X25519
 import qualified Crypto.PubKey.Curve448 as X448
 import qualified Crypto.PubKey.Ed25519 as Ed25519
 import qualified Crypto.PubKey.Ed448 as Ed448
-import Crypto.Random (getRandomBytes)
+import Crypto.Random (ChaChaDRG, getRandomBytes, randomBytesGenerate)
 import Data.ASN1.BinaryEncoding
 import Data.ASN1.Encoding
 import Data.ASN1.Types
@@ -147,11 +164,11 @@ import Data.Constraint (Dict (..))
 import Data.Kind (Constraint, Type)
 import Data.String
 import Data.Type.Equality
-import Data.Typeable (Typeable)
+import Data.Typeable (Proxy (Proxy), Typeable)
 import Data.X509
 import Database.SQLite.Simple.FromField (FromField (..))
 import Database.SQLite.Simple.ToField (ToField (..))
-import GHC.TypeLits (ErrorMessage (..), TypeError)
+import GHC.TypeLits (ErrorMessage (..), KnownNat, Nat, TypeError, natVal, type (+))
 import Network.Transport.Internal (decodeWord16, encodeWord16)
 import Simplex.Messaging.Encoding
 import Simplex.Messaging.Encoding.String
@@ -244,6 +261,12 @@ deriving instance Eq (PrivateKey a)

 deriving instance Show (PrivateKey a)

+instance StrEncoding (PrivateKey X25519) where
+  strEncode = strEncode . encodePrivKey
+  {-# INLINE strEncode #-}
+  strDecode = decodePrivKey
+  {-# INLINE strDecode #-}
+
 data APrivateKey
  = forall a.
    AlgorithmI a =>
@@ -284,6 +307,18 @@ instance Eq APrivateSignKey where

 deriving instance Show APrivateSignKey

+instance Encoding APrivateSignKey where
+  smpEncode = smpEncode . encodePrivKey
+  {-# INLINE smpEncode #-}
+  smpDecode = decodePrivKey
+  {-# INLINE smpDecode #-}
+
+instance StrEncoding APrivateSignKey where
+  strEncode = strEncode . encodePrivKey
+  {-# INLINE strEncode #-}
+  strDecode = decodePrivKey
+  {-# INLINE strDecode #-}
+
 data APublicVerifyKey
  = forall a.
    (AlgorithmI a, SignatureAlgorithm a) =>
@@ -658,6 +693,8 @@ data CryptoError
  | -- | message is larger that allowed padded length minus 2 (to prepend message length)
    -- (or required un-padded length is larger than the message length)
    CryptoLargeMsgError
+  | -- | padded message is shorter than 2 bytes
+    CryptoInvalidMsgError
  | -- | failure parsing message header
    CryptoHeaderError String
  | -- | no sending chain key in ratchet state
@@ -666,7 +703,9 @@ data CryptoError
    CERatchetHeader
  | -- | too many skipped messages
    CERatchetTooManySkipped
-  | -- | duplicate message number (or, possibly, skipped message that failed to decrypt?)
+  | -- | earlier message number (or, possibly, skipped message that failed to decrypt?)
+    CERatchetEarlierMessage
+  | -- | duplicate message number
    CERatchetDuplicateMessage
  deriving (Eq, Show, Exception)

@@ -767,9 +806,12 @@ decryptAEAD aesKey ivBytes ad msg (AuthTag authTag) = do
  aead <- initAEAD @AES256 aesKey ivBytes
  liftEither . unPad =<< maybeError AESDecryptError (AES.aeadSimpleDecrypt aead ad msg authTag)

+maxMsgLen :: Int
+maxMsgLen = 2 ^ (16 :: Int) - 3
+
 pad :: ByteString -> Int -> Either CryptoError ByteString
 pad msg paddedLen
-  | padLen >= 0 = Right $ encodeWord16 (fromIntegral len) <> msg <> B.replicate padLen '#'
+  | len <= maxMsgLen && padLen >= 0 = Right $ encodeWord16 (fromIntegral len) <> msg <> B.replicate padLen '#'
  | otherwise = Left CryptoLargeMsgError
  where
    len = B.length msg
@@ -777,12 +819,47 @@ pad msg paddedLen

 unPad :: ByteString -> Either CryptoError ByteString
 unPad padded
-  | B.length rest >= len = Right $ B.take len rest
-  | otherwise = Left CryptoLargeMsgError
+  | B.length lenWrd == 2 && B.length rest >= len = Right $ B.take len rest
+  | otherwise = Left CryptoInvalidMsgError
  where
    (lenWrd, rest) = B.splitAt 2 padded
    len = fromIntegral $ decodeWord16 lenWrd

+newtype MaxLenBS (i :: Nat) = MLBS {unMaxLenBS :: ByteString}
+
+pattern MaxLenBS :: ByteString -> MaxLenBS i
+pattern MaxLenBS s <- MLBS s
+
+{-# COMPLETE MaxLenBS #-}
+
+instance KnownNat i => Encoding (MaxLenBS i) where
+  smpEncode (MLBS s) = smpEncode s
+  smpP = first show . maxLenBS <$?> smpP
+
+instance KnownNat i => StrEncoding (MaxLenBS i) where
+  strEncode (MLBS s) = strEncode s
+  strP = first show . maxLenBS <$?> strP
+
+maxLenBS :: forall i. KnownNat i => ByteString -> Either CryptoError (MaxLenBS i)
+maxLenBS s
+  | B.length s > maxLength @i = Left CryptoLargeMsgError
+  | otherwise = Right $ MLBS s
+
+unsafeMaxLenBS :: forall i. KnownNat i => ByteString -> MaxLenBS i
+unsafeMaxLenBS = MLBS
+
+padMaxLenBS :: forall i. KnownNat i => MaxLenBS i -> MaxLenBS (i + 2)
+padMaxLenBS (MLBS msg) = MLBS $ encodeWord16 (fromIntegral len) <> msg <> B.replicate padLen '#'
+  where
+    len = B.length msg
+    padLen = maxLength @i - len
+
+appendMaxLenBS :: (KnownNat i, KnownNat j) => MaxLenBS i -> MaxLenBS j -> MaxLenBS (i + j)
+appendMaxLenBS (MLBS s1) (MLBS s2) = MLBS $ s1 <> s2
+
+maxLength :: forall i. KnownNat i => Int
+maxLength = fromIntegral (natVal $ Proxy @i)
+
 initAEAD :: forall c. AES.BlockCipher c => Key -> IV -> ExceptT CryptoError IO (AES.AEAD c)
 initAEAD (Key aesKey) (IV ivBytes) = do
  iv <- makeIV @c ivBytes
@@ -813,12 +890,12 @@ cryptoFailable = liftEither . first AESCipherError . CE.eitherCryptoError
 -- | Message signing.
 --
 -- Used by SMP clients to sign SMP commands and by SMP agents to sign messages.
-sign' :: SignatureAlgorithm a => PrivateKey a -> ByteString -> ExceptT CryptoError IO (Signature a)
-sign' (PrivateKeyEd25519 pk k) msg = pure . SignatureEd25519 $ Ed25519.sign pk k msg
-sign' (PrivateKeyEd448 pk k) msg = pure . SignatureEd448 $ Ed448.sign pk k msg
+sign' :: SignatureAlgorithm a => PrivateKey a -> ByteString -> Signature a
+sign' (PrivateKeyEd25519 pk k) msg = SignatureEd25519 $ Ed25519.sign pk k msg
+sign' (PrivateKeyEd448 pk k) msg = SignatureEd448 $ Ed448.sign pk k msg

-sign :: APrivateSignKey -> ByteString -> ExceptT CryptoError IO ASignature
-sign (APrivateSignKey a k) = fmap (ASignature a) . sign' k
+sign :: APrivateSignKey -> ByteString -> ASignature
+sign (APrivateSignKey a k) = ASignature a . sign' k

 -- | Signature verification.
 --
@@ -838,12 +915,17 @@ dh' (PublicKeyX448 k) (PrivateKeyX448 pk _) = DhSecretX448 $ X448.dh k pk

 -- | NaCl @crypto_box@ encrypt with a shared DH secret and 192-bit nonce.
 cbEncrypt :: DhSecret X25519 -> CbNonce -> ByteString -> Int -> Either CryptoError ByteString
-cbEncrypt secret (CbNonce nonce) msg paddedLen = cryptoBox <$> pad msg paddedLen
+cbEncrypt secret (CbNonce nonce) msg paddedLen = cryptoBox secret nonce <$> pad msg paddedLen
+
+-- | NaCl @crypto_box@ encrypt with a shared DH secret and 192-bit nonce.
+cbEncryptMaxLenBS :: KnownNat i => DhSecret X25519 -> CbNonce -> MaxLenBS i -> ByteString
+cbEncryptMaxLenBS secret (CbNonce nonce) = cryptoBox secret nonce . unMaxLenBS . padMaxLenBS
+
+cryptoBox :: DhSecret 'X25519 -> ByteString -> ByteString -> ByteString
+cryptoBox secret nonce s = BA.convert tag <> c
  where
-    cryptoBox s = BA.convert tag <> c
-      where
-        (rs, c) = xSalsa20 secret nonce s
-        tag = Poly1305.auth rs c
+    (rs, c) = xSalsa20 secret nonce s
+    tag = Poly1305.auth rs c

 -- | NaCl @crypto_box@ decrypt with a shared DH secret and 192-bit nonce.
 cbDecrypt :: DhSecret X25519 -> CbNonce -> ByteString -> Either CryptoError ByteString
@@ -857,7 +939,15 @@ cbDecrypt secret (CbNonce nonce) packet
    tag = Poly1305.auth rs c

 newtype CbNonce = CbNonce {unCbNonce :: ByteString}
-  deriving (Show)
+  deriving (Eq, Show)
+
+instance StrEncoding CbNonce where
+  strEncode (CbNonce s) = strEncode s
+  strP = cbNonce <$> strP
+
+instance ToJSON CbNonce where
+  toJSON = strToJSON
+  toEncoding = strToJEncoding

 cbNonce :: ByteString -> CbNonce
 cbNonce s
@@ -870,6 +960,12 @@ cbNonce s
 randomCbNonce :: IO CbNonce
 randomCbNonce = CbNonce <$> getRandomBytes 24

+pseudoRandomCbNonce :: TVar ChaChaDRG -> STM CbNonce
+pseudoRandomCbNonce gVar = CbNonce <$> pseudoRandomBytes 24 gVar
+
+pseudoRandomBytes :: Int -> TVar ChaChaDRG -> STM ByteString
+pseudoRandomBytes n gVar = stateTVar gVar $ randomBytesGenerate n
+
 instance Encoding CbNonce where
  smpEncode = unCbNonce
  smpP = CbNonce <$> A.take 24
@@ -41,11 +41,11 @@ import Simplex.Messaging.Parsers (blobFieldDecoder, parseE, parseE')
 import Simplex.Messaging.Util (tryE)
 import Simplex.Messaging.Version

-e2eEncryptVersion :: Version
-e2eEncryptVersion = 1
+currentE2EEncryptVersion :: Version
+currentE2EEncryptVersion = 2

-e2eEncryptVRange :: VersionRange
-e2eEncryptVRange = mkVersionRange 1 e2eEncryptVersion
+supportedE2EEncryptVRange :: VersionRange
+supportedE2EEncryptVRange = mkVersionRange 1 currentE2EEncryptVersion

 data E2ERatchetParams (a :: Algorithm)
  = E2ERatchetParams Version (PublicKey a) (PublicKey a)
@@ -96,20 +96,27 @@ data RatchetInitParams = RatchetInitParams
  deriving (Eq, Show)

 x3dhSnd :: DhAlgorithm a => PrivateKey a -> PrivateKey a -> E2ERatchetParams a -> RatchetInitParams
-x3dhSnd spk1 spk2 (E2ERatchetParams _ rk1 rk2) =
-  x3dh (publicKey spk1, rk1) (dh' rk1 spk2) (dh' rk2 spk1) (dh' rk2 spk2)
+x3dhSnd spk1 spk2 (E2ERatchetParams v rk1 rk2) =
+  x3dh v (publicKey spk1, rk1) (dh' rk1 spk2) (dh' rk2 spk1) (dh' rk2 spk2)

 x3dhRcv :: DhAlgorithm a => PrivateKey a -> PrivateKey a -> E2ERatchetParams a -> RatchetInitParams
-x3dhRcv rpk1 rpk2 (E2ERatchetParams _ sk1 sk2) =
-  x3dh (sk1, publicKey rpk1) (dh' sk2 rpk1) (dh' sk1 rpk2) (dh' sk2 rpk2)
+x3dhRcv rpk1 rpk2 (E2ERatchetParams v sk1 sk2) =
+  x3dh v (sk1, publicKey rpk1) (dh' sk2 rpk1) (dh' sk1 rpk2) (dh' sk2 rpk2)

-x3dh :: DhAlgorithm a => (PublicKey a, PublicKey a) -> DhSecret a -> DhSecret a -> DhSecret a -> RatchetInitParams
-x3dh (sk1, rk1) dh1 dh2 dh3 =
+x3dh :: DhAlgorithm a => Version -> (PublicKey a, PublicKey a) -> DhSecret a -> DhSecret a -> DhSecret a -> RatchetInitParams
+x3dh v (sk1, rk1) dh1 dh2 dh3 =
  RatchetInitParams {assocData, ratchetKey = RatchetKey sk, sndHK = Key hk, rcvNextHK = Key nhk}
  where
    assocData = Str $ pubKeyBytes sk1 <> pubKeyBytes rk1
-    (hk, rest) = B.splitAt 32 $ dhBytes' dh1 <> dhBytes' dh2 <> dhBytes' dh3
-    (nhk, sk) = B.splitAt 32 rest
+    dhs = dhBytes' dh1 <> dhBytes' dh2 <> dhBytes' dh3
+    (hk, nhk, sk)
+      -- for backwards compatibility with clients using agent version before 3.4.0
+      | v == 1 =
+        let (hk', rest) = B.splitAt 32 dhs
+         in uncurry (hk',,) $ B.splitAt 32 rest
+      | otherwise =
+        let salt = B.replicate 64 '\0'
+         in hkdf3 salt dhs "SimpleXX3DH"

 type RatchetX448 = Ratchet 'X448

@@ -210,12 +217,12 @@ instance FromField MessageKey where fromField = blobFieldDecoder smpDecode
 -- Please note that sPKey is not stored, and its public part together with random salt
 -- is sent to the recipient.
 initSndRatchet ::
-  forall a. (AlgorithmI a, DhAlgorithm a) => PublicKey a -> PrivateKey a -> RatchetInitParams -> Ratchet a
-initSndRatchet rcDHRr rcDHRs RatchetInitParams {assocData, ratchetKey, sndHK, rcvNextHK} = do
+  forall a. (AlgorithmI a, DhAlgorithm a) => VersionRange -> PublicKey a -> PrivateKey a -> RatchetInitParams -> Ratchet a
+initSndRatchet rcVersion rcDHRr rcDHRs RatchetInitParams {assocData, ratchetKey, sndHK, rcvNextHK} = do
  -- state.RK, state.CKs, state.NHKs = KDF_RK_HE(SK, DH(state.DHRs, state.DHRr))
  let (rcRK, rcCKs, rcNHKs) = rootKdf ratchetKey rcDHRr rcDHRs
   in Ratchet
-        { rcVersion = e2eEncryptVRange,
+        { rcVersion,
          rcAD = assocData,
          rcDHRs,
          rcRK,
@@ -233,10 +240,10 @@ initSndRatchet rcDHRr rcDHRs RatchetInitParams {assocData, ratchetKey, sndHK, rc
 -- Please note that the public part of rcDHRs was sent to the sender
 -- as part of the connection request and random salt was received from the sender.
 initRcvRatchet ::
-  forall a. (AlgorithmI a, DhAlgorithm a) => PrivateKey a -> RatchetInitParams -> Ratchet a
-initRcvRatchet rcDHRs RatchetInitParams {assocData, ratchetKey, sndHK, rcvNextHK} =
+  forall a. (AlgorithmI a, DhAlgorithm a) => VersionRange -> PrivateKey a -> RatchetInitParams -> Ratchet a
+initRcvRatchet rcVersion rcDHRs RatchetInitParams {assocData, ratchetKey, sndHK, rcvNextHK} =
  Ratchet
-    { rcVersion = e2eEncryptVRange,
+    { rcVersion,
      rcAD = assocData,
      rcDHRs,
      rcRK = ratchetKey,
@@ -416,7 +423,8 @@ rcDecrypt rc@Ratchet {rcRcv, rcAD = Str rcAD} rcMKSkipped msg' = do
    skipMessageKeys :: Word32 -> Ratchet a -> Either CryptoError (Ratchet a, SkippedMsgKeys)
    skipMessageKeys _ r@Ratchet {rcRcv = Nothing} = Right (r, M.empty)
    skipMessageKeys untilN r@Ratchet {rcRcv = Just rr@RcvRatchet {rcCKr, rcHKr}, rcNr}
-      | rcNr > untilN = Left CERatchetDuplicateMessage
+      | rcNr > untilN + 1 = Left CERatchetEarlierMessage
+      | rcNr == untilN + 1 = Left CERatchetDuplicateMessage
      | rcNr + maxSkip < untilN = Left CERatchetTooManySkipped
      | rcNr == untilN = Right (r, M.empty)
      | otherwise =
@@ -464,7 +472,6 @@ rcDecrypt rc@Ratchet {rcRcv, rcAD = Str rcAD} rcMKSkipped msg' = do
    decryptMessage :: MessageKey -> EncRatchetMessage -> ExceptT CryptoError IO (Either CryptoError ByteString)
    decryptMessage (MessageKey mk iv) EncRatchetMessage {emHeader, emBody, emAuthTag} =
      -- DECRYPT(mk, cipher-text, CONCAT(AD, enc_header))
-      -- TODO add associated data
      tryE $ decryptAEAD mk iv (rcAD <> emHeader) emBody emAuthTag

 rootKdf :: (AlgorithmI a, DhAlgorithm a) => RatchetKey -> PublicKey a -> PrivateKey a -> (RatchetKey, RatchetKey, Key)
@@ -13,6 +13,7 @@ module Simplex.Messaging.Encoding
    Large (..),
    smpEncodeList,
    smpListP,
+    lenEncode,
  )
 where

@@ -47,66 +48,100 @@ class Encoding a where

 instance Encoding Char where
  smpEncode = B.singleton
+  {-# INLINE smpEncode #-}
  smpP = A.anyChar
+  {-# INLINE smpP #-}
+
+instance Encoding Bool where
+  smpEncode = \case
+    True -> "T"
+    False -> "F"
+  {-# INLINE smpEncode #-}
+  smpP =
+    smpP >>= \case
+      'T' -> pure True
+      'F' -> pure False
+      _ -> fail "invalid Bool"
+  {-# INLINE smpP #-}

 instance Encoding Word16 where
  smpEncode = encodeWord16
+  {-# INLINE smpEncode #-}
  smpP = decodeWord16 <$> A.take 2
+  {-# INLINE smpP #-}

 instance Encoding Word32 where
  smpEncode = encodeWord32
+  {-# INLINE smpEncode #-}
  smpP = decodeWord32 <$> A.take 4
+  {-# INLINE smpP #-}

 instance Encoding Int64 where
  smpEncode i = w32 (i `shiftR` 32) <> w32 i
+  {-# INLINE smpEncode #-}
  smpP = do
    l <- w32P
    r <- w32P
    pure $ (l `shiftL` 32) .|. r
+  {-# INLINE smpP #-}

 w32 :: Int64 -> ByteString
 w32 = smpEncode @Word32 . fromIntegral
+{-# INLINE w32 #-}

 w32P :: Parser Int64
 w32P = fromIntegral <$> smpP @Word32
+{-# INLINE w32P #-}

 -- ByteStrings are assumed no longer than 255 bytes
 instance Encoding ByteString where
  smpEncode s = B.cons (lenEncode $ B.length s) s
+  {-# INLINE smpEncode #-}
  smpP = A.take =<< lenP
+  {-# INLINE smpP #-}

 lenEncode :: Int -> Char
 lenEncode = w2c . fromIntegral
+{-# INLINE lenEncode #-}

 lenP :: Parser Int
 lenP = fromIntegral . c2w <$> A.anyChar
+{-# INLINE lenP #-}

 instance Encoding a => Encoding (Maybe a) where
  smpEncode s = maybe "0" (("1" <>) . smpEncode) s
+  {-# INLINE smpEncode #-}
  smpP =
    smpP >>= \case
      '0' -> pure Nothing
      '1' -> Just <$> smpP
      _ -> fail "invalid Maybe tag"
+  {-# INLINE smpP #-}

 newtype Tail = Tail {unTail :: ByteString}

 instance Encoding Tail where
  smpEncode = unTail
+  {-# INLINE smpEncode #-}
  smpP = Tail <$> A.takeByteString
+  {-# INLINE smpP #-}

 -- newtype for encoding/decoding ByteStrings over 255 bytes with 2-bytes length prefix
 newtype Large = Large {unLarge :: ByteString}

 instance Encoding Large where
  smpEncode (Large s) = smpEncode @Word16 (fromIntegral $ B.length s) <> s
+  {-# INLINE smpEncode #-}
  smpP = do
    len <- fromIntegral <$> smpP @Word16
    Large <$> A.take len
+  {-# INLINE smpP #-}

 instance Encoding SystemTime where
  smpEncode = smpEncode . systemSeconds
+  {-# INLINE smpEncode #-}
  smpP = MkSystemTime <$> smpP <*> pure 0
+  {-# INLINE smpP #-}

 -- lists encode/parse as a sequence of items prefixed with list length (as 1 byte)
 smpEncodeList :: Encoding a => [a] -> ByteString
@@ -117,7 +152,9 @@ smpListP = (`A.count` smpP) =<< lenP

 instance Encoding String where
  smpEncode = smpEncode . B.pack
+  {-# INLINE smpEncode #-}
  smpP = B.unpack <$> smpP
+  {-# INLINE smpP #-}

 instance Encoding a => Encoding (L.NonEmpty a) where
  smpEncode = smpEncodeList . L.toList
@@ -128,16 +165,42 @@ instance Encoding a => Encoding (L.NonEmpty a) where

 instance (Encoding a, Encoding b) => Encoding (a, b) where
  smpEncode (a, b) = smpEncode a <> smpEncode b
+  {-# INLINE smpEncode #-}
  smpP = (,) <$> smpP <*> smpP
+  {-# INLINE smpP #-}

 instance (Encoding a, Encoding b, Encoding c) => Encoding (a, b, c) where
  smpEncode (a, b, c) = smpEncode a <> smpEncode b <> smpEncode c
+  {-# INLINE smpEncode #-}
  smpP = (,,) <$> smpP <*> smpP <*> smpP
+  {-# INLINE smpP #-}

 instance (Encoding a, Encoding b, Encoding c, Encoding d) => Encoding (a, b, c, d) where
  smpEncode (a, b, c, d) = smpEncode a <> smpEncode b <> smpEncode c <> smpEncode d
+  {-# INLINE smpEncode #-}
  smpP = (,,,) <$> smpP <*> smpP <*> smpP <*> smpP
+  {-# INLINE smpP #-}

 instance (Encoding a, Encoding b, Encoding c, Encoding d, Encoding e) => Encoding (a, b, c, d, e) where
  smpEncode (a, b, c, d, e) = smpEncode a <> smpEncode b <> smpEncode c <> smpEncode d <> smpEncode e
+  {-# INLINE smpEncode #-}
  smpP = (,,,,) <$> smpP <*> smpP <*> smpP <*> smpP <*> smpP
+  {-# INLINE smpP #-}
+
+instance (Encoding a, Encoding b, Encoding c, Encoding d, Encoding e, Encoding f) => Encoding (a, b, c, d, e, f) where
+  smpEncode (a, b, c, d, e, f) = smpEncode a <> smpEncode b <> smpEncode c <> smpEncode d <> smpEncode e <> smpEncode f
+  {-# INLINE smpEncode #-}
+  smpP = (,,,,,) <$> smpP <*> smpP <*> smpP <*> smpP <*> smpP <*> smpP
+  {-# INLINE smpP #-}
+
+instance (Encoding a, Encoding b, Encoding c, Encoding d, Encoding e, Encoding f, Encoding g) => Encoding (a, b, c, d, e, f, g) where
+  smpEncode (a, b, c, d, e, f, g) = smpEncode a <> smpEncode b <> smpEncode c <> smpEncode d <> smpEncode e <> smpEncode f <> smpEncode g
+  {-# INLINE smpEncode #-}
+  smpP = (,,,,,,) <$> smpP <*> smpP <*> smpP <*> smpP <*> smpP <*> smpP <*> smpP
+  {-# INLINE smpP #-}
+
+instance (Encoding a, Encoding b, Encoding c, Encoding d, Encoding e, Encoding f, Encoding g, Encoding h) => Encoding (a, b, c, d, e, f, g, h) where
+  smpEncode (a, b, c, d, e, f, g, h) = smpEncode a <> smpEncode b <> smpEncode c <> smpEncode d <> smpEncode e <> smpEncode f <> smpEncode g <> smpEncode h
+  {-# INLINE smpEncode #-}
+  smpP = (,,,,,,,) <$> smpP <*> smpP <*> smpP <*> smpP <*> smpP <*> smpP <*> smpP <*> smpP
+  {-# INLINE smpP #-}
@@ -2,9 +2,11 @@
 {-# LANGUAGE OverloadedStrings #-}

 module Simplex.Messaging.Encoding.String
-  ( StrEncoding (..),
+  ( TextEncoding (..),
+    StrEncoding (..),
    Str (..),
    strP_,
+    _strP,
    strToJSON,
    strToJEncoding,
    strParseJSON,
@@ -25,12 +27,24 @@ import qualified Data.ByteString.Base64.URL as U
 import Data.ByteString.Char8 (ByteString)
 import qualified Data.ByteString.Char8 as B
 import Data.Char (isAlphaNum)
+import Data.Int (Int64)
 import qualified Data.List.NonEmpty as L
+import Data.Set (Set)
+import qualified Data.Set as S
+import Data.Text (Text)
 import Data.Text.Encoding (decodeLatin1, encodeUtf8)
+import Data.Time.Clock (UTCTime)
+import Data.Time.Clock.System (SystemTime (..))
+import Data.Time.Format.ISO8601
 import Data.Word (Word16)
+import Simplex.Messaging.Encoding
 import Simplex.Messaging.Parsers (parseAll)
 import Simplex.Messaging.Util ((<$?>))

+class TextEncoding a where
+  textEncode :: a -> Text
+  textDecode :: Text -> Maybe a
+
 -- | Serializing human-readable and (where possible) URI-friendly strings for SMP and SMP agent protocols
 class StrEncoding a where
  {-# MINIMAL strEncode, (strDecode | strP) #-}
@@ -70,11 +84,47 @@ instance FromJSON Str where

 instance StrEncoding a => StrEncoding (Maybe a) where
  strEncode = maybe "" strEncode
+  {-# INLINE strEncode #-}
  strP = optional strP
+  {-# INLINE strP #-}

 instance StrEncoding Word16 where
  strEncode = B.pack . show
+  {-# INLINE strEncode #-}
  strP = A.decimal
+  {-# INLINE strP #-}
+
+instance StrEncoding Char where
+  strEncode = smpEncode
+  {-# INLINE strEncode #-}
+  strP = smpP
+  {-# INLINE strP #-}
+
+instance StrEncoding Bool where
+  strEncode = smpEncode
+  {-# INLINE strEncode #-}
+  strP = smpP
+  {-# INLINE strP #-}
+
+instance StrEncoding Int where
+  strEncode = B.pack . show
+  {-# INLINE strEncode #-}
+  strP = A.decimal
+  {-# INLINE strP #-}
+
+instance StrEncoding Int64 where
+  strEncode = B.pack . show
+  {-# INLINE strEncode #-}
+  strP = A.decimal
+  {-# INLINE strP #-}
+
+instance StrEncoding SystemTime where
+  strEncode = strEncode . systemSeconds
+  strP = MkSystemTime <$> strP <*> pure 0
+
+instance StrEncoding UTCTime where
+  strEncode = B.pack . iso8601Show
+  strP = maybe (Left "bad UTCTime") Right . iso8601ParseM . B.unpack <$?> A.takeTill (\c -> c == ' ' || c == '\n')

 -- lists encode/parse as comma-separated strings
 strEncodeList :: StrEncoding a => [a] -> ByteString
@@ -88,28 +138,43 @@ instance StrEncoding a => StrEncoding (L.NonEmpty a) where
  strEncode = strEncodeList . L.toList
  strP = L.fromList <$> listItem `A.sepBy1'` A.char ','

+instance (StrEncoding a, Ord a) => StrEncoding (Set a) where
+  strEncode = strEncodeList . S.toList
+  strP = S.fromList <$> listItem `A.sepBy'` A.char ','
+
 listItem :: StrEncoding a => Parser a
-listItem = parseAll strP <$?> A.takeTill (== ',')
+listItem = parseAll strP <$?> A.takeTill (\c -> c == ',' || c == ' ' || c == '\n')

 instance (StrEncoding a, StrEncoding b) => StrEncoding (a, b) where
  strEncode (a, b) = B.unwords [strEncode a, strEncode b]
+  {-# INLINE strEncode #-}
  strP = (,) <$> strP_ <*> strP
+  {-# INLINE strP #-}

 instance (StrEncoding a, StrEncoding b, StrEncoding c) => StrEncoding (a, b, c) where
  strEncode (a, b, c) = B.unwords [strEncode a, strEncode b, strEncode c]
+  {-# INLINE strEncode #-}
  strP = (,,) <$> strP_ <*> strP_ <*> strP
+  {-# INLINE strP #-}

 instance (StrEncoding a, StrEncoding b, StrEncoding c, StrEncoding d) => StrEncoding (a, b, c, d) where
  strEncode (a, b, c, d) = B.unwords [strEncode a, strEncode b, strEncode c, strEncode d]
+  {-# INLINE strEncode #-}
  strP = (,,,) <$> strP_ <*> strP_ <*> strP_ <*> strP
+  {-# INLINE strP #-}

 instance (StrEncoding a, StrEncoding b, StrEncoding c, StrEncoding d, StrEncoding e) => StrEncoding (a, b, c, d, e) where
  strEncode (a, b, c, d, e) = B.unwords [strEncode a, strEncode b, strEncode c, strEncode d, strEncode e]
+  {-# INLINE strEncode #-}
  strP = (,,,,) <$> strP_ <*> strP_ <*> strP_ <*> strP_ <*> strP
+  {-# INLINE strP #-}

 strP_ :: StrEncoding a => Parser a
 strP_ = strP <* A.space

+_strP :: StrEncoding a => Parser a
+_strP = A.space *> strP
+
 strToJSON :: StrEncoding a => a -> J.Value
 strToJSON = J.String . decodeLatin1 . strEncode

@@ -0,0 +1,64 @@
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+module Simplex.Messaging.Notifications.Client where
+
+import Control.Monad.Except
+import Control.Monad.Trans.Except
+import Data.Word (Word16)
+import Simplex.Messaging.Client
+import qualified Simplex.Messaging.Crypto as C
+import Simplex.Messaging.Notifications.Protocol
+import Simplex.Messaging.Util (bshow)
+
+type NtfClient = ProtocolClient NtfResponse
+
+ntfRegisterToken :: NtfClient -> C.APrivateSignKey -> NewNtfEntity 'Token -> ExceptT ProtocolClientError IO (NtfTokenId, C.PublicKeyX25519)
+ntfRegisterToken c pKey newTkn =
+  sendNtfCommand c (Just pKey) "" (TNEW newTkn) >>= \case
+    NRTknId tknId dhKey -> pure (tknId, dhKey)
+    r -> throwE . PCEUnexpectedResponse $ bshow r
+
+ntfVerifyToken :: NtfClient -> C.APrivateSignKey -> NtfTokenId -> NtfRegCode -> ExceptT ProtocolClientError IO ()
+ntfVerifyToken c pKey tknId code = okNtfCommand (TVFY code) c pKey tknId
+
+ntfCheckToken :: NtfClient -> C.APrivateSignKey -> NtfTokenId -> ExceptT ProtocolClientError IO NtfTknStatus
+ntfCheckToken c pKey tknId =
+  sendNtfCommand c (Just pKey) tknId TCHK >>= \case
+    NRTkn stat -> pure stat
+    r -> throwE . PCEUnexpectedResponse $ bshow r
+
+ntfReplaceToken :: NtfClient -> C.APrivateSignKey -> NtfTokenId -> DeviceToken -> ExceptT ProtocolClientError IO ()
+ntfReplaceToken c pKey tknId token = okNtfCommand (TRPL token) c pKey tknId
+
+ntfDeleteToken :: NtfClient -> C.APrivateSignKey -> NtfTokenId -> ExceptT ProtocolClientError IO ()
+ntfDeleteToken = okNtfCommand TDEL
+
+ntfEnableCron :: NtfClient -> C.APrivateSignKey -> NtfTokenId -> Word16 -> ExceptT ProtocolClientError IO ()
+ntfEnableCron c pKey tknId int = okNtfCommand (TCRN int) c pKey tknId
+
+ntfCreateSubscription :: NtfClient -> C.APrivateSignKey -> NewNtfEntity 'Subscription -> ExceptT ProtocolClientError IO NtfSubscriptionId
+ntfCreateSubscription c pKey newSub =
+  sendNtfCommand c (Just pKey) "" (SNEW newSub) >>= \case
+    NRSubId subId -> pure subId
+    r -> throwE . PCEUnexpectedResponse $ bshow r
+
+ntfCheckSubscription :: NtfClient -> C.APrivateSignKey -> NtfSubscriptionId -> ExceptT ProtocolClientError IO NtfSubStatus
+ntfCheckSubscription c pKey subId =
+  sendNtfCommand c (Just pKey) subId SCHK >>= \case
+    NRSub stat -> pure stat
+    r -> throwE . PCEUnexpectedResponse $ bshow r
+
+ntfDeleteSubscription :: NtfClient -> C.APrivateSignKey -> NtfSubscriptionId -> ExceptT ProtocolClientError IO ()
+ntfDeleteSubscription = okNtfCommand SDEL
+
+-- | Send notification server command
+sendNtfCommand :: NtfEntityI e => NtfClient -> Maybe C.APrivateSignKey -> NtfEntityId -> NtfCommand e -> ExceptT ProtocolClientError IO NtfResponse
+sendNtfCommand c pKey entId cmd = sendProtocolCommand c pKey entId (NtfCmd sNtfEntity cmd)
+
+okNtfCommand :: NtfEntityI e => NtfCommand e -> NtfClient -> C.APrivateSignKey -> NtfEntityId -> ExceptT ProtocolClientError IO ()
+okNtfCommand cmd c pKey entId =
+  sendNtfCommand c (Just pKey) entId cmd >>= \case
+    NROk -> return ()
+    r -> throwE . PCEUnexpectedResponse $ bshow r
@@ -0,0 +1,507 @@
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE StandaloneDeriving #-}
+{-# LANGUAGE TypeApplications #-}
+{-# LANGUAGE TypeFamilies #-}
+
+module Simplex.Messaging.Notifications.Protocol where
+
+import Data.Aeson (FromJSON (..), ToJSON (..), (.=))
+import qualified Data.Aeson as J
+import qualified Data.Aeson.Encoding as JE
+import qualified Data.Attoparsec.ByteString.Char8 as A
+import Data.ByteString.Char8 (ByteString)
+import qualified Data.ByteString.Char8 as B
+import Data.Kind
+import Data.Maybe (isNothing)
+import Data.Text.Encoding (decodeLatin1, encodeUtf8)
+import Data.Type.Equality
+import Data.Word (Word16)
+import Database.SQLite.Simple.FromField (FromField (..))
+import Database.SQLite.Simple.ToField (ToField (..))
+import Simplex.Messaging.Agent.Protocol (updateSMPServerHosts)
+import qualified Simplex.Messaging.Crypto as C
+import Simplex.Messaging.Encoding
+import Simplex.Messaging.Encoding.String
+import Simplex.Messaging.Notifications.Transport (ntfClientHandshake)
+import Simplex.Messaging.Parsers (fromTextField_)
+import Simplex.Messaging.Protocol hiding (Command (..), CommandTag (..))
+import Simplex.Messaging.Util (eitherToMaybe, (<$?>))
+
+data NtfEntity = Token | Subscription
+  deriving (Show)
+
+data SNtfEntity :: NtfEntity -> Type where
+  SToken :: SNtfEntity 'Token
+  SSubscription :: SNtfEntity 'Subscription
+
+instance TestEquality SNtfEntity where
+  testEquality SToken SToken = Just Refl
+  testEquality SSubscription SSubscription = Just Refl
+  testEquality _ _ = Nothing
+
+deriving instance Show (SNtfEntity e)
+
+class NtfEntityI (e :: NtfEntity) where sNtfEntity :: SNtfEntity e
+
+instance NtfEntityI 'Token where sNtfEntity = SToken
+
+instance NtfEntityI 'Subscription where sNtfEntity = SSubscription
+
+data NtfCommandTag (e :: NtfEntity) where
+  TNEW_ :: NtfCommandTag 'Token
+  TVFY_ :: NtfCommandTag 'Token
+  TCHK_ :: NtfCommandTag 'Token
+  TRPL_ :: NtfCommandTag 'Token
+  TDEL_ :: NtfCommandTag 'Token
+  TCRN_ :: NtfCommandTag 'Token
+  SNEW_ :: NtfCommandTag 'Subscription
+  SCHK_ :: NtfCommandTag 'Subscription
+  SDEL_ :: NtfCommandTag 'Subscription
+  PING_ :: NtfCommandTag 'Subscription
+
+deriving instance Show (NtfCommandTag e)
+
+data NtfCmdTag = forall e. NtfEntityI e => NCT (SNtfEntity e) (NtfCommandTag e)
+
+instance NtfEntityI e => Encoding (NtfCommandTag e) where
+  smpEncode = \case
+    TNEW_ -> "TNEW"
+    TVFY_ -> "TVFY"
+    TCHK_ -> "TCHK"
+    TRPL_ -> "TRPL"
+    TDEL_ -> "TDEL"
+    TCRN_ -> "TCRN"
+    SNEW_ -> "SNEW"
+    SCHK_ -> "SCHK"
+    SDEL_ -> "SDEL"
+    PING_ -> "PING"
+  smpP = messageTagP
+
+instance Encoding NtfCmdTag where
+  smpEncode (NCT _ t) = smpEncode t
+  smpP = messageTagP
+
+instance ProtocolMsgTag NtfCmdTag where
+  decodeTag = \case
+    "TNEW" -> Just $ NCT SToken TNEW_
+    "TVFY" -> Just $ NCT SToken TVFY_
+    "TCHK" -> Just $ NCT SToken TCHK_
+    "TRPL" -> Just $ NCT SToken TRPL_
+    "TDEL" -> Just $ NCT SToken TDEL_
+    "TCRN" -> Just $ NCT SToken TCRN_
+    "SNEW" -> Just $ NCT SSubscription SNEW_
+    "SCHK" -> Just $ NCT SSubscription SCHK_
+    "SDEL" -> Just $ NCT SSubscription SDEL_
+    "PING" -> Just $ NCT SSubscription PING_
+    _ -> Nothing
+
+instance NtfEntityI e => ProtocolMsgTag (NtfCommandTag e) where
+  decodeTag s = decodeTag s >>= (\(NCT _ t) -> checkEntity' t)
+
+newtype NtfRegCode = NtfRegCode ByteString
+  deriving (Eq, Show)
+
+instance Encoding NtfRegCode where
+  smpEncode (NtfRegCode code) = smpEncode code
+  smpP = NtfRegCode <$> smpP
+
+instance StrEncoding NtfRegCode where
+  strEncode (NtfRegCode m) = strEncode m
+  strDecode s = NtfRegCode <$> strDecode s
+  strP = NtfRegCode <$> strP
+
+instance FromJSON NtfRegCode where
+  parseJSON = strParseJSON "NtfRegCode"
+
+instance ToJSON NtfRegCode where
+  toJSON = strToJSON
+  toEncoding = strToJEncoding
+
+data NewNtfEntity (e :: NtfEntity) where
+  NewNtfTkn :: DeviceToken -> C.APublicVerifyKey -> C.PublicKeyX25519 -> NewNtfEntity 'Token
+  NewNtfSub :: NtfTokenId -> SMPQueueNtf -> NtfPrivateSignKey -> NewNtfEntity 'Subscription
+
+deriving instance Show (NewNtfEntity e)
+
+data ANewNtfEntity = forall e. NtfEntityI e => ANE (SNtfEntity e) (NewNtfEntity e)
+
+deriving instance Show ANewNtfEntity
+
+instance NtfEntityI e => Encoding (NewNtfEntity e) where
+  smpEncode = \case
+    NewNtfTkn tkn verifyKey dhPubKey -> smpEncode ('T', tkn, verifyKey, dhPubKey)
+    NewNtfSub tknId smpQueue notifierKey -> smpEncode ('S', tknId, smpQueue, notifierKey)
+  smpP = (\(ANE _ c) -> checkEntity c) <$?> smpP
+
+instance Encoding ANewNtfEntity where
+  smpEncode (ANE _ e) = smpEncode e
+  smpP =
+    A.anyChar >>= \case
+      'T' -> ANE SToken <$> (NewNtfTkn <$> smpP <*> smpP <*> smpP)
+      'S' -> ANE SSubscription <$> (NewNtfSub <$> smpP <*> smpP <*> smpP)
+      _ -> fail "bad ANewNtfEntity"
+
+instance Protocol NtfResponse where
+  type ProtoCommand NtfResponse = NtfCmd
+  type ProtoType NtfResponse = 'PNTF
+  protocolClientHandshake = ntfClientHandshake
+  protocolPing = NtfCmd SSubscription PING
+  protocolError = \case
+    NRErr e -> Just e
+    _ -> Nothing
+
+data NtfCommand (e :: NtfEntity) where
+  -- | register new device token for notifications
+  TNEW :: NewNtfEntity 'Token -> NtfCommand 'Token
+  -- | verify token - uses e2e encrypted random string sent to the device via PN to confirm that the device has the token
+  TVFY :: NtfRegCode -> NtfCommand 'Token
+  -- | check token status
+  TCHK :: NtfCommand 'Token
+  -- | replace device token (while keeping all existing subscriptions)
+  TRPL :: DeviceToken -> NtfCommand 'Token
+  -- | delete token - all subscriptions will be removed and no more notifications will be sent
+  TDEL :: NtfCommand 'Token
+  -- | enable periodic background notification to fetch the new messages - interval is in minutes, minimum is 20, 0 to disable
+  TCRN :: Word16 -> NtfCommand 'Token
+  -- | create SMP subscription
+  SNEW :: NewNtfEntity 'Subscription -> NtfCommand 'Subscription
+  -- | check SMP subscription status (response is SUB)
+  SCHK :: NtfCommand 'Subscription
+  -- | delete SMP subscription
+  SDEL :: NtfCommand 'Subscription
+  -- | keep-alive command
+  PING :: NtfCommand 'Subscription
+
+deriving instance Show (NtfCommand e)
+
+data NtfCmd = forall e. NtfEntityI e => NtfCmd (SNtfEntity e) (NtfCommand e)
+
+deriving instance Show NtfCmd
+
+instance NtfEntityI e => ProtocolEncoding (NtfCommand e) where
+  type Tag (NtfCommand e) = NtfCommandTag e
+  encodeProtocol _v = \case
+    TNEW newTkn -> e (TNEW_, ' ', newTkn)
+    TVFY code -> e (TVFY_, ' ', code)
+    TCHK -> e TCHK_
+    TRPL tkn -> e (TRPL_, ' ', tkn)
+    TDEL -> e TDEL_
+    TCRN int -> e (TCRN_, ' ', int)
+    SNEW newSub -> e (SNEW_, ' ', newSub)
+    SCHK -> e SCHK_
+    SDEL -> e SDEL_
+    PING -> e PING_
+    where
+      e :: Encoding a => a -> ByteString
+      e = smpEncode
+
+  protocolP _v tag = (\(NtfCmd _ c) -> checkEntity c) <$?> protocolP _v (NCT (sNtfEntity @e) tag)
+
+  checkCredentials (sig, _, entityId, _) cmd = case cmd of
+    -- TNEW and SNEW must have signature but NOT token/subscription IDs
+    TNEW {} -> sigNoEntity
+    SNEW {} -> sigNoEntity
+    PING
+      | isNothing sig && B.null entityId -> Right cmd
+      | otherwise -> Left $ CMD HAS_AUTH
+    -- other client commands must have both signature and entity ID
+    _
+      | isNothing sig || B.null entityId -> Left $ CMD NO_AUTH
+      | otherwise -> Right cmd
+    where
+      sigNoEntity
+        | isNothing sig = Left $ CMD NO_AUTH
+        | not (B.null entityId) = Left $ CMD HAS_AUTH
+        | otherwise = Right cmd
+
+instance ProtocolEncoding NtfCmd where
+  type Tag NtfCmd = NtfCmdTag
+  encodeProtocol _v (NtfCmd _ c) = encodeProtocol _v c
+
+  protocolP _v = \case
+    NCT SToken tag ->
+      NtfCmd SToken <$> case tag of
+        TNEW_ -> TNEW <$> _smpP
+        TVFY_ -> TVFY <$> _smpP
+        TCHK_ -> pure TCHK
+        TRPL_ -> TRPL <$> _smpP
+        TDEL_ -> pure TDEL
+        TCRN_ -> TCRN <$> _smpP
+    NCT SSubscription tag ->
+      NtfCmd SSubscription <$> case tag of
+        SNEW_ -> SNEW <$> _smpP
+        SCHK_ -> pure SCHK
+        SDEL_ -> pure SDEL
+        PING_ -> pure PING
+
+  checkCredentials t (NtfCmd e c) = NtfCmd e <$> checkCredentials t c
+
+data NtfResponseTag
+  = NRTknId_
+  | NRSubId_
+  | NROk_
+  | NRErr_
+  | NRTkn_
+  | NRSub_
+  | NRPong_
+  deriving (Show)
+
+instance Encoding NtfResponseTag where
+  smpEncode = \case
+    NRTknId_ -> "IDTKN" -- it should be "TID", "SID"
+    NRSubId_ -> "IDSUB"
+    NROk_ -> "OK"
+    NRErr_ -> "ERR"
+    NRTkn_ -> "TKN"
+    NRSub_ -> "SUB"
+    NRPong_ -> "PONG"
+  smpP = messageTagP
+
+instance ProtocolMsgTag NtfResponseTag where
+  decodeTag = \case
+    "IDTKN" -> Just NRTknId_
+    "IDSUB" -> Just NRSubId_
+    "OK" -> Just NROk_
+    "ERR" -> Just NRErr_
+    "TKN" -> Just NRTkn_
+    "SUB" -> Just NRSub_
+    "PONG" -> Just NRPong_
+    _ -> Nothing
+
+data NtfResponse
+  = NRTknId NtfEntityId C.PublicKeyX25519
+  | NRSubId NtfEntityId
+  | NROk
+  | NRErr ErrorType
+  | NRTkn NtfTknStatus
+  | NRSub NtfSubStatus
+  | NRPong
+  deriving (Show)
+
+instance ProtocolEncoding NtfResponse where
+  type Tag NtfResponse = NtfResponseTag
+  encodeProtocol _v = \case
+    NRTknId entId dhKey -> e (NRTknId_, ' ', entId, dhKey)
+    NRSubId entId -> e (NRSubId_, ' ', entId)
+    NROk -> e NROk_
+    NRErr err -> e (NRErr_, ' ', err)
+    NRTkn stat -> e (NRTkn_, ' ', stat)
+    NRSub stat -> e (NRSub_, ' ', stat)
+    NRPong -> e NRPong_
+    where
+      e :: Encoding a => a -> ByteString
+      e = smpEncode
+
+  protocolP _v = \case
+    NRTknId_ -> NRTknId <$> _smpP <*> smpP
+    NRSubId_ -> NRSubId <$> _smpP
+    NROk_ -> pure NROk
+    NRErr_ -> NRErr <$> _smpP
+    NRTkn_ -> NRTkn <$> _smpP
+    NRSub_ -> NRSub <$> _smpP
+    NRPong_ -> pure NRPong
+
+  checkCredentials (_, _, entId, _) cmd = case cmd of
+    -- IDTKN response must not have queue ID
+    NRTknId {} -> noEntity
+    -- IDSUB response must not have queue ID
+    NRSubId {} -> noEntity
+    -- ERR response does not always have entity ID
+    NRErr _ -> Right cmd
+    -- PONG response must not have queue ID
+    NRPong -> noEntity
+    -- other server responses must have entity ID
+    _
+      | B.null entId -> Left $ CMD NO_ENTITY
+      | otherwise -> Right cmd
+    where
+      noEntity
+        | B.null entId = Right cmd
+        | otherwise = Left $ CMD HAS_AUTH
+
+data SMPQueueNtf = SMPQueueNtf
+  { smpServer :: SMPServer,
+    notifierId :: NotifierId
+  }
+  deriving (Eq, Ord, Show)
+
+instance Encoding SMPQueueNtf where
+  smpEncode SMPQueueNtf {smpServer, notifierId} = smpEncode (smpServer, notifierId)
+  smpP = do
+    smpServer <- updateSMPServerHosts <$> smpP
+    notifierId <- smpP
+    pure SMPQueueNtf {smpServer, notifierId}
+
+instance StrEncoding SMPQueueNtf where
+  strEncode SMPQueueNtf {smpServer, notifierId} = strEncode smpServer <> "/" <> strEncode notifierId
+  strP = do
+    smpServer <- updateSMPServerHosts <$> strP
+    notifierId <- A.char '/' *> strP
+    pure SMPQueueNtf {smpServer, notifierId}
+
+data PushProvider = PPApnsDev | PPApnsProd | PPApnsTest
+  deriving (Eq, Ord, Show)
+
+instance Encoding PushProvider where
+  smpEncode = \case
+    PPApnsDev -> "AD"
+    PPApnsProd -> "AP"
+    PPApnsTest -> "AT"
+  smpP =
+    A.take 2 >>= \case
+      "AD" -> pure PPApnsDev
+      "AP" -> pure PPApnsProd
+      "AT" -> pure PPApnsTest
+      _ -> fail "bad PushProvider"
+
+instance StrEncoding PushProvider where
+  strEncode = \case
+    PPApnsDev -> "apns_dev"
+    PPApnsProd -> "apns_prod"
+    PPApnsTest -> "apns_test"
+  strP =
+    A.takeTill (== ' ') >>= \case
+      "apns_dev" -> pure PPApnsDev
+      "apns_prod" -> pure PPApnsProd
+      "apns_test" -> pure PPApnsTest
+      _ -> fail "bad PushProvider"
+
+instance FromField PushProvider where fromField = fromTextField_ $ eitherToMaybe . strDecode . encodeUtf8
+
+instance ToField PushProvider where toField = toField . decodeLatin1 . strEncode
+
+data DeviceToken = DeviceToken PushProvider ByteString
+  deriving (Eq, Ord, Show)
+
+instance Encoding DeviceToken where
+  smpEncode (DeviceToken p t) = smpEncode (p, t)
+  smpP = DeviceToken <$> smpP <*> smpP
+
+instance StrEncoding DeviceToken where
+  strEncode (DeviceToken p t) = strEncode p <> " " <> t
+  strP = DeviceToken <$> strP <* A.space <*> hexStringP
+    where
+      hexStringP =
+        A.takeWhile (\c -> A.isDigit c || (c >= 'a' && c <= 'f')) >>= \s ->
+          if even (B.length s) then pure s else fail "odd number of hex characters"
+
+instance ToJSON DeviceToken where
+  toEncoding (DeviceToken pp t) = J.pairs $ "pushProvider" .= decodeLatin1 (strEncode pp) <> "token" .= decodeLatin1 t
+  toJSON (DeviceToken pp t) = J.object ["pushProvider" .= decodeLatin1 (strEncode pp), "token" .= decodeLatin1 t]
+
+type NtfEntityId = ByteString
+
+type NtfSubscriptionId = NtfEntityId
+
+type NtfTokenId = NtfEntityId
+
+data NtfSubStatus
+  = -- | state after SNEW
+    NSNew
+  | -- | pending connection/subscription to SMP server
+    NSPending
+  | -- | connected and subscribed to SMP server
+    NSActive
+  | -- | disconnected/unsubscribed from SMP server
+    NSInactive
+  | -- | END received
+    NSEnd
+  | -- | SMP AUTH error
+    NSAuth
+  | -- | SMP error other than AUTH
+    NSErr ByteString
+  deriving (Eq, Show)
+
+ntfShouldSubscribe :: NtfSubStatus -> Bool
+ntfShouldSubscribe = \case
+  NSNew -> True
+  NSPending -> True
+  NSActive -> True
+  NSInactive -> True
+  NSEnd -> False
+  NSAuth -> False
+  NSErr _ -> False
+
+instance Encoding NtfSubStatus where
+  smpEncode = \case
+    NSNew -> "NEW"
+    NSPending -> "PENDING" -- e.g. after SMP server disconnect/timeout while ntf server is retrying to connect
+    NSActive -> "ACTIVE"
+    NSInactive -> "INACTIVE"
+    NSEnd -> "END"
+    NSAuth -> "AUTH"
+    NSErr err -> "ERR " <> err
+  smpP =
+    A.takeTill (== ' ') >>= \case
+      "NEW" -> pure NSNew
+      "PENDING" -> pure NSPending
+      "ACTIVE" -> pure NSActive
+      "INACTIVE" -> pure NSInactive
+      "END" -> pure NSEnd
+      "AUTH" -> pure NSAuth
+      "ERR" -> NSErr <$> (A.space *> A.takeByteString)
+      _ -> fail "bad NtfSubStatus"
+
+instance StrEncoding NtfSubStatus where
+  strEncode = smpEncode
+  strP = smpP
+
+data NtfTknStatus
+  = -- | Token created in DB
+    NTNew
+  | -- | state after registration (TNEW)
+    NTRegistered
+  | -- | if initial notification failed (push provider error) or verification failed
+    NTInvalid
+  | -- | Token confirmed via notification (accepted by push provider or verification code received by client)
+    NTConfirmed
+  | -- | after successful verification (TVFY)
+    NTActive
+  | -- | after it is no longer valid (push provider error)
+    NTExpired
+  deriving (Eq, Show)
+
+instance Encoding NtfTknStatus where
+  smpEncode = \case
+    NTNew -> "NEW"
+    NTRegistered -> "REGISTERED"
+    NTInvalid -> "INVALID"
+    NTConfirmed -> "CONFIRMED"
+    NTActive -> "ACTIVE"
+    NTExpired -> "EXPIRED"
+  smpP =
+    A.takeTill (== ' ') >>= \case
+      "NEW" -> pure NTNew
+      "REGISTERED" -> pure NTRegistered
+      "INVALID" -> pure NTInvalid
+      "CONFIRMED" -> pure NTConfirmed
+      "ACTIVE" -> pure NTActive
+      "EXPIRED" -> pure NTExpired
+      _ -> fail "bad NtfTknStatus"
+
+instance StrEncoding NtfTknStatus where
+  strEncode = smpEncode
+  strP = smpP
+
+instance FromField NtfTknStatus where fromField = fromTextField_ $ either (const Nothing) Just . smpDecode . encodeUtf8
+
+instance ToField NtfTknStatus where toField = toField . decodeLatin1 . smpEncode
+
+instance ToJSON NtfTknStatus where
+  toEncoding = JE.text . decodeLatin1 . smpEncode
+  toJSON = J.String . decodeLatin1 . smpEncode
+
+checkEntity :: forall t e e'. (NtfEntityI e, NtfEntityI e') => t e' -> Either String (t e)
+checkEntity c = case testEquality (sNtfEntity @e) (sNtfEntity @e') of
+  Just Refl -> Right c
+  Nothing -> Left "bad command party"
+
+checkEntity' :: forall t p p'. (NtfEntityI p, NtfEntityI p') => t p' -> Maybe (t p)
+checkEntity' c = case testEquality (sNtfEntity @p) (sNtfEntity @p') of
+  Just Refl -> Just c
+  _ -> Nothing
@@ -0,0 +1,576 @@
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE NumericUnderscores #-}
+{-# LANGUAGE OverloadedLists #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+{-# LANGUAGE TupleSections #-}
+
+module Simplex.Messaging.Notifications.Server where
+
+import Control.Concurrent.STM (stateTVar)
+import Control.Logger.Simple
+import Control.Monad.Except
+import Control.Monad.Reader
+import Data.ByteString.Char8 (ByteString)
+import qualified Data.ByteString.Char8 as B
+import Data.Functor (($>))
+import Data.List (intercalate)
+import Data.Map.Strict (Map)
+import qualified Data.Text as T
+import Data.Text.Encoding (decodeLatin1)
+import Data.Time.Clock (UTCTime (..), diffTimeToPicoseconds, getCurrentTime)
+import Data.Time.Clock.System (getSystemTime)
+import Data.Time.Format.ISO8601 (iso8601Show)
+import Network.Socket (ServiceName)
+import Simplex.Messaging.Client (ProtocolClientError (..))
+import Simplex.Messaging.Client.Agent
+import qualified Simplex.Messaging.Crypto as C
+import Simplex.Messaging.Encoding.String
+import Simplex.Messaging.Notifications.Protocol
+import Simplex.Messaging.Notifications.Server.Env
+import Simplex.Messaging.Notifications.Server.Push.APNS (PNMessageData (..), PushNotification (..), PushProviderError (..))
+import Simplex.Messaging.Notifications.Server.Stats
+import Simplex.Messaging.Notifications.Server.Store
+import Simplex.Messaging.Notifications.Server.StoreLog
+import Simplex.Messaging.Notifications.Transport
+import Simplex.Messaging.Protocol (ErrorType (..), ProtocolServer (host), SMPServer, SignedTransmission, Transmission, encodeTransmission, tGet, tPut)
+import qualified Simplex.Messaging.Protocol as SMP
+import Simplex.Messaging.Server
+import Simplex.Messaging.Server.Stats
+import qualified Simplex.Messaging.TMap as TM
+import Simplex.Messaging.Transport (ATransport (..), THandle (..), TProxy, Transport (..))
+import Simplex.Messaging.Transport.Server (runTransportServer)
+import Simplex.Messaging.Util
+import System.Exit (exitFailure)
+import System.IO (BufferMode (..), hPutStrLn, hSetBuffering)
+import System.Mem.Weak (deRefWeak)
+import UnliftIO (IOMode (..), async, uninterruptibleCancel, withFile)
+import UnliftIO.Concurrent (forkIO, killThread, mkWeakThreadId, threadDelay)
+import UnliftIO.Directory (doesFileExist, renameFile)
+import UnliftIO.Exception
+import UnliftIO.STM
+
+runNtfServer :: NtfServerConfig -> IO ()
+runNtfServer cfg = do
+  started <- newEmptyTMVarIO
+  runNtfServerBlocking started cfg
+
+runNtfServerBlocking :: TMVar Bool -> NtfServerConfig -> IO ()
+runNtfServerBlocking started cfg = runReaderT (ntfServer cfg started) =<< newNtfServerEnv cfg
+
+type M a = ReaderT NtfEnv IO a
+
+ntfServer :: NtfServerConfig -> TMVar Bool -> M ()
+ntfServer cfg@NtfServerConfig {transports, logTLSErrors} started = do
+  restoreServerStats
+  s <- asks subscriber
+  ps <- asks pushServer
+  subs <- readTVarIO =<< asks (subscriptions . store)
+  void . forkIO $ resubscribe s subs
+  raceAny_ (ntfSubscriber s : ntfPush ps : map runServer transports <> serverStatsThread_ cfg) `finally` stopServer
+  where
+    runServer :: (ServiceName, ATransport) -> M ()
+    runServer (tcpPort, ATransport t) = do
+      serverParams <- asks tlsServerParams
+      runTransportServer started tcpPort serverParams logTLSErrors (runClient t)
+
+    runClient :: Transport c => TProxy c -> c -> M ()
+    runClient _ h = do
+      kh <- asks serverIdentity
+      liftIO (runExceptT $ ntfServerHandshake h kh supportedNTFServerVRange) >>= \case
+        Right th -> runNtfClientTransport th
+        Left _ -> pure ()
+
+    stopServer :: M ()
+    stopServer = do
+      withNtfLog closeStoreLog
+      saveServerStats
+      asks (smpSubscribers . subscriber) >>= readTVarIO >>= mapM_ (\SMPSubscriber {subThreadId} -> readTVarIO subThreadId >>= mapM_ (liftIO . deRefWeak >=> mapM_ killThread))
+
+    serverStatsThread_ :: NtfServerConfig -> [M ()]
+    serverStatsThread_ NtfServerConfig {logStatsInterval = Just interval, logStatsStartTime, serverStatsLogFile} =
+      [logServerStats logStatsStartTime interval serverStatsLogFile]
+    serverStatsThread_ _ = []
+
+    logServerStats :: Int -> Int -> FilePath -> M ()
+    logServerStats startAt logInterval statsFilePath = do
+      initialDelay <- (startAt -) . fromIntegral . (`div` 1000000_000000) . diffTimeToPicoseconds . utctDayTime <$> liftIO getCurrentTime
+      liftIO $ putStrLn $ "server stats log enabled: " <> statsFilePath
+      threadDelay $ 1000000 * (initialDelay + if initialDelay < 0 then 86400 else 0)
+      NtfServerStats {fromTime, tknCreated, tknVerified, tknDeleted, subCreated, subDeleted, ntfReceived, ntfDelivered, activeTokens, activeSubs} <- asks serverStats
+      let interval = 1000000 * logInterval
+      withFile statsFilePath AppendMode $ \h -> liftIO $ do
+        hSetBuffering h LineBuffering
+        forever $ do
+          ts <- getCurrentTime
+          fromTime' <- atomically $ swapTVar fromTime ts
+          tknCreated' <- atomically $ swapTVar tknCreated 0
+          tknVerified' <- atomically $ swapTVar tknVerified 0
+          tknDeleted' <- atomically $ swapTVar tknDeleted 0
+          subCreated' <- atomically $ swapTVar subCreated 0
+          subDeleted' <- atomically $ swapTVar subDeleted 0
+          ntfReceived' <- atomically $ swapTVar ntfReceived 0
+          ntfDelivered' <- atomically $ swapTVar ntfDelivered 0
+          tkn <- atomically $ periodStatCounts activeTokens ts
+          sub <- atomically $ periodStatCounts activeSubs ts
+          hPutStrLn h $
+            intercalate
+              ","
+              [ iso8601Show $ utctDay fromTime',
+                show tknCreated',
+                show tknVerified',
+                show tknDeleted',
+                show subCreated',
+                show subDeleted',
+                show ntfReceived',
+                show ntfDelivered',
+                dayCount tkn,
+                weekCount tkn,
+                monthCount tkn,
+                dayCount sub,
+                weekCount sub,
+                monthCount sub
+              ]
+          threadDelay interval
+
+resubscribe :: NtfSubscriber -> Map NtfSubscriptionId NtfSubData -> M ()
+resubscribe NtfSubscriber {newSubQ} subs = do
+  d <- asks $ resubscribeDelay . config
+  forM_ subs $ \sub@NtfSubData {} ->
+    whenM (ntfShouldSubscribe <$> readTVarIO (subStatus sub)) $ do
+      atomically $ writeTBQueue newSubQ $ NtfSub sub
+      threadDelay d
+  liftIO $ logInfo "SMP connections resubscribed"
+
+ntfSubscriber :: NtfSubscriber -> M ()
+ntfSubscriber NtfSubscriber {smpSubscribers, newSubQ, smpAgent = ca@SMPClientAgent {msgQ, agentQ}} = do
+  raceAny_ [subscribe, receiveSMP, receiveAgent]
+  where
+    subscribe :: M ()
+    subscribe =
+      forever $
+        atomically (readTBQueue newSubQ) >>= \case
+          sub@(NtfSub NtfSubData {smpQueue = SMPQueueNtf {smpServer}}) -> do
+            SMPSubscriber {newSubQ = subscriberSubQ} <- getSMPSubscriber smpServer
+            atomically $ writeTQueue subscriberSubQ sub
+
+    getSMPSubscriber :: SMPServer -> M SMPSubscriber
+    getSMPSubscriber smpServer =
+      atomically (TM.lookup smpServer smpSubscribers) >>= maybe createSMPSubscriber pure
+      where
+        createSMPSubscriber = do
+          sub@SMPSubscriber {subThreadId} <- atomically newSMPSubscriber
+          atomically $ TM.insert smpServer sub smpSubscribers
+          tId <- mkWeakThreadId =<< forkIO (runSMPSubscriber sub)
+          atomically . writeTVar subThreadId $ Just tId
+          pure sub
+
+    runSMPSubscriber :: SMPSubscriber -> M ()
+    runSMPSubscriber SMPSubscriber {newSubQ = subscriberSubQ} =
+      forever $
+        atomically (peekTQueue subscriberSubQ)
+          >>= \(NtfSub NtfSubData {smpQueue, notifierKey}) -> do
+            updateSubStatus smpQueue NSPending
+            let SMPQueueNtf {smpServer, notifierId} = smpQueue
+            liftIO (runExceptT $ subscribeQueue ca smpServer ((SPNotifier, notifierId), notifierKey)) >>= \case
+              Right _ -> do
+                updateSubStatus smpQueue NSActive
+                void . atomically $ readTQueue subscriberSubQ
+              Left err -> do
+                handleSubError smpQueue err
+                case err of
+                  PCEResponseTimeout -> pure ()
+                  PCENetworkError -> pure ()
+                  _ -> void . atomically $ readTQueue subscriberSubQ
+
+    receiveSMP :: M ()
+    receiveSMP = forever $ do
+      (srv, _, _, ntfId, msg) <- atomically $ readTBQueue msgQ
+      let smpQueue = SMPQueueNtf srv ntfId
+      case msg of
+        SMP.NMSG nmsgNonce encNMsgMeta -> do
+          ntfTs <- liftIO getSystemTime
+          st <- asks store
+          NtfPushServer {pushQ} <- asks pushServer
+          stats <- asks serverStats
+          atomically $ updatePeriodStats (activeSubs stats) ntfId
+          atomically $
+            findNtfSubscriptionToken st smpQueue
+              >>= mapM_ (\tkn -> writeTBQueue pushQ (tkn, PNMessage PNMessageData {smpQueue, ntfTs, nmsgNonce, encNMsgMeta}))
+          incNtfStat ntfReceived
+        SMP.END -> updateSubStatus smpQueue NSEnd
+        _ -> pure ()
+
+    receiveAgent =
+      forever $
+        atomically (readTBQueue agentQ) >>= \case
+          CAConnected _ -> pure ()
+          CADisconnected srv subs -> do
+            logInfo $ "SMP server disconnected " <> showServer' srv <> " (" <> tshow (length subs) <> ") subscriptions"
+            forM_ subs $ \(_, ntfId) -> do
+              let smpQueue = SMPQueueNtf srv ntfId
+              updateSubStatus smpQueue NSInactive
+          CAReconnected srv ->
+            logInfo $ "SMP server reconnected " <> showServer' srv
+          CAResubscribed srv sub -> do
+            let ntfId = snd sub
+                smpQueue = SMPQueueNtf srv ntfId
+            updateSubStatus smpQueue NSActive
+          CASubError srv (_, ntfId) err -> do
+            logError $ "SMP subscription error on server " <> showServer' srv <> ": " <> tshow err
+            handleSubError (SMPQueueNtf srv ntfId) err
+      where
+        showServer' = decodeLatin1 . strEncode . host
+
+    handleSubError :: SMPQueueNtf -> ProtocolClientError -> M ()
+    handleSubError smpQueue = \case
+      PCEProtocolError AUTH -> updateSubStatus smpQueue NSAuth
+      PCEProtocolError e -> updateErr "SMP error " e
+      PCEIOError e -> updateErr "IOError " e
+      PCEResponseError e -> updateErr "ResponseError " e
+      PCEUnexpectedResponse r -> updateErr "UnexpectedResponse " r
+      PCETransportError e -> updateErr "TransportError " e
+      PCESignatureError e -> updateErr "SignatureError " e
+      PCEIncompatibleHost -> updateSubStatus smpQueue $ NSErr "IncompatibleHost"
+      PCEResponseTimeout -> pure ()
+      PCENetworkError -> pure ()
+      where
+        updateErr :: Show e => ByteString -> e -> M ()
+        updateErr errType e = updateSubStatus smpQueue . NSErr $ errType <> bshow e
+
+    updateSubStatus smpQueue status = do
+      st <- asks store
+      atomically (findNtfSubscription st smpQueue)
+        >>= mapM_
+          ( \NtfSubData {ntfSubId, subStatus} -> do
+              atomically $ writeTVar subStatus status
+              withNtfLog $ \sl -> logSubscriptionStatus sl ntfSubId status
+          )
+
+ntfPush :: NtfPushServer -> M ()
+ntfPush s@NtfPushServer {pushQ} = forever $ do
+  (tkn@NtfTknData {ntfTknId, token = DeviceToken pp _, tknStatus}, ntf) <- atomically (readTBQueue pushQ)
+  liftIO $ logDebug $ "sending push notification to " <> T.pack (show pp)
+  status <- readTVarIO tknStatus
+  case ntf of
+    PNVerification _
+      | status /= NTInvalid && status /= NTExpired ->
+        deliverNotification pp tkn ntf >>= \case
+          Right _ -> do
+            status_ <- atomically $ stateTVar tknStatus $ \status' -> if status' == NTActive then (Nothing, NTActive) else (Just NTConfirmed, NTConfirmed)
+            forM_ status_ $ \status' -> withNtfLog $ \sl -> logTokenStatus sl ntfTknId status'
+          _ -> pure ()
+      | otherwise -> logError "bad notification token status"
+    PNCheckMessages -> checkActiveTkn status $ do
+      void $ deliverNotification pp tkn ntf
+    PNMessage {} -> checkActiveTkn status $ do
+      stats <- asks serverStats
+      atomically $ updatePeriodStats (activeTokens stats) ntfTknId
+      void $ deliverNotification pp tkn ntf
+      incNtfStat ntfDelivered
+  where
+    checkActiveTkn :: NtfTknStatus -> M () -> M ()
+    checkActiveTkn status action
+      | status == NTActive = action
+      | otherwise = liftIO $ logError "bad notification token status"
+    deliverNotification :: PushProvider -> NtfTknData -> PushNotification -> M (Either PushProviderError ())
+    deliverNotification pp tkn@NtfTknData {ntfTknId, tknStatus} ntf = do
+      deliver <- liftIO $ getPushClient s pp
+      liftIO (runExceptT $ deliver tkn ntf) >>= \case
+        Right _ -> pure $ Right ()
+        Left e -> case e of
+          PPConnection _ -> retryDeliver
+          PPRetryLater -> retryDeliver
+          PPCryptoError _ -> err e
+          PPResponseError _ _ -> err e
+          PPTokenInvalid -> updateTknStatus NTInvalid >> err e
+          PPPermanentError -> err e
+      where
+        retryDeliver :: M (Either PushProviderError ())
+        retryDeliver = do
+          deliver <- liftIO $ newPushClient s pp
+          liftIO (runExceptT $ deliver tkn ntf) >>= either err (pure . Right)
+        updateTknStatus :: NtfTknStatus -> M ()
+        updateTknStatus status = do
+          atomically $ writeTVar tknStatus status
+          withNtfLog $ \sl -> logTokenStatus sl ntfTknId status
+        err e = logError (T.pack $ "Push provider error (" <> show pp <> "): " <> show e) $> Left e
+
+runNtfClientTransport :: Transport c => THandle c -> M ()
+runNtfClientTransport th@THandle {sessionId} = do
+  qSize <- asks $ clientQSize . config
+  ts <- liftIO getSystemTime
+  c <- atomically $ newNtfServerClient qSize sessionId ts
+  s <- asks subscriber
+  ps <- asks pushServer
+  expCfg <- asks $ inactiveClientExpiration . config
+  raceAny_ ([liftIO $ send th c, client c s ps, receive th c] <> disconnectThread_ c expCfg)
+    `finally` liftIO (clientDisconnected c)
+  where
+    disconnectThread_ c expCfg = maybe [] ((: []) . liftIO . disconnectTransport th c activeAt) expCfg
+
+clientDisconnected :: NtfServerClient -> IO ()
+clientDisconnected NtfServerClient {connected} = atomically $ writeTVar connected False
+
+receive :: Transport c => THandle c -> NtfServerClient -> M ()
+receive th NtfServerClient {rcvQ, sndQ, activeAt} = forever $ do
+  ts <- tGet th
+  forM_ ts $ \t@(_, _, (corrId, entId, cmdOrError)) -> do
+    atomically . writeTVar activeAt =<< liftIO getSystemTime
+    logDebug "received transmission"
+    case cmdOrError of
+      Left e -> write sndQ (corrId, entId, NRErr e)
+      Right cmd ->
+        verifyNtfTransmission t cmd >>= \case
+          VRVerified req -> write rcvQ req
+          VRFailed -> write sndQ (corrId, entId, NRErr AUTH)
+  where
+    write q t = atomically $ writeTBQueue q t
+
+send :: Transport c => THandle c -> NtfServerClient -> IO ()
+send h@THandle {thVersion = v} NtfServerClient {sndQ, sessionId, activeAt} = forever $ do
+  t <- atomically $ readTBQueue sndQ
+  void . liftIO $ tPut h [(Nothing, encodeTransmission v sessionId t)]
+  atomically . writeTVar activeAt =<< liftIO getSystemTime
+
+-- instance Show a => Show (TVar a) where
+--   show x = unsafePerformIO $ show <$> readTVarIO x
+
+data VerificationResult = VRVerified NtfRequest | VRFailed
+
+verifyNtfTransmission :: SignedTransmission NtfCmd -> NtfCmd -> M VerificationResult
+verifyNtfTransmission (sig_, signed, (corrId, entId, _)) cmd = do
+  st <- asks store
+  case cmd of
+    NtfCmd SToken c@(TNEW tkn@(NewNtfTkn _ k _)) -> do
+      r_ <- atomically $ getNtfTokenRegistration st tkn
+      pure $
+        if verifyCmdSignature sig_ signed k
+          then case r_ of
+            Just t@NtfTknData {tknVerifyKey}
+              | k == tknVerifyKey -> verifiedTknCmd t c
+              | otherwise -> VRFailed
+            _ -> VRVerified (NtfReqNew corrId (ANE SToken tkn))
+          else VRFailed
+    NtfCmd SToken c -> do
+      t_ <- atomically $ getNtfToken st entId
+      verifyToken t_ (`verifiedTknCmd` c)
+    NtfCmd SSubscription c@(SNEW sub@(NewNtfSub tknId smpQueue _)) -> do
+      s_ <- atomically $ findNtfSubscription st smpQueue
+      case s_ of
+        Nothing -> do
+          t_ <- atomically $ getActiveNtfToken st tknId
+          verifyToken' t_ $ VRVerified (NtfReqNew corrId (ANE SSubscription sub))
+        Just s@NtfSubData {tokenId = subTknId} ->
+          if subTknId == tknId
+            then do
+              t_ <- atomically $ getActiveNtfToken st subTknId
+              verifyToken' t_ $ verifiedSubCmd s c
+            else pure $ maybe False (dummyVerifyCmd signed) sig_ `seq` VRFailed
+    NtfCmd SSubscription c -> do
+      s_ <- atomically $ getNtfSubscription st entId
+      case s_ of
+        Just s@NtfSubData {tokenId = subTknId} -> do
+          t_ <- atomically $ getActiveNtfToken st subTknId
+          verifyToken' t_ $ verifiedSubCmd s c
+        _ -> pure $ maybe False (dummyVerifyCmd signed) sig_ `seq` VRFailed
+  where
+    verifiedTknCmd t c = VRVerified (NtfReqCmd SToken (NtfTkn t) (corrId, entId, c))
+    verifiedSubCmd s c = VRVerified (NtfReqCmd SSubscription (NtfSub s) (corrId, entId, c))
+    verifyToken :: Maybe NtfTknData -> (NtfTknData -> VerificationResult) -> M VerificationResult
+    verifyToken t_ positiveVerificationResult =
+      pure $ case t_ of
+        Just t@NtfTknData {tknVerifyKey} ->
+          if verifyCmdSignature sig_ signed tknVerifyKey
+            then positiveVerificationResult t
+            else VRFailed
+        _ -> maybe False (dummyVerifyCmd signed) sig_ `seq` VRFailed
+    verifyToken' :: Maybe NtfTknData -> VerificationResult -> M VerificationResult
+    verifyToken' t_ = verifyToken t_ . const
+
+client :: NtfServerClient -> NtfSubscriber -> NtfPushServer -> M ()
+client NtfServerClient {rcvQ, sndQ} NtfSubscriber {newSubQ, smpAgent = ca} NtfPushServer {pushQ, intervalNotifiers} =
+  forever $
+    atomically (readTBQueue rcvQ)
+      >>= processCommand
+      >>= atomically . writeTBQueue sndQ
+  where
+    processCommand :: NtfRequest -> M (Transmission NtfResponse)
+    processCommand = \case
+      NtfReqNew corrId (ANE SToken newTkn@(NewNtfTkn _ _ dhPubKey)) -> do
+        logDebug "TNEW - new token"
+        st <- asks store
+        ks@(srvDhPubKey, srvDhPrivKey) <- liftIO C.generateKeyPair'
+        let dhSecret = C.dh' dhPubKey srvDhPrivKey
+        tknId <- getId
+        regCode <- getRegCode
+        tkn <- atomically $ mkNtfTknData tknId newTkn ks dhSecret regCode
+        atomically $ addNtfToken st tknId tkn
+        atomically $ writeTBQueue pushQ (tkn, PNVerification regCode)
+        withNtfLog (`logCreateToken` tkn)
+        incNtfStat tknCreated
+        pure (corrId, "", NRTknId tknId srvDhPubKey)
+      NtfReqCmd SToken (NtfTkn tkn@NtfTknData {ntfTknId, tknStatus, tknRegCode, tknDhSecret, tknDhKeys = (srvDhPubKey, srvDhPrivKey), tknCronInterval}) (corrId, tknId, cmd) -> do
+        status <- readTVarIO tknStatus
+        (corrId,tknId,) <$> case cmd of
+          TNEW (NewNtfTkn _ _ dhPubKey) -> do
+            logDebug "TNEW - registered token"
+            let dhSecret = C.dh' dhPubKey srvDhPrivKey
+            -- it is required that DH secret is the same, to avoid failed verifications if notification is delaying
+            if tknDhSecret == dhSecret
+              then do
+                atomically $ writeTBQueue pushQ (tkn, PNVerification tknRegCode)
+                pure $ NRTknId ntfTknId srvDhPubKey
+              else pure $ NRErr AUTH
+          TVFY code -- this allows repeated verification for cases when client connection dropped before server response
+            | (status == NTRegistered || status == NTConfirmed || status == NTActive) && tknRegCode == code -> do
+              logDebug "TVFY - token verified"
+              st <- asks store
+              atomically $ writeTVar tknStatus NTActive
+              tIds <- atomically $ removeInactiveTokenRegistrations st tkn
+              forM_ tIds cancelInvervalNotifications
+              withNtfLog $ \s -> logTokenStatus s tknId NTActive
+              incNtfStat tknVerified
+              pure NROk
+            | otherwise -> do
+              logDebug "TVFY - incorrect code or token status"
+              pure $ NRErr AUTH
+          TCHK -> do
+            logDebug "TCHK"
+            pure $ NRTkn status
+          TRPL token' -> do
+            logDebug "TRPL - replace token"
+            st <- asks store
+            regCode <- getRegCode
+            atomically $ do
+              removeTokenRegistration st tkn
+              writeTVar tknStatus NTRegistered
+              let tkn' = tkn {token = token', tknRegCode = regCode}
+              addNtfToken st tknId tkn'
+              writeTBQueue pushQ (tkn', PNVerification regCode)
+            withNtfLog $ \s -> logUpdateToken s tknId token' regCode
+            incNtfStat tknDeleted
+            incNtfStat tknCreated
+            pure NROk
+          TDEL -> do
+            logDebug "TDEL"
+            st <- asks store
+            qs <- atomically $ deleteNtfToken st tknId
+            forM_ qs $ \SMPQueueNtf {smpServer, notifierId} ->
+              atomically $ removeSubscription ca smpServer (SPNotifier, notifierId)
+            cancelInvervalNotifications tknId
+            withNtfLog (`logDeleteToken` tknId)
+            incNtfStat tknDeleted
+            pure NROk
+          TCRN 0 -> do
+            logDebug "TCRN 0"
+            atomically $ writeTVar tknCronInterval 0
+            cancelInvervalNotifications tknId
+            withNtfLog $ \s -> logTokenCron s tknId 0
+            pure NROk
+          TCRN int
+            | int < 20 -> pure $ NRErr QUOTA
+            | otherwise -> do
+              logDebug "TCRN"
+              atomically $ writeTVar tknCronInterval int
+              atomically (TM.lookup tknId intervalNotifiers) >>= \case
+                Nothing -> runIntervalNotifier int
+                Just IntervalNotifier {interval, action} ->
+                  unless (interval == int) $ do
+                    uninterruptibleCancel action
+                    runIntervalNotifier int
+              withNtfLog $ \s -> logTokenCron s tknId int
+              pure NROk
+            where
+              runIntervalNotifier interval = do
+                action <- async . intervalNotifier $ fromIntegral interval * 1000000 * 60
+                let notifier = IntervalNotifier {action, token = tkn, interval}
+                atomically $ TM.insert tknId notifier intervalNotifiers
+                where
+                  intervalNotifier delay = forever $ do
+                    threadDelay delay
+                    atomically $ writeTBQueue pushQ (tkn, PNCheckMessages)
+      NtfReqNew corrId (ANE SSubscription newSub) -> do
+        logDebug "SNEW - new subscription"
+        st <- asks store
+        subId <- getId
+        sub <- atomically $ mkNtfSubData subId newSub
+        resp <-
+          atomically (addNtfSubscription st subId sub) >>= \case
+            Just _ -> atomically (writeTBQueue newSubQ $ NtfSub sub) $> NRSubId subId
+            _ -> pure $ NRErr AUTH
+        withNtfLog (`logCreateSubscription` sub)
+        incNtfStat subCreated
+        pure (corrId, "", resp)
+      NtfReqCmd SSubscription (NtfSub NtfSubData {smpQueue = SMPQueueNtf {smpServer, notifierId}, notifierKey = registeredNKey, subStatus}) (corrId, subId, cmd) -> do
+        status <- readTVarIO subStatus
+        (corrId,subId,) <$> case cmd of
+          SNEW (NewNtfSub _ _ notifierKey) -> do
+            logDebug "SNEW - existing subscription"
+            -- possible improvement: retry if subscription failed, if pending or AUTH do nothing
+            pure $
+              if notifierKey == registeredNKey
+                then NRSubId subId
+                else NRErr AUTH
+          SCHK -> do
+            logDebug "SCHK"
+            pure $ NRSub status
+          SDEL -> do
+            logDebug "SDEL"
+            st <- asks store
+            atomically $ deleteNtfSubscription st subId
+            atomically $ removeSubscription ca smpServer (SPNotifier, notifierId)
+            withNtfLog (`logDeleteSubscription` subId)
+            incNtfStat subDeleted
+            pure NROk
+          PING -> pure NRPong
+    getId :: M NtfEntityId
+    getId = getRandomBytes =<< asks (subIdBytes . config)
+    getRegCode :: M NtfRegCode
+    getRegCode = NtfRegCode <$> (getRandomBytes =<< asks (regCodeBytes . config))
+    getRandomBytes :: Int -> M ByteString
+    getRandomBytes n = do
+      gVar <- asks idsDrg
+      atomically (C.pseudoRandomBytes n gVar)
+    cancelInvervalNotifications :: NtfTokenId -> M ()
+    cancelInvervalNotifications tknId =
+      atomically (TM.lookupDelete tknId intervalNotifiers)
+        >>= mapM_ (uninterruptibleCancel . action)
+
+withNtfLog :: (StoreLog 'WriteMode -> IO a) -> M ()
+withNtfLog action = liftIO . mapM_ action =<< asks storeLog
+
+incNtfStat :: (NtfServerStats -> TVar Int) -> M ()
+incNtfStat statSel = do
+  stats <- asks serverStats
+  atomically $ modifyTVar' (statSel stats) (+ 1)
+
+saveServerStats :: M ()
+saveServerStats =
+  asks (serverStatsBackupFile . config)
+    >>= mapM_ (\f -> asks serverStats >>= atomically . getNtfServerStatsData >>= liftIO . saveStats f)
+  where
+    saveStats f stats = do
+      logInfo $ "saving server stats to file " <> T.pack f
+      B.writeFile f $ strEncode stats
+      logInfo "server stats saved"
+
+restoreServerStats :: M ()
+restoreServerStats = asks (serverStatsBackupFile . config) >>= mapM_ restoreStats
+  where
+    restoreStats f = whenM (doesFileExist f) $ do
+      logInfo $ "restoring server stats from file " <> T.pack f
+      liftIO (strDecode <$> B.readFile f) >>= \case
+        Right d -> do
+          s <- asks serverStats
+          atomically $ setNtfServerStats s d
+          renameFile f $ f <> ".bak"
+          logInfo "server stats restored"
+        Left e -> do
+          logInfo $ "error restoring server stats: " <> T.pack e
+          liftIO exitFailure
@@ -0,0 +1,166 @@
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE KindSignatures #-}
+{-# LANGUAGE NamedFieldPuns #-}
+
+module Simplex.Messaging.Notifications.Server.Env where
+
+import Control.Concurrent (ThreadId)
+import Control.Concurrent.Async (Async)
+import Control.Monad.IO.Unlift
+import Crypto.Random
+import Data.ByteString.Char8 (ByteString)
+import Data.Time.Clock (getCurrentTime)
+import Data.Time.Clock.System (SystemTime)
+import Data.Word (Word16)
+import Data.X509.Validation (Fingerprint (..))
+import Network.Socket
+import qualified Network.TLS as T
+import Numeric.Natural
+import Simplex.Messaging.Client.Agent
+import qualified Simplex.Messaging.Crypto as C
+import Simplex.Messaging.Notifications.Protocol
+import Simplex.Messaging.Notifications.Server.Push.APNS
+import Simplex.Messaging.Notifications.Server.Stats
+import Simplex.Messaging.Notifications.Server.Store
+import Simplex.Messaging.Notifications.Server.StoreLog
+import Simplex.Messaging.Protocol (CorrId, SMPServer, Transmission)
+import Simplex.Messaging.Server.Expiration
+import Simplex.Messaging.TMap (TMap)
+import qualified Simplex.Messaging.TMap as TM
+import Simplex.Messaging.Transport (ATransport)
+import Simplex.Messaging.Transport.Server (loadFingerprint, loadTLSServerParams)
+import System.IO (IOMode (..))
+import System.Mem.Weak (Weak)
+import UnliftIO.STM
+
+data NtfServerConfig = NtfServerConfig
+  { transports :: [(ServiceName, ATransport)],
+    subIdBytes :: Int,
+    regCodeBytes :: Int,
+    clientQSize :: Natural,
+    subQSize :: Natural,
+    pushQSize :: Natural,
+    smpAgentCfg :: SMPClientAgentConfig,
+    apnsConfig :: APNSPushClientConfig,
+    inactiveClientExpiration :: Maybe ExpirationConfig,
+    storeLogFile :: Maybe FilePath,
+    resubscribeDelay :: Int, -- microseconds
+    -- CA certificate private key is not needed for initialization
+    caCertificateFile :: FilePath,
+    privateKeyFile :: FilePath,
+    certificateFile :: FilePath,
+    -- stats config - see SMP server config
+    logStatsInterval :: Maybe Int,
+    logStatsStartTime :: Int,
+    serverStatsLogFile :: FilePath,
+    serverStatsBackupFile :: Maybe FilePath,
+    logTLSErrors :: Bool
+  }
+
+defaultInactiveClientExpiration :: ExpirationConfig
+defaultInactiveClientExpiration =
+  ExpirationConfig
+    { ttl = 7200, -- 2 hours
+      checkInterval = 3600 -- seconds, 1 hour
+    }
+
+data NtfEnv = NtfEnv
+  { config :: NtfServerConfig,
+    subscriber :: NtfSubscriber,
+    pushServer :: NtfPushServer,
+    store :: NtfStore,
+    storeLog :: Maybe (StoreLog 'WriteMode),
+    idsDrg :: TVar ChaChaDRG,
+    serverIdentity :: C.KeyHash,
+    tlsServerParams :: T.ServerParams,
+    serverIdentity :: C.KeyHash,
+    serverStats :: NtfServerStats
+  }
+
+newNtfServerEnv :: (MonadUnliftIO m, MonadRandom m) => NtfServerConfig -> m NtfEnv
+newNtfServerEnv config@NtfServerConfig {subQSize, pushQSize, smpAgentCfg, apnsConfig, storeLogFile, caCertificateFile, certificateFile, privateKeyFile} = do
+  idsDrg <- newTVarIO =<< drgNew
+  store <- atomically newNtfStore
+  storeLog <- liftIO $ mapM (`readWriteNtfStore` store) storeLogFile
+  subscriber <- atomically $ newNtfSubscriber subQSize smpAgentCfg
+  pushServer <- atomically $ newNtfPushServer pushQSize apnsConfig
+  tlsServerParams <- liftIO $ loadTLSServerParams caCertificateFile certificateFile privateKeyFile
+  Fingerprint fp <- liftIO $ loadFingerprint caCertificateFile
+  serverStats <- atomically . newNtfServerStats =<< liftIO getCurrentTime
+  pure NtfEnv {config, subscriber, pushServer, store, storeLog, idsDrg, tlsServerParams, serverIdentity = C.KeyHash fp, serverStats}
+
+data NtfSubscriber = NtfSubscriber
+  { smpSubscribers :: TMap SMPServer SMPSubscriber,
+    newSubQ :: TBQueue (NtfEntityRec 'Subscription),
+    smpAgent :: SMPClientAgent
+  }
+
+newNtfSubscriber :: Natural -> SMPClientAgentConfig -> STM NtfSubscriber
+newNtfSubscriber qSize smpAgentCfg = do
+  smpSubscribers <- TM.empty
+  newSubQ <- newTBQueue qSize
+  smpAgent <- newSMPClientAgent smpAgentCfg
+  pure NtfSubscriber {smpSubscribers, newSubQ, smpAgent}
+
+data SMPSubscriber = SMPSubscriber
+  { newSubQ :: TQueue (NtfEntityRec 'Subscription),
+    subThreadId :: TVar (Maybe (Weak ThreadId))
+  }
+
+newSMPSubscriber :: STM SMPSubscriber
+newSMPSubscriber = do
+  newSubQ <- newTQueue
+  subThreadId <- newTVar Nothing
+  pure SMPSubscriber {newSubQ, subThreadId}
+
+data NtfPushServer = NtfPushServer
+  { pushQ :: TBQueue (NtfTknData, PushNotification),
+    pushClients :: TMap PushProvider PushProviderClient,
+    intervalNotifiers :: TMap NtfTokenId IntervalNotifier,
+    apnsConfig :: APNSPushClientConfig
+  }
+
+data IntervalNotifier = IntervalNotifier
+  { action :: Async (),
+    token :: NtfTknData,
+    interval :: Word16
+  }
+
+newNtfPushServer :: Natural -> APNSPushClientConfig -> STM NtfPushServer
+newNtfPushServer qSize apnsConfig = do
+  pushQ <- newTBQueue qSize
+  pushClients <- TM.empty
+  intervalNotifiers <- TM.empty
+  pure NtfPushServer {pushQ, pushClients, intervalNotifiers, apnsConfig}
+
+newPushClient :: NtfPushServer -> PushProvider -> IO PushProviderClient
+newPushClient NtfPushServer {apnsConfig, pushClients} pp = do
+  c <- apnsPushProviderClient <$> createAPNSPushClient (apnsProviderHost pp) apnsConfig
+  atomically $ TM.insert pp c pushClients
+  pure c
+
+getPushClient :: NtfPushServer -> PushProvider -> IO PushProviderClient
+getPushClient s@NtfPushServer {pushClients} pp =
+  atomically (TM.lookup pp pushClients) >>= maybe (newPushClient s pp) pure
+
+data NtfRequest
+  = NtfReqNew CorrId ANewNtfEntity
+  | forall e. NtfEntityI e => NtfReqCmd (SNtfEntity e) (NtfEntityRec e) (Transmission (NtfCommand e))
+
+data NtfServerClient = NtfServerClient
+  { rcvQ :: TBQueue NtfRequest,
+    sndQ :: TBQueue (Transmission NtfResponse),
+    sessionId :: ByteString,
+    connected :: TVar Bool,
+    activeAt :: TVar SystemTime
+  }
+
+newNtfServerClient :: Natural -> ByteString -> SystemTime -> STM NtfServerClient
+newNtfServerClient qSize sessionId ts = do
+  rcvQ <- newTBQueue qSize
+  sndQ <- newTBQueue qSize
+  connected <- newTVar True
+  activeAt <- newTVar ts
+  return NtfServerClient {rcvQ, sndQ, sessionId, connected, activeAt}
@@ -0,0 +1,174 @@
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedLists #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE PatternSynonyms #-}
+
+module Simplex.Messaging.Notifications.Server.Main where
+
+import Data.Either (fromRight)
+import Data.Functor (($>))
+import Data.Ini (lookupValue, readIniFile)
+import Data.Maybe (fromMaybe)
+import qualified Data.Text as T
+import Network.Socket (HostName)
+import Options.Applicative
+import Simplex.Messaging.Client.Agent (defaultSMPClientAgentConfig)
+import qualified Simplex.Messaging.Crypto as C
+import Simplex.Messaging.Notifications.Server (runNtfServer)
+import Simplex.Messaging.Notifications.Server.Env (NtfServerConfig (..))
+import Simplex.Messaging.Notifications.Server.Push.APNS (defaultAPNSPushClientConfig)
+import Simplex.Messaging.Protocol (ProtoServerWithAuth (..), pattern NtfServer)
+import Simplex.Messaging.Server.CLI
+import Simplex.Messaging.Transport.Client (TransportHost (..))
+import System.Directory (createDirectoryIfMissing, doesFileExist)
+import System.FilePath (combine)
+import System.IO (BufferMode (..), hSetBuffering, stderr, stdout)
+import Text.Read (readMaybe)
+
+ntfServerVersion :: String
+ntfServerVersion = "1.3.0"
+
+ntfServerCLI :: FilePath -> FilePath -> IO ()
+ntfServerCLI cfgPath logPath =
+  getCliCommand' (cliCommandP cfgPath logPath iniFile) serverVersion >>= \case
+    Init opts ->
+      doesFileExist iniFile >>= \case
+        True -> exitError $ "Error: server is already initialized (" <> iniFile <> " exists).\nRun `" <> executableName <> " start`."
+        _ -> initializeServer opts
+    Start ->
+      doesFileExist iniFile >>= \case
+        True -> readIniFile iniFile >>= either exitError runServer
+        _ -> exitError $ "Error: server is not initialized (" <> iniFile <> " does not exist).\nRun `" <> executableName <> " init`."
+    Delete -> do
+      confirmOrExit "WARNING: deleting the server will make all queues inaccessible, because the server identity (certificate fingerprint) will change.\nTHIS CANNOT BE UNDONE!"
+      deleteDirIfExists cfgPath
+      deleteDirIfExists logPath
+      putStrLn "Deleted configuration and log files"
+  where
+    iniFile = combine cfgPath "ntf-server.ini"
+    serverVersion = "SMP notifications server v" <> ntfServerVersion
+    defaultServerPort = "443"
+    executableName = "ntf-server"
+    storeLogFilePath = combine logPath "ntf-server-store.log"
+    initializeServer InitOptions {enableStoreLog, signAlgorithm, ip, fqdn} = do
+      clearDirIfExists cfgPath
+      clearDirIfExists logPath
+      createDirectoryIfMissing True cfgPath
+      createDirectoryIfMissing True logPath
+      let x509cfg = defaultX509Config {commonName = fromMaybe ip fqdn, signAlgorithm}
+      fp <- createServerX509 cfgPath x509cfg
+      let host = fromMaybe (if ip == "127.0.0.1" then "<hostnames>" else ip) fqdn
+          srv = ProtoServerWithAuth (NtfServer [THDomainName host] "" (C.KeyHash fp)) Nothing
+      writeFile iniFile $ iniFileContent host
+      putStrLn $ "Server initialized, you can modify configuration in " <> iniFile <> ".\nRun `" <> executableName <> " start` to start server."
+      warnCAPrivateKeyFile cfgPath x509cfg
+      printServiceInfo serverVersion srv
+      where
+        iniFileContent host =
+          "[STORE_LOG]\n\
+          \# The server uses STM memory for persistence,\n\
+          \# that will be lost on restart (e.g., as with redis).\n\
+          \# This option enables saving memory to append only log,\n\
+          \# and restoring it when the server is started.\n\
+          \# Log is compacted on start (deleted objects are removed).\n"
+            <> ("enable: " <> onOff enableStoreLog <> "\n\n")
+            <> "log_stats: off\n\n\
+               \[TRANSPORT]\n\
+               \# host is only used to print server address on start\n"
+            <> ("host: " <> host <> "\n")
+            <> ("port: " <> defaultServerPort <> "\n")
+            <> "log_tls_errors: off\n\
+               \websockets: off\n"
+    runServer ini = do
+      hSetBuffering stdout LineBuffering
+      hSetBuffering stderr LineBuffering
+      fp <- checkSavedFingerprint cfgPath defaultX509Config
+      let host = fromRight "<hostnames>" $ T.unpack <$> lookupValue "TRANSPORT" "host" ini
+          port = T.unpack $ strictIni "TRANSPORT" "port" ini
+          cfg@NtfServerConfig {transports, storeLogFile} = serverConfig
+          srv = ProtoServerWithAuth (NtfServer [THDomainName host] (if port == "443" then "" else port) (C.KeyHash fp)) Nothing
+      printServiceInfo serverVersion srv
+      printServerConfig transports storeLogFile
+      runNtfServer cfg
+      where
+        enableStoreLog = settingIsOn "STORE_LOG" "enable" ini
+        logStats = settingIsOn "STORE_LOG" "log_stats" ini
+        c = combine cfgPath . ($ defaultX509Config)
+        serverConfig =
+          NtfServerConfig
+            { transports = iniTransports ini,
+              subIdBytes = 24,
+              regCodeBytes = 32,
+              clientQSize = 16,
+              subQSize = 64,
+              pushQSize = 128,
+              smpAgentCfg = defaultSMPClientAgentConfig,
+              apnsConfig = defaultAPNSPushClientConfig,
+              inactiveClientExpiration = Nothing,
+              storeLogFile = enableStoreLog $> storeLogFilePath,
+              resubscribeDelay = 50000, -- 50ms
+              caCertificateFile = c caCrtFile,
+              privateKeyFile = c serverKeyFile,
+              certificateFile = c serverCrtFile,
+              logStatsInterval = logStats $> 86400, -- seconds
+              logStatsStartTime = 0, -- seconds from 00:00 UTC
+              serverStatsLogFile = combine logPath "ntf-server-stats.daily.log",
+              serverStatsBackupFile = logStats $> combine logPath "ntf-server-stats.log",
+              logTLSErrors = fromMaybe False $ iniOnOff "TRANSPORT" "log_tls_errors" ini
+            }
+
+data CliCommand
+  = Init InitOptions
+  | Start
+  | Delete
+
+data InitOptions = InitOptions
+  { enableStoreLog :: Bool,
+    signAlgorithm :: SignAlgorithm,
+    ip :: HostName,
+    fqdn :: Maybe HostName
+  }
+  deriving (Show)
+
+cliCommandP :: FilePath -> FilePath -> FilePath -> Parser CliCommand
+cliCommandP cfgPath logPath iniFile =
+  hsubparser
+    ( command "init" (info (Init <$> initP) (progDesc $ "Initialize server - creates " <> cfgPath <> " and " <> logPath <> " directories and configuration files"))
+        <> command "start" (info (pure Start) (progDesc $ "Start server (configuration: " <> iniFile <> ")"))
+        <> command "delete" (info (pure Delete) (progDesc "Delete configuration and log files"))
+    )
+  where
+    initP :: Parser InitOptions
+    initP =
+      InitOptions
+        <$> switch
+          ( long "store-log"
+              <> short 'l'
+              <> help "Enable store log for persistence"
+          )
+        <*> option
+          (maybeReader readMaybe)
+          ( long "sign-algorithm"
+              <> short 'a'
+              <> help "Signature algorithm used for TLS certificates: ED25519, ED448"
+              <> value ED448
+              <> showDefault
+              <> metavar "ALG"
+          )
+        <*> strOption
+          ( long "ip"
+              <> help
+                "Server IP address, used as Common Name for TLS online certificate if FQDN is not supplied"
+              <> value "127.0.0.1"
+              <> showDefault
+              <> metavar "IP"
+          )
+        <*> (optional . strOption)
+          ( long "fqdn"
+              <> short 'n'
+              <> help "Server FQDN used as Common Name for TLS online certificate"
+              <> showDefault
+              <> metavar "FQDN"
+          )
@@ -0,0 +1 @@
+local.env
@@ -0,0 +1,373 @@
+{-# LANGUAGE DeriveAnyClass #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# OPTIONS_GHC -Wno-unrecognised-pragmas #-}
+
+{-# HLINT ignore "Use newtype instead of data" #-}
+
+module Simplex.Messaging.Notifications.Server.Push.APNS where
+
+import Control.Exception (Exception)
+import Control.Logger.Simple
+import Control.Monad.Except
+import Crypto.Hash.Algorithms (SHA256 (..))
+import qualified Crypto.PubKey.ECC.ECDSA as EC
+import qualified Crypto.PubKey.ECC.Types as ECT
+import Crypto.Random (ChaChaDRG, drgNew)
+import qualified Crypto.Store.PKCS8 as PK
+import Data.ASN1.BinaryEncoding (DER (..))
+import Data.ASN1.Encoding
+import Data.ASN1.Types
+import Data.Aeson (FromJSON, ToJSON, (.=))
+import qualified Data.Aeson as J
+import qualified Data.Aeson.Encoding as JE
+import Data.Bifunctor (first)
+import qualified Data.ByteString.Base64.URL as U
+import Data.ByteString.Builder (lazyByteString)
+import Data.ByteString.Char8 (ByteString)
+import qualified Data.ByteString.Lazy.Char8 as LB
+import qualified Data.CaseInsensitive as CI
+import Data.Int (Int64)
+import Data.Map.Strict (Map)
+import Data.Text (Text)
+import qualified Data.Text as T
+import Data.Time.Clock.System
+import qualified Data.X509 as X
+import GHC.Generics (Generic)
+import Network.HTTP.Types (HeaderName, Status)
+import qualified Network.HTTP.Types as N
+import Network.HTTP2.Client (Request)
+import qualified Network.HTTP2.Client as H
+import Network.Socket (HostName, ServiceName)
+import qualified Simplex.Messaging.Crypto as C
+import Simplex.Messaging.Encoding.String
+import Simplex.Messaging.Notifications.Protocol
+import Simplex.Messaging.Notifications.Server.Store (NtfTknData (..))
+import Simplex.Messaging.Protocol (EncNMsgMeta)
+import Simplex.Messaging.Transport.HTTP2.Client
+import Simplex.Messaging.Util (safeDecodeUtf8)
+import System.Environment (getEnv)
+import UnliftIO.STM
+
+data JWTHeader = JWTHeader
+  { alg :: Text, -- key algorithm, ES256 for APNS
+    kid :: Text -- key ID
+  }
+  deriving (Show, Generic)
+
+instance ToJSON JWTHeader where toEncoding = J.genericToEncoding J.defaultOptions
+
+data JWTClaims = JWTClaims
+  { iss :: Text, -- issuer, team ID for APNS
+    iat :: Int64 -- issue time, seconds from epoch
+  }
+  deriving (Show, Generic)
+
+instance ToJSON JWTClaims where toEncoding = J.genericToEncoding J.defaultOptions
+
+data JWTToken = JWTToken JWTHeader JWTClaims
+  deriving (Show)
+
+mkJWTToken :: JWTHeader -> Text -> IO JWTToken
+mkJWTToken hdr iss = do
+  iat <- systemSeconds <$> getSystemTime
+  pure $ JWTToken hdr JWTClaims {iss, iat}
+
+type SignedJWTToken = ByteString
+
+signedJWTToken :: EC.PrivateKey -> JWTToken -> IO SignedJWTToken
+signedJWTToken pk (JWTToken hdr claims) = do
+  let hc = jwtEncode hdr <> "." <> jwtEncode claims
+  sig <- EC.sign pk SHA256 hc
+  pure $ hc <> "." <> serialize sig
+  where
+    jwtEncode :: ToJSON a => a -> ByteString
+    jwtEncode = U.encodeUnpadded . LB.toStrict . J.encode
+    serialize sig = U.encodeUnpadded $ encodeASN1' DER [Start Sequence, IntVal (EC.sign_r sig), IntVal (EC.sign_s sig), End Sequence]
+
+readECPrivateKey :: FilePath -> IO EC.PrivateKey
+readECPrivateKey f = do
+  -- this pattern match is specific to APNS key type, it may need to be extended for other push providers
+  [PK.Unprotected (X.PrivKeyEC X.PrivKeyEC_Named {privkeyEC_name, privkeyEC_priv})] <- PK.readKeyFile f
+  pure EC.PrivateKey {private_curve = ECT.getCurveByName privkeyEC_name, private_d = privkeyEC_priv}
+
+data PushNotification
+  = PNVerification NtfRegCode
+  | PNMessage PNMessageData
+  -- | PNAlert Text
+  | PNCheckMessages
+  deriving (Show)
+
+data PNMessageData = PNMessageData
+  { smpQueue :: SMPQueueNtf,
+    ntfTs :: SystemTime,
+    nmsgNonce :: C.CbNonce,
+    encNMsgMeta :: EncNMsgMeta
+  }
+  deriving (Show)
+
+instance StrEncoding PNMessageData where
+  strEncode PNMessageData {smpQueue, ntfTs, nmsgNonce, encNMsgMeta} =
+    strEncode (smpQueue, ntfTs, nmsgNonce, encNMsgMeta)
+  strP = do
+    (smpQueue, ntfTs, nmsgNonce, encNMsgMeta) <- strP
+    pure PNMessageData {smpQueue, ntfTs, nmsgNonce, encNMsgMeta}
+
+data APNSNotification = APNSNotification {aps :: APNSNotificationBody, notificationData :: Maybe J.Value}
+  deriving (Show, Generic)
+
+instance ToJSON APNSNotification where
+  toJSON = J.genericToJSON J.defaultOptions {J.omitNothingFields = True}
+  toEncoding = J.genericToEncoding J.defaultOptions {J.omitNothingFields = True}
+
+data APNSNotificationBody
+  = APNSBackground {contentAvailable :: Int}
+  | APNSMutableContent {mutableContent :: Int, alert :: APNSAlertBody, category :: Maybe Text}
+  | APNSAlert {alert :: APNSAlertBody, badge :: Maybe Int, sound :: Maybe Text, category :: Maybe Text}
+  deriving (Show, Generic)
+
+apnsJSONOptions :: J.Options
+apnsJSONOptions = J.defaultOptions {J.omitNothingFields = True, J.sumEncoding = J.UntaggedValue, J.fieldLabelModifier = J.camelTo2 '-'}
+
+instance ToJSON APNSNotificationBody where
+  toJSON = J.genericToJSON apnsJSONOptions
+  toEncoding = J.genericToEncoding apnsJSONOptions
+
+type APNSNotificationData = Map Text Text
+
+data APNSAlertBody = APNSAlertObject {title :: Text, subtitle :: Text, body :: Text} | APNSAlertText Text
+  deriving (Show)
+
+instance ToJSON APNSAlertBody where
+  toEncoding = \case
+    APNSAlertObject {title, subtitle, body} -> J.pairs $ "title" .= title <> "subtitle" .= subtitle <> "body" .= body
+    APNSAlertText t -> JE.text t
+  toJSON = \case
+    APNSAlertObject {title, subtitle, body} -> J.object ["title" .= title, "subtitle" .= subtitle, "body" .= body]
+    APNSAlertText t -> J.String t
+
+-- APNS notification types
+--
+-- Visible alerts:
+-- {
+--    "aps" : {
+--       "alert" : {
+--          "title" : "Game Request",
+--          "subtitle" : "Five Card Draw",
+--          "body" : "Bob wants to play poker"
+--       },
+--       "badge" : 9,
+--       "sound" : "bingbong.aiff",
+--       "category" : "GAME_INVITATION"
+--    },
+--    "gameID" : "12345678"
+-- }
+--
+-- Simple text alert:
+-- {"aps":{"alert":"you have a new message"}}
+--
+-- Background notification to fetch content
+-- {"aps":{"content-available":1}}
+--
+-- Mutable content notification that must be shown but can be processed before before being shown (up to 30 sec)
+-- {
+--    "aps" : {
+--       "category" : "SECRET",
+--       "mutable-content" : 1,
+--       "alert" : {
+--          "title" : "Secret Message!",
+--          "body"  : "(Encrypted)"
+--      },
+--    },
+--    "ENCRYPTED_DATA" : "Salted__·öîQÊ$UDì_¶Ù∞èΩ^¬%gq∞NÿÒQùw"
+-- }
+
+data APNSPushClientConfig = APNSPushClientConfig
+  { tokenTTL :: Int64,
+    authKeyFileEnv :: String,
+    authKeyAlg :: Text,
+    authKeyIdEnv :: String,
+    paddedNtfLength :: Int,
+    appName :: ByteString,
+    appTeamId :: Text,
+    apnsPort :: ServiceName,
+    http2cfg :: HTTP2ClientConfig
+  }
+  deriving (Show)
+
+apnsProviderHost :: PushProvider -> HostName
+apnsProviderHost = \case
+  PPApnsTest -> "localhost"
+  PPApnsDev -> "api.sandbox.push.apple.com"
+  PPApnsProd -> "api.push.apple.com"
+
+defaultAPNSPushClientConfig :: APNSPushClientConfig
+defaultAPNSPushClientConfig =
+  APNSPushClientConfig
+    { tokenTTL = 1800, -- 30 minutes
+      authKeyFileEnv = "APNS_KEY_FILE", -- the environment variables APNS_KEY_FILE and APNS_KEY_ID must be set, or the server would fail to start
+      authKeyAlg = "ES256",
+      authKeyIdEnv = "APNS_KEY_ID",
+      paddedNtfLength = 512,
+      appName = "chat.simplex.app",
+      appTeamId = "5NN7GUYB6T",
+      apnsPort = "443",
+      http2cfg = defaultHTTP2ClientConfig
+    }
+
+data APNSPushClient = APNSPushClient
+  { https2Client :: TVar (Maybe HTTP2Client),
+    privateKey :: EC.PrivateKey,
+    jwtHeader :: JWTHeader,
+    jwtToken :: TVar (JWTToken, SignedJWTToken),
+    nonceDrg :: TVar ChaChaDRG,
+    apnsHost :: HostName,
+    apnsCfg :: APNSPushClientConfig
+  }
+
+createAPNSPushClient :: HostName -> APNSPushClientConfig -> IO APNSPushClient
+createAPNSPushClient apnsHost apnsCfg@APNSPushClientConfig {authKeyFileEnv, authKeyAlg, authKeyIdEnv, appTeamId} = do
+  https2Client <- newTVarIO Nothing
+  void $ connectHTTPS2 apnsHost apnsCfg https2Client
+  privateKey <- readECPrivateKey =<< getEnv authKeyFileEnv
+  authKeyId <- T.pack <$> getEnv authKeyIdEnv
+  let jwtHeader = JWTHeader {alg = authKeyAlg, kid = authKeyId}
+  jwtToken <- newTVarIO =<< mkApnsJWTToken appTeamId jwtHeader privateKey
+  nonceDrg <- drgNew >>= newTVarIO
+  pure APNSPushClient {https2Client, privateKey, jwtHeader, jwtToken, nonceDrg, apnsHost, apnsCfg}
+
+getApnsJWTToken :: APNSPushClient -> IO SignedJWTToken
+getApnsJWTToken APNSPushClient {apnsCfg = APNSPushClientConfig {appTeamId, tokenTTL}, privateKey, jwtHeader, jwtToken} = do
+  (jwt, signedJWT) <- readTVarIO jwtToken
+  age <- jwtTokenAge jwt
+  if age < tokenTTL
+    then pure signedJWT
+    else do
+      t@(_, signedJWT') <- mkApnsJWTToken appTeamId jwtHeader privateKey
+      atomically $ writeTVar jwtToken t
+      pure signedJWT'
+  where
+    jwtTokenAge (JWTToken _ JWTClaims {iat}) = subtract iat . systemSeconds <$> getSystemTime
+
+mkApnsJWTToken :: Text -> JWTHeader -> EC.PrivateKey -> IO (JWTToken, SignedJWTToken)
+mkApnsJWTToken appTeamId jwtHeader privateKey = do
+  jwt <- mkJWTToken jwtHeader appTeamId
+  signedJWT <- signedJWTToken privateKey jwt
+  pure (jwt, signedJWT)
+
+connectHTTPS2 :: HostName -> APNSPushClientConfig -> TVar (Maybe HTTP2Client) -> IO (Either HTTP2ClientError HTTP2Client)
+connectHTTPS2 apnsHost APNSPushClientConfig {apnsPort, http2cfg} https2Client = do
+  r <- getHTTP2Client apnsHost apnsPort http2cfg disconnected
+  case r of
+    Right client -> atomically . writeTVar https2Client $ Just client
+    Left e -> putStrLn $ "Error connecting to APNS: " <> show e
+  pure r
+  where
+    disconnected = atomically $ writeTVar https2Client Nothing
+
+getApnsHTTP2Client :: APNSPushClient -> IO (Either HTTP2ClientError HTTP2Client)
+getApnsHTTP2Client APNSPushClient {https2Client, apnsHost, apnsCfg} =
+  readTVarIO https2Client >>= maybe (connectHTTPS2 apnsHost apnsCfg https2Client) (pure . Right)
+
+disconnectApnsHTTP2Client :: APNSPushClient -> IO ()
+disconnectApnsHTTP2Client APNSPushClient {https2Client} =
+  readTVarIO https2Client >>= mapM_ closeHTTP2Client >> atomically (writeTVar https2Client Nothing)
+
+ntfCategoryCheckMessage :: Text
+ntfCategoryCheckMessage = "NTF_CAT_CHECK_MESSAGE"
+
+apnsNotification :: NtfTknData -> C.CbNonce -> Int -> PushNotification -> Either C.CryptoError APNSNotification
+apnsNotification NtfTknData {tknDhSecret} nonce paddedLen = \case
+  PNVerification (NtfRegCode code) ->
+    encrypt code $ \code' ->
+      apn APNSBackground {contentAvailable = 1} . Just $ J.object ["nonce" .= nonce, "verification" .= code']
+  PNMessage pnMessageData ->
+    encrypt (strEncode pnMessageData) $ \ntfData ->
+      apn apnMutableContent . Just $ J.object ["nonce" .= nonce, "message" .= ntfData]
+  -- PNAlert text -> Right $ apn (apnAlert $ APNSAlertText text) Nothing
+  PNCheckMessages -> Right $ apn APNSBackground {contentAvailable = 1} . Just $ J.object ["checkMessages" .= True]
+  where
+    encrypt :: ByteString -> (Text -> APNSNotification) -> Either C.CryptoError APNSNotification
+    encrypt ntfData f = f . safeDecodeUtf8 . U.encode <$> C.cbEncrypt tknDhSecret nonce ntfData paddedLen
+    apn aps notificationData = APNSNotification {aps, notificationData}
+    apnMutableContent = APNSMutableContent {mutableContent = 1, alert = APNSAlertText "Encrypted message or another app event", category = Just ntfCategoryCheckMessage}
+    -- apnAlert alert = APNSAlert {alert, badge = Nothing, sound = Nothing, category = Nothing}
+
+apnsRequest :: APNSPushClient -> ByteString -> APNSNotification -> IO Request
+apnsRequest c tkn ntf@APNSNotification {aps} = do
+  signedJWT <- getApnsJWTToken c
+  pure $ H.requestBuilder N.methodPost path (headers signedJWT) (lazyByteString $ J.encode ntf)
+  where
+    path = "/3/device/" <> tkn
+    headers signedJWT =
+      [ (hApnsTopic, appName $ apnsCfg (c :: APNSPushClient)),
+        (hApnsPushType, pushType aps),
+        (N.hAuthorization, "bearer " <> signedJWT)
+      ]
+        <> [(hApnsPriority, "5") | isBackground aps]
+    isBackground = \case
+      APNSBackground {} -> True
+      _ -> False
+    pushType = \case
+      APNSBackground {} -> "background"
+      _ -> "alert"
+
+data PushProviderError
+  = PPConnection HTTP2ClientError
+  | PPCryptoError C.CryptoError
+  | PPResponseError (Maybe Status) Text
+  | PPTokenInvalid
+  | PPRetryLater
+  | PPPermanentError
+  deriving (Show, Exception)
+
+type PushProviderClient = NtfTknData -> PushNotification -> ExceptT PushProviderError IO ()
+
+-- this is not a newtype on purpose to have a correct JSON encoding as a record
+data APNSErrorResponse = APNSErrorResponse {reason :: Text}
+  deriving (Generic, FromJSON)
+
+apnsPushProviderClient :: APNSPushClient -> PushProviderClient
+apnsPushProviderClient c@APNSPushClient {nonceDrg, apnsCfg} tkn@NtfTknData {token = DeviceToken _ tknStr} pn = do
+  http2 <- liftHTTPS2 $ getApnsHTTP2Client c
+  nonce <- atomically $ C.pseudoRandomCbNonce nonceDrg
+  apnsNtf <- liftEither $ first PPCryptoError $ apnsNotification tkn nonce (paddedNtfLength apnsCfg) pn
+  req <- liftIO $ apnsRequest c tknStr apnsNtf
+  HTTP2Response {response, respBody} <- liftHTTPS2 $ sendRequest http2 req
+  let status = H.responseStatus response
+      reason' = maybe "" reason $ J.decodeStrict' respBody
+  logDebug $ "APNS response: " <> T.pack (show status) <> " " <> reason'
+  result status reason'
+  where
+    result :: Maybe Status -> Text -> ExceptT PushProviderError IO ()
+    result status reason'
+      | status == Just N.ok200 = pure ()
+      | status == Just N.badRequest400 =
+        case reason' of
+          "BadDeviceToken" -> throwError PPTokenInvalid
+          "DeviceTokenNotForTopic" -> throwError PPTokenInvalid
+          "TopicDisallowed" -> throwError PPPermanentError
+          _ -> err status reason'
+      | status == Just N.forbidden403 = case reason' of
+        "ExpiredProviderToken" -> throwError PPPermanentError -- there should be no point retrying it as the token was refreshed
+        "InvalidProviderToken" -> throwError PPPermanentError
+        _ -> err status reason'
+      | status == Just N.gone410 = throwError PPTokenInvalid
+      | status == Just N.serviceUnavailable503 = liftIO (disconnectApnsHTTP2Client c) >> throwError PPRetryLater
+      -- Just tooManyRequests429 -> TooManyRequests - too many requests for the same token
+      | otherwise = err status reason'
+    err :: Maybe Status -> Text -> ExceptT PushProviderError IO ()
+    err s r = throwError $ PPResponseError s r
+    liftHTTPS2 a = ExceptT $ first PPConnection <$> a
+
+hApnsTopic :: HeaderName
+hApnsTopic = CI.mk "apns-topic"
+
+hApnsPushType :: HeaderName
+hApnsPushType = CI.mk "apns-push-type"
+
+hApnsPriority :: HeaderName
+hApnsPriority = CI.mk "apns-priority"
@@ -0,0 +1,26 @@
+#!/bin/sh
+
+export TEAM_ID=5NN7GUYB6T
+# export APNS_KEY_FILE=""
+# export APNS_KEY_ID=""
+export TOPIC=chat.simplex.app
+# export DEVICE_TOKEN=
+export APNS_HOST_NAME=api.sandbox.push.apple.com
+
+export JWT_ISSUE_TIME=$(date +%s)
+export JWT_HEADER=$(printf '{"alg":"ES256","kid":"%s"}' "${APNS_KEY_ID}" | openssl base64 -e -A | tr -- '+/' '-_' | tr -d =)
+export JWT_CLAIMS=$(printf '{"iss":"%s","iat":%d}' "${TEAM_ID}" "${JWT_ISSUE_TIME}" | openssl base64 -e -A | tr -- '+/' '-_' | tr -d =)
+export JWT_HEADER_CLAIMS="${JWT_HEADER}.${JWT_CLAIMS}"
+
+export JWT_SIGNED_HEADER_CLAIMS=$(printf "${JWT_HEADER_CLAIMS}" | openssl dgst -binary -sha256 -sign "${APNS_KEY_FILE}" | openssl base64 -e -A | tr -- '+/' '-_' | tr -d =)
+export AUTHENTICATION_TOKEN="${JWT_HEADER}.${JWT_CLAIMS}.${JWT_SIGNED_HEADER_CLAIMS}"
+
+# simple alert
+# curl -v --header "apns-topic: $TOPIC" --header "apns-push-type: alert" --header "authorization: bearer $AUTHENTICATION_TOKEN" --data '{"aps":{"alert":"you have a new message"},"data":{"test":"123"}}' --http2 https://${APNS_HOST_NAME}/3/device/${DEVICE_TOKEN}
+
+# background notification
+# curl -v --header "apns-topic: $TOPIC" --header "apns-push-type: background" --header "apns-priority: 5" --header "authorization: bearer $AUTHENTICATION_TOKEN" --data '{"aps":{"content-available":1}}' --http2 https://${APNS_HOST_NAME}/3/device/${DEVICE_TOKEN}
+
+# mutable-content notification
+# NTF_CAT_CHECK_MESSAGE category will not show alert if the app is in foreground
+curl -v --header "apns-topic: $TOPIC" --header "apns-push-type: alert" --header "authorization: bearer $AUTHENTICATION_TOKEN" --data '{"aps":{"category": "NTF_CAT_CHECK_MESSAGE__SECRET", "mutable-content": 1, "alert":"received encrypted message"}, "data": {"test":"123"}}' --http2 https://${APNS_HOST_NAME}/3/device/${DEVICE_TOKEN}
@@ -0,0 +1,113 @@
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+module Simplex.Messaging.Notifications.Server.Stats where
+
+import Control.Applicative (optional)
+import qualified Data.Attoparsec.ByteString.Char8 as A
+import qualified Data.ByteString.Char8 as B
+import Data.Time.Clock (UTCTime)
+import Simplex.Messaging.Encoding.String
+import Simplex.Messaging.Notifications.Protocol (NtfTokenId)
+import Simplex.Messaging.Protocol (NotifierId)
+import Simplex.Messaging.Server.Stats
+import UnliftIO.STM
+
+data NtfServerStats = NtfServerStats
+  { fromTime :: TVar UTCTime,
+    tknCreated :: TVar Int,
+    tknVerified :: TVar Int,
+    tknDeleted :: TVar Int,
+    subCreated :: TVar Int,
+    subDeleted :: TVar Int,
+    ntfReceived :: TVar Int,
+    ntfDelivered :: TVar Int,
+    activeTokens :: PeriodStats NtfTokenId,
+    activeSubs :: PeriodStats NotifierId
+  }
+
+data NtfServerStatsData = NtfServerStatsData
+  { _fromTime :: UTCTime,
+    _tknCreated :: Int,
+    _tknVerified :: Int,
+    _tknDeleted :: Int,
+    _subCreated :: Int,
+    _subDeleted :: Int,
+    _ntfReceived :: Int,
+    _ntfDelivered :: Int,
+    _activeTokens :: PeriodStatsData NtfTokenId,
+    _activeSubs :: PeriodStatsData NotifierId
+  }
+
+newNtfServerStats :: UTCTime -> STM NtfServerStats
+newNtfServerStats ts = do
+  fromTime <- newTVar ts
+  tknCreated <- newTVar 0
+  tknVerified <- newTVar 0
+  tknDeleted <- newTVar 0
+  subCreated <- newTVar 0
+  subDeleted <- newTVar 0
+  ntfReceived <- newTVar 0
+  ntfDelivered <- newTVar 0
+  activeTokens <- newPeriodStats
+  activeSubs <- newPeriodStats
+  pure NtfServerStats {fromTime, tknCreated, tknVerified, tknDeleted, subCreated, subDeleted, ntfReceived, ntfDelivered, activeTokens, activeSubs}
+
+getNtfServerStatsData :: NtfServerStats -> STM NtfServerStatsData
+getNtfServerStatsData s = do
+  _fromTime <- readTVar $ fromTime (s :: NtfServerStats)
+  _tknCreated <- readTVar $ tknCreated s
+  _tknVerified <- readTVar $ tknVerified s
+  _tknDeleted <- readTVar $ tknDeleted s
+  _subCreated <- readTVar $ subCreated s
+  _subDeleted <- readTVar $ subDeleted s
+  _ntfReceived <- readTVar $ ntfReceived s
+  _ntfDelivered <- readTVar $ ntfDelivered s
+  _activeTokens <- getPeriodStatsData $ activeTokens s
+  _activeSubs <- getPeriodStatsData $ activeSubs s
+  pure NtfServerStatsData {_fromTime, _tknCreated, _tknVerified, _tknDeleted, _subCreated, _subDeleted, _ntfReceived, _ntfDelivered, _activeTokens, _activeSubs}
+
+setNtfServerStats :: NtfServerStats -> NtfServerStatsData -> STM ()
+setNtfServerStats s d = do
+  writeTVar (fromTime (s :: NtfServerStats)) $! _fromTime (d :: NtfServerStatsData)
+  writeTVar (tknCreated s) $! _tknCreated d
+  writeTVar (tknVerified s) $! _tknVerified d
+  writeTVar (tknDeleted s) $! _tknDeleted d
+  writeTVar (subCreated s) $! _subCreated d
+  writeTVar (subDeleted s) $! _subDeleted d
+  writeTVar (ntfReceived s) $! _ntfReceived d
+  writeTVar (ntfDelivered s) $! _ntfDelivered d
+  setPeriodStats (activeTokens s) (_activeTokens d)
+  setPeriodStats (activeSubs s) (_activeSubs d)
+
+instance StrEncoding NtfServerStatsData where
+  strEncode NtfServerStatsData {_fromTime, _tknCreated, _tknVerified, _tknDeleted, _subCreated, _subDeleted, _ntfReceived, _ntfDelivered, _activeTokens, _activeSubs} =
+    B.unlines
+      [ "fromTime=" <> strEncode _fromTime,
+        "tknCreated=" <> strEncode _tknCreated,
+        "tknVerified=" <> strEncode _tknVerified,
+        "tknDeleted=" <> strEncode _tknDeleted,
+        "subCreated=" <> strEncode _subCreated,
+        "subDeleted=" <> strEncode _subDeleted,
+        "ntfReceived=" <> strEncode _ntfReceived,
+        "ntfDelivered=" <> strEncode _ntfDelivered,
+        "activeTokens:",
+        strEncode _activeTokens,
+        "activeSubs:",
+        strEncode _activeSubs
+      ]
+  strP = do
+    _fromTime <- "fromTime=" *> strP <* A.endOfLine
+    _tknCreated <- "tknCreated=" *> strP <* A.endOfLine
+    _tknVerified <- "tknVerified=" *> strP <* A.endOfLine
+    _tknDeleted <- "tknDeleted=" *> strP <* A.endOfLine
+    _subCreated <- "subCreated=" *> strP <* A.endOfLine
+    _subDeleted <- "subDeleted=" *> strP <* A.endOfLine
+    _ntfReceived <- "ntfReceived=" *> strP <* A.endOfLine
+    _ntfDelivered <- "ntfDelivered=" *> strP <* A.endOfLine
+    _ <- "activeTokens:" <* A.endOfLine
+    _activeTokens <- strP <* A.endOfLine
+    _ <- "activeSubs:" <* A.endOfLine
+    _activeSubs <- strP <* optional A.endOfLine
+    pure NtfServerStatsData {_fromTime, _tknCreated, _tknVerified, _tknDeleted, _subCreated, _subDeleted, _ntfReceived, _ntfDelivered, _activeTokens, _activeSubs}
@@ -0,0 +1,193 @@
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE KindSignatures #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+
+module Simplex.Messaging.Notifications.Server.Store where
+
+import Control.Concurrent.STM
+import Control.Monad
+import Data.ByteString.Char8 (ByteString)
+import Data.Functor (($>))
+import qualified Data.Map.Strict as M
+import Data.Maybe (catMaybes)
+import Data.Set (Set)
+import qualified Data.Set as S
+import Data.Word (Word16)
+import qualified Simplex.Messaging.Crypto as C
+import Simplex.Messaging.Notifications.Protocol
+import Simplex.Messaging.Protocol (NtfPrivateSignKey)
+import Simplex.Messaging.TMap (TMap)
+import qualified Simplex.Messaging.TMap as TM
+import Simplex.Messaging.Util (whenM, ($>>=))
+
+data NtfStore = NtfStore
+  { tokens :: TMap NtfTokenId NtfTknData,
+    -- multiple registrations exist to protect from malicious registrations if token is compromised
+    tokenRegistrations :: TMap DeviceToken (TMap ByteString NtfTokenId),
+    subscriptions :: TMap NtfSubscriptionId NtfSubData,
+    tokenSubscriptions :: TMap NtfTokenId (TVar (Set NtfSubscriptionId)),
+    subscriptionLookup :: TMap SMPQueueNtf NtfSubscriptionId
+  }
+
+newNtfStore :: STM NtfStore
+newNtfStore = do
+  tokens <- TM.empty
+  tokenRegistrations <- TM.empty
+  subscriptions <- TM.empty
+  tokenSubscriptions <- TM.empty
+  subscriptionLookup <- TM.empty
+  pure NtfStore {tokens, tokenRegistrations, subscriptions, tokenSubscriptions, subscriptionLookup}
+
+data NtfTknData = NtfTknData
+  { ntfTknId :: NtfTokenId,
+    token :: DeviceToken,
+    tknStatus :: TVar NtfTknStatus,
+    tknVerifyKey :: C.APublicVerifyKey,
+    tknDhKeys :: C.KeyPair 'C.X25519,
+    tknDhSecret :: C.DhSecretX25519,
+    tknRegCode :: NtfRegCode,
+    tknCronInterval :: TVar Word16
+  }
+
+mkNtfTknData :: NtfTokenId -> NewNtfEntity 'Token -> C.KeyPair 'C.X25519 -> C.DhSecretX25519 -> NtfRegCode -> STM NtfTknData
+mkNtfTknData ntfTknId (NewNtfTkn token tknVerifyKey _) tknDhKeys tknDhSecret tknRegCode = do
+  tknStatus <- newTVar NTRegistered
+  tknCronInterval <- newTVar 0
+  pure NtfTknData {ntfTknId, token, tknStatus, tknVerifyKey, tknDhKeys, tknDhSecret, tknRegCode, tknCronInterval}
+
+data NtfSubData = NtfSubData
+  { ntfSubId :: NtfSubscriptionId,
+    smpQueue :: SMPQueueNtf,
+    notifierKey :: NtfPrivateSignKey,
+    tokenId :: NtfTokenId,
+    subStatus :: TVar NtfSubStatus
+  }
+
+data NtfEntityRec (e :: NtfEntity) where
+  NtfTkn :: NtfTknData -> NtfEntityRec 'Token
+  NtfSub :: NtfSubData -> NtfEntityRec 'Subscription
+
+getNtfToken :: NtfStore -> NtfTokenId -> STM (Maybe NtfTknData)
+getNtfToken st tknId = TM.lookup tknId (tokens st)
+
+addNtfToken :: NtfStore -> NtfTokenId -> NtfTknData -> STM ()
+addNtfToken st tknId tkn@NtfTknData {token, tknVerifyKey} = do
+  TM.insert tknId tkn $ tokens st
+  TM.lookup token regs >>= \case
+    Just tIds -> TM.insert regKey tknId tIds
+    _ -> do
+      tIds <- TM.singleton regKey tknId
+      TM.insert token tIds regs
+  where
+    regs = tokenRegistrations st
+    regKey = C.toPubKey C.pubKeyBytes tknVerifyKey
+
+getNtfTokenRegistration :: NtfStore -> NewNtfEntity 'Token -> STM (Maybe NtfTknData)
+getNtfTokenRegistration st (NewNtfTkn token tknVerifyKey _) =
+  TM.lookup token (tokenRegistrations st)
+    $>>= TM.lookup regKey
+    $>>= (`TM.lookup` tokens st)
+  where
+    regKey = C.toPubKey C.pubKeyBytes tknVerifyKey
+
+removeInactiveTokenRegistrations :: NtfStore -> NtfTknData -> STM [NtfTokenId]
+removeInactiveTokenRegistrations st NtfTknData {ntfTknId = tId, token} =
+  TM.lookup token (tokenRegistrations st)
+    >>= maybe (pure []) removeRegs
+  where
+    removeRegs :: TMap ByteString NtfTokenId -> STM [NtfTokenId]
+    removeRegs tknRegs = do
+      tIds <- filter ((/= tId) . snd) . M.assocs <$> readTVar tknRegs
+      forM_ tIds $ \(regKey, tId') -> do
+        TM.delete regKey tknRegs
+        TM.delete tId' $ tokens st
+        void $ deleteTokenSubs st tId'
+      pure $ map snd tIds
+
+removeTokenRegistration :: NtfStore -> NtfTknData -> STM ()
+removeTokenRegistration st NtfTknData {ntfTknId = tId, token, tknVerifyKey} =
+  TM.lookup token (tokenRegistrations st) >>= mapM_ removeReg
+  where
+    removeReg regs =
+      TM.lookup k regs
+        >>= mapM_ (\tId' -> when (tId == tId') $ TM.delete k regs)
+    k = C.toPubKey C.pubKeyBytes tknVerifyKey
+
+deleteNtfToken :: NtfStore -> NtfTokenId -> STM [SMPQueueNtf]
+deleteNtfToken st tknId = do
+  void $
+    TM.lookupDelete tknId (tokens st) $>>= \NtfTknData {token, tknVerifyKey} ->
+      TM.lookup token regs $>>= \tIds ->
+        TM.delete (regKey tknVerifyKey) tIds
+          >> whenM (TM.null tIds) (TM.delete token regs) $> Just ()
+  deleteTokenSubs st tknId
+  where
+    regs = tokenRegistrations st
+    regKey = C.toPubKey C.pubKeyBytes
+
+deleteTokenSubs :: NtfStore -> NtfTokenId -> STM [SMPQueueNtf]
+deleteTokenSubs st tknId = do
+  qs <-
+    TM.lookupDelete tknId (tokenSubscriptions st)
+      >>= mapM (readTVar >=> mapM deleteSub . S.toList)
+  pure $ maybe [] catMaybes qs
+  where
+    deleteSub subId = do
+      TM.lookupDelete subId (subscriptions st)
+        $>>= \NtfSubData {smpQueue} ->
+          TM.delete smpQueue (subscriptionLookup st) $> Just smpQueue
+
+getNtfSubscription :: NtfStore -> NtfSubscriptionId -> STM (Maybe NtfSubData)
+getNtfSubscription st subId =
+  TM.lookup subId (subscriptions st)
+
+findNtfSubscription :: NtfStore -> SMPQueueNtf -> STM (Maybe NtfSubData)
+findNtfSubscription st smpQueue = do
+  TM.lookup smpQueue (subscriptionLookup st)
+    $>>= \subId -> TM.lookup subId (subscriptions st)
+
+findNtfSubscriptionToken :: NtfStore -> SMPQueueNtf -> STM (Maybe NtfTknData)
+findNtfSubscriptionToken st smpQueue = do
+  findNtfSubscription st smpQueue
+    $>>= \NtfSubData {tokenId} -> getActiveNtfToken st tokenId
+
+getActiveNtfToken :: NtfStore -> NtfTokenId -> STM (Maybe NtfTknData)
+getActiveNtfToken st tknId =
+  getNtfToken st tknId $>>= \tkn@NtfTknData {tknStatus} -> do
+    tStatus <- readTVar tknStatus
+    pure $ if tStatus == NTActive then Just tkn else Nothing
+
+mkNtfSubData :: NtfSubscriptionId -> NewNtfEntity 'Subscription -> STM NtfSubData
+mkNtfSubData ntfSubId (NewNtfSub tokenId smpQueue notifierKey) = do
+  subStatus <- newTVar NSNew
+  pure NtfSubData {ntfSubId, smpQueue, tokenId, subStatus, notifierKey}
+
+addNtfSubscription :: NtfStore -> NtfSubscriptionId -> NtfSubData -> STM (Maybe ())
+addNtfSubscription st subId sub@NtfSubData {smpQueue, tokenId} =
+  TM.lookup tokenId (tokenSubscriptions st) >>= maybe newTokenSub pure >>= insertSub
+  where
+    newTokenSub = do
+      ts <- newTVar S.empty
+      TM.insert tokenId ts $ tokenSubscriptions st
+      pure ts
+    insertSub ts = do
+      modifyTVar' ts $ S.insert subId
+      TM.insert subId sub $ subscriptions st
+      TM.insert smpQueue subId (subscriptionLookup st)
+      -- return Nothing if subscription existed before
+      pure $ Just ()
+
+deleteNtfSubscription :: NtfStore -> NtfSubscriptionId -> STM ()
+deleteNtfSubscription st subId = do
+  TM.lookupDelete subId (subscriptions st)
+    >>= mapM_
+      ( \NtfSubData {smpQueue, tokenId} -> do
+          TM.delete smpQueue $ subscriptionLookup st
+          ts_ <- TM.lookup tokenId (tokenSubscriptions st)
+          forM_ ts_ $ \ts -> modifyTVar' ts $ S.delete subId
+      )
@@ -0,0 +1,227 @@
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+module Simplex.Messaging.Notifications.Server.StoreLog
+  ( StoreLog,
+    NtfStoreLogRecord (..),
+    readWriteNtfStore,
+    logCreateToken,
+    logTokenStatus,
+    logUpdateToken,
+    logTokenCron,
+    logDeleteToken,
+    logCreateSubscription,
+    logSubscriptionStatus,
+    logDeleteSubscription,
+    closeStoreLog,
+  )
+where
+
+import Control.Concurrent.STM
+import Control.Monad (void)
+import qualified Data.Attoparsec.ByteString.Char8 as A
+import qualified Data.ByteString.Char8 as B
+import Data.Word (Word16)
+import qualified Simplex.Messaging.Crypto as C
+import Simplex.Messaging.Encoding.String
+import Simplex.Messaging.Notifications.Protocol
+import Simplex.Messaging.Notifications.Server.Store
+import Simplex.Messaging.Protocol (NtfPrivateSignKey)
+import Simplex.Messaging.Server.StoreLog
+import Simplex.Messaging.Util (whenM)
+import System.Directory (doesFileExist, renameFile)
+import System.IO
+
+data NtfStoreLogRecord
+  = CreateToken NtfTknRec
+  | TokenStatus NtfTokenId NtfTknStatus
+  | UpdateToken NtfTokenId DeviceToken NtfRegCode
+  | TokenCron NtfTokenId Word16
+  | DeleteToken NtfTokenId
+  | CreateSubscription NtfSubRec
+  | SubscriptionStatus NtfSubscriptionId NtfSubStatus
+  | DeleteSubscription NtfSubscriptionId
+
+data NtfTknRec = NtfTknRec
+  { ntfTknId :: NtfTokenId,
+    token :: DeviceToken,
+    tknStatus :: NtfTknStatus,
+    tknVerifyKey :: C.APublicVerifyKey,
+    tknDhKeys :: C.KeyPair 'C.X25519,
+    tknDhSecret :: C.DhSecretX25519,
+    tknRegCode :: NtfRegCode,
+    tknCronInterval :: Word16
+  }
+
+mkTknData :: NtfTknRec -> STM NtfTknData
+mkTknData NtfTknRec {ntfTknId, token, tknStatus = status, tknVerifyKey, tknDhKeys, tknDhSecret, tknRegCode, tknCronInterval = cronInt} = do
+  tknStatus <- newTVar status
+  tknCronInterval <- newTVar cronInt
+  pure NtfTknData {ntfTknId, token, tknStatus, tknVerifyKey, tknDhKeys, tknDhSecret, tknRegCode, tknCronInterval}
+
+mkTknRec :: NtfTknData -> STM NtfTknRec
+mkTknRec NtfTknData {ntfTknId, token, tknStatus = status, tknVerifyKey, tknDhKeys, tknDhSecret, tknRegCode, tknCronInterval = cronInt} = do
+  tknStatus <- readTVar status
+  tknCronInterval <- readTVar cronInt
+  pure NtfTknRec {ntfTknId, token, tknStatus, tknVerifyKey, tknDhKeys, tknDhSecret, tknRegCode, tknCronInterval}
+
+data NtfSubRec = NtfSubRec
+  { ntfSubId :: NtfSubscriptionId,
+    smpQueue :: SMPQueueNtf,
+    notifierKey :: NtfPrivateSignKey,
+    tokenId :: NtfTokenId,
+    subStatus :: NtfSubStatus
+  }
+
+mkSubData :: NtfSubRec -> STM NtfSubData
+mkSubData NtfSubRec {ntfSubId, smpQueue, notifierKey, tokenId, subStatus = status} = do
+  subStatus <- newTVar status
+  pure NtfSubData {ntfSubId, smpQueue, notifierKey, tokenId, subStatus}
+
+mkSubRec :: NtfSubData -> STM NtfSubRec
+mkSubRec NtfSubData {ntfSubId, smpQueue, notifierKey, tokenId, subStatus = status} = do
+  subStatus <- readTVar status
+  pure NtfSubRec {ntfSubId, smpQueue, notifierKey, tokenId, subStatus}
+
+instance StrEncoding NtfStoreLogRecord where
+  strEncode = \case
+    CreateToken tknRec -> strEncode (Str "TCREATE", tknRec)
+    TokenStatus tknId tknStatus -> strEncode (Str "TSTATUS", tknId, tknStatus)
+    UpdateToken tknId token regCode -> strEncode (Str "TUPDATE", tknId, token, regCode)
+    TokenCron tknId cronInt -> strEncode (Str "TCRON", tknId, cronInt)
+    DeleteToken tknId -> strEncode (Str "TDELETE", tknId)
+    CreateSubscription subRec -> strEncode (Str "SCREATE", subRec)
+    SubscriptionStatus subId subStatus -> strEncode (Str "SSTATUS", subId, subStatus)
+    DeleteSubscription subId -> strEncode (Str "SDELETE", subId)
+  strP =
+    A.choice
+      [ "TCREATE " *> (CreateToken <$> strP),
+        "TSTATUS " *> (TokenStatus <$> strP_ <*> strP),
+        "TUPDATE " *> (UpdateToken <$> strP_ <*> strP_ <*> strP),
+        "TCRON " *> (TokenCron <$> strP_ <*> strP),
+        "TDELETE " *> (DeleteToken <$> strP),
+        "SCREATE " *> (CreateSubscription <$> strP),
+        "SSTATUS " *> (SubscriptionStatus <$> strP_ <*> strP),
+        "SDELETE " *> (DeleteSubscription <$> strP)
+      ]
+
+instance StrEncoding NtfTknRec where
+  strEncode NtfTknRec {ntfTknId, token, tknStatus, tknVerifyKey, tknDhKeys, tknDhSecret, tknRegCode, tknCronInterval} =
+    B.unwords
+      [ "tknId=" <> strEncode ntfTknId,
+        "token=" <> strEncode token,
+        "tokenStatus=" <> strEncode tknStatus,
+        "verifyKey=" <> strEncode tknVerifyKey,
+        "dhKeys=" <> strEncode tknDhKeys,
+        "dhSecret=" <> strEncode tknDhSecret,
+        "regCode=" <> strEncode tknRegCode,
+        "cron=" <> strEncode tknCronInterval
+      ]
+  strP = do
+    ntfTknId <- "tknId=" *> strP_
+    token <- "token=" *> strP_
+    tknStatus <- "tokenStatus=" *> strP_
+    tknVerifyKey <- "verifyKey=" *> strP_
+    tknDhKeys <- "dhKeys=" *> strP_
+    tknDhSecret <- "dhSecret=" *> strP_
+    tknRegCode <- "regCode=" *> strP_
+    tknCronInterval <- "cron=" *> strP
+    pure NtfTknRec {ntfTknId, token, tknStatus, tknVerifyKey, tknDhKeys, tknDhSecret, tknRegCode, tknCronInterval}
+
+instance StrEncoding NtfSubRec where
+  strEncode NtfSubRec {ntfSubId, smpQueue, notifierKey, tokenId, subStatus} =
+    B.unwords
+      [ "subId=" <> strEncode ntfSubId,
+        "smpQueue=" <> strEncode smpQueue,
+        "notifierKey=" <> strEncode notifierKey,
+        "tknId=" <> strEncode tokenId,
+        "subStatus=" <> strEncode subStatus
+      ]
+  strP = do
+    ntfSubId <- "subId=" *> strP_
+    smpQueue <- "smpQueue=" *> strP_
+    notifierKey <- "notifierKey=" *> strP_
+    tokenId <- "tknId=" *> strP_
+    subStatus <- "subStatus=" *> strP
+    pure NtfSubRec {ntfSubId, smpQueue, notifierKey, tokenId, subStatus}
+
+logNtfStoreRecord :: StoreLog 'WriteMode -> NtfStoreLogRecord -> IO ()
+logNtfStoreRecord = writeStoreLogRecord
+
+logCreateToken :: StoreLog 'WriteMode -> NtfTknData -> IO ()
+logCreateToken s tkn = logNtfStoreRecord s . CreateToken =<< atomically (mkTknRec tkn)
+
+logTokenStatus :: StoreLog 'WriteMode -> NtfTokenId -> NtfTknStatus -> IO ()
+logTokenStatus s tknId tknStatus = logNtfStoreRecord s $ TokenStatus tknId tknStatus
+
+logUpdateToken :: StoreLog 'WriteMode -> NtfTokenId -> DeviceToken -> NtfRegCode -> IO ()
+logUpdateToken s tknId token regCode = logNtfStoreRecord s $ UpdateToken tknId token regCode
+
+logTokenCron :: StoreLog 'WriteMode -> NtfTokenId -> Word16 -> IO ()
+logTokenCron s tknId cronInt = logNtfStoreRecord s $ TokenCron tknId cronInt
+
+logDeleteToken :: StoreLog 'WriteMode -> NtfTokenId -> IO ()
+logDeleteToken s tknId = logNtfStoreRecord s $ DeleteToken tknId
+
+logCreateSubscription :: StoreLog 'WriteMode -> NtfSubData -> IO ()
+logCreateSubscription s sub = logNtfStoreRecord s . CreateSubscription =<< atomically (mkSubRec sub)
+
+logSubscriptionStatus :: StoreLog 'WriteMode -> NtfSubscriptionId -> NtfSubStatus -> IO ()
+logSubscriptionStatus s subId subStatus = logNtfStoreRecord s $ SubscriptionStatus subId subStatus
+
+logDeleteSubscription :: StoreLog 'WriteMode -> NtfSubscriptionId -> IO ()
+logDeleteSubscription s subId = logNtfStoreRecord s $ DeleteSubscription subId
+
+readWriteNtfStore :: FilePath -> NtfStore -> IO (StoreLog 'WriteMode)
+readWriteNtfStore f st = do
+  whenM (doesFileExist f) $ do
+    readNtfStore f st
+    renameFile f $ f <> ".bak"
+  s <- openWriteStoreLog f
+  writeNtfStore s st
+  pure s
+
+readNtfStore :: FilePath -> NtfStore -> IO ()
+readNtfStore f st = mapM_ addNtfLogRecord . B.lines =<< B.readFile f
+  where
+    addNtfLogRecord s = case strDecode s of
+      Left e -> B.putStrLn $ "Log parsing error (" <> B.pack e <> "): " <> B.take 100 s
+      Right lr -> atomically $ case lr of
+        CreateToken r@NtfTknRec {ntfTknId} -> do
+          tkn <- mkTknData r
+          addNtfToken st ntfTknId tkn
+        TokenStatus tknId status ->
+          getNtfToken st tknId
+            >>= mapM_ (\NtfTknData {tknStatus} -> writeTVar tknStatus status)
+        UpdateToken tknId token' tknRegCode ->
+          getNtfToken st tknId
+            >>= mapM_
+              ( \tkn@NtfTknData {tknStatus} -> do
+                  removeTokenRegistration st tkn
+                  writeTVar tknStatus NTRegistered
+                  addNtfToken st tknId tkn {token = token', tknRegCode}
+              )
+        TokenCron tknId cronInt ->
+          getNtfToken st tknId
+            >>= mapM_ (\NtfTknData {tknCronInterval} -> writeTVar tknCronInterval cronInt)
+        DeleteToken tknId ->
+          void $ deleteNtfToken st tknId
+        CreateSubscription r@NtfSubRec {ntfSubId} -> do
+          sub <- mkSubData r
+          void $ addNtfSubscription st ntfSubId sub
+        SubscriptionStatus subId status ->
+          getNtfSubscription st subId
+            >>= mapM_ (\NtfSubData {subStatus} -> writeTVar subStatus status)
+        DeleteSubscription subId ->
+          deleteNtfSubscription st subId
+
+writeNtfStore :: StoreLog 'WriteMode -> NtfStore -> IO ()
+writeNtfStore s NtfStore {tokens, subscriptions} = do
+  atomically (readTVar tokens >>= mapM mkTknRec)
+    >>= mapM_ (writeStoreLogRecord s . CreateToken)
+  atomically (readTVar subscriptions >>= mapM mkSubRec)
+    >>= mapM_ (writeStoreLogRecord s . CreateSubscription)
@@ -0,0 +1,72 @@
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+
+module Simplex.Messaging.Notifications.Transport where
+
+import Control.Monad.Except
+import qualified Simplex.Messaging.Crypto as C
+import Simplex.Messaging.Encoding
+import Simplex.Messaging.Transport
+import Simplex.Messaging.Version
+
+ntfBlockSize :: Int
+ntfBlockSize = 512
+
+supportedNTFServerVRange :: VersionRange
+supportedNTFServerVRange = mkVersionRange 1 1
+
+data NtfServerHandshake = NtfServerHandshake
+  { ntfVersionRange :: VersionRange,
+    sessionId :: SessionId
+  }
+
+data NtfClientHandshake = NtfClientHandshake
+  { -- | agreed SMP notifications server protocol version
+    ntfVersion :: Version,
+    -- | server identity - CA certificate fingerprint
+    keyHash :: C.KeyHash
+  }
+
+instance Encoding NtfServerHandshake where
+  smpEncode NtfServerHandshake {ntfVersionRange, sessionId} =
+    smpEncode (ntfVersionRange, sessionId)
+  smpP = do
+    (ntfVersionRange, sessionId) <- smpP
+    pure NtfServerHandshake {ntfVersionRange, sessionId}
+
+instance Encoding NtfClientHandshake where
+  smpEncode NtfClientHandshake {ntfVersion, keyHash} = smpEncode (ntfVersion, keyHash)
+  smpP = do
+    (ntfVersion, keyHash) <- smpP
+    pure NtfClientHandshake {ntfVersion, keyHash}
+
+-- | Notifcations server transport handshake.
+ntfServerHandshake :: forall c. Transport c => c -> C.KeyHash -> VersionRange -> ExceptT TransportError IO (THandle c)
+ntfServerHandshake c kh ntfVRange = do
+  let th@THandle {sessionId} = ntfTHandle c
+  sendHandshake th $ NtfServerHandshake {sessionId, ntfVersionRange = ntfVRange}
+  getHandshake th >>= \case
+    NtfClientHandshake {ntfVersion, keyHash}
+      | keyHash /= kh ->
+        throwError $ TEHandshake IDENTITY
+      | ntfVersion `isCompatible` ntfVRange -> do
+        pure (th :: THandle c) {thVersion = ntfVersion}
+      | otherwise -> throwError $ TEHandshake VERSION
+
+-- | Notifcations server client transport handshake.
+ntfClientHandshake :: forall c. Transport c => c -> C.KeyHash -> VersionRange -> ExceptT TransportError IO (THandle c)
+ntfClientHandshake c keyHash ntfVRange = do
+  let th@THandle {sessionId} = ntfTHandle c
+  NtfServerHandshake {sessionId = sessId, ntfVersionRange} <- getHandshake th
+  if sessionId /= sessId
+    then throwError TEBadSession
+    else case ntfVersionRange `compatibleVersion` ntfVRange of
+      Just (Compatible ntfVersion) -> do
+        sendHandshake th $ NtfClientHandshake {ntfVersion, keyHash}
+        pure (th :: THandle c) {thVersion = ntfVersion}
+      Nothing -> throwError $ TEHandshake VERSION
+
+ntfTHandle :: Transport c => c -> THandle c
+ntfTHandle c = THandle {connection = c, sessionId = tlsUnique c, blockSize = ntfBlockSize, thVersion = 0, batch = False}
@@ -0,0 +1,197 @@
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+module Simplex.Messaging.Notifications.Types where
+
+import qualified Data.Attoparsec.ByteString.Char8 as A
+import Data.Text.Encoding (decodeLatin1, encodeUtf8)
+import Data.Time (UTCTime)
+import Database.SQLite.Simple.FromField (FromField (..))
+import Database.SQLite.Simple.ToField (ToField (..))
+import Simplex.Messaging.Agent.Protocol (ConnId, NotificationsMode (..))
+import qualified Simplex.Messaging.Crypto as C
+import Simplex.Messaging.Encoding
+import Simplex.Messaging.Notifications.Protocol
+import Simplex.Messaging.Parsers (blobFieldDecoder, fromTextField_)
+import Simplex.Messaging.Protocol (NotifierId, NtfServer, SMPServer)
+
+data NtfTknAction
+  = NTARegister
+  | NTAVerify NtfRegCode -- code to verify token
+  | NTACheck
+  | NTADelete
+  deriving (Show)
+
+instance Encoding NtfTknAction where
+  smpEncode = \case
+    NTARegister -> "R"
+    NTAVerify code -> smpEncode ('V', code)
+    NTACheck -> "C"
+    NTADelete -> "D"
+  smpP =
+    A.anyChar >>= \case
+      'R' -> pure NTARegister
+      'V' -> NTAVerify <$> smpP
+      'C' -> pure NTACheck
+      'D' -> pure NTADelete
+      _ -> fail "bad NtfTknAction"
+
+instance FromField NtfTknAction where fromField = blobFieldDecoder smpDecode
+
+instance ToField NtfTknAction where toField = toField . smpEncode
+
+data NtfToken = NtfToken
+  { deviceToken :: DeviceToken,
+    ntfServer :: NtfServer,
+    ntfTokenId :: Maybe NtfTokenId,
+    -- | key used by the ntf server to verify transmissions
+    ntfPubKey :: C.APublicVerifyKey,
+    -- | key used by the ntf client to sign transmissions
+    ntfPrivKey :: C.APrivateSignKey,
+    -- | client's DH keys (to repeat registration if necessary)
+    ntfDhKeys :: C.KeyPair 'C.X25519,
+    -- | shared DH secret used to encrypt/decrypt notifications e2e
+    ntfDhSecret :: Maybe C.DhSecretX25519,
+    -- | token status
+    ntfTknStatus :: NtfTknStatus,
+    -- | pending token action and the earliest time
+    ntfTknAction :: Maybe NtfTknAction,
+    ntfMode :: NotificationsMode
+  }
+  deriving (Show)
+
+newNtfToken :: DeviceToken -> NtfServer -> C.ASignatureKeyPair -> C.KeyPair 'C.X25519 -> NotificationsMode -> NtfToken
+newNtfToken deviceToken ntfServer (ntfPubKey, ntfPrivKey) ntfDhKeys ntfMode =
+  NtfToken
+    { deviceToken,
+      ntfServer,
+      ntfTokenId = Nothing,
+      ntfPubKey,
+      ntfPrivKey,
+      ntfDhKeys,
+      ntfDhSecret = Nothing,
+      ntfTknStatus = NTNew,
+      ntfTknAction = Just NTARegister,
+      ntfMode
+    }
+
+data NtfSubAction = NtfSubNTFAction NtfSubNTFAction | NtfSubSMPAction NtfSubSMPAction
+  deriving (Show)
+
+isDeleteNtfSubAction :: NtfSubAction -> Bool
+isDeleteNtfSubAction = \case
+  NtfSubNTFAction a -> case a of
+    NSACreate -> False
+    NSACheck -> False
+    NSADelete -> True
+    NSARotate -> True
+  NtfSubSMPAction a -> case a of
+    NSASmpKey -> False
+    NSASmpDelete -> True
+
+type NtfActionTs = UTCTime
+
+data NtfSubNTFAction
+  = NSACreate
+  | NSACheck
+  | NSADelete
+  | NSARotate
+  deriving (Show)
+
+instance Encoding NtfSubNTFAction where
+  smpEncode = \case
+    NSACreate -> "N"
+    NSACheck -> "C"
+    NSADelete -> "D"
+    NSARotate -> "R"
+  smpP =
+    A.anyChar >>= \case
+      'N' -> pure NSACreate
+      'C' -> pure NSACheck
+      'D' -> pure NSADelete
+      'R' -> pure NSARotate
+      _ -> fail "bad NtfSubNTFAction"
+
+instance FromField NtfSubNTFAction where fromField = blobFieldDecoder smpDecode
+
+instance ToField NtfSubNTFAction where toField = toField . smpEncode
+
+data NtfSubSMPAction
+  = NSASmpKey
+  | NSASmpDelete
+  deriving (Show)
+
+instance Encoding NtfSubSMPAction where
+  smpEncode = \case
+    NSASmpKey -> "K"
+    NSASmpDelete -> "D"
+  smpP =
+    A.anyChar >>= \case
+      'K' -> pure NSASmpKey
+      'D' -> pure NSASmpDelete
+      _ -> fail "bad NtfSubSMPAction"
+
+instance FromField NtfSubSMPAction where fromField = blobFieldDecoder smpDecode
+
+instance ToField NtfSubSMPAction where toField = toField . smpEncode
+
+data NtfAgentSubStatus
+  = -- | subscription started
+    NASNew
+  | -- | state after NKEY - notifier ID is assigned to queue on SMP server
+    NASKey
+  | -- | state after SNEW - subscription created on notification server
+    NASCreated NtfSubStatus
+  | -- | state after SDEL (subscription is deleted on notification server)
+    NASOff
+  | -- | state after NDEL (notifier credentials are deleted on SMP server)
+    -- Can only exist transiently - if subscription record was updated by notification supervisor mid worker operation,
+    -- and hence got updated instead of being fully deleted in the database post operation by worker
+    NASDeleted
+  deriving (Eq, Show)
+
+instance Encoding NtfAgentSubStatus where
+  smpEncode = \case
+    NASNew -> "NEW"
+    NASKey -> "KEY"
+    NASCreated status -> "CREATED " <> smpEncode status
+    NASOff -> "OFF"
+    NASDeleted -> "DELETED"
+  smpP =
+    A.takeTill (== ' ') >>= \case
+      "NEW" -> pure NASNew
+      "KEY" -> pure NASKey
+      "CREATED" -> do
+        _ <- A.space
+        NASCreated <$> smpP
+      "OFF" -> pure NASOff
+      "DELETED" -> pure NASDeleted
+      _ -> fail "bad NtfAgentSubStatus"
+
+instance FromField NtfAgentSubStatus where fromField = fromTextField_ $ either (const Nothing) Just . smpDecode . encodeUtf8
+
+instance ToField NtfAgentSubStatus where toField = toField . decodeLatin1 . smpEncode
+
+data NtfSubscription = NtfSubscription
+  { connId :: ConnId,
+    smpServer :: SMPServer,
+    ntfQueueId :: Maybe NotifierId,
+    ntfServer :: NtfServer,
+    ntfSubId :: Maybe NtfSubscriptionId,
+    ntfSubStatus :: NtfAgentSubStatus
+  }
+  deriving (Show)
+
+newNtfSubscription :: ConnId -> SMPServer -> Maybe NotifierId -> NtfServer -> NtfAgentSubStatus -> NtfSubscription
+newNtfSubscription connId smpServer ntfQueueId ntfServer ntfSubStatus =
+  NtfSubscription
+    { connId,
+      smpServer,
+      ntfQueueId,
+      ntfServer,
+      ntfSubId = Nothing,
+      ntfSubStatus
+    }
@@ -13,6 +13,8 @@ import Data.ByteString.Base64
 import Data.ByteString.Char8 (ByteString)
 import qualified Data.ByteString.Char8 as B
 import Data.Char (isAlphaNum, toLower)
+import Data.Text (Text)
+import qualified Data.Text as T
 import Data.Time.Clock (UTCTime)
 import Data.Time.ISO8601 (parseISO8601)
 import Data.Typeable (Typeable)
@@ -81,6 +83,14 @@ blobFieldDecoder dec = \case
      Left e -> returnError ConversionFailed f ("couldn't parse field: " ++ e)
  f -> returnError ConversionFailed f "expecting SQLBlob column type"

+fromTextField_ :: (Typeable a) => (Text -> Maybe a) -> Field -> Ok a
+fromTextField_ fromText = \case
+  f@(Field (SQLText t) _) ->
+    case fromText t of
+      Just x -> Ok x
+      _ -> returnError ConversionFailed f ("invalid text: " <> T.unpack t)
+  f -> returnError ConversionFailed f "expecting SQLText column type"
+
 fstToLower :: String -> String
 fstToLower "" = ""
 fstToLower (h : t) = toLower h : t
@@ -98,7 +108,7 @@ enumJSON tagModifier =
    }

 sumTypeJSON :: (String -> String) -> J.Options
-#if defined(darwin_HOST_OS)
+#if defined(darwin_HOST_OS) && defined(swiftJSON)
 sumTypeJSON = singleFieldJSON
 #else
 sumTypeJSON = taggedObjectJSON
@@ -108,6 +118,7 @@ taggedObjectJSON :: (String -> String) -> J.Options
 taggedObjectJSON tagModifier =
  J.defaultOptions
    { J.sumEncoding = J.TaggedObject "type" "data",
+      J.tagSingleConstructors = True,
      J.constructorTagModifier = tagModifier,
      J.allNullaryToStringTag = False,
      J.nullaryToObject = True,
@@ -118,6 +129,7 @@ singleFieldJSON :: (String -> String) -> J.Options
 singleFieldJSON tagModifier =
  J.defaultOptions
    { J.sumEncoding = J.ObjectWithSingleField,
+      J.tagSingleConstructors = True,
      J.constructorTagModifier = tagModifier,
      J.allNullaryToStringTag = False,
      J.nullaryToObject = True,
@@ -5,6 +5,8 @@
 {-# LANGUAGE KindSignatures #-}
 {-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE NumericUnderscores #-}
+{-# LANGUAGE OverloadedLists #-}
 {-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE ScopedTypeVariables #-}
@@ -23,34 +25,61 @@
 -- and optional append only log of SMP queue records.
 --
 -- See https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md
-module Simplex.Messaging.Server (runSMPServer, runSMPServerBlocking) where
+module Simplex.Messaging.Server
+  ( runSMPServer,
+    runSMPServerBlocking,
+    disconnectTransport,
+    verifyCmdSignature,
+    dummyVerifyCmd,
+  )
+where

-import Control.Concurrent.STM (stateTVar)
+import Control.Logger.Simple
 import Control.Monad
 import Control.Monad.Except
 import Control.Monad.IO.Unlift
 import Control.Monad.Reader
 import Crypto.Random
+import Data.Bifunctor (first)
+import Data.ByteString.Base64 (encode)
 import Data.ByteString.Char8 (ByteString)
 import qualified Data.ByteString.Char8 as B
+import Data.Either (fromRight, partitionEithers)
 import Data.Functor (($>))
+import Data.List (intercalate)
+import qualified Data.List.NonEmpty as L
 import qualified Data.Map.Strict as M
 import Data.Maybe (isNothing)
-import Data.Time.Clock.System (getSystemTime)
+import qualified Data.Text as T
+import Data.Text.Encoding (decodeLatin1)
+import Data.Time.Clock (UTCTime (..), diffTimeToPicoseconds, getCurrentTime)
+import Data.Time.Clock.System (SystemTime (..), getSystemTime)
+import Data.Time.Format.ISO8601 (iso8601Show)
 import Data.Type.Equality
+import GHC.TypeLits (KnownNat)
 import Network.Socket (ServiceName)
 import qualified Simplex.Messaging.Crypto as C
+import Simplex.Messaging.Encoding (Encoding (smpEncode))
+import Simplex.Messaging.Encoding.String
 import Simplex.Messaging.Protocol
 import Simplex.Messaging.Server.Env.STM
+import Simplex.Messaging.Server.Expiration
 import Simplex.Messaging.Server.MsgStore
-import Simplex.Messaging.Server.MsgStore.STM (MsgQueue)
+import Simplex.Messaging.Server.MsgStore.STM
 import Simplex.Messaging.Server.QueueStore
-import Simplex.Messaging.Server.QueueStore.STM (QueueStore)
+import Simplex.Messaging.Server.QueueStore.STM
+import Simplex.Messaging.Server.Stats
 import Simplex.Messaging.Server.StoreLog
+import Simplex.Messaging.TMap (TMap)
+import qualified Simplex.Messaging.TMap as TM
 import Simplex.Messaging.Transport
 import Simplex.Messaging.Transport.Server
 import Simplex.Messaging.Util
+import System.Exit (exitFailure)
+import System.IO (hPutStrLn)
+import System.Mem.Weak (deRefWeak)
 import UnliftIO.Concurrent
+import UnliftIO.Directory (doesFileExist, renameFile)
 import UnliftIO.Exception
 import UnliftIO.IO
 import UnliftIO.STM
@@ -58,7 +87,7 @@ import UnliftIO.STM
 -- | Runs an SMP server using passed configuration.
 --
 -- See a full server here: https://github.com/simplex-chat/simplexmq/blob/master/apps/smp-server/Main.hs
-runSMPServer :: (MonadRandom m, MonadUnliftIO m) => ServerConfig -> m ()
+runSMPServer :: ServerConfig -> IO ()
 runSMPServer cfg = do
  started <- newEmptyTMVarIO
  runSMPServerBlocking started cfg
@@ -67,39 +96,40 @@ runSMPServer cfg = do
 --
 -- This function uses passed TMVar to signal when the server is ready to accept TCP requests (True)
 -- and when it is disconnected from the TCP socket once the server thread is killed (False).
-runSMPServerBlocking :: (MonadRandom m, MonadUnliftIO m) => TMVar Bool -> ServerConfig -> m ()
-runSMPServerBlocking started cfg@ServerConfig {transports} = do
-  env <- newEnv cfg
-  runReaderT smpServer env
-  where
-    smpServer :: (MonadUnliftIO m', MonadReader Env m') => m' ()
-    smpServer = do
-      s <- asks server
-      raceAny_
-        ( serverThread s subscribedQ subscribers subscriptions cancelSub :
-          serverThread s ntfSubscribedQ notifiers ntfSubscriptions (\_ -> pure ()) :
-          map runServer transports
-        )
-        `finally` withLog closeStoreLog
+runSMPServerBlocking :: TMVar Bool -> ServerConfig -> IO ()
+runSMPServerBlocking started cfg = newEnv cfg >>= runReaderT (smpServer started cfg)

-    runServer :: (MonadUnliftIO m', MonadReader Env m') => (ServiceName, ATransport) -> m' ()
+type M a = ReaderT Env IO a
+
+smpServer :: TMVar Bool -> ServerConfig -> M ()
+smpServer started cfg@ServerConfig {transports, logTLSErrors} = do
+  s <- asks server
+  restoreServerMessages
+  restoreServerStats
+  raceAny_
+    ( serverThread s subscribedQ subscribers subscriptions cancelSub :
+      serverThread s ntfSubscribedQ notifiers ntfSubscriptions (\_ -> pure ()) :
+      map runServer transports <> expireMessagesThread_ cfg <> serverStatsThread_ cfg
+    )
+    `finally` (withLog closeStoreLog >> saveServerMessages >> saveServerStats)
+  where
+    runServer :: (ServiceName, ATransport) -> M ()
    runServer (tcpPort, ATransport t) = do
      serverParams <- asks tlsServerParams
-      runTransportServer started tcpPort serverParams (runClient t)
+      runTransportServer started tcpPort serverParams logTLSErrors (runClient t)

    serverThread ::
-      forall m' s.
-      MonadUnliftIO m' =>
+      forall s.
      Server ->
      (Server -> TBQueue (QueueId, Client)) ->
-      (Server -> TVar (M.Map QueueId Client)) ->
-      (Client -> TVar (M.Map QueueId s)) ->
-      (s -> m' ()) ->
-      m' ()
+      (Server -> TMap QueueId Client) ->
+      (Client -> TMap QueueId s) ->
+      (s -> IO ()) ->
+      M ()
    serverThread s subQ subs clientSubs unsub = forever $ do
      atomically updateSubscribers
-        >>= fmap join . mapM endPreviousSubscriptions
-        >>= mapM_ unsub
+        $>>= endPreviousSubscriptions
+        >>= liftIO . mapM_ unsub
      where
        updateSubscribers :: STM (Maybe (QueueId, Client))
        updateSubscribers = do
@@ -110,36 +140,109 @@ runSMPServerBlocking started cfg@ServerConfig {transports} = do
                  else do
                    yes <- readTVar $ connected c'
                    pure $ if yes then Just (qId, c') else Nothing
-          stateTVar (subs s) (\cs -> (M.lookup qId cs, M.insert qId clnt cs))
-            >>= fmap join . mapM clientToBeNotified
-        endPreviousSubscriptions :: (QueueId, Client) -> m' (Maybe s)
+          TM.lookupInsert qId clnt (subs s) $>>= clientToBeNotified
+        endPreviousSubscriptions :: (QueueId, Client) -> M (Maybe s)
        endPreviousSubscriptions (qId, c) = do
          void . forkIO . atomically $
-            writeTBQueue (sndQ c) (CorrId "", qId, END)
-          atomically . stateTVar (clientSubs c) $ \ss -> (M.lookup qId ss, M.delete qId ss)
+            writeTBQueue (sndQ c) [(CorrId "", qId, END)]
+          atomically $ TM.lookupDelete qId (clientSubs c)

-    runClient :: (Transport c, MonadUnliftIO m, MonadReader Env m) => TProxy c -> c -> m ()
+    expireMessagesThread_ :: ServerConfig -> [M ()]
+    expireMessagesThread_ ServerConfig {messageExpiration = Just msgExp} = [expireMessages msgExp]
+    expireMessagesThread_ _ = []
+
+    expireMessages :: ExpirationConfig -> M ()
+    expireMessages expCfg = do
+      ms <- asks msgStore
+      quota <- asks $ msgQueueQuota . config
+      let interval = checkInterval expCfg * 1000000
+      forever $ do
+        threadDelay interval
+        old <- liftIO $ expireBeforeEpoch expCfg
+        rIds <- M.keysSet <$> readTVarIO ms
+        forM_ rIds $ \rId ->
+          atomically (getMsgQueue ms rId quota)
+            >>= atomically . (`deleteExpiredMsgs` old)
+
+    serverStatsThread_ :: ServerConfig -> [M ()]
+    serverStatsThread_ ServerConfig {logStatsInterval = Just interval, logStatsStartTime, serverStatsLogFile} =
+      [logServerStats logStatsStartTime interval serverStatsLogFile]
+    serverStatsThread_ _ = []
+
+    logServerStats :: Int -> Int -> FilePath -> M ()
+    logServerStats startAt logInterval statsFilePath = do
+      initialDelay <- (startAt -) . fromIntegral . (`div` 1000000_000000) . diffTimeToPicoseconds . utctDayTime <$> liftIO getCurrentTime
+      liftIO $ putStrLn $ "server stats log enabled: " <> statsFilePath
+      threadDelay $ 1000000 * (initialDelay + if initialDelay < 0 then 86400 else 0)
+      ServerStats {fromTime, qCreated, qSecured, qDeleted, msgSent, msgRecv, activeQueues, msgSentNtf, msgRecvNtf, activeQueuesNtf, qCount, msgCount} <- asks serverStats
+      let interval = 1000000 * logInterval
+      withFile statsFilePath AppendMode $ \h -> liftIO $ do
+        hSetBuffering h LineBuffering
+        forever $ do
+          ts <- getCurrentTime
+          fromTime' <- atomically $ swapTVar fromTime ts
+          qCreated' <- atomically $ swapTVar qCreated 0
+          qSecured' <- atomically $ swapTVar qSecured 0
+          qDeleted' <- atomically $ swapTVar qDeleted 0
+          msgSent' <- atomically $ swapTVar msgSent 0
+          msgRecv' <- atomically $ swapTVar msgRecv 0
+          ps <- atomically $ periodStatCounts activeQueues ts
+          msgSentNtf' <- atomically $ swapTVar msgSentNtf 0
+          msgRecvNtf' <- atomically $ swapTVar msgRecvNtf 0
+          psNtf <- atomically $ periodStatCounts activeQueuesNtf ts
+          qCount' <- readTVarIO qCount
+          msgCount' <- readTVarIO msgCount
+          hPutStrLn h $
+            intercalate
+              ","
+              [ iso8601Show $ utctDay fromTime',
+                show qCreated',
+                show qSecured',
+                show qDeleted',
+                show msgSent',
+                show msgRecv',
+                dayCount ps,
+                weekCount ps,
+                monthCount ps,
+                show msgSentNtf',
+                show msgRecvNtf',
+                dayCount psNtf,
+                weekCount psNtf,
+                monthCount psNtf,
+                show qCount',
+                show msgCount'
+              ]
+          threadDelay interval
+
+    runClient :: Transport c => TProxy c -> c -> M ()
    runClient _ h = do
      kh <- asks serverIdentity
-      liftIO (runExceptT $ serverHandshake h kh) >>= \case
+      smpVRange <- asks $ smpServerVRange . config
+      liftIO (runExceptT $ smpServerHandshake h kh smpVRange) >>= \case
        Right th -> runClientTransport th
        Left _ -> pure ()

-runClientTransport :: (Transport c, MonadUnliftIO m, MonadReader Env m) => THandle c -> m ()
-runClientTransport th@THandle {sessionId} = do
+runClientTransport :: Transport c => THandle c -> M ()
+runClientTransport th@THandle {thVersion, sessionId} = do
  q <- asks $ tbqSize . config
-  c <- atomically $ newClient q sessionId
+  ts <- liftIO getSystemTime
+  c <- atomically $ newClient q thVersion sessionId ts
  s <- asks server
-  raceAny_ [send th c, client c s, receive th c]
+  expCfg <- asks $ inactiveClientExpiration . config
+  raceAny_ ([liftIO $ send th c, client c s, receive th c] <> disconnectThread_ c expCfg)
    `finally` clientDisconnected c
+  where
+    disconnectThread_ c (Just expCfg) = [liftIO $ disconnectTransport th c activeAt expCfg]
+    disconnectThread_ _ _ = []

-clientDisconnected :: (MonadUnliftIO m, MonadReader Env m) => Client -> m ()
+clientDisconnected :: Client -> M ()
 clientDisconnected c@Client {subscriptions, connected} = do
  atomically $ writeTVar connected False
  subs <- readTVarIO subscriptions
-  mapM_ cancelSub subs
+  liftIO $ mapM_ cancelSub subs
+  atomically $ writeTVar subscriptions M.empty
  cs <- asks $ subscribers . server
-  atomically . mapM_ (modifyTVar cs . M.update deleteCurrentClient) $ M.keys subs
+  atomically . mapM_ (\rId -> TM.update deleteCurrentClient rId cs) $ M.keys subs
  where
    deleteCurrentClient :: Client -> Maybe Client
    deleteCurrentClient c'
@@ -149,55 +252,84 @@ clientDisconnected c@Client {subscriptions, connected} = do
 sameClientSession :: Client -> Client -> Bool
 sameClientSession Client {sessionId} Client {sessionId = s'} = sessionId == s'

-cancelSub :: MonadUnliftIO m => Sub -> m ()
-cancelSub = \case
-  Sub {subThread = SubThread t} -> killThread t
-  _ -> return ()
+cancelSub :: TVar Sub -> IO ()
+cancelSub sub =
+  readTVarIO sub >>= \case
+    Sub {subThread = SubThread t} -> liftIO $ deRefWeak t >>= mapM_ killThread
+    _ -> return ()

-receive :: (Transport c, MonadUnliftIO m, MonadReader Env m) => THandle c -> Client -> m ()
-receive th Client {rcvQ, sndQ} = forever $ do
-  (sig, signed, (corrId, queueId, cmdOrError)) <- tGet th
-  case cmdOrError of
-    Left e -> write sndQ (corrId, queueId, ERR e)
-    Right cmd -> do
-      verified <- verifyTransmission sig signed queueId cmd
-      if verified
-        then write rcvQ (corrId, queueId, cmd)
-        else write sndQ (corrId, queueId, ERR AUTH)
+receive :: Transport c => THandle c -> Client -> M ()
+receive th Client {rcvQ, sndQ, activeAt} = forever $ do
+  ts <- L.toList <$> tGet th
+  atomically . writeTVar activeAt =<< liftIO getSystemTime
+  as <- partitionEithers <$> mapM cmdAction ts
+  write sndQ $ fst as
+  write rcvQ $ snd as
  where
-    write q t = atomically $ writeTBQueue q t
+    cmdAction :: SignedTransmission Cmd -> M (Either (Transmission BrokerMsg) (Maybe QueueRec, Transmission Cmd))
+    cmdAction (sig, signed, (corrId, queueId, cmdOrError)) =
+      case cmdOrError of
+        Left e -> pure $ Left (corrId, queueId, ERR e)
+        Right cmd -> verified <$> verifyTransmission sig signed queueId cmd
+          where
+            verified = \case
+              VRVerified qr -> Right (qr, (corrId, queueId, cmd))
+              VRFailed -> Left (corrId, queueId, ERR AUTH)
+    write q = mapM_ (atomically . writeTBQueue q) . L.nonEmpty

-send :: (Transport c, MonadUnliftIO m) => THandle c -> Client -> m ()
-send h Client {sndQ, sessionId} = forever $ do
-  t <- atomically $ readTBQueue sndQ
-  liftIO $ tPut h (Nothing, encodeTransmission sessionId t)
+send :: Transport c => THandle c -> Client -> IO ()
+send h@THandle {thVersion = v} Client {sndQ, sessionId, activeAt} = forever $ do
+  ts <- atomically $ L.sortWith tOrder <$> readTBQueue sndQ
+  void . liftIO . tPut h $ L.map ((Nothing,) . encodeTransmission v sessionId) ts
+  atomically . writeTVar activeAt =<< liftIO getSystemTime
+  where
+    tOrder :: Transmission BrokerMsg -> Int
+    tOrder (_, _, cmd) = case cmd of
+      MSG {} -> 0
+      _ -> 1

-verifyTransmission ::
-  forall m. (MonadUnliftIO m, MonadReader Env m) => Maybe C.ASignature -> ByteString -> QueueId -> Cmd -> m Bool
+disconnectTransport :: Transport c => THandle c -> client -> (client -> TVar SystemTime) -> ExpirationConfig -> IO ()
+disconnectTransport THandle {connection} c activeAt expCfg = do
+  let interval = checkInterval expCfg * 1000000
+  forever . liftIO $ do
+    threadDelay interval
+    old <- expireBeforeEpoch expCfg
+    ts <- readTVarIO $ activeAt c
+    when (systemSeconds ts < old) $ closeConnection connection
+
+data VerificationResult = VRVerified (Maybe QueueRec) | VRFailed
+
+verifyTransmission :: Maybe C.ASignature -> ByteString -> QueueId -> Cmd -> M VerificationResult
 verifyTransmission sig_ signed queueId cmd = do
  case cmd of
-    Cmd SRecipient (NEW k _) -> pure $ verifySignature k
-    Cmd SRecipient _ -> verifyCmd SRecipient $ verifySignature . recipientKey
-    Cmd SSender (SEND _) -> verifyCmd SSender $ verifyMaybe . senderKey
-    Cmd SSender PING -> pure True
-    Cmd SNotifier NSUB -> verifyCmd SNotifier $ verifyMaybe . fmap snd . notifier
+    Cmd SRecipient (NEW k _ _) -> pure $ Nothing `verified` verifyCmdSignature sig_ signed k
+    Cmd SRecipient _ -> verifyCmd SRecipient $ verifyCmdSignature sig_ signed . recipientKey
+    Cmd SSender SEND {} -> verifyCmd SSender $ verifyMaybe . senderKey
+    Cmd SSender PING -> pure $ VRVerified Nothing
+    Cmd SNotifier NSUB -> verifyCmd SNotifier $ verifyMaybe . fmap notifierKey . notifier
  where
-    verifyCmd :: SParty p -> (QueueRec -> Bool) -> m Bool
+    verifyCmd :: SParty p -> (QueueRec -> Bool) -> M VerificationResult
    verifyCmd party f = do
      st <- asks queueStore
-      q <- atomically $ getQueue st party queueId
-      pure $ either (const $ maybe False dummyVerify sig_ `seq` False) f q
+      q_ <- atomically (getQueue st party queueId)
+      pure $ case q_ of
+        Right q -> Just q `verified` f q
+        _ -> maybe False (dummyVerifyCmd signed) sig_ `seq` VRFailed
    verifyMaybe :: Maybe C.APublicVerifyKey -> Bool
-    verifyMaybe = maybe (isNothing sig_) verifySignature
-    verifySignature :: C.APublicVerifyKey -> Bool
-    verifySignature key = maybe False (verify key) sig_
+    verifyMaybe = maybe (isNothing sig_) $ verifyCmdSignature sig_ signed
+    verified q cond = if cond then VRVerified q else VRFailed
+
+verifyCmdSignature :: Maybe C.ASignature -> ByteString -> C.APublicVerifyKey -> Bool
+verifyCmdSignature sig_ signed key = maybe False (verify key) sig_
+  where
    verify :: C.APublicVerifyKey -> C.ASignature -> Bool
    verify (C.APublicVerifyKey a k) sig@(C.ASignature a' s) =
      case (testEquality a a', C.signatureSize k == C.signatureSize s) of
        (Just Refl, True) -> C.verify' k s signed
-        _ -> dummyVerify sig `seq` False
-    dummyVerify :: C.ASignature -> Bool
-    dummyVerify (C.ASignature _ s) = C.verify' (dummyPublicKey s) s signed
+        _ -> dummyVerifyCmd signed sig `seq` False
+
+dummyVerifyCmd :: ByteString -> C.ASignature -> Bool
+dummyVerifyCmd signed (C.ASignature _ s) = C.verify' (dummyPublicKey s) s signed

 -- These dummy keys are used with `dummyVerify` function to mitigate timing attacks
 -- by having the same time of the response whether a queue exists or nor, for all valid key/signature sizes
@@ -213,33 +345,43 @@ dummyKeyEd448 :: C.PublicKey 'C.Ed448
 dummyKeyEd448 = "MEMwBQYDK2VxAzoA6ibQc9XpkSLtwrf7PLvp81qW/etiumckVFImCMRdftcG/XopbOSaq9qyLhrgJWKOLyNrQPNVvpMA"

 client :: forall m. (MonadUnliftIO m, MonadReader Env m) => Client -> Server -> m ()
-client clnt@Client {subscriptions, ntfSubscriptions, rcvQ, sndQ} Server {subscribedQ, ntfSubscribedQ, notifiers} =
+client clnt@Client {thVersion, subscriptions, ntfSubscriptions, rcvQ, sndQ} Server {subscribedQ, ntfSubscribedQ, notifiers} =
  forever $
    atomically (readTBQueue rcvQ)
-      >>= processCommand
+      >>= mapM processCommand
      >>= atomically . writeTBQueue sndQ
  where
-    processCommand :: Transmission Cmd -> m (Transmission BrokerMsg)
-    processCommand (corrId, queueId, cmd) = do
+    processCommand :: (Maybe QueueRec, Transmission Cmd) -> m (Transmission BrokerMsg)
+    processCommand (qr_, (corrId, queueId, cmd)) = do
      st <- asks queueStore
      case cmd of
        Cmd SSender command ->
          case command of
-            SEND msgBody -> sendMessage st msgBody
+            SEND flags msgBody -> withQueue $ \qr -> sendMessage qr flags msgBody
            PING -> pure (corrId, "", PONG)
        Cmd SNotifier NSUB -> subscribeNotifications
        Cmd SRecipient command ->
          case command of
-            NEW rKey dhKey -> createQueue st rKey dhKey
-            SUB -> subscribeQueue queueId
-            ACK -> acknowledgeMsg
+            NEW rKey dhKey auth ->
+              ifM
+                allowNew
+                (createQueue st rKey dhKey)
+                (pure (corrId, queueId, ERR AUTH))
+              where
+                allowNew = do
+                  ServerConfig {allowNewQueues, newQueueBasicAuth} <- asks config
+                  pure $ allowNewQueues && maybe True ((== auth) . Just) newQueueBasicAuth
+            SUB -> withQueue (`subscribeQueue` queueId)
+            GET -> withQueue getMessage
+            ACK msgId -> withQueue (`acknowledgeMsg` msgId)
            KEY sKey -> secureQueue_ st sKey
-            NKEY nKey -> addQueueNotifier_ st nKey
+            NKEY nKey dhKey -> addQueueNotifier_ st nKey dhKey
+            NDEL -> deleteQueueNotifier_ st
            OFF -> suspendQueue_ st
            DEL -> delQueueAndMsgs st
      where
        createQueue :: QueueStore -> RcvPublicVerifyKey -> RcvPublicDhKey -> m (Transmission BrokerMsg)
-        createQueue st recipientKey dhKey = do
+        createQueue st recipientKey dhKey = time "NEW" $ do
          (rcvPublicDhKey, privDhKey) <- liftIO C.generateKeyPair'
          let rcvDhSecret = C.dh' dhKey privDhKey
              qik (rcvId, sndId) = QIK {rcvId, sndId, rcvPublicDhKey}
@@ -261,12 +403,16 @@ client clnt@Client {subscriptions, ntfSubscriptions, rcvQ, sndQ} Server {subscri
            addQueueRetry n qik qRec = do
              ids@(rId, _) <- getIds
              -- create QueueRec record with these ids and keys
-              atomically (addQueue st $ qRec ids) >>= \case
+              let qr = qRec ids
+              atomically (addQueue st qr) >>= \case
                Left DUPLICATE_ -> addQueueRetry (n - 1) qik qRec
                Left e -> pure $ ERR e
                Right _ -> do
                  withLog (`logCreateById` rId)
-                  subscribeQueue rId $> IDS (qik ids)
+                  stats <- asks serverStats
+                  atomically $ modifyTVar' (qCreated stats) (+ 1)
+                  atomically $ modifyTVar' (qCount stats) (+ 1)
+                  subscribeQueue qr rId $> IDS (qik ids)

            logCreateById :: StoreLog 'WriteMode -> RecipientId -> IO ()
            logCreateById s rId =
@@ -280,141 +426,262 @@ client clnt@Client {subscriptions, ntfSubscriptions, rcvQ, sndQ} Server {subscri
              liftM2 (,) (randomId n) (randomId n)

        secureQueue_ :: QueueStore -> SndPublicVerifyKey -> m (Transmission BrokerMsg)
-        secureQueue_ st sKey = do
+        secureQueue_ st sKey = time "KEY" $ do
          withLog $ \s -> logSecureQueue s queueId sKey
+          stats <- asks serverStats
+          atomically $ modifyTVar' (qSecured stats) (+ 1)
          atomically $ (corrId,queueId,) . either ERR (const OK) <$> secureQueue st queueId sKey

-        addQueueNotifier_ :: QueueStore -> NtfPublicVerifyKey -> m (Transmission BrokerMsg)
-        addQueueNotifier_ st nKey = (corrId,queueId,) <$> addNotifierRetry 3
+        addQueueNotifier_ :: QueueStore -> NtfPublicVerifyKey -> RcvNtfPublicDhKey -> m (Transmission BrokerMsg)
+        addQueueNotifier_ st notifierKey dhKey = time "NKEY" $ do
+          (rcvPublicDhKey, privDhKey) <- liftIO C.generateKeyPair'
+          let rcvNtfDhSecret = C.dh' dhKey privDhKey
+          (corrId,queueId,) <$> addNotifierRetry 3 rcvPublicDhKey rcvNtfDhSecret
          where
-            addNotifierRetry :: Int -> m BrokerMsg
-            addNotifierRetry 0 = pure $ ERR INTERNAL
-            addNotifierRetry n = do
-              nId <- randomId =<< asks (queueIdBytes . config)
-              atomically (addQueueNotifier st queueId nId nKey) >>= \case
-                Left DUPLICATE_ -> addNotifierRetry $ n - 1
+            addNotifierRetry :: Int -> RcvNtfPublicDhKey -> RcvNtfDhSecret -> m BrokerMsg
+            addNotifierRetry 0 _ _ = pure $ ERR INTERNAL
+            addNotifierRetry n rcvPublicDhKey rcvNtfDhSecret = do
+              notifierId <- randomId =<< asks (queueIdBytes . config)
+              let ntfCreds = NtfCreds {notifierId, notifierKey, rcvNtfDhSecret}
+              atomically (addQueueNotifier st queueId ntfCreds) >>= \case
+                Left DUPLICATE_ -> addNotifierRetry (n - 1) rcvPublicDhKey rcvNtfDhSecret
                Left e -> pure $ ERR e
                Right _ -> do
-                  withLog $ \s -> logAddNotifier s queueId nId nKey
-                  pure $ NID nId
+                  withLog $ \s -> logAddNotifier s queueId ntfCreds
+                  pure $ NID notifierId rcvPublicDhKey
+
+        deleteQueueNotifier_ :: QueueStore -> m (Transmission BrokerMsg)
+        deleteQueueNotifier_ st = do
+          withLog (`logDeleteNotifier` queueId)
+          okResp <$> atomically (deleteQueueNotifier st queueId)

        suspendQueue_ :: QueueStore -> m (Transmission BrokerMsg)
        suspendQueue_ st = do
-          withLog (`logDeleteQueue` queueId)
+          withLog (`logSuspendQueue` queueId)
          okResp <$> atomically (suspendQueue st queueId)

-        subscribeQueue :: RecipientId -> m (Transmission BrokerMsg)
-        subscribeQueue rId =
-          atomically (getSubscription rId) >>= deliverMessage tryPeekMsg rId
-
-        getSubscription :: RecipientId -> STM Sub
-        getSubscription rId = do
-          subs <- readTVar subscriptions
-          case M.lookup rId subs of
-            Just s -> tryTakeTMVar (delivered s) $> s
-            Nothing -> do
+        subscribeQueue :: QueueRec -> RecipientId -> m (Transmission BrokerMsg)
+        subscribeQueue qr rId = do
+          atomically (TM.lookup rId subscriptions) >>= \case
+            Nothing ->
+              newSub >>= deliver
+            Just sub ->
+              readTVarIO sub >>= \case
+                Sub {subThread = ProhibitSub} ->
+                  -- cannot use SUB in the same connection where GET was used
+                  pure (corrId, rId, ERR $ CMD PROHIBITED)
+                s ->
+                  atomically (tryTakeTMVar $ delivered s) >> deliver sub
+          where
+            newSub :: m (TVar Sub)
+            newSub = time "SUB newSub" . atomically $ do
              writeTBQueue subscribedQ (rId, clnt)
-              s <- newSubscription
-              writeTVar subscriptions $ M.insert rId s subs
-              return s
+              sub <- newTVar =<< newSubscription NoSub
+              TM.insert rId sub subscriptions
+              pure sub
+            deliver :: TVar Sub -> m (Transmission BrokerMsg)
+            deliver sub = do
+              q <- getStoreMsgQueue "SUB" rId
+              msg_ <- atomically $ tryPeekMsg q
+              deliverMessage "SUB" qr rId sub q msg_
+
+        getMessage :: QueueRec -> m (Transmission BrokerMsg)
+        getMessage qr = time "GET" $ do
+          atomically (TM.lookup queueId subscriptions) >>= \case
+            Nothing ->
+              atomically newSub >>= getMessage_
+            Just sub ->
+              readTVarIO sub >>= \case
+                s@Sub {subThread = ProhibitSub} ->
+                  atomically (tryTakeTMVar $ delivered s)
+                    >> getMessage_ s
+                -- cannot use GET in the same connection where there is an active subscription
+                _ -> pure (corrId, queueId, ERR $ CMD PROHIBITED)
+          where
+            newSub :: STM Sub
+            newSub = do
+              s <- newSubscription ProhibitSub
+              sub <- newTVar s
+              TM.insert queueId sub subscriptions
+              pure s
+            getMessage_ :: Sub -> m (Transmission BrokerMsg)
+            getMessage_ s = do
+              q <- getStoreMsgQueue "GET" queueId
+              atomically $
+                tryPeekMsg q >>= \case
+                  Just msg ->
+                    let encMsg = encryptMsg qr msg
+                     in setDelivered s msg $> (corrId, queueId, MSG encMsg)
+                  _ -> pure (corrId, queueId, OK)
+
+        withQueue :: (QueueRec -> m (Transmission BrokerMsg)) -> m (Transmission BrokerMsg)
+        withQueue action = maybe (pure $ err AUTH) action qr_

        subscribeNotifications :: m (Transmission BrokerMsg)
-        subscribeNotifications = atomically $ do
-          subs <- readTVar ntfSubscriptions
-          when (isNothing $ M.lookup queueId subs) $ do
+        subscribeNotifications = time "NSUB" . atomically $ do
+          unlessM (TM.member queueId ntfSubscriptions) $ do
            writeTBQueue ntfSubscribedQ (queueId, clnt)
-            writeTVar ntfSubscriptions $ M.insert queueId () subs
+            TM.insert queueId () ntfSubscriptions
          pure ok

-        acknowledgeMsg :: m (Transmission BrokerMsg)
-        acknowledgeMsg =
-          atomically (withSub queueId $ \s -> const s <$$> tryTakeTMVar (delivered s))
-            >>= \case
-              Just (Just s) -> deliverMessage tryDelPeekMsg queueId s
-              _ -> return $ err NO_MSG
+        acknowledgeMsg :: QueueRec -> MsgId -> m (Transmission BrokerMsg)
+        acknowledgeMsg qr msgId = time "ACK" $ do
+          atomically (TM.lookup queueId subscriptions) >>= \case
+            Nothing -> pure $ err NO_MSG
+            Just sub ->
+              atomically (getDelivered sub) >>= \case
+                Just s -> do
+                  q <- getStoreMsgQueue "ACK" queueId
+                  case s of
+                    Sub {subThread = ProhibitSub} -> do
+                      deletedMsg_ <- atomically $ tryDelMsg q msgId
+                      mapM_ updateStats deletedMsg_
+                      pure ok
+                    _ -> do
+                      (deletedMsg_, msg_) <- atomically $ tryDelPeekMsg q msgId
+                      mapM_ updateStats deletedMsg_
+                      deliverMessage "ACK" qr queueId sub q msg_
+                _ -> pure $ err NO_MSG
+          where
+            getDelivered :: TVar Sub -> STM (Maybe Sub)
+            getDelivered sub = do
+              s@Sub {delivered} <- readTVar sub
+              tryTakeTMVar delivered $>>= \msgId' ->
+                if msgId == msgId' || B.null msgId
+                  then pure $ Just s
+                  else putTMVar delivered msgId' $> Nothing
+            updateStats :: Message -> m ()
+            updateStats = \case
+              MessageQuota {} -> pure ()
+              Message {msgFlags} -> do
+                stats <- asks serverStats
+                atomically $ modifyTVar' (msgRecv stats) (+ 1)
+                atomically $ modifyTVar' (msgCount stats) (+ 1)
+                atomically $ updatePeriodStats (activeQueues stats) queueId
+                when (notification msgFlags) $ do
+                  atomically $ modifyTVar' (msgRecvNtf stats) (+ 1)
+                  atomically $ updatePeriodStats (activeQueuesNtf stats) queueId

-        withSub :: RecipientId -> (Sub -> STM a) -> STM (Maybe a)
-        withSub rId f = readTVar subscriptions >>= mapM f . M.lookup rId
-
-        sendMessage :: QueueStore -> MsgBody -> m (Transmission BrokerMsg)
-        sendMessage st msgBody
+        sendMessage :: QueueRec -> MsgFlags -> MsgBody -> m (Transmission BrokerMsg)
+        sendMessage qr msgFlags msgBody
          | B.length msgBody > maxMessageLength = pure $ err LARGE_MSG
-          | otherwise = do
-            qr <- atomically $ getQueue st SSender queueId
-            either (return . err) storeMessage qr
+          | otherwise = case status qr of
+            QueueOff -> return $ err AUTH
+            QueueActive ->
+              case C.maxLenBS msgBody of
+                Left _ -> pure $ err LARGE_MSG
+                Right body -> do
+                  msg_ <- time "SEND" $ do
+                    q <- getStoreMsgQueue "SEND" $ recipientId qr
+                    expireMessages q
+                    atomically . writeMsg q =<< mkMessage body
+                  case msg_ of
+                    Nothing -> pure $ err QUOTA
+                    Just msg -> time "SEND ok" $ do
+                      stats <- asks serverStats
+                      when (notification msgFlags) $ do
+                        atomically . trySendNotification msg =<< asks idsDrg
+                        atomically $ modifyTVar' (msgSentNtf stats) (+ 1)
+                        atomically $ updatePeriodStats (activeQueuesNtf stats) (recipientId qr)
+                      atomically $ modifyTVar' (msgSent stats) (+ 1)
+                      atomically $ modifyTVar' (msgCount stats) (subtract 1)
+                      atomically $ updatePeriodStats (activeQueues stats) (recipientId qr)
+                      pure ok
          where
-            storeMessage :: QueueRec -> m (Transmission BrokerMsg)
-            storeMessage qr = case status qr of
-              QueueOff -> return $ err AUTH
-              QueueActive ->
-                mkMessage >>= \case
-                  Left _ -> pure $ err LARGE_MSG
-                  Right msg -> do
-                    ms <- asks msgStore
-                    quota <- asks $ msgQueueQuota . config
-                    atomically $ do
-                      q <- getMsgQueue ms (recipientId qr) quota
-                      ifM (isFull q) (pure $ err QUOTA) $ do
-                        trySendNotification
-                        writeMsg q msg
-                        pure ok
-              where
-                mkMessage :: m (Either C.CryptoError Message)
-                mkMessage = do
-                  msgId <- randomId =<< asks (msgIdBytes . config)
-                  ts <- liftIO getSystemTime
-                  let c = C.cbEncrypt (rcvDhSecret qr) (C.cbNonce msgId) msgBody (maxMessageLength + 2)
-                  pure $ Message msgId ts <$> c
+            mkMessage :: C.MaxLenBS MaxMessageLen -> m Message
+            mkMessage body = do
+              msgId <- randomId =<< asks (msgIdBytes . config)
+              msgTs <- liftIO getSystemTime
+              pure $ Message msgId msgTs msgFlags body

-                trySendNotification :: STM ()
-                trySendNotification =
-                  forM_ (notifier qr) $ \(nId, _) ->
-                    mapM_ (writeNtf nId) . M.lookup nId =<< readTVar notifiers
+            expireMessages :: MsgQueue -> m ()
+            expireMessages q = do
+              msgExp <- asks $ messageExpiration . config
+              old <- liftIO $ mapM expireBeforeEpoch msgExp
+              atomically $ mapM_ (deleteExpiredMsgs q) old

-                writeNtf :: NotifierId -> Client -> STM ()
-                writeNtf nId Client {sndQ = q} =
-                  unlessM (isFullTBQueue sndQ) $
-                    writeTBQueue q (CorrId "", nId, NMSG)
+            trySendNotification :: Message -> TVar ChaChaDRG -> STM ()
+            trySendNotification msg ntfNonceDrg =
+              forM_ (notifier qr) $ \NtfCreds {notifierId, rcvNtfDhSecret} ->
+                mapM_ (writeNtf notifierId msg rcvNtfDhSecret ntfNonceDrg) =<< TM.lookup notifierId notifiers

-        deliverMessage :: (MsgQueue -> STM (Maybe Message)) -> RecipientId -> Sub -> m (Transmission BrokerMsg)
-        deliverMessage tryPeek rId = \case
-          Sub {subThread = NoSub} -> do
-            ms <- asks msgStore
-            quota <- asks $ msgQueueQuota . config
-            q <- atomically $ getMsgQueue ms rId quota
-            atomically (tryPeek q) >>= \case
-              Nothing -> forkSub q $> ok
-              Just msg -> atomically setDelivered $> (corrId, rId, msgCmd msg)
-          _ -> pure ok
+            writeNtf :: NotifierId -> Message -> RcvNtfDhSecret -> TVar ChaChaDRG -> Client -> STM ()
+            writeNtf nId msg rcvNtfDhSecret ntfNonceDrg Client {sndQ = q} =
+              unlessM (isFullTBQueue q) $ case msg of
+                Message {msgId, msgTs} -> do
+                  (nmsgNonce, encNMsgMeta) <- mkMessageNotification msgId msgTs rcvNtfDhSecret ntfNonceDrg
+                  writeTBQueue q [(CorrId "", nId, NMSG nmsgNonce encNMsgMeta)]
+                _ -> pure ()
+
+            mkMessageNotification :: ByteString -> SystemTime -> RcvNtfDhSecret -> TVar ChaChaDRG -> STM (C.CbNonce, EncNMsgMeta)
+            mkMessageNotification msgId msgTs rcvNtfDhSecret ntfNonceDrg = do
+              cbNonce <- C.pseudoRandomCbNonce ntfNonceDrg
+              let msgMeta = NMsgMeta {msgId, msgTs}
+                  encNMsgMeta = C.cbEncrypt rcvNtfDhSecret cbNonce (smpEncode msgMeta) 128
+              pure . (cbNonce,) $ fromRight "" encNMsgMeta
+
+        deliverMessage :: T.Text -> QueueRec -> RecipientId -> TVar Sub -> MsgQueue -> Maybe Message -> m (Transmission BrokerMsg)
+        deliverMessage name qr rId sub q msg_ = time (name <> " deliver") $ do
+          readTVarIO sub >>= \case
+            s@Sub {subThread = NoSub} ->
+              case msg_ of
+                Just msg ->
+                  let encMsg = encryptMsg qr msg
+                   in atomically (setDelivered s msg) $> (corrId, rId, MSG encMsg)
+                _ -> forkSub $> ok
+            _ -> pure ok
          where
-            forkSub :: MsgQueue -> m ()
-            forkSub q = do
-              atomically . setSub $ \s -> s {subThread = SubPending}
-              t <- forkIO $ subscriber q
-              atomically . setSub $ \case
+            forkSub :: m ()
+            forkSub = do
+              atomically . modifyTVar' sub $ \s -> s {subThread = SubPending}
+              t <- mkWeakThreadId =<< forkIO subscriber
+              atomically . modifyTVar' sub $ \case
                s@Sub {subThread = SubPending} -> s {subThread = SubThread t}
                s -> s
+              where
+                subscriber = do
+                  msg <- atomically $ peekMsg q
+                  time "subscriber" . atomically $ do
+                    let encMsg = encryptMsg qr msg
+                    writeTBQueue sndQ [(CorrId "", rId, MSG encMsg)]
+                    s <- readTVar sub
+                    void $ setDelivered s msg
+                    writeTVar sub $! s {subThread = NoSub}

-            subscriber :: MsgQueue -> m ()
-            subscriber q = atomically $ do
-              msg <- peekMsg q
-              writeTBQueue sndQ (CorrId "", rId, msgCmd msg)
-              setSub (\s -> s {subThread = NoSub})
-              void setDelivered
+        time :: T.Text -> m a -> m a
+        time name = timed name queueId

-            setSub :: (Sub -> Sub) -> STM ()
-            setSub f = modifyTVar subscriptions $ M.adjust f rId
+        encryptMsg :: QueueRec -> Message -> RcvMessage
+        encryptMsg qr msg = case msg of
+          Message {msgFlags, msgBody}
+            | thVersion == 1 || thVersion == 2 -> encrypt msgFlags msgBody
+            | otherwise -> encrypt msgFlags $ encodeRcvMsgBody RcvMsgBody {msgTs = msgTs', msgFlags, msgBody}
+          MessageQuota {} ->
+            encrypt noMsgFlags $ encodeRcvMsgBody (RcvMsgQuota msgTs')
+          where
+            encrypt :: KnownNat i => MsgFlags -> C.MaxLenBS i -> RcvMessage
+            encrypt msgFlags body =
+              let encBody = EncRcvMsgBody $ C.cbEncryptMaxLenBS (rcvDhSecret qr) (C.cbNonce msgId') body
+               in RcvMessage msgId' msgTs' msgFlags encBody
+            msgId' = msgId (msg :: Message)
+            msgTs' = msgTs (msg :: Message)

-            setDelivered :: STM (Maybe Bool)
-            setDelivered = withSub rId $ \s -> tryPutTMVar (delivered s) ()
+        setDelivered :: Sub -> Message -> STM Bool
+        setDelivered s msg = tryPutTMVar (delivered s) $ msgId (msg :: Message)

-            msgCmd :: Message -> BrokerMsg
-            msgCmd Message {msgId, ts, msgBody} = MSG msgId ts msgBody
+        getStoreMsgQueue :: T.Text -> RecipientId -> m MsgQueue
+        getStoreMsgQueue name rId = time (name <> " getMsgQueue") $ do
+          ms <- asks msgStore
+          quota <- asks $ msgQueueQuota . config
+          atomically $ getMsgQueue ms rId quota

        delQueueAndMsgs :: QueueStore -> m (Transmission BrokerMsg)
        delQueueAndMsgs st = do
          withLog (`logDeleteQueue` queueId)
          ms <- asks msgStore
+          stats <- asks serverStats
+          atomically $ modifyTVar' (qDeleted stats) (+ 1)
+          atomically $ modifyTVar' (qCount stats) (subtract 1)
          atomically $
            deleteQueue st queueId >>= \case
              Left e -> pure $ err e
@@ -434,14 +701,100 @@ withLog action = do
  env <- ask
  liftIO . mapM_ action $ storeLog (env :: Env)

+timed :: MonadUnliftIO m => T.Text -> RecipientId -> m a -> m a
+timed name qId a = do
+  t <- liftIO getSystemTime
+  r <- a
+  t' <- liftIO getSystemTime
+  let int = diff t t'
+  when (int > sec) . logDebug $ T.unwords [name, tshow $ encode qId, tshow int]
+  pure r
+  where
+    diff t t' = (systemSeconds t' - systemSeconds t) * sec + fromIntegral (systemNanoseconds t' - systemNanoseconds t)
+    sec = 1000_000000
+
 randomId :: (MonadUnliftIO m, MonadReader Env m) => Int -> m ByteString
 randomId n = do
  gVar <- asks idsDrg
-  atomically (randomBytes n gVar)
+  atomically (C.pseudoRandomBytes n gVar)

-randomBytes :: Int -> TVar ChaChaDRG -> STM ByteString
-randomBytes n gVar = do
-  g <- readTVar gVar
-  let (bytes, g') = randomBytesGenerate n g
-  writeTVar gVar g'
-  return bytes
+saveServerMessages :: (MonadUnliftIO m, MonadReader Env m) => m ()
+saveServerMessages = asks (storeMsgsFile . config) >>= mapM_ saveMessages
+  where
+    saveMessages f = do
+      logInfo $ "saving messages to file " <> T.pack f
+      ms <- asks msgStore
+      liftIO . withFile f WriteMode $ \h ->
+        readTVarIO ms >>= mapM_ (saveQueueMsgs ms h) . M.keys
+      logInfo "messages saved"
+      where
+        saveQueueMsgs ms h rId =
+          atomically (flushMsgQueue ms rId)
+            >>= mapM_ (B.hPutStrLn h . strEncode . MLRv3 rId)
+
+restoreServerMessages :: forall m. (MonadUnliftIO m, MonadReader Env m) => m ()
+restoreServerMessages = asks (storeMsgsFile . config) >>= mapM_ restoreMessages
+  where
+    restoreMessages f = whenM (doesFileExist f) $ do
+      logInfo $ "restoring messages from file " <> T.pack f
+      st <- asks queueStore
+      ms <- asks msgStore
+      quota <- asks $ msgQueueQuota . config
+      runExceptT (liftIO (B.readFile f) >>= mapM_ (restoreMsg st ms quota) . B.lines) >>= \case
+        Left e -> do
+          logError . T.pack $ "error restoring messages: " <> e
+          liftIO exitFailure
+        _ -> do
+          renameFile f $ f <> ".bak"
+          logInfo "messages restored"
+      where
+        restoreMsg st ms quota s = do
+          r <- liftEither . first (msgErr "parsing") $ strDecode s
+          case r of
+            MLRv3 rId msg -> addToMsgQueue rId msg
+            MLRv1 rId encMsg -> do
+              qr <- liftEitherError (msgErr "queue unknown") . atomically $ getQueue st SRecipient rId
+              msg' <- updateMsgV1toV3 qr encMsg
+              addToMsgQueue rId msg'
+          where
+            addToMsgQueue rId msg = do
+              full <- atomically $ do
+                q <- getMsgQueue ms rId quota
+                isNothing <$> writeMsg q msg
+              case msg of
+                Message {} ->
+                  when full . logError . decodeLatin1 $ "message queue " <> strEncode rId <> " is full, message not restored: " <> strEncode (msgId (msg :: Message))
+                MessageQuota {} -> pure ()
+            updateMsgV1toV3 QueueRec {rcvDhSecret} RcvMessage {msgId, msgTs, msgFlags, msgBody = EncRcvMsgBody body} = do
+              let nonce = C.cbNonce msgId
+              msgBody <- liftEither . first (msgErr "v1 message decryption") $ C.maxLenBS =<< C.cbDecrypt rcvDhSecret nonce body
+              pure Message {msgId, msgTs, msgFlags, msgBody}
+            msgErr :: Show e => String -> e -> String
+            msgErr op e = op <> " error (" <> show e <> "): " <> B.unpack (B.take 100 s)
+
+saveServerStats :: (MonadUnliftIO m, MonadReader Env m) => m ()
+saveServerStats =
+  asks (serverStatsBackupFile . config)
+    >>= mapM_ (\f -> asks serverStats >>= atomically . getServerStatsData >>= liftIO . saveStats f)
+  where
+    saveStats f stats = do
+      logInfo $ "saving server stats to file " <> T.pack f
+      B.writeFile f $ strEncode stats
+      logInfo "server stats saved"
+
+restoreServerStats :: (MonadUnliftIO m, MonadReader Env m) => m ()
+restoreServerStats = asks (serverStatsBackupFile . config) >>= mapM_ restoreStats
+  where
+    restoreStats f = whenM (doesFileExist f) $ do
+      logInfo $ "restoring server stats from file " <> T.pack f
+      liftIO (strDecode <$> B.readFile f) >>= \case
+        Right d -> do
+          s <- asks serverStats
+          _qCount <- fmap (length . M.keys) . readTVarIO . queues =<< asks queueStore
+          _msgCount <- foldM (\n q -> (n +) <$> readTVarIO (size q)) 0 =<< readTVarIO =<< asks msgStore
+          atomically $ setServerStats s d {_qCount, _msgCount}
+          renameFile f $ f <> ".bak"
+          logInfo "server stats restored"
+        Left e -> do
+          logInfo $ "error restoring server stats: " <> T.pack e
+          liftIO exitFailure
@@ -0,0 +1,230 @@
+{-# LANGUAGE DataKinds #-}
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE FlexibleContexts #-}
+{-# LANGUAGE GADTs #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE TypeApplications #-}
+
+module Simplex.Messaging.Server.CLI where
+
+import Control.Monad
+import Data.ByteString.Char8 (ByteString)
+import qualified Data.ByteString.Char8 as B
+import Data.Either (fromRight)
+import Data.Ini (Ini, lookupValue)
+import Data.Text (Text)
+import qualified Data.Text as T
+import Data.X509.Validation (Fingerprint (..))
+import Network.Socket (HostName, ServiceName)
+import Options.Applicative
+import Simplex.Messaging.Encoding.String
+import Simplex.Messaging.Protocol (ProtoServerWithAuth (..), ProtocolServer (..), ProtocolTypeI)
+import Simplex.Messaging.Transport (ATransport (..), TLS, Transport (..))
+import Simplex.Messaging.Transport.Server (loadFingerprint)
+import Simplex.Messaging.Transport.WebSockets (WS)
+import Simplex.Messaging.Util (whenM)
+import System.Directory (doesDirectoryExist, listDirectory, removeDirectoryRecursive, removePathForcibly)
+import System.Exit (exitFailure)
+import System.FilePath (combine)
+import System.IO (IOMode (..), hFlush, hGetLine, stdout, withFile)
+import System.Process (readCreateProcess, shell)
+
+exitError :: String -> IO ()
+exitError msg = putStrLn msg >> exitFailure
+
+confirmOrExit :: String -> IO ()
+confirmOrExit s =
+  withPrompt (s <> "\nContinue (Y/n): ") $ do
+    ok <- getLine
+    when (ok /= "Y") $ putStrLn "Server NOT deleted" >> exitFailure
+
+data SignAlgorithm = ED448 | ED25519
+  deriving (Read, Show)
+
+data X509Config = X509Config
+  { commonName :: HostName,
+    signAlgorithm :: SignAlgorithm,
+    caKeyFile :: FilePath,
+    caCrtFile :: FilePath,
+    serverKeyFile :: FilePath,
+    serverCrtFile :: FilePath,
+    fingerprintFile :: FilePath,
+    opensslCaConfFile :: FilePath,
+    opensslServerConfFile :: FilePath,
+    serverCsrFile :: FilePath
+  }
+
+defaultX509Config :: X509Config
+defaultX509Config =
+  X509Config
+    { commonName = "127.0.0.1",
+      signAlgorithm = ED448,
+      caKeyFile = "ca.key",
+      caCrtFile = "ca.crt",
+      serverKeyFile = "server.key",
+      serverCrtFile = "server.crt",
+      fingerprintFile = "fingerprint",
+      opensslCaConfFile = "openssl_ca.conf",
+      opensslServerConfFile = "openssl_server.conf",
+      serverCsrFile = "server.csr"
+    }
+
+getCliCommand' :: Parser cmd -> String -> IO cmd
+getCliCommand' cmdP version =
+  customExecParser
+    (prefs showHelpOnEmpty)
+    ( info
+        (helper <*> versionOption <*> cmdP)
+        (header version <> fullDesc)
+    )
+  where
+    versionOption = infoOption version (long "version" <> short 'v' <> help "Show version")
+
+createServerX509 :: FilePath -> X509Config -> IO ByteString
+createServerX509 cfgPath x509cfg = do
+  createOpensslCaConf
+  createOpensslServerConf
+  let alg = show $ signAlgorithm (x509cfg :: X509Config)
+  -- CA certificate (identity/offline)
+  run $ "openssl genpkey -algorithm " <> alg <> " -out " <> c caKeyFile
+  run $ "openssl req -new -x509 -days 999999 -config " <> c opensslCaConfFile <> " -extensions v3 -key " <> c caKeyFile <> " -out " <> c caCrtFile
+  -- server certificate (online)
+  run $ "openssl genpkey -algorithm " <> alg <> " -out " <> c serverKeyFile
+  run $ "openssl req -new -config " <> c opensslServerConfFile <> " -reqexts v3 -key " <> c serverKeyFile <> " -out " <> c serverCsrFile
+  run $ "openssl x509 -req -days 999999 -extfile " <> c opensslServerConfFile <> " -extensions v3 -in " <> c serverCsrFile <> " -CA " <> c caCrtFile <> " -CAkey " <> c caKeyFile <> " -CAcreateserial -out " <> c serverCrtFile
+  saveFingerprint
+  where
+    run cmd = void $ readCreateProcess (shell cmd) ""
+    c = combine cfgPath . ($ x509cfg)
+    createOpensslCaConf =
+      writeFile
+        (c opensslCaConfFile)
+        "[req]\n\
+        \distinguished_name = req_distinguished_name\n\
+        \prompt = no\n\n\
+        \[req_distinguished_name]\n\
+        \CN = SMP server CA\n\
+        \O = SimpleX\n\n\
+        \[v3]\n\
+        \subjectKeyIdentifier = hash\n\
+        \authorityKeyIdentifier = keyid:always\n\
+        \basicConstraints = critical,CA:true\n"
+    createOpensslServerConf =
+      writeFile
+        (c opensslServerConfFile)
+        ( "[req]\n\
+          \distinguished_name = req_distinguished_name\n\
+          \prompt = no\n\n\
+          \[req_distinguished_name]\n"
+            <> ("CN = " <> commonName x509cfg <> "\n\n")
+            <> "[v3]\n\
+               \basicConstraints = CA:FALSE\n\
+               \keyUsage = digitalSignature, nonRepudiation, keyAgreement\n\
+               \extendedKeyUsage = serverAuth\n"
+        )
+
+    saveFingerprint = do
+      Fingerprint fp <- loadFingerprint $ c caCrtFile
+      withFile (c fingerprintFile) WriteMode (`B.hPutStrLn` strEncode fp)
+      pure fp
+
+warnCAPrivateKeyFile :: FilePath -> X509Config -> IO ()
+warnCAPrivateKeyFile cfgPath X509Config {caKeyFile} =
+  putStrLn $
+    "----------\n\
+    \You should store CA private key securely and delete it from the server.\n\
+    \If server TLS credential is compromised this key can be used to sign a new one, \
+    \keeping the same server identity and established connections.\n\
+    \CA private key location:\n"
+      <> combine cfgPath caKeyFile
+      <> "\n----------"
+
+data IniOptions = IniOptions
+  { enableStoreLog :: Bool,
+    port :: ServiceName,
+    enableWebsockets :: Bool
+  }
+
+mkIniOptions :: Ini -> IniOptions
+mkIniOptions ini =
+  IniOptions
+    { enableStoreLog = (== "on") $ strictIni "STORE_LOG" "enable" ini,
+      port = T.unpack $ strictIni "TRANSPORT" "port" ini,
+      enableWebsockets = (== "on") $ strictIni "TRANSPORT" "websockets" ini
+    }
+
+strictIni :: Text -> Text -> Ini -> Text
+strictIni section key ini =
+  fromRight (error . T.unpack $ "no key " <> key <> " in section " <> section) $
+    lookupValue section key ini
+
+readStrictIni :: Read a => Text -> Text -> Ini -> a
+readStrictIni section key = read . T.unpack . strictIni section key
+
+iniOnOff :: Text -> Text -> Ini -> Maybe Bool
+iniOnOff section name ini = case lookupValue section name ini of
+  Right "on" -> Just True
+  Right "off" -> Just False
+  Right s -> error . T.unpack $ "invalid INI setting " <> name <> ": " <> s
+  _ -> Nothing
+
+withPrompt :: String -> IO a -> IO a
+withPrompt s a = putStr s >> hFlush stdout >> a
+
+onOffPrompt :: String -> Bool -> IO Bool
+onOffPrompt prompt def =
+  withPrompt (prompt <> if def then " (Yn): " else " (yN): ") $
+    getLine >>= \case
+      "" -> pure def
+      "y" -> pure True
+      "Y" -> pure True
+      "n" -> pure False
+      "N" -> pure False
+      _ -> putStrLn "Invalid input, please enter 'y' or 'n'" >> onOffPrompt prompt def
+
+onOff :: Bool -> String
+onOff True = "on"
+onOff _ = "off"
+
+settingIsOn :: Text -> Text -> Ini -> Maybe ()
+settingIsOn section name ini
+  | iniOnOff section name ini == Just True = Just ()
+  | otherwise = Nothing
+
+checkSavedFingerprint :: FilePath -> X509Config -> IO ByteString
+checkSavedFingerprint cfgPath x509cfg = do
+  savedFingerprint <- withFile (c fingerprintFile) ReadMode hGetLine
+  Fingerprint fp <- loadFingerprint (c caCrtFile)
+  when (B.pack savedFingerprint /= strEncode fp) $
+    exitError "Stored fingerprint is invalid."
+  pure fp
+  where
+    c = combine cfgPath . ($ x509cfg)
+
+iniTransports :: Ini -> [(String, ATransport)]
+iniTransports ini =
+  let port = T.unpack $ strictIni "TRANSPORT" "port" ini
+      enableWebsockets = (== "on") $ strictIni "TRANSPORT" "websockets" ini
+   in (port, transport @TLS) : [("80", transport @WS) | enableWebsockets]
+
+printServerConfig :: [(ServiceName, ATransport)] -> Maybe FilePath -> IO ()
+printServerConfig transports logFile = do
+  putStrLn $ case logFile of
+    Just f -> "Store log: " <> f
+    _ -> "Store log disabled."
+  forM_ transports $ \(p, ATransport t) ->
+    putStrLn $ "Listening on port " <> p <> " (" <> transportName t <> ")..."
+
+deleteDirIfExists :: FilePath -> IO ()
+deleteDirIfExists path = whenM (doesDirectoryExist path) $ removeDirectoryRecursive path
+
+printServiceInfo :: ProtocolTypeI p => String -> ProtoServerWithAuth p -> IO ()
+printServiceInfo serverVersion srv@(ProtoServerWithAuth ProtocolServer {keyHash} _) = do
+  putStrLn serverVersion
+  B.putStrLn $ "Fingerprint: " <> strEncode keyHash
+  B.putStrLn $ "Server address: " <> strEncode srv
+
+clearDirIfExists :: FilePath -> IO ()
+clearDirIfExists path = whenM (doesDirectoryExist path) $ listDirectory path >>= mapM_ (removePathForcibly . combine path)
@@ -9,37 +9,82 @@ import Control.Concurrent (ThreadId)
 import Control.Monad.IO.Unlift
 import Crypto.Random
 import Data.ByteString.Char8 (ByteString)
+import Data.List.NonEmpty (NonEmpty)
 import Data.Map.Strict (Map)
 import qualified Data.Map.Strict as M
+import Data.Time.Clock (getCurrentTime)
+import Data.Time.Clock.System (SystemTime)
 import Data.X509.Validation (Fingerprint (..))
 import Network.Socket (ServiceName)
 import qualified Network.TLS as T
 import Numeric.Natural
 import Simplex.Messaging.Crypto (KeyHash (..))
 import Simplex.Messaging.Protocol
+import Simplex.Messaging.Server.Expiration
 import Simplex.Messaging.Server.MsgStore.STM
-import Simplex.Messaging.Server.QueueStore (QueueRec (..))
+import Simplex.Messaging.Server.QueueStore (NtfCreds (..), QueueRec (..))
 import Simplex.Messaging.Server.QueueStore.STM
+import Simplex.Messaging.Server.Stats
 import Simplex.Messaging.Server.StoreLog
+import Simplex.Messaging.TMap (TMap)
+import qualified Simplex.Messaging.TMap as TM
 import Simplex.Messaging.Transport (ATransport)
 import Simplex.Messaging.Transport.Server (loadFingerprint, loadTLSServerParams)
+import Simplex.Messaging.Version
 import System.IO (IOMode (..))
+import System.Mem.Weak (Weak)
 import UnliftIO.STM

 data ServerConfig = ServerConfig
  { transports :: [(ServiceName, ATransport)],
    tbqSize :: Natural,
    serverTbqSize :: Natural,
-    msgQueueQuota :: Natural,
+    msgQueueQuota :: Int,
    queueIdBytes :: Int,
    msgIdBytes :: Int,
-    storeLog :: Maybe (StoreLog 'ReadMode),
-    -- CA certificate private key is not needed for initialization
+    storeLogFile :: Maybe FilePath,
+    storeMsgsFile :: Maybe FilePath,
+    -- | set to False to prohibit creating new queues
+    allowNewQueues :: Bool,
+    -- | simple password that the clients need to pass in handshake to be able to create new queues
+    newQueueBasicAuth :: Maybe BasicAuth,
+    -- | time after which the messages can be removed from the queues and check interval, seconds
+    messageExpiration :: Maybe ExpirationConfig,
+    -- | time after which the socket with inactive client can be disconnected (without any messages or commands, incl. PING),
+    -- and check interval, seconds
+    inactiveClientExpiration :: Maybe ExpirationConfig,
+    -- | log SMP server usage statistics, only aggregates are logged, seconds
+    logStatsInterval :: Maybe Int,
+    -- | time of the day when the stats are logged first, to log at consistent times,
+    -- irrespective of when the server is started (seconds from 00:00 UTC)
+    logStatsStartTime :: Int,
+    -- | file to log stats
+    serverStatsLogFile :: FilePath,
+    -- | file to save and restore stats
+    serverStatsBackupFile :: Maybe FilePath,
+    -- | CA certificate private key is not needed for initialization
    caCertificateFile :: FilePath,
    privateKeyFile :: FilePath,
-    certificateFile :: FilePath
+    certificateFile :: FilePath,
+    -- | SMP client-server protocol version range
+    smpServerVRange :: VersionRange,
+    logTLSErrors :: Bool
  }

+defaultMessageExpiration :: ExpirationConfig
+defaultMessageExpiration =
+  ExpirationConfig
+    { ttl = 30 * 86400, -- seconds, 30 days
+      checkInterval = 43200 -- seconds, 12 hours
+    }
+
+defaultInactiveClientExpiration :: ExpirationConfig
+defaultInactiveClientExpiration =
+  ExpirationConfig
+    { ttl = 86400, -- seconds, 24 hours
+      checkInterval = 43200 -- seconds, 12 hours
+    }
+
 data Env = Env
  { config :: ServerConfig,
    server :: Server,
@@ -48,80 +93,83 @@ data Env = Env
    msgStore :: STMMsgStore,
    idsDrg :: TVar ChaChaDRG,
    storeLog :: Maybe (StoreLog 'WriteMode),
-    tlsServerParams :: T.ServerParams
+    tlsServerParams :: T.ServerParams,
+    serverStats :: ServerStats
  }

 data Server = Server
  { subscribedQ :: TBQueue (RecipientId, Client),
-    subscribers :: TVar (Map RecipientId Client),
+    subscribers :: TMap RecipientId Client,
    ntfSubscribedQ :: TBQueue (NotifierId, Client),
-    notifiers :: TVar (Map NotifierId Client)
+    notifiers :: TMap NotifierId Client
  }

 data Client = Client
-  { subscriptions :: TVar (Map RecipientId Sub),
-    ntfSubscriptions :: TVar (Map NotifierId ()),
-    rcvQ :: TBQueue (Transmission Cmd),
-    sndQ :: TBQueue (Transmission BrokerMsg),
+  { subscriptions :: TMap RecipientId (TVar Sub),
+    ntfSubscriptions :: TMap NotifierId (),
+    rcvQ :: TBQueue (NonEmpty (Maybe QueueRec, Transmission Cmd)),
+    sndQ :: TBQueue (NonEmpty (Transmission BrokerMsg)),
+    thVersion :: Version,
    sessionId :: ByteString,
-    connected :: TVar Bool
+    connected :: TVar Bool,
+    activeAt :: TVar SystemTime
  }

-data SubscriptionThread = NoSub | SubPending | SubThread ThreadId
+data SubscriptionThread = NoSub | SubPending | SubThread (Weak ThreadId) | ProhibitSub

 data Sub = Sub
  { subThread :: SubscriptionThread,
-    delivered :: TMVar ()
+    delivered :: TMVar MsgId
  }

 newServer :: Natural -> STM Server
 newServer qSize = do
  subscribedQ <- newTBQueue qSize
-  subscribers <- newTVar M.empty
+  subscribers <- TM.empty
  ntfSubscribedQ <- newTBQueue qSize
-  notifiers <- newTVar M.empty
+  notifiers <- TM.empty
  return Server {subscribedQ, subscribers, ntfSubscribedQ, notifiers}

-newClient :: Natural -> ByteString -> STM Client
-newClient qSize sessionId = do
-  subscriptions <- newTVar M.empty
-  ntfSubscriptions <- newTVar M.empty
+newClient :: Natural -> Version -> ByteString -> SystemTime -> STM Client
+newClient qSize thVersion sessionId ts = do
+  subscriptions <- TM.empty
+  ntfSubscriptions <- TM.empty
  rcvQ <- newTBQueue qSize
  sndQ <- newTBQueue qSize
  connected <- newTVar True
-  return Client {subscriptions, ntfSubscriptions, rcvQ, sndQ, sessionId, connected}
+  activeAt <- newTVar ts
+  return Client {subscriptions, ntfSubscriptions, rcvQ, sndQ, thVersion, sessionId, connected, activeAt}

-newSubscription :: STM Sub
-newSubscription = do
+newSubscription :: SubscriptionThread -> STM Sub
+newSubscription subThread = do
  delivered <- newEmptyTMVar
-  return Sub {subThread = NoSub, delivered}
+  return Sub {subThread, delivered}

 newEnv :: forall m. (MonadUnliftIO m, MonadRandom m) => ServerConfig -> m Env
-newEnv config@ServerConfig {caCertificateFile, certificateFile, privateKeyFile} = do
+newEnv config@ServerConfig {caCertificateFile, certificateFile, privateKeyFile, storeLogFile} = do
  server <- atomically $ newServer (serverTbqSize config)
  queueStore <- atomically newQueueStore
  msgStore <- atomically newMsgStore
  idsDrg <- drgNew >>= newTVarIO
-  s' <- restoreQueues queueStore `mapM` storeLog (config :: ServerConfig)
+  storeLog <- liftIO $ openReadStoreLog `mapM` storeLogFile
+  s' <- restoreQueues queueStore `mapM` storeLog
  tlsServerParams <- liftIO $ loadTLSServerParams caCertificateFile certificateFile privateKeyFile
  Fingerprint fp <- liftIO $ loadFingerprint caCertificateFile
  let serverIdentity = KeyHash fp
-  return Env {config, server, serverIdentity, queueStore, msgStore, idsDrg, storeLog = s', tlsServerParams}
+  serverStats <- atomically . newServerStats =<< liftIO getCurrentTime
+  return Env {config, server, serverIdentity, queueStore, msgStore, idsDrg, storeLog = s', tlsServerParams, serverStats}
  where
    restoreQueues :: QueueStore -> StoreLog 'ReadMode -> m (StoreLog 'WriteMode)
-    restoreQueues queueStore s = do
-      (queues, s') <- liftIO $ readWriteStoreLog s
-      atomically $
-        modifyTVar queueStore $ \d ->
-          d
-            { queues,
-              senders = M.foldr' addSender M.empty queues,
-              notifiers = M.foldr' addNotifier M.empty queues
-            }
+    restoreQueues QueueStore {queues, senders, notifiers} s = do
+      (qs, s') <- liftIO $ readWriteStoreLog s
+      atomically $ do
+        writeTVar queues =<< mapM newTVar qs
+        writeTVar senders $! M.foldr' addSender M.empty qs
+        writeTVar notifiers $! M.foldr' addNotifier M.empty qs
      pure s'
    addSender :: QueueRec -> Map SenderId RecipientId -> Map SenderId RecipientId
    addSender q = M.insert (senderId q) (recipientId q)
    addNotifier :: QueueRec -> Map NotifierId RecipientId -> Map NotifierId RecipientId
    addNotifier q = case notifier q of
      Nothing -> id
-      Just (nId, _) -> M.insert nId (recipientId q)
+      Just NtfCreds {notifierId} -> M.insert notifierId (recipientId q)
@@ -0,0 +1,17 @@
+{-# LANGUAGE NamedFieldPuns #-}
+
+module Simplex.Messaging.Server.Expiration where
+
+import Control.Monad.IO.Class
+import Data.Int (Int64)
+import Data.Time.Clock.System (SystemTime (..), getSystemTime)
+
+data ExpirationConfig = ExpirationConfig
+  { -- time after which the entity can be expired, seconds
+    ttl :: Int64,
+    -- interval to check expiration, seconds
+    checkInterval :: Int
+  }
+
+expireBeforeEpoch :: ExpirationConfig -> IO Int64
+expireBeforeEpoch ExpirationConfig {ttl} = subtract ttl . systemSeconds <$> liftIO getSystemTime
@@ -0,0 +1,285 @@
+{-# LANGUAGE ApplicativeDo #-}
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedLists #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE PatternSynonyms #-}
+
+module Simplex.Messaging.Server.Main where
+
+import Control.Monad (void)
+import Crypto.Random (getRandomBytes)
+import qualified Data.ByteString.Char8 as B
+import Data.Either (fromRight)
+import Data.Functor (($>))
+import Data.Ini (lookupValue, readIniFile)
+import Data.Maybe (fromMaybe)
+import qualified Data.Text as T
+import Data.Text.Encoding (encodeUtf8)
+import Network.Socket (HostName)
+import Options.Applicative
+import qualified Simplex.Messaging.Crypto as C
+import Simplex.Messaging.Encoding.String
+import Simplex.Messaging.Protocol (BasicAuth (..), ProtoServerWithAuth (ProtoServerWithAuth), pattern SMPServer)
+import Simplex.Messaging.Server (runSMPServer)
+import Simplex.Messaging.Server.CLI
+import Simplex.Messaging.Server.Env.STM (ServerConfig (..), defaultInactiveClientExpiration, defaultMessageExpiration)
+import Simplex.Messaging.Server.Expiration
+import Simplex.Messaging.Transport (simplexMQVersion, supportedSMPServerVRange)
+import Simplex.Messaging.Transport.Client (TransportHost (..))
+import Simplex.Messaging.Util (safeDecodeUtf8)
+import System.Directory (createDirectoryIfMissing, doesFileExist)
+import System.FilePath (combine)
+import System.IO (BufferMode (..), hSetBuffering, stderr, stdout)
+import Text.Read (readMaybe)
+
+smpServerCLI :: FilePath -> FilePath -> IO ()
+smpServerCLI cfgPath logPath =
+  getCliCommand' (cliCommandP cfgPath logPath iniFile) serverVersion >>= \case
+    Init opts ->
+      doesFileExist iniFile >>= \case
+        True -> exitError $ "Error: server is already initialized (" <> iniFile <> " exists).\nRun `" <> executableName <> " start`."
+        _ -> initializeServer opts
+    Start ->
+      doesFileExist iniFile >>= \case
+        True -> readIniFile iniFile >>= either exitError runServer
+        _ -> exitError $ "Error: server is not initialized (" <> iniFile <> " does not exist).\nRun `" <> executableName <> " init`."
+    Delete -> do
+      confirmOrExit "WARNING: deleting the server will make all queues inaccessible, because the server identity (certificate fingerprint) will change.\nTHIS CANNOT BE UNDONE!"
+      deleteDirIfExists cfgPath
+      deleteDirIfExists logPath
+      putStrLn "Deleted configuration and log files"
+  where
+    iniFile = combine cfgPath "smp-server.ini"
+    serverVersion = "SMP server v" <> simplexMQVersion
+    defaultServerPort = "5223"
+    executableName = "smp-server"
+    storeLogFilePath = combine logPath "smp-server-store.log"
+    initializeServer opts
+      | scripted opts = initialize opts
+      | otherwise = do
+        putStrLn "Use `smp-server init -h` for available options."
+        void $ withPrompt "SMP server will be initialized (press Enter)" getLine
+        enableStoreLog <- onOffPrompt "Enable store log to restore queues and messages on server restart" True
+        logStats <- onOffPrompt "Enable logging daily statistics" False
+        putStrLn "Require a password to create new messaging queues?"
+        password <- withPrompt "'r' for random (default), 'n' - no password, or enter password: " serverPassword
+        let host = fromMaybe (ip opts) (fqdn opts)
+        host' <- withPrompt ("Enter server FQDN or IP address for certificate (" <> host <> "): ") getLine
+        initialize opts {enableStoreLog, logStats, fqdn = if null host' then fqdn opts else Just host', password}
+      where
+        serverPassword =
+          getLine >>= \case
+            "" -> pure $ Just SPRandom
+            "r" -> pure $ Just SPRandom
+            "n" -> pure Nothing
+            s ->
+              case strDecode $ encodeUtf8 $ T.pack s of
+                Right auth -> pure . Just $ ServerPassword auth
+                _ -> putStrLn "Invalid password. Only latin letters, digits and symbols other than '@' and ':' are allowed" >> serverPassword
+        initialize InitOptions {enableStoreLog, logStats, signAlgorithm, ip, fqdn, password} = do
+          clearDirIfExists cfgPath
+          clearDirIfExists logPath
+          createDirectoryIfMissing True cfgPath
+          createDirectoryIfMissing True logPath
+          let x509cfg = defaultX509Config {commonName = fromMaybe ip fqdn, signAlgorithm}
+          fp <- createServerX509 cfgPath x509cfg
+          basicAuth <- mapM createServerPassword password
+          let host = fromMaybe (if ip == "127.0.0.1" then "<hostnames>" else ip) fqdn
+              srv = ProtoServerWithAuth (SMPServer [THDomainName host] "" (C.KeyHash fp)) basicAuth
+          writeFile iniFile $ iniFileContent host basicAuth
+          putStrLn $ "Server initialized, you can modify configuration in " <> iniFile <> ".\nRun `" <> executableName <> " start` to start server."
+          warnCAPrivateKeyFile cfgPath x509cfg
+          printServiceInfo serverVersion srv
+          where
+            createServerPassword = \case
+              ServerPassword s -> pure s
+              SPRandom -> BasicAuth . strEncode <$> (getRandomBytes 32 :: IO B.ByteString)
+            iniFileContent host basicAuth =
+              "[STORE_LOG]\n\
+              \# The server uses STM memory for persistence,\n\
+              \# that will be lost on restart (e.g., as with redis).\n\
+              \# This option enables saving memory to append only log,\n\
+              \# and restoring it when the server is started.\n\
+              \# Log is compacted on start (deleted objects are removed).\n"
+                <> ("enable: " <> onOff enableStoreLog <> "\n\n")
+                <> "# Undelivered messages are optionally saved and restored when the server restarts,\n\
+                   \# they are preserved in the .bak file until the next restart.\n"
+                <> ("restore_messages: " <> onOff enableStoreLog <> "\n\n")
+                <> "# Log daily server statistics to CSV file\n"
+                <> ("log_stats: " <> onOff logStats <> "\n\n")
+                <> "[AUTH]\n\
+                   \# Set new_queues option to off to completely prohibit creating new messaging queues.\n\
+                   \# This can be useful when you want to decommission the server, but not all connections are switched yet.\n\
+                   \new_queues: on\n\n\
+                   \# Use create_password option to enable basic auth to create new messaging queues.\n\
+                   \# The password should be used as part of server address in client configuration:\n\
+                   \# smp://fingerprint:password@host1,host2\n\
+                   \# The password will not be shared with the connecting contacts, you must share it only\n\
+                   \# with the users who you want to allow creating messaging queues on your server.\n"
+                <> ( case basicAuth of
+                       Just auth -> "create_password: " <> T.unpack (safeDecodeUtf8 $ strEncode auth)
+                       _ -> "# create_password: password to create new queues (any printable ASCII characters without whitespace, '@', ':' and '/')"
+                   )
+                <> "\n\n\
+                   \[TRANSPORT]\n\
+                   \# host is only used to print server address on start\n"
+                <> ("host: " <> host <> "\n")
+                <> ("port: " <> defaultServerPort <> "\n")
+                <> "log_tls_errors: off\n\
+                   \websockets: off\n\n\
+                   \[INACTIVE_CLIENTS]\n\
+                   \# TTL and interval to check inactive clients\n\
+                   \disconnect: off\n"
+                <> ("# ttl: " <> show (ttl defaultInactiveClientExpiration) <> "\n")
+                <> ("# check_interval: " <> show (checkInterval defaultInactiveClientExpiration) <> "\n")
+    runServer ini = do
+      hSetBuffering stdout LineBuffering
+      hSetBuffering stderr LineBuffering
+      fp <- checkSavedFingerprint cfgPath defaultX509Config
+      let host = fromRight "<hostnames>" $ T.unpack <$> lookupValue "TRANSPORT" "host" ini
+          port = T.unpack $ strictIni "TRANSPORT" "port" ini
+          cfg@ServerConfig {transports, storeLogFile, newQueueBasicAuth, inactiveClientExpiration} = serverConfig
+          srv = ProtoServerWithAuth (SMPServer [THDomainName host] (if port == "5223" then "" else port) (C.KeyHash fp)) newQueueBasicAuth
+      printServiceInfo serverVersion srv
+      printServerConfig transports storeLogFile
+      putStrLn $ case inactiveClientExpiration of
+        Just ExpirationConfig {ttl, checkInterval} -> "expiring clients inactive for " <> show ttl <> " seconds every " <> show checkInterval <> " seconds"
+        _ -> "not expiring inactive clients"
+      putStrLn $
+        "creating new queues "
+          <> if allowNewQueues cfg
+            then maybe "allowed" (const "requires password") newQueueBasicAuth
+            else "NOT allowed"
+      runSMPServer cfg
+      where
+        enableStoreLog = settingIsOn "STORE_LOG" "enable" ini
+        logStats = settingIsOn "STORE_LOG" "log_stats" ini
+        c = combine cfgPath . ($ defaultX509Config)
+        serverConfig =
+          ServerConfig
+            { transports = iniTransports ini,
+              tbqSize = 32,
+              serverTbqSize = 128,
+              msgQueueQuota = 128,
+              queueIdBytes = 24,
+              msgIdBytes = 24, -- must be at least 24 bytes, it is used as 192-bit nonce for XSalsa20
+              caCertificateFile = c caCrtFile,
+              privateKeyFile = c serverKeyFile,
+              certificateFile = c serverCrtFile,
+              storeLogFile = enableStoreLog $> storeLogFilePath,
+              storeMsgsFile =
+                let messagesPath = combine logPath "smp-server-messages.log"
+                 in case iniOnOff "STORE_LOG" "restore_messages" ini of
+                      Just True -> Just messagesPath
+                      Just False -> Nothing
+                      -- if the setting is not set, it is enabled when store log is enabled
+                      _ -> enableStoreLog $> messagesPath,
+              -- allow creating new queues by default
+              allowNewQueues = fromMaybe True $ iniOnOff "AUTH" "new_queues" ini,
+              newQueueBasicAuth = case lookupValue "AUTH" "create_password" ini of
+                Right auth -> either error Just . strDecode $ encodeUtf8 auth
+                _ -> Nothing,
+              messageExpiration = Just defaultMessageExpiration,
+              inactiveClientExpiration =
+                settingIsOn "INACTIVE_CLIENTS" "disconnect" ini
+                  $> ExpirationConfig
+                    { ttl = readStrictIni "INACTIVE_CLIENTS" "ttl" ini,
+                      checkInterval = readStrictIni "INACTIVE_CLIENTS" "check_interval" ini
+                    },
+              logStatsInterval = logStats $> 86400, -- seconds
+              logStatsStartTime = 0, -- seconds from 00:00 UTC
+              serverStatsLogFile = combine logPath "smp-server-stats.daily.log",
+              serverStatsBackupFile = logStats $> combine logPath "smp-server-stats.log",
+              smpServerVRange = supportedSMPServerVRange,
+              logTLSErrors = fromMaybe False $ iniOnOff "TRANSPORT" "log_tls_errors" ini
+            }
+
+data CliCommand
+  = Init InitOptions
+  | Start
+  | Delete
+
+data InitOptions = InitOptions
+  { enableStoreLog :: Bool,
+    logStats :: Bool,
+    signAlgorithm :: SignAlgorithm,
+    ip :: HostName,
+    fqdn :: Maybe HostName,
+    password :: Maybe ServerPassword,
+    scripted :: Bool
+  }
+  deriving (Show)
+
+data ServerPassword = ServerPassword BasicAuth | SPRandom
+  deriving (Show)
+
+cliCommandP :: FilePath -> FilePath -> FilePath -> Parser CliCommand
+cliCommandP cfgPath logPath iniFile =
+  hsubparser
+    ( command "init" (info (Init <$> initP) (progDesc $ "Initialize server - creates " <> cfgPath <> " and " <> logPath <> " directories and configuration files"))
+        <> command "start" (info (pure Start) (progDesc $ "Start server (configuration: " <> iniFile <> ")"))
+        <> command "delete" (info (pure Delete) (progDesc "Delete configuration and log files"))
+    )
+  where
+    initP :: Parser InitOptions
+    initP = do
+      enableStoreLog <-
+        switch
+          ( long "store-log"
+              <> short 'l'
+              <> help "Enable store log for persistence"
+          )
+      logStats <-
+        switch
+          ( long "daily-stats"
+              <> short 's'
+              <> help "Enable logging daily server statistics"
+          )
+      signAlgorithm <-
+        option
+          (maybeReader readMaybe)
+          ( long "sign-algorithm"
+              <> short 'a'
+              <> help "Signature algorithm used for TLS certificates: ED25519, ED448"
+              <> value ED448
+              <> showDefault
+              <> metavar "ALG"
+          )
+      ip <-
+        strOption
+          ( long "ip"
+              <> help
+                "Server IP address, used as Common Name for TLS online certificate if FQDN is not supplied"
+              <> value "127.0.0.1"
+              <> showDefault
+              <> metavar "IP"
+          )
+      fqdn <-
+        (optional . strOption)
+          ( long "fqdn"
+              <> short 'n'
+              <> help "Server FQDN used as Common Name for TLS online certificate"
+              <> showDefault
+              <> metavar "FQDN"
+          )
+      password <-
+        flag' Nothing (long "no-password" <> help "Allow creating new queues without password")
+          <|> Just
+            <$> option
+              parseBasicAuth
+              ( long "password"
+                  <> metavar "PASSWORD"
+                  <> help "Set password to create new messaging queues"
+                  <> value SPRandom
+              )
+      scripted <-
+        switch
+          ( long "yes"
+              <> short 'y'
+              <> help "Non-interactive initialization using command-line options"
+          )
+      pure InitOptions {enableStoreLog, logStats, signAlgorithm, ip, fqdn, password, scripted}
+    parseBasicAuth :: ReadM ServerPassword
+    parseBasicAuth = eitherReader $ fmap ServerPassword . strDecode . B.pack
@@ -1,24 +1,16 @@
-{-# LANGUAGE FunctionalDependencies #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE OverloadedStrings #-}

 module Simplex.Messaging.Server.MsgStore where

-import Data.Time.Clock.System (SystemTime)
-import Numeric.Natural
-import Simplex.Messaging.Protocol (MsgBody, MsgId, RecipientId)
+import Control.Applicative ((<|>))
+import Simplex.Messaging.Encoding.String
+import Simplex.Messaging.Protocol (Message (..), RcvMessage (..), RecipientId)

-data Message = Message
-  { msgId :: MsgId,
-    ts :: SystemTime,
-    msgBody :: MsgBody
-  }
+data MsgLogRecord = MLRv3 RecipientId Message | MLRv1 RecipientId RcvMessage

-class MonadMsgStore s q m | s -> q where
-  getMsgQueue :: s -> RecipientId -> Natural -> m q
-  delMsgQueue :: s -> RecipientId -> m ()
-
-class MonadMsgQueue q m where
-  isFull :: q -> m Bool
-  writeMsg :: q -> Message -> m () -- non blocking
-  tryPeekMsg :: q -> m (Maybe Message) -- non blocking
-  peekMsg :: q -> m Message -- blocking
-  tryDelPeekMsg :: q -> m (Maybe Message) -- atomic delete (== read) last and peek next message, if available
+instance StrEncoding MsgLogRecord where
+  strEncode = \case
+    MLRv3 rId msg -> strEncode (Str "v3", rId, msg)
+    MLRv1 rId msg -> strEncode (rId, msg)
+  strP = "v3 " *> (MLRv3 <$> strP_ <*> strP) <|> MLRv1 <$> strP_ <*> strP
@@ -1,55 +1,120 @@
 {-# LANGUAGE ConstraintKinds #-}
 {-# LANGUAGE FlexibleContexts #-}
 {-# LANGUAGE FlexibleInstances #-}
-{-# LANGUAGE InstanceSigs #-}
+{-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE TupleSections #-}

-module Simplex.Messaging.Server.MsgStore.STM where
+module Simplex.Messaging.Server.MsgStore.STM
+  ( STMMsgStore,
+    MsgQueue (..),
+    newMsgStore,
+    getMsgQueue,
+    delMsgQueue,
+    flushMsgQueue,
+    writeMsg,
+    tryPeekMsg,
+    peekMsg,
+    tryDelMsg,
+    tryDelPeekMsg,
+    deleteExpiredMsgs,
+  )
+where

-import Data.Map.Strict (Map)
-import qualified Data.Map.Strict as M
-import Numeric.Natural
-import Simplex.Messaging.Protocol (RecipientId)
-import Simplex.Messaging.Server.MsgStore
+import Control.Concurrent.STM.TQueue (flushTQueue)
+import Control.Monad (when)
+import qualified Data.ByteString.Char8 as B
+import Data.Functor (($>))
+import Data.Int (Int64)
+import Data.Time.Clock.System (SystemTime (systemSeconds))
+import Simplex.Messaging.Protocol (Message (..), MsgId, RecipientId)
+import Simplex.Messaging.TMap (TMap)
+import qualified Simplex.Messaging.TMap as TM
 import UnliftIO.STM

-newtype MsgQueue = MsgQueue {msgQueue :: TBQueue Message}
+data MsgQueue = MsgQueue
+  { msgQueue :: TQueue Message,
+    quota :: Int,
+    canWrite :: TVar Bool,
+    size :: TVar Int
+  }

-newtype MsgStoreData = MsgStoreData {messages :: Map RecipientId MsgQueue}
-
-type STMMsgStore = TVar MsgStoreData
+type STMMsgStore = TMap RecipientId MsgQueue

 newMsgStore :: STM STMMsgStore
-newMsgStore = newTVar $ MsgStoreData M.empty
+newMsgStore = TM.empty

-instance MonadMsgStore STMMsgStore MsgQueue STM where
-  getMsgQueue :: STMMsgStore -> RecipientId -> Natural -> STM MsgQueue
-  getMsgQueue store rId quota = do
-    m <- messages <$> readTVar store
-    maybe (newQ m) return $ M.lookup rId m
-    where
-      newQ m' = do
-        q <- MsgQueue <$> newTBQueue quota
-        writeTVar store . MsgStoreData $ M.insert rId q m'
-        return q
+getMsgQueue :: STMMsgStore -> RecipientId -> Int -> STM MsgQueue
+getMsgQueue st rId quota = maybe newQ pure =<< TM.lookup rId st
+  where
+    newQ = do
+      msgQueue <- newTQueue
+      canWrite <- newTVar True
+      size <- newTVar 0
+      let q = MsgQueue {msgQueue, quota, canWrite, size}
+      TM.insert rId q st
+      pure q

-  delMsgQueue :: STMMsgStore -> RecipientId -> STM ()
-  delMsgQueue store rId =
-    modifyTVar store $ MsgStoreData . M.delete rId . messages
+delMsgQueue :: STMMsgStore -> RecipientId -> STM ()
+delMsgQueue st rId = TM.delete rId st

-instance MonadMsgQueue MsgQueue STM where
-  isFull :: MsgQueue -> STM Bool
-  isFull = isFullTBQueue . msgQueue
+flushMsgQueue :: STMMsgStore -> RecipientId -> STM [Message]
+flushMsgQueue st rId = TM.lookupDelete rId st >>= maybe (pure []) (flushTQueue . msgQueue)

-  writeMsg :: MsgQueue -> Message -> STM ()
-  writeMsg = writeTBQueue . msgQueue
+writeMsg :: MsgQueue -> Message -> STM (Maybe Message)
+writeMsg MsgQueue {msgQueue = q, quota, canWrite, size} msg = do
+  canWrt <- readTVar canWrite
+  empty <- isEmptyTQueue q
+  if canWrt || empty
+    then do
+      canWrt' <- (quota >) <$> readTVar size
+      writeTVar canWrite $! canWrt'
+      modifyTVar' size (+ 1)
+      if canWrt'
+        then writeTQueue q msg $> Just msg
+        else writeTQueue q msgQuota $> Nothing
+    else pure Nothing
+  where
+    msgQuota = MessageQuota {msgId = msgId msg, msgTs = msgTs msg}

-  tryPeekMsg :: MsgQueue -> STM (Maybe Message)
-  tryPeekMsg = tryPeekTBQueue . msgQueue
+tryPeekMsg :: MsgQueue -> STM (Maybe Message)
+tryPeekMsg = tryPeekTQueue . msgQueue
+{-# INLINE tryPeekMsg #-}

-  peekMsg :: MsgQueue -> STM Message
-  peekMsg = peekTBQueue . msgQueue
+peekMsg :: MsgQueue -> STM Message
+peekMsg = peekTQueue . msgQueue
+{-# INLINE peekMsg #-}

-  -- atomic delete (== read) last and peek next message if available
-  tryDelPeekMsg :: MsgQueue -> STM (Maybe Message)
-  tryDelPeekMsg (MsgQueue q) = tryReadTBQueue q >> tryPeekTBQueue q
+tryDelMsg :: MsgQueue -> MsgId -> STM (Maybe Message)
+tryDelMsg mq msgId' =
+  tryPeekMsg mq >>= \case
+    msg_@(Just msg)
+      | msgId msg == msgId' || B.null msgId' -> tryDeleteMsg mq >> pure msg_
+      | otherwise -> pure Nothing
+    _ -> pure Nothing
+
+-- atomic delete (== read) last and peek next message if available
+tryDelPeekMsg :: MsgQueue -> MsgId -> STM (Maybe Message, Maybe Message)
+tryDelPeekMsg mq msgId' =
+  tryPeekMsg mq >>= \case
+    msg_@(Just msg)
+      | msgId msg == msgId' || B.null msgId' -> (msg_,) <$> (tryDeleteMsg mq >> tryPeekMsg mq)
+      | otherwise -> pure (Nothing, msg_)
+    _ -> pure (Nothing, Nothing)
+
+deleteExpiredMsgs :: MsgQueue -> Int64 -> STM ()
+deleteExpiredMsgs mq old = loop
+  where
+    loop = tryPeekMsg mq >>= mapM_ delOldMsg
+    delOldMsg = \case
+      Message {msgTs} ->
+        when (systemSeconds msgTs < old) $
+          tryDeleteMsg mq >> loop
+      _ -> pure ()
+
+tryDeleteMsg :: MsgQueue -> STM ()
+tryDeleteMsg MsgQueue {msgQueue = q, size} =
+  tryReadTQueue q >>= \case
+    Just _ -> modifyTVar' size (subtract 1)
+    _ -> pure ()
@@ -1,27 +1,35 @@
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE KindSignatures #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
+{-# LANGUAGE NamedFieldPuns #-}

 module Simplex.Messaging.Server.QueueStore where

+import Simplex.Messaging.Encoding.String
 import Simplex.Messaging.Protocol

 data QueueRec = QueueRec
-  { recipientId :: RecipientId,
-    recipientKey :: RcvPublicVerifyKey,
-    rcvDhSecret :: RcvDhSecret,
-    senderId :: SenderId,
-    senderKey :: Maybe SndPublicVerifyKey,
-    notifier :: Maybe (NotifierId, NtfPublicVerifyKey),
-    status :: QueueStatus
+  { recipientId :: !RecipientId,
+    recipientKey :: !RcvPublicVerifyKey,
+    rcvDhSecret :: !RcvDhSecret,
+    senderId :: !SenderId,
+    senderKey :: !(Maybe SndPublicVerifyKey),
+    notifier :: !(Maybe NtfCreds),
+    status :: !ServerQueueStatus
  }
+  deriving (Eq, Show)

-data QueueStatus = QueueActive | QueueOff deriving (Eq, Show)
+data NtfCreds = NtfCreds
+  { notifierId :: !NotifierId,
+    notifierKey :: !NtfPublicVerifyKey,
+    rcvNtfDhSecret :: !RcvNtfDhSecret
+  }
+  deriving (Eq, Show)

-class MonadQueueStore s m where
-  addQueue :: s -> QueueRec -> m (Either ErrorType ())
-  getQueue :: s -> SParty p -> QueueId -> m (Either ErrorType QueueRec)
-  secureQueue :: s -> RecipientId -> SndPublicVerifyKey -> m (Either ErrorType QueueRec)
-  addQueueNotifier :: s -> RecipientId -> NotifierId -> NtfPublicVerifyKey -> m (Either ErrorType QueueRec)
-  suspendQueue :: s -> RecipientId -> m (Either ErrorType ())
-  deleteQueue :: s -> RecipientId -> m (Either ErrorType ())
+instance StrEncoding NtfCreds where
+  strEncode NtfCreds {notifierId, notifierKey, rcvNtfDhSecret} = strEncode (notifierId, notifierKey, rcvNtfDhSecret)
+  strP = do
+    (notifierId, notifierKey, rcvNtfDhSecret) <- strP
+    pure NtfCreds {notifierId, notifierKey, rcvNtfDhSecret}
+
+data ServerQueueStatus = QueueActive | QueueOff deriving (Eq, Show)
@@ -1,117 +1,111 @@
 {-# LANGUAGE DataKinds #-}
 {-# LANGUAGE FlexibleInstances #-}
 {-# LANGUAGE GADTs #-}
-{-# LANGUAGE InstanceSigs #-}
 {-# LANGUAGE KindSignatures #-}
+{-# LANGUAGE LambdaCase #-}
 {-# LANGUAGE MultiParamTypeClasses #-}
 {-# LANGUAGE NamedFieldPuns #-}
 {-# LANGUAGE RankNTypes #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE UndecidableInstances #-}

-module Simplex.Messaging.Server.QueueStore.STM where
+module Simplex.Messaging.Server.QueueStore.STM
+  ( QueueStore (..),
+    newQueueStore,
+    addQueue,
+    getQueue,
+    secureQueue,
+    addQueueNotifier,
+    deleteQueueNotifier,
+    suspendQueue,
+    deleteQueue,
+  )
+where

-import Data.Map.Strict (Map)
-import qualified Data.Map.Strict as M
+import Control.Monad
+import Data.Functor (($>))
 import Simplex.Messaging.Protocol
 import Simplex.Messaging.Server.QueueStore
+import Simplex.Messaging.TMap (TMap)
+import qualified Simplex.Messaging.TMap as TM
+import Simplex.Messaging.Util (ifM, ($>>=))
 import UnliftIO.STM

-data QueueStoreData = QueueStoreData
-  { queues :: Map RecipientId QueueRec,
-    senders :: Map SenderId RecipientId,
-    notifiers :: Map NotifierId RecipientId
+data QueueStore = QueueStore
+  { queues :: TMap RecipientId (TVar QueueRec),
+    senders :: TMap SenderId RecipientId,
+    notifiers :: TMap NotifierId RecipientId
  }

-type QueueStore = TVar QueueStoreData
-
 newQueueStore :: STM QueueStore
-newQueueStore = newTVar QueueStoreData {queues = M.empty, senders = M.empty, notifiers = M.empty}
+newQueueStore = do
+  queues <- TM.empty
+  senders <- TM.empty
+  notifiers <- TM.empty
+  pure QueueStore {queues, senders, notifiers}

-instance MonadQueueStore QueueStore STM where
-  addQueue :: QueueStore -> QueueRec -> STM (Either ErrorType ())
-  addQueue store qRec@QueueRec {recipientId = rId, senderId = sId} = do
-    cs@QueueStoreData {queues, senders} <- readTVar store
-    if M.member rId queues || M.member sId senders
-      then return $ Left DUPLICATE_
-      else do
-        writeTVar store $
-          cs
-            { queues = M.insert rId qRec queues,
-              senders = M.insert sId rId senders
-            }
-        return $ Right ()
-
-  getQueue :: QueueStore -> SParty p -> QueueId -> STM (Either ErrorType QueueRec)
-  getQueue st party qId = do
-    cs <- readTVar st
-    pure $ case party of
-      SRecipient -> getRcpQueue cs qId
-      SSender -> getPartyQueue cs senders
-      SNotifier -> getPartyQueue cs notifiers
-    where
-      getPartyQueue ::
-        QueueStoreData ->
-        (QueueStoreData -> Map QueueId RecipientId) ->
-        Either ErrorType QueueRec
-      getPartyQueue cs recipientIds =
-        case M.lookup qId $ recipientIds cs of
-          Just rId -> getRcpQueue cs rId
-          Nothing -> Left AUTH
-
-  secureQueue :: QueueStore -> RecipientId -> SndPublicVerifyKey -> STM (Either ErrorType QueueRec)
-  secureQueue store rId sKey =
-    updateQueues store rId $ \cs c ->
-      case senderKey c of
-        Just _ -> (Left AUTH, cs)
-        _ -> (Right c, cs {queues = M.insert rId c {senderKey = Just sKey} (queues cs)})
-
-  addQueueNotifier :: QueueStore -> RecipientId -> NotifierId -> NtfPublicVerifyKey -> STM (Either ErrorType QueueRec)
-  addQueueNotifier store rId nId nKey = do
-    cs@QueueStoreData {queues, notifiers} <- readTVar store
-    if M.member nId notifiers
-      then pure $ Left DUPLICATE_
-      else case M.lookup rId queues of
-        Nothing -> pure $ Left AUTH
-        Just q -> case notifier q of
-          Just _ -> pure $ Left AUTH
-          _ -> do
-            writeTVar store $
-              cs
-                { queues = M.insert rId q {notifier = Just (nId, nKey)} queues,
-                  notifiers = M.insert nId rId notifiers
-                }
-            pure $ Right q
-
-  suspendQueue :: QueueStore -> RecipientId -> STM (Either ErrorType ())
-  suspendQueue store rId =
-    updateQueues store rId $ \cs c ->
-      (Right (), cs {queues = M.insert rId c {status = QueueOff} (queues cs)})
-
-  deleteQueue :: QueueStore -> RecipientId -> STM (Either ErrorType ())
-  deleteQueue store rId =
-    updateQueues store rId $ \cs c ->
-      ( Right (),
-        cs
-          { queues = M.delete rId (queues cs),
-            senders = M.delete (senderId c) (senders cs)
-          }
-      )
-
-updateQueues ::
-  QueueStore ->
-  RecipientId ->
-  (QueueStoreData -> QueueRec -> (Either ErrorType a, QueueStoreData)) ->
-  STM (Either ErrorType a)
-updateQueues store rId update = do
-  cs <- readTVar store
-  let conn = getRcpQueue cs rId
-  either (return . Left) (_update cs) conn
+addQueue :: QueueStore -> QueueRec -> STM (Either ErrorType ())
+addQueue QueueStore {queues, senders} q@QueueRec {recipientId = rId, senderId = sId} = do
+  ifM hasId (pure $ Left DUPLICATE_) $ do
+    qVar <- newTVar q
+    TM.insert rId qVar queues
+    TM.insert sId rId senders
+    pure $ Right ()
  where
-    _update cs c = do
-      let (res, cs') = update cs c
-      writeTVar store cs'
-      return res
+    hasId = (||) <$> TM.member rId queues <*> TM.member sId senders

-getRcpQueue :: QueueStoreData -> RecipientId -> Either ErrorType QueueRec
-getRcpQueue cs rId = maybe (Left AUTH) Right . M.lookup rId $ queues cs
+getQueue :: QueueStore -> SParty p -> QueueId -> STM (Either ErrorType QueueRec)
+getQueue QueueStore {queues, senders, notifiers} party qId =
+  toResult <$> (mapM readTVar =<< getVar)
+  where
+    getVar = case party of
+      SRecipient -> TM.lookup qId queues
+      SSender -> TM.lookup qId senders $>>= (`TM.lookup` queues)
+      SNotifier -> TM.lookup qId notifiers $>>= (`TM.lookup` queues)
+
+secureQueue :: QueueStore -> RecipientId -> SndPublicVerifyKey -> STM (Either ErrorType QueueRec)
+secureQueue QueueStore {queues} rId sKey =
+  withQueue rId queues $ \qVar ->
+    readTVar qVar >>= \q -> case senderKey q of
+      Just k -> pure $ if sKey == k then Just q else Nothing
+      _ ->
+        let q' = q {senderKey = Just sKey}
+         in writeTVar qVar q' $> Just q'
+
+addQueueNotifier :: QueueStore -> RecipientId -> NtfCreds -> STM (Either ErrorType QueueRec)
+addQueueNotifier QueueStore {queues, notifiers} rId ntfCreds@NtfCreds {notifierId = nId} = do
+  ifM (TM.member nId notifiers) (pure $ Left DUPLICATE_) $
+    withQueue rId queues $ \qVar -> do
+      q <- readTVar qVar
+      forM_ (notifier q) $ (`TM.delete` notifiers) . notifierId
+      writeTVar qVar $! q {notifier = Just ntfCreds}
+      TM.insert nId rId notifiers
+      pure $ Just q
+
+deleteQueueNotifier :: QueueStore -> RecipientId -> STM (Either ErrorType ())
+deleteQueueNotifier QueueStore {queues, notifiers} rId =
+  withQueue rId queues $ \qVar -> do
+    q <- readTVar qVar
+    forM_ (notifier q) $ \NtfCreds {notifierId} -> TM.delete notifierId notifiers
+    writeTVar qVar $! q {notifier = Nothing}
+    pure $ Just ()
+
+suspendQueue :: QueueStore -> RecipientId -> STM (Either ErrorType ())
+suspendQueue QueueStore {queues} rId =
+  withQueue rId queues $ \qVar -> modifyTVar' qVar (\q -> q {status = QueueOff}) $> Just ()
+
+deleteQueue :: QueueStore -> RecipientId -> STM (Either ErrorType ())
+deleteQueue QueueStore {queues, senders, notifiers} rId = do
+  TM.lookupDelete rId queues >>= \case
+    Just qVar ->
+      readTVar qVar >>= \q -> do
+        TM.delete (senderId q) senders
+        forM_ (notifier q) $ \NtfCreds {notifierId} -> TM.delete notifierId notifiers
+        pure $ Right ()
+    _ -> pure $ Left AUTH
+
+toResult :: Maybe a -> Either ErrorType a
+toResult = maybe (Left AUTH) Right
+
+withQueue :: RecipientId -> TMap RecipientId (TVar QueueRec) -> (TVar QueueRec -> STM (Maybe a)) -> STM (Either ErrorType a)
+withQueue rId queues f = toResult <$> TM.lookup rId queues $>>= f
@@ -0,0 +1,209 @@
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE PatternSynonyms #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+
+module Simplex.Messaging.Server.Stats where
+
+import Control.Applicative (optional, (<|>))
+import qualified Data.Attoparsec.ByteString.Char8 as A
+import qualified Data.ByteString.Char8 as B
+import Data.Set (Set)
+import qualified Data.Set as S
+import Data.Time.Calendar.Month.Compat (pattern MonthDay)
+import Data.Time.Calendar.OrdinalDate (mondayStartWeek)
+import Data.Time.Clock (UTCTime (..))
+import Simplex.Messaging.Encoding.String
+import Simplex.Messaging.Protocol (RecipientId)
+import UnliftIO.STM
+
+data ServerStats = ServerStats
+  { fromTime :: TVar UTCTime,
+    qCreated :: TVar Int,
+    qSecured :: TVar Int,
+    qDeleted :: TVar Int,
+    msgSent :: TVar Int,
+    msgRecv :: TVar Int,
+    activeQueues :: PeriodStats RecipientId,
+    msgSentNtf :: TVar Int,
+    msgRecvNtf :: TVar Int,
+    activeQueuesNtf :: PeriodStats RecipientId,
+    qCount :: TVar Int,
+    msgCount :: TVar Int
+  }
+
+data ServerStatsData = ServerStatsData
+  { _fromTime :: UTCTime,
+    _qCreated :: Int,
+    _qSecured :: Int,
+    _qDeleted :: Int,
+    _msgSent :: Int,
+    _msgRecv :: Int,
+    _activeQueues :: PeriodStatsData RecipientId,
+    _msgSentNtf :: Int,
+    _msgRecvNtf :: Int,
+    _activeQueuesNtf :: PeriodStatsData RecipientId,
+    _qCount :: Int,
+    _msgCount :: Int
+  }
+  deriving (Show)
+
+newServerStats :: UTCTime -> STM ServerStats
+newServerStats ts = do
+  fromTime <- newTVar ts
+  qCreated <- newTVar 0
+  qSecured <- newTVar 0
+  qDeleted <- newTVar 0
+  msgSent <- newTVar 0
+  msgRecv <- newTVar 0
+  activeQueues <- newPeriodStats
+  msgSentNtf <- newTVar 0
+  msgRecvNtf <- newTVar 0
+  activeQueuesNtf <- newPeriodStats
+  qCount <- newTVar 0
+  msgCount <- newTVar 0
+  pure ServerStats {fromTime, qCreated, qSecured, qDeleted, msgSent, msgRecv, activeQueues, msgSentNtf, msgRecvNtf, activeQueuesNtf, qCount, msgCount}
+
+getServerStatsData :: ServerStats -> STM ServerStatsData
+getServerStatsData s = do
+  _fromTime <- readTVar $ fromTime s
+  _qCreated <- readTVar $ qCreated s
+  _qSecured <- readTVar $ qSecured s
+  _qDeleted <- readTVar $ qDeleted s
+  _msgSent <- readTVar $ msgSent s
+  _msgRecv <- readTVar $ msgRecv s
+  _activeQueues <- getPeriodStatsData $ activeQueues s
+  _msgSentNtf <- readTVar $ msgSentNtf s
+  _msgRecvNtf <- readTVar $ msgRecvNtf s
+  _activeQueuesNtf <- getPeriodStatsData $ activeQueuesNtf s
+  _qCount <- readTVar $ qCount s
+  _msgCount <- readTVar $ msgCount s
+  pure ServerStatsData {_fromTime, _qCreated, _qSecured, _qDeleted, _msgSent, _msgRecv, _activeQueues, _msgSentNtf, _msgRecvNtf, _activeQueuesNtf, _qCount, _msgCount}
+
+setServerStats :: ServerStats -> ServerStatsData -> STM ()
+setServerStats s d = do
+  writeTVar (fromTime s) $! _fromTime d
+  writeTVar (qCreated s) $! _qCreated d
+  writeTVar (qSecured s) $! _qSecured d
+  writeTVar (qDeleted s) $! _qDeleted d
+  writeTVar (msgSent s) $! _msgSent d
+  writeTVar (msgRecv s) $! _msgRecv d
+  setPeriodStats (activeQueues s) (_activeQueues d)
+  writeTVar (msgSentNtf s) $! _msgSentNtf d
+  writeTVar (msgRecvNtf s) $! _msgRecvNtf d
+  setPeriodStats (activeQueuesNtf s) (_activeQueuesNtf d)
+  writeTVar (qCount s) $! _qCount d
+  writeTVar (msgCount s) $! _qCount d
+
+instance StrEncoding ServerStatsData where
+  strEncode ServerStatsData {_fromTime, _qCreated, _qSecured, _qDeleted, _msgSent, _msgRecv, _msgSentNtf, _msgRecvNtf, _activeQueues, _activeQueuesNtf} =
+    B.unlines
+      [ "fromTime=" <> strEncode _fromTime,
+        "qCreated=" <> strEncode _qCreated,
+        "qSecured=" <> strEncode _qSecured,
+        "qDeleted=" <> strEncode _qDeleted,
+        "msgSent=" <> strEncode _msgSent,
+        "msgRecv=" <> strEncode _msgRecv,
+        "msgSentNtf=" <> strEncode _msgSentNtf,
+        "msgRecvNtf=" <> strEncode _msgRecvNtf,
+        "activeQueues:",
+        strEncode _activeQueues,
+        "activeQueuesNtf:",
+        strEncode _activeQueuesNtf
+      ]
+  strP = do
+    _fromTime <- "fromTime=" *> strP <* A.endOfLine
+    _qCreated <- "qCreated=" *> strP <* A.endOfLine
+    _qSecured <- "qSecured=" *> strP <* A.endOfLine
+    _qDeleted <- "qDeleted=" *> strP <* A.endOfLine
+    _msgSent <- "msgSent=" *> strP <* A.endOfLine
+    _msgRecv <- "msgRecv=" *> strP <* A.endOfLine
+    _msgSentNtf <- "msgSentNtf=" *> strP <* A.endOfLine <|> pure 0
+    _msgRecvNtf <- "msgRecvNtf=" *> strP <* A.endOfLine <|> pure 0
+    _activeQueues <-
+      optional ("activeQueues:" <* A.endOfLine) >>= \case
+        Just _ -> strP <* optional A.endOfLine
+        _ -> do
+          _day <- "dayMsgQueues=" *> strP <* A.endOfLine
+          _week <- "weekMsgQueues=" *> strP <* A.endOfLine
+          _month <- "monthMsgQueues=" *> strP <* optional A.endOfLine
+          pure PeriodStatsData {_day, _week, _month}
+    _activeQueuesNtf <-
+      optional ("activeQueuesNtf:" <* A.endOfLine) >>= \case
+        Just _ -> strP <* optional A.endOfLine
+        _ -> pure newPeriodStatsData
+    pure ServerStatsData {_fromTime, _qCreated, _qSecured, _qDeleted, _msgSent, _msgRecv, _msgSentNtf, _msgRecvNtf, _activeQueues, _activeQueuesNtf, _qCount = 0, _msgCount = 0}
+
+data PeriodStats a = PeriodStats
+  { day :: TVar (Set a),
+    week :: TVar (Set a),
+    month :: TVar (Set a)
+  }
+
+newPeriodStats :: STM (PeriodStats a)
+newPeriodStats = do
+  day <- newTVar S.empty
+  week <- newTVar S.empty
+  month <- newTVar S.empty
+  pure PeriodStats {day, week, month}
+
+data PeriodStatsData a = PeriodStatsData
+  { _day :: Set a,
+    _week :: Set a,
+    _month :: Set a
+  }
+  deriving (Show)
+
+newPeriodStatsData :: PeriodStatsData a
+newPeriodStatsData = PeriodStatsData {_day = S.empty, _week = S.empty, _month = S.empty}
+
+getPeriodStatsData :: PeriodStats a -> STM (PeriodStatsData a)
+getPeriodStatsData s = do
+  _day <- readTVar $ day s
+  _week <- readTVar $ week s
+  _month <- readTVar $ month s
+  pure PeriodStatsData {_day, _week, _month}
+
+setPeriodStats :: PeriodStats a -> PeriodStatsData a -> STM ()
+setPeriodStats s d = do
+  writeTVar (day s) $! _day d
+  writeTVar (week s) $! _week d
+  writeTVar (month s) $! _month d
+
+instance (Ord a, StrEncoding a) => StrEncoding (PeriodStatsData a) where
+  strEncode PeriodStatsData {_day, _week, _month} =
+    "day=" <> strEncode _day <> "\nweek=" <> strEncode _week <> "\nmonth=" <> strEncode _month
+  strP = do
+    _day <- "day=" *> strP <* A.endOfLine
+    _week <- "week=" *> strP <* A.endOfLine
+    _month <- "month=" *> strP
+    pure PeriodStatsData {_day, _week, _month}
+
+data PeriodStatCounts = PeriodStatCounts
+  { dayCount :: String,
+    weekCount :: String,
+    monthCount :: String
+  }
+
+periodStatCounts :: forall a. PeriodStats a -> UTCTime -> STM PeriodStatCounts
+periodStatCounts ps ts = do
+  let d = utctDay ts
+      (_, wDay) = mondayStartWeek d
+      MonthDay _ mDay = d
+  dayCount <- periodCount 1 $ day ps
+  weekCount <- periodCount wDay $ week ps
+  monthCount <- periodCount mDay $ month ps
+  pure PeriodStatCounts {dayCount, weekCount, monthCount}
+  where
+    periodCount :: Int -> TVar (Set a) -> STM String
+    periodCount 1 pVar = show . S.size <$> swapTVar pVar S.empty
+    periodCount _ _ = pure ""
+
+updatePeriodStats :: Ord a => PeriodStats a -> a -> STM ()
+updatePeriodStats stats pId = do
+  updatePeriod day
+  updatePeriod week
+  updatePeriod month
+  where
+    updatePeriod pSel = modifyTVar' (pSel stats) (S.insert pId)
@@ -13,10 +13,13 @@ module Simplex.Messaging.Server.StoreLog
    openReadStoreLog,
    storeLogFilePath,
    closeStoreLog,
+    writeStoreLogRecord,
    logCreateQueue,
    logSecureQueue,
    logAddNotifier,
+    logSuspendQueue,
    logDeleteQueue,
+    logDeleteNotifier,
    readWriteStoreLog,
  )
 where
@@ -34,7 +37,7 @@ import Data.Map.Strict (Map)
 import qualified Data.Map.Strict as M
 import Simplex.Messaging.Encoding.String
 import Simplex.Messaging.Protocol
-import Simplex.Messaging.Server.QueueStore (QueueRec (..), QueueStatus (..))
+import Simplex.Messaging.Server.QueueStore (NtfCreds (..), QueueRec (..), ServerQueueStatus (..))
 import Simplex.Messaging.Transport (trimCR)
 import System.Directory (doesFileExist)
 import System.IO
@@ -48,8 +51,10 @@ data StoreLog (a :: IOMode) where
 data StoreLogRecord
  = CreateQueue QueueRec
  | SecureQueue QueueId SndPublicVerifyKey
-  | AddNotifier QueueId NotifierId NtfPublicVerifyKey
+  | AddNotifier QueueId NtfCreds
+  | SuspendQueue QueueId
  | DeleteQueue QueueId
+  | DeleteNotifier QueueId

 instance StrEncoding QueueRec where
  strEncode QueueRec {recipientId, recipientKey, rcvDhSecret, senderId, senderKey, notifier} =
@@ -62,7 +67,7 @@ instance StrEncoding QueueRec where
      ]
      <> maybe "" notifierStr notifier
    where
-      notifierStr (nId, nKey) = " nid=" <> strEncode nId <> " nk=" <> strEncode nKey
+      notifierStr ntfCreds = " notifier=" <> strEncode ntfCreds

  strP = do
    recipientId <- "rid=" *> strP_
@@ -70,24 +75,31 @@ instance StrEncoding QueueRec where
    rcvDhSecret <- "rdh=" *> strP_
    senderId <- "sid=" *> strP_
    senderKey <- "sk=" *> strP
-    notifier <- optional $ (,) <$> (" nid=" *> strP_) <*> ("nk=" *> strP)
+    notifier <- optional $ " notifier=" *> strP
    pure QueueRec {recipientId, recipientKey, rcvDhSecret, senderId, senderKey, notifier, status = QueueActive}

 instance StrEncoding StoreLogRecord where
  strEncode = \case
    CreateQueue q -> strEncode (Str "CREATE", q)
    SecureQueue rId sKey -> strEncode (Str "SECURE", rId, sKey)
-    AddNotifier rId nId nKey -> strEncode (Str "NOTIFIER", rId, nId, nKey)
+    AddNotifier rId ntfCreds -> strEncode (Str "NOTIFIER", rId, ntfCreds)
+    SuspendQueue rId -> strEncode (Str "SUSPEND", rId)
    DeleteQueue rId -> strEncode (Str "DELETE", rId)
+    DeleteNotifier rId -> strEncode (Str "NDELETE", rId)

  strP =
    "CREATE " *> (CreateQueue <$> strP)
      <|> "SECURE " *> (SecureQueue <$> strP_ <*> strP)
-      <|> "NOTIFIER " *> (AddNotifier <$> strP_ <*> strP_ <*> strP)
+      <|> "NOTIFIER " *> (AddNotifier <$> strP_ <*> strP)
+      <|> "SUSPEND " *> (SuspendQueue <$> strP)
      <|> "DELETE " *> (DeleteQueue <$> strP)
+      <|> "NDELETE " *> (DeleteNotifier <$> strP)

 openWriteStoreLog :: FilePath -> IO (StoreLog 'WriteMode)
-openWriteStoreLog f = WriteStoreLog f <$> openFile f WriteMode
+openWriteStoreLog f = do
+  h <- openFile f WriteMode
+  hSetBuffering h LineBuffering
+  pure $ WriteStoreLog f h

 openReadStoreLog :: FilePath -> IO (StoreLog 'ReadMode)
 openReadStoreLog f = do
@@ -104,7 +116,7 @@ closeStoreLog = \case
  WriteStoreLog _ h -> hClose h
  ReadStoreLog _ h -> hClose h

-writeStoreLogRecord :: StoreLog 'WriteMode -> StoreLogRecord -> IO ()
+writeStoreLogRecord :: StrEncoding r => StoreLog 'WriteMode -> r -> IO ()
 writeStoreLogRecord (WriteStoreLog _ h) r = do
  B.hPutStrLn h $ strEncode r
  hFlush h
@@ -115,12 +127,18 @@ logCreateQueue s = writeStoreLogRecord s . CreateQueue
 logSecureQueue :: StoreLog 'WriteMode -> QueueId -> SndPublicVerifyKey -> IO ()
 logSecureQueue s qId sKey = writeStoreLogRecord s $ SecureQueue qId sKey

-logAddNotifier :: StoreLog 'WriteMode -> QueueId -> NotifierId -> NtfPublicVerifyKey -> IO ()
-logAddNotifier s qId nId nKey = writeStoreLogRecord s $ AddNotifier qId nId nKey
+logAddNotifier :: StoreLog 'WriteMode -> QueueId -> NtfCreds -> IO ()
+logAddNotifier s qId ntfCreds = writeStoreLogRecord s $ AddNotifier qId ntfCreds
+
+logSuspendQueue :: StoreLog 'WriteMode -> QueueId -> IO ()
+logSuspendQueue s = writeStoreLogRecord s . SuspendQueue

 logDeleteQueue :: StoreLog 'WriteMode -> QueueId -> IO ()
 logDeleteQueue s = writeStoreLogRecord s . DeleteQueue

+logDeleteNotifier :: StoreLog 'WriteMode -> QueueId -> IO ()
+logDeleteNotifier s = writeStoreLogRecord s . DeleteNotifier
+
 readWriteStoreLog :: StoreLog 'ReadMode -> IO (Map RecipientId QueueRec, StoreLog 'WriteMode)
 readWriteStoreLog s@(ReadStoreLog f _) = do
  qs <- readQueues s
@@ -149,7 +167,9 @@ readQueues (ReadStoreLog _ h) = LB.hGetContents h >>= returnResult . procStoreLo
    procLogRecord m = \case
      CreateQueue q -> M.insert (recipientId q) q m
      SecureQueue qId sKey -> M.adjust (\q -> q {senderKey = Just sKey}) qId m
-      AddNotifier qId nId nKey -> M.adjust (\q -> q {notifier = Just (nId, nKey)}) qId m
+      AddNotifier qId ntfCreds -> M.adjust (\q -> q {notifier = Just ntfCreds}) qId m
+      SuspendQueue qId -> M.adjust (\q -> q {status = QueueOff}) qId m
      DeleteQueue qId -> M.delete qId m
+      DeleteNotifier qId -> M.adjust (\q -> q {notifier = Nothing}) qId m
    printError :: LogParsingError -> IO ()
    printError (e, s) = B.putStrLn $ "Error parsing log: " <> B.pack e <> " - " <> s
@@ -0,0 +1,87 @@
+module Simplex.Messaging.TMap
+  ( TMap,
+    empty,
+    singleton,
+    clear,
+    Simplex.Messaging.TMap.null,
+    Simplex.Messaging.TMap.lookup,
+    member,
+    insert,
+    delete,
+    lookupInsert,
+    lookupDelete,
+    adjust,
+    update,
+    alter,
+    alterF,
+    union,
+  )
+where
+
+import Control.Concurrent.STM
+import Data.Map.Strict (Map)
+import qualified Data.Map.Strict as M
+
+type TMap k a = TVar (Map k a)
+
+empty :: STM (TMap k a)
+empty = newTVar M.empty
+{-# INLINE empty #-}
+
+singleton :: k -> a -> STM (TMap k a)
+singleton k v = newTVar $ M.singleton k v
+{-# INLINE singleton #-}
+
+clear :: TMap k a -> STM ()
+clear m = writeTVar m M.empty
+{-# INLINE clear #-}
+
+null :: TMap k a -> STM Bool
+null m = M.null <$> readTVar m
+{-# INLINE null #-}
+
+lookup :: Ord k => k -> TMap k a -> STM (Maybe a)
+lookup k m = M.lookup k <$> readTVar m
+{-# INLINE lookup #-}
+
+member :: Ord k => k -> TMap k a -> STM Bool
+member k m = M.member k <$> readTVar m
+{-# INLINE member #-}
+
+insert :: Ord k => k -> a -> TMap k a -> STM ()
+insert k v m = modifyTVar' m $ M.insert k v
+{-# INLINE insert #-}
+
+delete :: Ord k => k -> TMap k a -> STM ()
+delete k m = modifyTVar' m $ M.delete k
+{-# INLINE delete #-}
+
+lookupInsert :: Ord k => k -> a -> TMap k a -> STM (Maybe a)
+lookupInsert k v m = stateTVar m $ \mv -> (M.lookup k mv, M.insert k v mv)
+{-# INLINE lookupInsert #-}
+
+lookupDelete :: Ord k => k -> TMap k a -> STM (Maybe a)
+lookupDelete k m = stateTVar m $ \mv -> (M.lookup k mv, M.delete k mv)
+{-# INLINE lookupDelete #-}
+
+adjust :: Ord k => (a -> a) -> k -> TMap k a -> STM ()
+adjust f k m = modifyTVar' m $ M.adjust f k
+{-# INLINE adjust #-}
+
+update :: Ord k => (a -> Maybe a) -> k -> TMap k a -> STM ()
+update f k m = modifyTVar' m $ M.update f k
+{-# INLINE update #-}
+
+alter :: Ord k => (Maybe a -> Maybe a) -> k -> TMap k a -> STM ()
+alter f k m = modifyTVar' m $ M.alter f k
+{-# INLINE alter #-}
+
+alterF :: Ord k => (Maybe a -> STM (Maybe a)) -> k -> TMap k a -> STM ()
+alterF f k m = do
+  mv <- M.alterF f k =<< readTVar m
+  writeTVar m $! mv
+{-# INLINE alterF #-}
+
+union :: Ord k => Map k a -> TMap k a -> STM ()
+union m' m = modifyTVar' m $ M.union m'
+{-# INLINE union #-}
@@ -26,9 +26,9 @@
 -- See https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md#appendix-a
 module Simplex.Messaging.Transport
  ( -- * SMP transport parameters
-    smpBlockSize,
-    supportedSMPVersions,
+    supportedSMPServerVRange,
    simplexMQVersion,
+    smpBlockSize,

    -- * Transport connection class
    Transport (..),
@@ -38,6 +38,7 @@ module Simplex.Messaging.Transport

    -- * TLS Transport
    TLS (..),
+    SessionId,
    connectTLS,
    closeTLS,
    supportedParameters,
@@ -46,12 +47,15 @@ module Simplex.Messaging.Transport
    -- * SMP transport
    THandle (..),
    TransportError (..),
-    serverHandshake,
-    clientHandshake,
+    HandshakeError (..),
+    smpServerHandshake,
+    smpClientHandshake,
    tPutBlock,
    tGetBlock,
    serializeTransportError,
    transportErrorP,
+    sendHandshake,
+    getHandshake,

    -- * Trim trailing CR
    trimCR,
@@ -71,16 +75,18 @@ import qualified Data.ByteString.Char8 as B
 import qualified Data.ByteString.Lazy as BL
 import Data.Default (def)
 import Data.Functor (($>))
+import Data.Version (showVersion)
 import GHC.Generics (Generic)
 import GHC.IO.Handle.Internals (ioe_EOF)
 import Generic.Random (genericArbitraryU)
 import Network.Socket
 import qualified Network.TLS as T
 import qualified Network.TLS.Extra as TE
+import qualified Paths_simplexmq as SMQ
 import qualified Simplex.Messaging.Crypto as C
 import Simplex.Messaging.Encoding
 import Simplex.Messaging.Parsers (dropPrefix, parse, parseRead1, sumTypeJSON)
-import Simplex.Messaging.Util (bshow)
+import Simplex.Messaging.Util (bshow, catchAll, catchAll_)
 import Simplex.Messaging.Version
 import Test.QuickCheck (Arbitrary (..))
 import UnliftIO.Exception (Exception)
@@ -92,11 +98,11 @@ import UnliftIO.STM
 smpBlockSize :: Int
 smpBlockSize = 16384

-supportedSMPVersions :: VersionRange
-supportedSMPVersions = mkVersionRange 1 1
+supportedSMPServerVRange :: VersionRange
+supportedSMPServerVRange = mkVersionRange 1 5

 simplexMQVersion :: String
-simplexMQVersion = "1.0.3"
+simplexMQVersion = showVersion SMQ.version

 -- * Transport connection class

@@ -115,7 +121,7 @@ class Transport c where
  getClientConnection :: T.Context -> IO c

  -- | tls-unique channel binding per RFC5929
-  tlsUnique :: c -> ByteString
+  tlsUnique :: c -> SessionId

  -- | Close connection
  closeConnection :: c -> IO ()
@@ -150,12 +156,14 @@ data TLS = TLS
    getLock :: TMVar ()
  }

-connectTLS :: T.TLSParams p => p -> Socket -> IO T.Context
-connectTLS params sock =
-  E.bracketOnError (T.contextNew sock params) closeTLS $ \ctx -> do
-    T.handshake ctx
-      `E.catch` \(e :: E.SomeException) -> putStrLn ("exception: " <> show e) >> E.throwIO e
-    pure ctx
+connectTLS :: T.TLSParams p => Maybe HostName -> Bool -> p -> Socket -> IO T.Context
+connectTLS host_ logErrors params sock =
+  E.bracketOnError (T.contextNew sock params) closeTLS $ \ctx ->
+    logHandshakeErrors (T.handshake ctx) $> ctx
+  where
+    logHandshakeErrors = if logErrors then (`catchAll` logThrow) else id
+    logThrow e = putStrLn ("TLS error" <> host <> ": " <> show e) >> E.throwIO e
+    host = maybe "" (\h -> " (" <> h <> ")") host_

 getTLS :: TransportPeer -> T.Context -> IO TLS
 getTLS tlsPeer cxt = withTlsUnique tlsPeer cxt newTLS
@@ -175,8 +183,9 @@ withTlsUnique peer cxt f =

 closeTLS :: T.Context -> IO ()
 closeTLS ctx =
-  (T.bye ctx >> T.contextClose ctx) -- sometimes socket was closed before 'TLS.bye'
-    `E.catch` (\(_ :: E.SomeException) -> pure ()) -- so we catch the 'Broken pipe' error here
+  T.bye ctx -- sometimes socket was closed before 'TLS.bye' so we catch the 'Broken pipe' error here
+    `E.finally` T.contextClose ctx
+    `catchAll_` pure ()

 supportedParameters :: T.Supported
 supportedParameters =
@@ -207,16 +216,17 @@ instance Transport TLS where
      $ do
        b <- readChunks =<< readTVarIO buffer
        let (s, b') = B.splitAt n b
-        atomically $ writeTVar buffer b'
+        atomically $ writeTVar buffer $! b'
        pure s
    where
      readChunks :: ByteString -> IO ByteString
      readChunks b
        | B.length b >= n = pure b
-        | otherwise = readChunks . (b <>) =<< T.recvData tlsContext `E.catch` handleEOF
-      handleEOF = \case
-        T.Error_EOF -> E.throwIO TEBadBlock
-        e -> E.throwIO e
+        | otherwise =
+          T.recvData tlsContext >>= \case
+            -- https://hackage.haskell.org/package/tls-1.6.0/docs/Network-TLS.html#v:recvData
+            "" -> ioe_EOF
+            s -> readChunks $ b <> s

  cPut :: TLS -> ByteString -> IO ()
  cPut tls = T.sendData (tlsContext tls) . BL.fromStrict
@@ -229,7 +239,7 @@ instance Transport TLS where
      $ do
        b <- readChunks =<< readTVarIO buffer
        let (s, b') = B.break (== '\n') b
-        atomically $ writeTVar buffer (B.drop 1 b') -- drop '\n' we made a break at
+        atomically $ writeTVar buffer $! B.drop 1 b' -- drop '\n' we made a break at
        pure $ trimCR s
    where
      readChunks :: ByteString -> IO ByteString
@@ -250,14 +260,21 @@ trimCR s = if B.last s == '\r' then B.init s else s
 -- | The handle for SMP encrypted transport connection over Transport .
 data THandle c = THandle
  { connection :: c,
-    sessionId :: ByteString,
-    -- | agreed SMP server protocol version
-    smpVersion :: Version
+    sessionId :: SessionId,
+    blockSize :: Int,
+    -- | agreed server protocol version
+    thVersion :: Version,
+    -- | send multiple transmissions in a single block
+    -- based on protocol and protocol version
+    batch :: Bool
  }

+-- | TLS-unique channel binding
+type SessionId = ByteString
+
 data ServerHandshake = ServerHandshake
  { smpVersionRange :: VersionRange,
-    sessionId :: ByteString
+    sessionId :: SessionId
  }

 data ClientHandshake = ClientHandshake
@@ -332,53 +349,55 @@ serializeTransportError = \case

 -- | Pad and send block to SMP transport.
 tPutBlock :: Transport c => THandle c -> ByteString -> IO (Either TransportError ())
-tPutBlock THandle {connection = c} block =
+tPutBlock THandle {connection = c, blockSize} block =
  bimapM (const $ pure TELargeMsg) (cPut c) $
-    C.pad block smpBlockSize
+    C.pad block blockSize

 -- | Receive block from SMP transport.
 tGetBlock :: Transport c => THandle c -> IO (Either TransportError ByteString)
-tGetBlock THandle {connection = c} =
-  cGet c smpBlockSize >>= \case
+tGetBlock THandle {connection = c, blockSize} =
+  cGet c blockSize >>= \case
    "" -> ioe_EOF
    msg -> pure . first (const TELargeMsg) $ C.unPad msg

 -- | Server SMP transport handshake.
 --
 -- See https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md#appendix-a
-serverHandshake :: forall c. Transport c => c -> C.KeyHash -> ExceptT TransportError IO (THandle c)
-serverHandshake c kh = do
-  let th@THandle {sessionId} = tHandle c
-  sendHandshake th $ ServerHandshake {sessionId, smpVersionRange = supportedSMPVersions}
+smpServerHandshake :: forall c. Transport c => c -> C.KeyHash -> VersionRange -> ExceptT TransportError IO (THandle c)
+smpServerHandshake c kh smpVRange = do
+  let th@THandle {sessionId} = smpTHandle c
+  sendHandshake th $ ServerHandshake {sessionId, smpVersionRange = smpVRange}
  getHandshake th >>= \case
    ClientHandshake {smpVersion, keyHash}
      | keyHash /= kh ->
        throwE $ TEHandshake IDENTITY
-      | smpVersion `isCompatible` supportedSMPVersions -> do
-        pure (th :: THandle c) {smpVersion}
+      | smpVersion `isCompatible` smpVRange -> do
+        pure $ smpThHandle th smpVersion
      | otherwise -> throwE $ TEHandshake VERSION

 -- | Client SMP transport handshake.
 --
 -- See https://github.com/simplex-chat/simplexmq/blob/master/protocol/simplex-messaging.md#appendix-a
-clientHandshake :: forall c. Transport c => c -> C.KeyHash -> ExceptT TransportError IO (THandle c)
-clientHandshake c keyHash = do
-  let th@THandle {sessionId} = tHandle c
+smpClientHandshake :: forall c. Transport c => c -> C.KeyHash -> VersionRange -> ExceptT TransportError IO (THandle c)
+smpClientHandshake c keyHash smpVRange = do
+  let th@THandle {sessionId} = smpTHandle c
  ServerHandshake {sessionId = sessId, smpVersionRange} <- getHandshake th
  if sessionId /= sessId
    then throwE TEBadSession
-    else case smpVersionRange `compatibleVersion` supportedSMPVersions of
+    else case smpVersionRange `compatibleVersion` smpVRange of
      Just (Compatible smpVersion) -> do
        sendHandshake th $ ClientHandshake {smpVersion, keyHash}
-        pure (th :: THandle c) {smpVersion}
+        pure $ smpThHandle th smpVersion
      Nothing -> throwE $ TEHandshake VERSION

+smpThHandle :: forall c. THandle c -> Version -> THandle c
+smpThHandle th v = (th :: THandle c) {thVersion = v, batch = v >= 4}
+
 sendHandshake :: (Transport c, Encoding smp) => THandle c -> smp -> ExceptT TransportError IO ()
 sendHandshake th = ExceptT . tPutBlock th . smpEncode

 getHandshake :: (Transport c, Encoding smp) => THandle c -> ExceptT TransportError IO smp
 getHandshake th = ExceptT $ (parse smpP (TEHandshake PARSE) =<<) <$> tGetBlock th

-tHandle :: Transport c => c -> THandle c
-tHandle c =
-  THandle {connection = c, sessionId = tlsUnique c, smpVersion = 0}
+smpTHandle :: Transport c => c -> THandle c
+smpTHandle c = THandle {connection = c, sessionId = tlsUnique c, blockSize = smpBlockSize, thVersion = 0, batch = False}
@@ -1,38 +1,135 @@
+{-# LANGUAGE FlexibleInstances #-}
+{-# LANGUAGE LambdaCase #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
 {-# LANGUAGE ScopedTypeVariables #-}

 module Simplex.Messaging.Transport.Client
  ( runTransportClient,
-    clientHandshake,
+    runTLSTransportClient,
+    smpClientHandshake,
+    defaultSMPPort,
+    defaultTransportClientConfig,
+    defaultSocksProxy,
+    TransportClientConfig (..),
+    SocksProxy,
+    TransportHost (..),
+    TransportHosts (..),
+    TransportHosts_ (..),
  )
 where

+import Control.Applicative (optional)
 import Control.Monad.Except
 import Control.Monad.IO.Unlift
+import Data.Aeson (FromJSON (..), ToJSON (..))
+import qualified Data.Attoparsec.ByteString.Char8 as A
 import Data.ByteString.Char8 (ByteString)
 import qualified Data.ByteString.Char8 as B
 import Data.Default (def)
+import Data.List.NonEmpty (NonEmpty (..))
+import qualified Data.List.NonEmpty as L
+import Data.Maybe (fromMaybe)
+import Data.String
+import Data.Word (Word8)
 import qualified Data.X509 as X
 import qualified Data.X509.CertificateStore as XS
 import Data.X509.Validation (Fingerprint (..))
 import qualified Data.X509.Validation as XV
 import GHC.IO.Exception (IOErrorType (..))
 import Network.Socket
+import Network.Socks5
 import qualified Network.TLS as T
 import qualified Simplex.Messaging.Crypto as C
+import Simplex.Messaging.Encoding
+import Simplex.Messaging.Encoding.String
+import Simplex.Messaging.Parsers (parseAll, parseString)
 import Simplex.Messaging.Transport
+import Simplex.Messaging.Transport.KeepAlive
+import Simplex.Messaging.Util (bshow, (<$?>))
 import System.IO.Error
+import Text.Read (readMaybe)
 import UnliftIO.Exception (IOException)
 import qualified UnliftIO.Exception as E

-- | Connect to passed TCP host:port and pass handle to the client.
-runTransportClient :: Transport c => MonadUnliftIO m => HostName -> ServiceName -> C.KeyHash -> (c -> m a) -> m a
-runTransportClient host port keyHash client = do
-  let clientParams = mkTLSClientParams host port keyHash
-  c <- liftIO $ startTCPClient host port clientParams
-  client c `E.finally` liftIO (closeConnection c)
+data TransportHost
+  = THIPv4 (Word8, Word8, Word8, Word8)
+  | THOnionHost ByteString
+  | THDomainName HostName
+  deriving (Eq, Ord, Show)

-startTCPClient :: forall c. Transport c => HostName -> ServiceName -> T.ClientParams -> IO c
-startTCPClient host port clientParams = withSocketsDo $ resolve >>= tryOpen err
+instance Encoding TransportHost where
+  smpEncode = smpEncode . strEncode
+  smpP = parseAll strP <$?> smpP
+
+instance StrEncoding TransportHost where
+  strEncode = \case
+    THIPv4 (a1, a2, a3, a4) -> B.intercalate "." $ map bshow [a1, a2, a3, a4]
+    THOnionHost host -> host
+    THDomainName host -> B.pack host
+  strP =
+    A.choice
+      [ THIPv4 <$> ((,,,) <$> ipNum <*> ipNum <*> ipNum <*> A.decimal),
+        THOnionHost <$> ((<>) <$> A.takeTill (== '.') <*> A.string ".onion"),
+        THDomainName . B.unpack <$> A.takeWhile1 (A.notInClass ":#,;/ ")
+      ]
+    where
+      ipNum = A.decimal <* A.char '.'
+
+instance ToJSON TransportHost where
+  toEncoding = strToJEncoding
+  toJSON = strToJSON
+
+newtype TransportHosts = TransportHosts {thList :: NonEmpty TransportHost}
+
+instance StrEncoding TransportHosts where
+  strEncode = strEncodeList . L.toList . thList
+  strP = TransportHosts . L.fromList <$> strP `A.sepBy1'` A.char ','
+
+newtype TransportHosts_ = TransportHosts_ {thList_ :: [TransportHost]}
+
+instance StrEncoding TransportHosts_ where
+  strEncode = strEncodeList . thList_
+  strP = TransportHosts_ <$> strP `A.sepBy'` A.char ','
+
+instance IsString TransportHost where fromString = parseString strDecode
+
+instance IsString (NonEmpty TransportHost) where fromString = parseString strDecode
+
+data TransportClientConfig = TransportClientConfig
+  { socksProxy :: Maybe SocksProxy,
+    tcpKeepAlive :: Maybe KeepAliveOpts,
+    logTLSErrors :: Bool
+  }
+  deriving (Eq, Show)
+
+defaultTransportClientConfig :: TransportClientConfig
+defaultTransportClientConfig = TransportClientConfig Nothing (Just defaultKeepAliveOpts) True
+
+-- | Connect to passed TCP host:port and pass handle to the client.
+runTransportClient :: (Transport c, MonadUnliftIO m) => TransportClientConfig -> TransportHost -> ServiceName -> Maybe C.KeyHash -> (c -> m a) -> m a
+runTransportClient = runTLSTransportClient supportedParameters Nothing
+
+runTLSTransportClient :: (Transport c, MonadUnliftIO m) => T.Supported -> Maybe XS.CertificateStore -> TransportClientConfig -> TransportHost -> ServiceName -> Maybe C.KeyHash -> (c -> m a) -> m a
+runTLSTransportClient tlsParams caStore_ TransportClientConfig {socksProxy, tcpKeepAlive, logTLSErrors} host port keyHash client = do
+  let hostName = B.unpack $ strEncode host
+      clientParams = mkTLSClientParams tlsParams caStore_ hostName port keyHash
+      connectTCP = case socksProxy of
+        Just proxy -> connectSocksClient proxy $ hostAddr host
+        _ -> connectTCPClient hostName
+  c <- liftIO $ do
+    sock <- connectTCP port
+    mapM_ (setSocketKeepAlive sock) tcpKeepAlive
+    connectTLS (Just hostName) logTLSErrors clientParams sock >>= getClientConnection
+  client c `E.finally` liftIO (closeConnection c)
+  where
+    hostAddr = \case
+      THIPv4 addr -> SocksAddrIPV4 $ tupleToHostAddress addr
+      THOnionHost h -> SocksAddrDomainName h
+      THDomainName h -> SocksAddrDomainName $ B.pack h
+
+connectTCPClient :: HostName -> ServiceName -> IO Socket
+connectTCPClient host port = withSocketsDo $ resolve >>= tryOpen err
  where
    err :: IOException
    err = mkIOError NoSuchThing "no address" Nothing Nothing
@@ -42,25 +139,60 @@ startTCPClient host port clientParams = withSocketsDo $ resolve >>= tryOpen err
      let hints = defaultHints {addrSocketType = Stream}
       in getAddrInfo (Just hints) (Just host) (Just port)

-    tryOpen :: IOException -> [AddrInfo] -> IO c
+    tryOpen :: IOException -> [AddrInfo] -> IO Socket
    tryOpen e [] = E.throwIO e
    tryOpen _ (addr : as) =
      E.try (open addr) >>= either (`tryOpen` as) pure

-    open :: AddrInfo -> IO c
+    open :: AddrInfo -> IO Socket
    open addr = do
      sock <- socket (addrFamily addr) (addrSocketType addr) (addrProtocol addr)
      connect sock $ addrAddress addr
-      ctx <- connectTLS clientParams sock
-      getClientConnection ctx
+      pure sock

-mkTLSClientParams :: HostName -> ServiceName -> C.KeyHash -> T.ClientParams
-mkTLSClientParams host port keyHash = do
+defaultSMPPort :: PortNumber
+defaultSMPPort = 5223
+
+connectSocksClient :: SocksProxy -> SocksHostAddress -> ServiceName -> IO Socket
+connectSocksClient (SocksProxy addr) hostAddr _port = do
+  let port = if null _port then defaultSMPPort else fromMaybe defaultSMPPort $ readMaybe _port
+  fst <$> socksConnect (defaultSocksConf addr) (SocksAddress hostAddr port)
+
+defaultSocksHost :: HostAddress
+defaultSocksHost = tupleToHostAddress (127, 0, 0, 1)
+
+defaultSocksProxy :: SocksProxy
+defaultSocksProxy = SocksProxy $ SockAddrInet 9050 defaultSocksHost
+
+newtype SocksProxy = SocksProxy SockAddr
+  deriving (Eq)
+
+instance Show SocksProxy where show (SocksProxy addr) = show addr
+
+instance StrEncoding SocksProxy where
+  strEncode = B.pack . show
+  strP = do
+    host <- maybe defaultSocksHost tupleToHostAddress <$> optional ipv4P
+    port <- fromMaybe 9050 <$> optional (A.char ':' *> (fromInteger <$> A.decimal))
+    pure . SocksProxy $ SockAddrInet port host
+    where
+      ipv4P = (,,,) <$> ipNum <*> ipNum <*> ipNum <*> A.decimal
+      ipNum = A.decimal <* A.char '.'
+
+instance ToJSON SocksProxy where
+  toJSON = strToJSON
+  toEncoding = strToJEncoding
+
+instance FromJSON SocksProxy where
+  parseJSON = strParseJSON "SocksProxy"
+
+mkTLSClientParams :: T.Supported -> Maybe XS.CertificateStore -> HostName -> ServiceName -> Maybe C.KeyHash -> T.ClientParams
+mkTLSClientParams supported caStore_ host port keyHash_ = do
  let p = B.pack port
  (T.defaultParamsClient host p)
-    { T.clientShared = def,
-      T.clientHooks = def {T.onServerCertificate = \_ _ _ -> validateCertificateChain keyHash host p},
-      T.clientSupported = supportedParameters
+    { T.clientShared = maybe def (\caStore -> def {T.sharedCAStore = caStore}) caStore_,
+      T.clientHooks = maybe def (\keyHash -> def {T.onServerCertificate = \_ _ _ -> validateCertificateChain keyHash host p}) keyHash_,
+      T.clientSupported = supported
    }

 validateCertificateChain :: C.KeyHash -> HostName -> ByteString -> X.CertificateChain -> IO [XV.FailedReason]
@@ -0,0 +1,36 @@
+module Simplex.Messaging.Transport.HTTP2 where
+
+import qualified Control.Exception as E
+import Data.Default (def)
+import Foreign (mallocBytes)
+import Network.HPACK (BufferSize)
+import Network.HTTP2.Client (Config (..), defaultPositionReadMaker, freeSimpleConfig)
+import qualified Network.TLS as T
+import qualified Network.TLS.Extra as TE
+import Simplex.Messaging.Transport (TLS, Transport (cGet, cPut))
+import qualified System.TimeManager as TI
+
+withTlsConfig :: TLS -> BufferSize -> (Config -> IO ()) -> IO ()
+withTlsConfig c sz = E.bracket (allocTlsConfig c sz) freeSimpleConfig
+
+allocTlsConfig :: TLS -> BufferSize -> IO Config
+allocTlsConfig c sz = do
+  buf <- mallocBytes sz
+  tm <- TI.initialize $ 30 * 1000000
+  pure
+    Config
+      { confWriteBuffer = buf,
+        confBufferSize = sz,
+        confSendAll = cPut c,
+        confReadN = cGet c,
+        confPositionReadMaker = defaultPositionReadMaker,
+        confTimeoutManager = tm
+      }
+
+http2TLSParams :: T.Supported
+http2TLSParams =
+  def
+    { T.supportedVersions = [T.TLS13, T.TLS12],
+      T.supportedCiphers = TE.ciphersuite_strong_det,
+      T.supportedSecureRenegotiation = False
+    }
@@ -0,0 +1,126 @@
+{-# LANGUAGE DuplicateRecordFields #-}
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE ScopedTypeVariables #-}
+
+module Simplex.Messaging.Transport.HTTP2.Client where
+
+import Control.Concurrent.Async
+import Control.Exception (IOException)
+import qualified Control.Exception as E
+import Control.Monad.Except
+import Data.ByteString.Char8 (ByteString)
+import qualified Data.ByteString.Char8 as B
+import Data.Maybe (isNothing)
+import qualified Data.X509.CertificateStore as XS
+import Network.HPACK (HeaderTable)
+import Network.HTTP2.Client (ClientConfig (..), Request, Response)
+import qualified Network.HTTP2.Client as H
+import Network.Socket (HostName, ServiceName)
+import qualified Network.TLS as T
+import Numeric.Natural (Natural)
+import Simplex.Messaging.Transport.Client (TransportClientConfig (..), TransportHost (..), runTLSTransportClient)
+import Simplex.Messaging.Transport.HTTP2 (http2TLSParams, withTlsConfig)
+import UnliftIO.STM
+import UnliftIO.Timeout
+
+data HTTP2Client = HTTP2Client
+  { action :: Maybe (Async ()),
+    connected :: TVar Bool,
+    host :: HostName,
+    port :: ServiceName,
+    config :: HTTP2ClientConfig,
+    reqQ :: TBQueue (Request, TMVar HTTP2Response)
+  }
+
+data HTTP2Response = HTTP2Response
+  { response :: Response,
+    respBody :: ByteString,
+    respTrailers :: Maybe HeaderTable
+  }
+
+data HTTP2ClientConfig = HTTP2ClientConfig
+  { qSize :: Natural,
+    connTimeout :: Int,
+    transportConfig :: TransportClientConfig,
+    caStoreFile :: FilePath,
+    suportedTLSParams :: T.Supported
+  }
+  deriving (Show)
+
+defaultHTTP2ClientConfig :: HTTP2ClientConfig
+defaultHTTP2ClientConfig =
+  HTTP2ClientConfig
+    { qSize = 64,
+      connTimeout = 10000000,
+      transportConfig = TransportClientConfig Nothing Nothing True,
+      caStoreFile = "/etc/ssl/cert.pem",
+      suportedTLSParams = http2TLSParams
+    }
+
+data HTTP2ClientError = HCResponseTimeout | HCNetworkError | HCNetworkError1 | HCIOError IOException
+  deriving (Show)
+
+getHTTP2Client :: HostName -> ServiceName -> HTTP2ClientConfig -> IO () -> IO (Either HTTP2ClientError HTTP2Client)
+getHTTP2Client host port config@HTTP2ClientConfig {transportConfig, connTimeout, caStoreFile, suportedTLSParams} disconnected =
+  (atomically mkHTTPS2Client >>= runClient)
+    `E.catch` \(e :: IOException) -> pure . Left $ HCIOError e
+  where
+    mkHTTPS2Client :: STM HTTP2Client
+    mkHTTPS2Client = do
+      connected <- newTVar False
+      reqQ <- newTBQueue $ qSize config
+      pure HTTP2Client {action = Nothing, connected, host, port, config, reqQ}
+
+    runClient :: HTTP2Client -> IO (Either HTTP2ClientError HTTP2Client)
+    runClient c = do
+      cVar <- newEmptyTMVarIO
+      caStore <- XS.readCertificateStore caStoreFile
+      when (isNothing caStore) . putStrLn $ "Error loading CertificateStore from " <> caStoreFile
+      action <-
+        async $
+          runHTTP2Client suportedTLSParams caStore transportConfig host port (client c cVar)
+            `E.finally` atomically (putTMVar cVar $ Left HCNetworkError)
+      conn_ <- connTimeout `timeout` atomically (takeTMVar cVar)
+      pure $ case conn_ of
+        Just (Right ()) -> Right c {action = Just action}
+        Just (Left e) -> Left e
+        Nothing -> Left HCNetworkError1
+
+    client :: HTTP2Client -> TMVar (Either HTTP2ClientError ()) -> (Request -> (Response -> IO ()) -> IO ()) -> IO ()
+    client c cVar sendReq = do
+      atomically $ do
+        writeTVar (connected c) True
+        putTMVar cVar $ Right ()
+      process c sendReq `E.finally` disconnected
+
+    process :: HTTP2Client -> (Request -> (Response -> IO ()) -> IO ()) -> IO ()
+    process HTTP2Client {reqQ} sendReq = forever $ do
+      (req, respVar) <- atomically $ readTBQueue reqQ
+      sendReq req $ \r -> do
+        let writeResp respBody respTrailers = atomically $ putTMVar respVar HTTP2Response {response = r, respBody, respTrailers}
+        respBody <- getResponseBody r ""
+        respTrailers <- H.getResponseTrailers r
+        writeResp respBody respTrailers
+
+    getResponseBody :: Response -> ByteString -> IO ByteString
+    getResponseBody r s =
+      H.getResponseBodyChunk r >>= \chunk ->
+        if B.null chunk then pure s else getResponseBody r $ s <> chunk
+
+-- | Disconnects client from the server and terminates client threads.
+closeHTTP2Client :: HTTP2Client -> IO ()
+closeHTTP2Client = mapM_ uninterruptibleCancel . action
+
+sendRequest :: HTTP2Client -> Request -> IO (Either HTTP2ClientError HTTP2Response)
+sendRequest HTTP2Client {reqQ, config} req = do
+  resp <- newEmptyTMVarIO
+  atomically $ writeTBQueue reqQ (req, resp)
+  maybe (Left HCResponseTimeout) Right <$> (connTimeout config `timeout` atomically (takeTMVar resp))
+
+runHTTP2Client :: T.Supported -> Maybe XS.CertificateStore -> TransportClientConfig -> HostName -> ServiceName -> ((Request -> (Response -> IO ()) -> IO ()) -> IO ()) -> IO ()
+runHTTP2Client tlsParams caStore tcConfig host port client =
+  runTLSTransportClient tlsParams caStore tcConfig (THDomainName host) port Nothing $ \c ->
+    withTlsConfig c 16384 (`run` client)
+  where
+    run = H.run $ ClientConfig "https" (B.pack host) 20
@@ -0,0 +1,71 @@
+{-# LANGUAGE NamedFieldPuns #-}
+{-# LANGUAGE OverloadedStrings #-}
+
+module Simplex.Messaging.Transport.HTTP2.Server where
+
+import Control.Concurrent.Async (Async, async, uninterruptibleCancel)
+import Control.Concurrent.STM
+import Control.Monad
+import Data.ByteString (ByteString)
+import qualified Data.ByteString.Char8 as B
+import Network.HPACK (HeaderTable)
+import Network.HTTP2.Server (Aux, PushPromise, Request, Response)
+import qualified Network.HTTP2.Server as H
+import Network.Socket
+import qualified Network.TLS as T
+import Numeric.Natural (Natural)
+import Simplex.Messaging.Transport.HTTP2 (withTlsConfig)
+import Simplex.Messaging.Transport.Server (loadSupportedTLSServerParams, runTransportServer)
+
+type HTTP2ServerFunc = (Request -> (Response -> IO ()) -> IO ())
+
+data HTTP2ServerConfig = HTTP2ServerConfig
+  { qSize :: Natural,
+    http2Port :: ServiceName,
+    serverSupported :: T.Supported,
+    caCertificateFile :: FilePath,
+    privateKeyFile :: FilePath,
+    certificateFile :: FilePath,
+    logTLSErrors :: Bool
+  }
+  deriving (Show)
+
+data HTTP2Request = HTTP2Request
+  { request :: Request,
+    reqBody :: ByteString,
+    reqTrailers :: Maybe HeaderTable,
+    sendResponse :: Response -> IO ()
+  }
+
+data HTTP2Server = HTTP2Server
+  { action :: Async (),
+    reqQ :: TBQueue HTTP2Request
+  }
+
+getHTTP2Server :: HTTP2ServerConfig -> IO HTTP2Server
+getHTTP2Server HTTP2ServerConfig {qSize, http2Port, serverSupported, caCertificateFile, certificateFile, privateKeyFile, logTLSErrors} = do
+  tlsServerParams <- loadSupportedTLSServerParams serverSupported caCertificateFile certificateFile privateKeyFile
+  started <- newEmptyTMVarIO
+  reqQ <- newTBQueueIO qSize
+  action <- async $
+    runHTTP2Server started http2Port tlsServerParams logTLSErrors $ \r sendResponse -> do
+      reqBody <- getRequestBody r ""
+      reqTrailers <- H.getRequestTrailers r
+      atomically $ writeTBQueue reqQ HTTP2Request {request = r, reqBody, reqTrailers, sendResponse}
+  void . atomically $ takeTMVar started
+  pure HTTP2Server {action, reqQ}
+  where
+    getRequestBody :: Request -> ByteString -> IO ByteString
+    getRequestBody r s =
+      H.getRequestBodyChunk r >>= \chunk ->
+        if B.null chunk then pure s else getRequestBody r $ s <> chunk
+
+closeHTTP2Server :: HTTP2Server -> IO ()
+closeHTTP2Server = uninterruptibleCancel . action
+
+runHTTP2Server :: TMVar Bool -> ServiceName -> T.ServerParams -> Bool -> HTTP2ServerFunc -> IO ()
+runHTTP2Server started port serverParams logTLSErrors http2Server =
+  runTransportServer started port serverParams logTLSErrors $ \c -> withTlsConfig c 16384 (`H.run` server)
+  where
+    server :: Request -> Aux -> (Response -> [PushPromise] -> IO ()) -> IO ()
+    server req _aux sendResp = http2Server req (`sendResp` [])
@@ -0,0 +1,70 @@
+{-# LANGUAGE CApiFFI #-}
+{-# LANGUAGE CPP #-}
+{-# LANGUAGE DeriveAnyClass #-}
+{-# LANGUAGE DeriveGeneric #-}
+{-# LANGUAGE NamedFieldPuns #-}
+
+module Simplex.Messaging.Transport.KeepAlive where
+
+import Data.Aeson (FromJSON (..), ToJSON (..))
+import qualified Data.Aeson as J
+import Foreign.C (CInt (..))
+import GHC.Generics (Generic)
+import Network.Socket
+
+data KeepAliveOpts = KeepAliveOpts
+  { keepIdle :: Int,
+    keepIntvl :: Int,
+    keepCnt :: Int
+  }
+  deriving (Eq, Show, Generic, FromJSON)
+
+instance ToJSON KeepAliveOpts where toEncoding = J.genericToEncoding J.defaultOptions
+
+defaultKeepAliveOpts :: KeepAliveOpts
+defaultKeepAliveOpts =
+  KeepAliveOpts
+    { keepIdle = 30,
+      keepIntvl = 15,
+      keepCnt = 4
+    }
+
+_SOL_TCP :: CInt
+_SOL_TCP = 6
+
+#if defined(mingw32_HOST_OS)
+-- Windows
+
+-- The values are copied from windows::Win32::Networking::WinSock
+-- https://microsoft.github.io/windows-docs-rs/doc/windows/Win32/Networking/WinSock/index.html
+
+_TCP_KEEPIDLE :: CInt
+_TCP_KEEPIDLE = 3
+
+_TCP_KEEPINTVL :: CInt
+_TCP_KEEPINTVL = 17
+
+_TCP_KEEPCNT :: CInt
+_TCP_KEEPCNT = 16
+
+#else
+-- Mac/Linux
+
+#if defined(darwin_HOST_OS)
+foreign import capi "netinet/tcp.h value TCP_KEEPALIVE" _TCP_KEEPIDLE :: CInt
+#else
+foreign import capi "netinet/tcp.h value TCP_KEEPIDLE" _TCP_KEEPIDLE :: CInt
+#endif
+
+foreign import capi "netinet/tcp.h value TCP_KEEPINTVL" _TCP_KEEPINTVL :: CInt
+
+foreign import capi "netinet/tcp.h value TCP_KEEPCNT" _TCP_KEEPCNT :: CInt
+
+#endif
+
+setSocketKeepAlive :: Socket -> KeepAliveOpts -> IO ()
+setSocketKeepAlive sock KeepAliveOpts {keepCnt, keepIdle, keepIntvl} = do
+  setSocketOption sock KeepAlive 1
+  setSocketOption sock (SockOpt _SOL_TCP _TCP_KEEPIDLE) keepIdle
+  setSocketOption sock (SockOpt _SOL_TCP _TCP_KEEPINTVL) keepIntvl
+  setSocketOption sock (SockOpt _SOL_TCP _TCP_KEEPCNT) keepCnt
@@ -4,25 +4,30 @@

 module Simplex.Messaging.Transport.Server
  ( runTransportServer,
+    runTCPServer,
+    loadSupportedTLSServerParams,
    loadTLSServerParams,
    loadFingerprint,
-    serverHandshake,
+    smpServerHandshake,
  )
 where

+import Control.Concurrent.STM (stateTVar)
 import Control.Monad.Except
 import Control.Monad.IO.Unlift
 import qualified Crypto.Store.X509 as SX
 import Data.Default (def)
-import Data.Set (Set)
-import qualified Data.Set as S
 import qualified Data.X509 as X
 import Data.X509.Validation (Fingerprint (..))
 import qualified Data.X509.Validation as XV
 import Network.Socket
 import qualified Network.TLS as T
+import Simplex.Messaging.TMap (TMap)
+import qualified Simplex.Messaging.TMap as TM
 import Simplex.Messaging.Transport
+import Simplex.Messaging.Util (catchAll_)
 import System.Exit (exitFailure)
+import System.Mem.Weak (Weak, deRefWeak)
 import UnliftIO.Concurrent
 import qualified UnliftIO.Exception as E
 import UnliftIO.STM
@@ -30,30 +35,35 @@ import UnliftIO.STM
 -- | Run transport server (plain TCP or WebSockets) on passed TCP port and signal when server started and stopped via passed TMVar.
 --
 -- All accepted connections are passed to the passed function.
-runTransportServer :: forall c m. (Transport c, MonadUnliftIO m) => TMVar Bool -> ServiceName -> T.ServerParams -> (c -> m ()) -> m ()
-runTransportServer started port serverParams server = do
+runTransportServer :: forall c m. (Transport c, MonadUnliftIO m) => TMVar Bool -> ServiceName -> T.ServerParams -> Bool -> (c -> m ()) -> m ()
+runTransportServer started port serverParams logTLSErrors server = do
  u <- askUnliftIO
-  liftIO $ do
-    clients <- newTVarIO S.empty
+  liftIO . runTCPServer started port $ \conn ->
    E.bracket
-      (startTCPServer started port)
-      (closeServer clients)
-      $ \sock -> forever $ do
-        (connSock, _) <- accept sock
-        tid <- forkIO $ connectClient u connSock `E.catch` \(_ :: E.SomeException) -> pure ()
-        atomically . modifyTVar clients $ S.insert tid
-  where
-    connectClient :: UnliftIO m -> Socket -> IO ()
-    connectClient u connSock =
-      E.bracket
-        (connectTLS serverParams connSock >>= getServerConnection)
-        closeConnection
-        (unliftIO u . server)
-    closeServer :: TVar (Set ThreadId) -> Socket -> IO ()
-    closeServer clients sock = do
-      readTVarIO clients >>= mapM_ killThread
-      close sock
-      void . atomically $ tryPutTMVar started False
+      (connectTLS Nothing logTLSErrors serverParams conn >>= getServerConnection)
+      closeConnection
+      (unliftIO u . server)
+
+-- | Run TCP server without TLS
+runTCPServer :: TMVar Bool -> ServiceName -> (Socket -> IO ()) -> IO ()
+runTCPServer started port server = do
+  clients <- atomically TM.empty
+  clientId <- newTVarIO 0
+  E.bracket
+    (startTCPServer started port)
+    (closeServer started clients)
+    $ \sock -> forever . E.bracketOnError (accept sock) (close . fst) $ \(conn, _peer) -> do
+      -- catchAll_ is needed here in case the connection was closed earlier
+      cId <- atomically $ stateTVar clientId $ \cId -> let cId' = cId + 1 in (cId', cId')
+      let closeConn _ = atomically (TM.delete cId clients) >> gracefulClose conn 5000 `catchAll_` pure ()
+      tId <- mkWeakThreadId =<< server conn `forkFinally` closeConn
+      atomically $ TM.insert cId tId clients
+
+closeServer :: TMVar Bool -> TMap Int (Weak ThreadId) -> Socket -> IO ()
+closeServer started clients sock = do
+  readTVarIO clients >>= mapM_ (deRefWeak >=> mapM_ killThread)
+  close sock
+  void . atomically $ tryPutTMVar started False

 startTCPServer :: TMVar Bool -> ServiceName -> IO Socket
 startTCPServer started port = withSocketsDo $ resolve >>= open >>= setStarted
@@ -71,7 +81,10 @@ startTCPServer started port = withSocketsDo $ resolve >>= open >>= setStarted
    setStarted sock = atomically (tryPutTMVar started True) >> pure sock

 loadTLSServerParams :: FilePath -> FilePath -> FilePath -> IO T.ServerParams
-loadTLSServerParams caCertificateFile certificateFile privateKeyFile =
+loadTLSServerParams = loadSupportedTLSServerParams supportedParameters
+
+loadSupportedTLSServerParams :: T.Supported -> FilePath -> FilePath -> FilePath -> IO T.ServerParams
+loadSupportedTLSServerParams serverSupported caCertificateFile certificateFile privateKeyFile =
  fromCredential <$> loadServerCredential
  where
    loadServerCredential :: IO T.Credential
@@ -85,7 +98,7 @@ loadTLSServerParams caCertificateFile certificateFile privateKeyFile =
        { T.serverWantClientCert = False,
          T.serverShared = def {T.sharedCredentials = T.Credentials [credential]},
          T.serverHooks = def,
-          T.serverSupported = supportedParameters
+          T.serverSupported = serverSupported
        }

 loadFingerprint :: FilePath -> IO Fingerprint
--- a/Show More
+++ b/Show More