Narasimha-sc
937e688c0a
No behaviour change. The review rounds left the flow carrying their own reasoning: 267 of the 759 added lines were comments, and the fixes had accreted structure that was no longer needed. createProfileForInvitation runs on Main via withApi, as the pickers' own handlers always did, instead of withBGApi with three withContext(Dispatchers.Main) blocks inside it. Every call it makes suspends into IO - sendCmd hops there itself - so Main is never blocked, and the whole class of off-main model mutation that two rounds of review found simply cannot arise. That removes the two coroutine imports as well. hasModalOpenNotClosing is gone: while the form is open it is necessarily the last modal on the fullscreen stack, so the entry guard uses isLastModalOpenNotClosing and one function covers both call sites. The rest is comments. Kept the ones that record why something non-obvious is the way it is - the placement, the main-thread choice, the guards - and dropped the narration of what the earlier attempts got wrong, which belongs in the history and the plan. One comment described code that is not there at all; it is the commit message's job to say why the chatId write was removed. 759 -> 667 added lines, 267 -> 189 of them comments.
SimpleX Chat iOS app
This file provides guidance when working with code in this repository.
iOS App Overview
The iOS app is a SwiftUI application that interfaces with the Haskell core library via FFI. It shares the SimpleXChat framework with two extensions: Notification Service Extension (NSE) for push notifications and Share Extension (SE) for sharing content from other apps.
Build & Development
Open SimpleX.xcodeproj in Xcode. The project has five targets:
- SimpleX (iOS) - Main app (Bundle ID:
chat.simplex.app) - SimpleXChat - Framework containing FFI bridge and shared types
- SimpleX NSE - Notification Service Extension
- SimpleX SE - Share Extension
- Tests iOS - UI tests
Build and run via Xcode (Product > Build/Run). Tests run via Product > Test or:
xcodebuild test -scheme "SimpleX (iOS)" -destination 'platform=iOS Simulator,name=iPhone 15'
Deployment target: iOS 15.0+, Swift 5.0.
Architecture
Haskell Core Integration
The app calls the Haskell core library through C FFI defined in SimpleXChat/SimpleX.h:
chat_migrate_init_key()- Initialize/migrate databasechat_send_cmd_retry()- Send command to chat controllerchat_recv_msg_wait()- Receive messages from controller
Swift wrappers in SimpleXChat/API.swift:
chatMigrateInit()- Initialize chat controllersendSimpleXCmd<R>()- Send typed commands and parse responsesrecvSimpleXMsg<R>()- Receive typed messages
Haskell runtime initialization (SimpleXChat/hs_init.c) uses different memory configurations:
- Main app: 64MB heap
- NSE: 512KB heap (minimal footprint for background processing)
- SE: 1MB heap
Pre-compiled Haskell libraries are in Libraries/{ios,mac,sim}/.
State Management
- ChatModel (
Shared/Model/ChatModel.swift) - Main singletonObservableObjectfor app-wide state (chat list, active chat, users) - ItemsModel - Manages chat items within a selected chat (similar to Kotlin's ChatsContext)
- AppTheme - Theme management and customization
App Structure
Entry point: Shared/SimpleXApp.swift
Key directories in Shared/:
Model/- Data models and API layer (ChatModel.swift,SimpleXAPI.swift)Views/- SwiftUI views organized by feature:ChatList/- Chat list and user pickerChat/- Message display and compositionCall/- VoIP call UIUserSettings/- App settingsLocalAuth/- Passcode and biometric authenticationDatabase/- Database initialization and migration
Shared Data Between Targets
All three targets share data via App Group (group.chat.simplex.app):
SimpleXChat/AppGroup.swift- GroupDefaults wrapper for typed shared preferences- Keychain for sensitive data:
kcDatabasePassword,kcAppPassword,kcSelfDestructPassword
Key Types
Types are defined in SimpleXChat/:
ChatTypes.swift- User, Chat, Message, Group typesAPITypes.swift- API request/response types
Commands follow ChatCmdProtocol (has cmdString property), sent as JSON through FFI.
Localization
31 languages supported. Localization files in SimpleX Localizations/.
Workflow:
Product > Export Localizations- Export XLIFF filesProduct > Import Localizations- Import updated translations
SimpleX Assets
The app includes optional assets behind the SIMPLEX_ASSETS Swift compilation flag. Without setup, the app builds normally without them.
Setup
Create Local.xcconfig (gitignored) in the apps/ios/ directory:
SIMPLEX_ASSETS_DIR = /path/to/assets
SWIFT_ACTIVE_COMPILATION_CONDITIONS = $(inherited) SIMPLEX_ASSETS
The copy script (scripts/ios/copy-assets.sh) runs as a build phase on each build but exits immediately if SIMPLEX_ASSETS is not set.
Updating assets
When source images change, regenerate resized images (requires ImageMagick):
cd path/to/assets && ./resize.sh
Background Capabilities
Configured in Info.plist:
- Background modes: audio, fetch, remote-notification, voip
- URL scheme:
simplex://for deep linking - BGTaskScheduler:
chat.simplex.app.receive