types

simplex-chat.cabal

@@ -130,6 +130,7 @@ library
           Simplex.Chat.Store.Postgres.Migrations.M20260122_has_link
           Simplex.Chat.Store.Postgres.Migrations.M20260222_chat_relays
           Simplex.Chat.Store.Postgres.Migrations.M20260403_item_viewed
+          Simplex.Chat.Store.Postgres.Migrations.M20260407_channel_comments
   else
       exposed-modules:
           Simplex.Chat.Archive
@@ -282,6 +283,7 @@ library
           Simplex.Chat.Store.SQLite.Migrations.M20260122_has_link
           Simplex.Chat.Store.SQLite.Migrations.M20260222_chat_relays
           Simplex.Chat.Store.SQLite.Migrations.M20260403_item_viewed
+          Simplex.Chat.Store.SQLite.Migrations.M20260407_channel_comments
   other-modules:
       Paths_simplex_chat
   hs-source-dirs:

src/Simplex/Chat/Messages.hs

@@ -158,12 +158,22 @@ chatTypeStr = \case
 chatNameStr :: ChatName -> String
 chatNameStr (ChatName cType name) = T.unpack $ chatTypeStr cType <> if T.any isSpace name then "'" <> name <> "'" else name
 
-data ChatRef = ChatRef {chatType :: ChatType, chatId :: Int64, chatScope :: Maybe GroupChatScope}
+data ChatRef = ChatRef
+  { chatType :: ChatType,
+    chatId :: Int64,
+    chatScope :: Maybe GroupChatScope,
+    -- Set when referring to the comments thread of a specific channel post.
+    -- Mutually exclusive with chatScope at the call site.
+    channelMsg_ :: Maybe ChatItemId
+  }
   deriving (Eq, Show, Ord)
 
 data ChatInfo (c :: ChatType) where
   DirectChat :: Contact -> ChatInfo 'CTDirect
-  GroupChat :: GroupInfo -> Maybe GroupChatScopeInfo -> ChatInfo 'CTGroup
+  -- The third parameter `Maybe ChannelMsgInfo` identifies the comments thread of a
+  -- specific channel post; it is `Nothing` for the main channel chat and for the
+  -- member-support scope. The two `Maybe` fields are mutually exclusive in practice.
+  GroupChat :: GroupInfo -> Maybe GroupChatScopeInfo -> Maybe ChannelMsgInfo -> ChatInfo 'CTGroup
   LocalChat :: NoteFolder -> ChatInfo 'CTLocal
   ContactRequest :: UserContactRequest -> ChatInfo 'CTContactRequest
   ContactConnection :: PendingContactConnection -> ChatInfo 'CTContactConnection
@@ -174,6 +184,16 @@ deriving instance Show (ChatInfo c)
 data GroupChatScopeInfo = GCSIMemberSupport {groupMember_ :: Maybe GroupMember}
   deriving (Show)
 
+-- Identifies the parent channel post of a comments thread.
+-- Both fields are co-determined: the SharedMsgId is extracted from `channelMsgItem`
+-- by the smart constructor in Store/Messages.hs, so the field is total at the
+-- type-system level.
+data ChannelMsgInfo = ChannelMsgInfo
+  { channelMsgItem :: CChatItem 'CTGroup,
+    channelMsgSharedId :: SharedMsgId
+  }
+  deriving (Show)
+
 toChatScope :: GroupChatScopeInfo -> GroupChatScope
 toChatScope = \case
   GCSIMemberSupport {groupMember_} -> GCSMemberSupport $ groupMemberId' <$> groupMember_
@@ -184,21 +204,22 @@ toMsgScope GroupInfo {membership} = \case
 
 chatInfoToRef :: ChatInfo c -> Maybe ChatRef
 chatInfoToRef = \case
-  DirectChat Contact {contactId} -> Just $ ChatRef CTDirect contactId Nothing
-  GroupChat GroupInfo {groupId} scopeInfo -> Just $ ChatRef CTGroup groupId (toChatScope <$> scopeInfo)
-  LocalChat NoteFolder {noteFolderId} -> Just $ ChatRef CTLocal noteFolderId Nothing
-  ContactRequest UserContactRequest {contactRequestId} -> Just $ ChatRef CTContactRequest contactRequestId Nothing
-  ContactConnection PendingContactConnection {pccConnId} -> Just $ ChatRef CTContactConnection pccConnId Nothing
+  DirectChat Contact {contactId} -> Just $ ChatRef CTDirect contactId Nothing Nothing
+  GroupChat GroupInfo {groupId} scopeInfo channelMsgInfo ->
+    Just $ ChatRef CTGroup groupId (toChatScope <$> scopeInfo) (cChatItemId . channelMsgItem <$> channelMsgInfo)
+  LocalChat NoteFolder {noteFolderId} -> Just $ ChatRef CTLocal noteFolderId Nothing Nothing
+  ContactRequest UserContactRequest {contactRequestId} -> Just $ ChatRef CTContactRequest contactRequestId Nothing Nothing
+  ContactConnection PendingContactConnection {pccConnId} -> Just $ ChatRef CTContactConnection pccConnId Nothing Nothing
   CInfoInvalidJSON {} -> Nothing
 
 chatInfoMembership :: ChatInfo c -> Maybe GroupMember
 chatInfoMembership = \case
-  GroupChat GroupInfo {membership} _scopeInfo -> Just membership
+  GroupChat GroupInfo {membership} _scopeInfo _channelMsgInfo -> Just membership
   _ -> Nothing
 
 data JSONChatInfo
   = JCInfoDirect {contact :: Contact}
-  | JCInfoGroup {groupInfo :: GroupInfo, groupChatScope :: Maybe GroupChatScopeInfo}
+  | JCInfoGroup {groupInfo :: GroupInfo, groupChatScope :: Maybe GroupChatScopeInfo, channelMsgInfo :: Maybe ChannelMsgInfo}
   | JCInfoLocal {noteFolder :: NoteFolder}
   | JCInfoContactRequest {contactRequest :: UserContactRequest}
   | JCInfoContactConnection {contactConnection :: PendingContactConnection}
@@ -206,6 +227,8 @@ data JSONChatInfo
 
 $(JQ.deriveJSON (sumTypeJSON $ dropPrefix "GCSI") ''GroupChatScopeInfo)
 
+$(JQ.deriveJSON defaultJSON ''ChannelMsgInfo)
+
 $(JQ.deriveToJSON (sumTypeJSON $ dropPrefix "JCInfo") ''JSONChatInfo)
 
 instance FromJSON JSONChatInfo where
@@ -224,7 +247,7 @@ instance ToJSON (ChatInfo c) where
 jsonChatInfo :: ChatInfo c -> JSONChatInfo
 jsonChatInfo = \case
   DirectChat c -> JCInfoDirect c
-  GroupChat g s -> JCInfoGroup g s
+  GroupChat g s cm -> JCInfoGroup g s cm
   LocalChat l -> JCInfoLocal l
   ContactRequest g -> JCInfoContactRequest g
   ContactConnection c -> JCInfoContactConnection c
@@ -237,7 +260,7 @@ deriving instance Show AChatInfo
 jsonAChatInfo :: JSONChatInfo -> AChatInfo
 jsonAChatInfo = \case
   JCInfoDirect c -> AChatInfo SCTDirect $ DirectChat c
-  JCInfoGroup g s -> AChatInfo SCTGroup $ GroupChat g s
+  JCInfoGroup g s cm -> AChatInfo SCTGroup $ GroupChat g s cm
   JCInfoLocal l -> AChatInfo SCTLocal $ LocalChat l
   JCInfoContactRequest g -> AChatInfo SCTContactRequest $ ContactRequest g
   JCInfoContactConnection c -> AChatInfo SCTContactConnection $ ContactConnection c
@@ -406,9 +429,9 @@ toChatInfo :: ChatDirection c d -> ChatInfo c
 toChatInfo = \case
   CDDirectSnd c -> DirectChat c
   CDDirectRcv c -> DirectChat c
-  CDGroupSnd g s -> GroupChat g s
-  CDGroupRcv g s _ -> GroupChat g s
-  CDChannelRcv g s -> GroupChat g s
+  CDGroupSnd g s -> GroupChat g s Nothing
+  CDGroupRcv g s _ -> GroupChat g s Nothing
+  CDChannelRcv g s -> GroupChat g s Nothing
   CDLocalSnd l -> LocalChat l
   CDLocalRcv l -> LocalChat l
 
@@ -513,6 +536,12 @@ data CIMeta (c :: ChatType) (d :: MsgDirection) = CIMeta
     forwardedByMember :: Maybe GroupMemberId,
     showGroupAsSender :: ShowGroupAsSender,
     msgSigned :: Maybe MsgSigStatus,
+    -- Set on a comment row; references the parent channel post.
+    parentChatItemId :: Maybe ChatItemId,
+    -- Set on a parent channel post; running total of non-deleted comments.
+    commentsTotal :: Int,
+    -- Set on a parent channel post; True locks the post against new comments.
+    commentsDisabled :: Bool,
     createdAt :: UTCTime,
     updatedAt :: UTCTime
   }
@@ -520,12 +549,12 @@ data CIMeta (c :: ChatType) (d :: MsgDirection) = CIMeta
 
 type ShowGroupAsSender = Bool
 
-mkCIMeta :: forall c d. ChatTypeI c => ChatItemId -> CIContent d -> Text -> CIStatus d -> Maybe Bool -> Maybe SharedMsgId -> Maybe CIForwardedFrom -> Maybe (CIDeleted c) -> Bool -> Maybe CITimed -> Maybe Bool -> Bool -> Bool -> UTCTime -> ChatItemTs -> Maybe GroupMemberId -> Bool -> Maybe MsgSigStatus -> UTCTime -> UTCTime -> CIMeta c d
-mkCIMeta itemId itemContent itemText itemStatus sentViaProxy itemSharedMsgId itemForwarded itemDeleted itemEdited itemTimed itemLive userMention hasLink_ currentTs itemTs forwardedByMember showGroupAsSender msgSigned createdAt updatedAt =
+mkCIMeta :: forall c d. ChatTypeI c => ChatItemId -> CIContent d -> Text -> CIStatus d -> Maybe Bool -> Maybe SharedMsgId -> Maybe CIForwardedFrom -> Maybe (CIDeleted c) -> Bool -> Maybe CITimed -> Maybe Bool -> Bool -> Bool -> UTCTime -> ChatItemTs -> Maybe GroupMemberId -> Bool -> Maybe MsgSigStatus -> Maybe ChatItemId -> Int -> Bool -> UTCTime -> UTCTime -> CIMeta c d
+mkCIMeta itemId itemContent itemText itemStatus sentViaProxy itemSharedMsgId itemForwarded itemDeleted itemEdited itemTimed itemLive userMention hasLink_ currentTs itemTs forwardedByMember showGroupAsSender msgSigned parentChatItemId commentsTotal commentsDisabled createdAt updatedAt =
   let deletable = deletable' itemContent itemDeleted itemTs nominalDay currentTs
       editable = deletable && isNothing itemForwarded
       hasLink = BoolDef hasLink_
-   in CIMeta {itemId, itemTs, itemText, itemStatus, sentViaProxy, itemSharedMsgId, itemForwarded, itemDeleted, itemEdited, itemTimed, itemLive, userMention, hasLink, deletable, editable, forwardedByMember, showGroupAsSender, msgSigned, createdAt, updatedAt}
+   in CIMeta {itemId, itemTs, itemText, itemStatus, sentViaProxy, itemSharedMsgId, itemForwarded, itemDeleted, itemEdited, itemTimed, itemLive, userMention, hasLink, deletable, editable, forwardedByMember, showGroupAsSender, msgSigned, parentChatItemId, commentsTotal, commentsDisabled, createdAt, updatedAt}
 
 deletable' :: forall c d. ChatTypeI c => CIContent d -> Maybe (CIDeleted c) -> UTCTime -> NominalDiffTime -> UTCTime -> Bool
 deletable' itemContent itemDeleted itemTs allowedInterval currentTs =
@@ -557,6 +586,9 @@ dummyMeta itemId ts itemText =
       forwardedByMember = Nothing,
       showGroupAsSender = False,
       msgSigned = Nothing,
+      parentChatItemId = Nothing,
+      commentsTotal = 0,
+      commentsDisabled = False,
       createdAt = ts,
       updatedAt = ts
     }

src/Simplex/Chat/Protocol.hs

@@ -82,12 +82,13 @@ import Simplex.Messaging.Version hiding (version)
 -- 15 - support specifying message scopes for group messages (2025-03-12)
 -- 16 - support short link data (2025-06-10)
 -- 17 - allow host voice messages during member approval regardless of group voice setting (2026-02-10)
+-- 18 - support comments on channel posts (2026-04-07)
 
 -- This should not be used directly in code, instead use `maxVersion chatVRange` from ChatConfig.
 -- This indirection is needed for backward/forward compatibility testing.
 -- Testing with real app versions is still needed, as tests use the current code with different version ranges, not the old code.
 currentChatVersion :: VersionChat
-currentChatVersion = VersionChat 17
+currentChatVersion = VersionChat 18
 
 -- This should not be used directly in code, instead use `chatVRange` from ChatConfig (see comment above)
 supportedChatVRange :: VersionRangeChat
@@ -154,6 +155,10 @@ shortLinkDataVersion = VersionChat 16
 memberSupportVoiceVersion :: VersionChat
 memberSupportVoiceVersion = VersionChat 17
 
+-- support comments on channel posts (merged MsgContainer with optional `parent`, XGrpCommentsDisabled)
+commentsVersion :: VersionChat
+commentsVersion = VersionChat 18
+
 agentToChatVersion :: VersionSMPA -> VersionChat
 agentToChatVersion v
   | v < pqdrSMPAgentVersion = initialChatVersion
@@ -451,6 +456,8 @@ data ChatMsgEvent (e :: MsgEncoding) where
   XGrpDel :: ChatMsgEvent 'Json
   XGrpInfo :: GroupProfile -> ChatMsgEvent 'Json
   XGrpPrefs :: GroupPreferences -> ChatMsgEvent 'Json
+  -- Governance: lock/unlock commenting on a specific channel post, addressed by its SharedMsgId.
+  XGrpCommentsDisabled :: {parentMsgId :: SharedMsgId, disabled :: Bool} -> ChatMsgEvent 'Json
   XGrpDirectInv :: ConnReqInvitation -> Maybe MsgContent -> Maybe MsgScope -> ChatMsgEvent 'Json
   XGrpMsgForward :: GrpMsgForward -> ChatMessage 'Json -> ChatMsgEvent 'Json
   XInfoProbe :: Probe -> ChatMsgEvent 'Json
@@ -631,24 +638,58 @@ instance FromField MsgContentTag where fromField = fromTextField_ $ eitherToMayb
 
 instance ToField MsgContentTag where toField = toField . safeDecodeUtf8 . strEncode
 
-data MsgContainer
-  = MCSimple ExtMsgContent
-  | MCQuote QuotedMsg ExtMsgContent
-  | MCComment MsgRef ExtMsgContent
-  | MCForward ExtMsgContent
+-- Wire JSON 1:1 with parsed form. The three discriminator fields `quote`, `parent`,
+-- and `forward` are independent and may co-occur (e.g. a comment that quotes another
+-- comment carries both `parent` and `quote`). `forward` is a plain Bool (not Maybe Bool)
+-- to match the existing wire format exactly: the serializer only emits `"forward": true`
+-- and the parser treats absent/false as "not a forward".
+data MsgContainer = MsgContainer
+  { content :: MsgContent,
+    -- the key used in mentions is a locally (per message) unique display name of member.
+    -- Suffixes _1, _2 should be appended to make names locally unique.
+    -- It should be done in the UI, as they will be part of the text, and validated in the API.
+    mentions :: Map MemberName MsgMention,
+    file :: Maybe FileInvitation,
+    ttl :: Maybe Int,
+    live :: Maybe Bool,
+    scope :: Maybe MsgScope,
+    asGroup :: Maybe Bool,
+    quote :: Maybe QuotedMsg,
+    parent :: Maybe MsgRef,
+    forward :: Bool
+  }
   deriving (Eq, Show)
 
-mcExtMsgContent :: MsgContainer -> ExtMsgContent
-mcExtMsgContent = \case
-  MCSimple c -> c
-  MCQuote _ c -> c
-  MCComment _ c -> c
-  MCForward c -> c
+-- Base value used by the smart constructors and for record-update on send sites.
+mc :: MsgContainer
+mc =
+  MsgContainer
+    { content = MCText "",
+      mentions = M.empty,
+      file = Nothing,
+      ttl = Nothing,
+      live = Nothing,
+      scope = Nothing,
+      asGroup = Nothing,
+      quote = Nothing,
+      parent = Nothing,
+      forward = False
+    }
+
+mcSimple :: MsgContent -> MsgContainer
+mcSimple c = mc {content = c}
+
+mcQuote :: QuotedMsg -> MsgContent -> MsgContainer
+mcQuote q c = mc {content = c, quote = Just q}
+
+mcComment :: MsgRef -> MsgContent -> MsgContainer
+mcComment p c = mc {content = c, parent = Just p}
+
+mcForward :: MsgContent -> MsgContainer
+mcForward c = mc {content = c, forward = True}
 
 isMCForward :: MsgContainer -> Bool
-isMCForward = \case
-  MCForward _ -> True
-  _ -> False
+isMCForward MsgContainer {forward} = forward
 
 data MsgContent
   = MCText {text :: Text}
@@ -722,20 +763,6 @@ msgContentTag = \case
   MCChat {} -> MCChat_
   MCUnknown {tag} -> MCUnknown_ tag
 
-data ExtMsgContent = ExtMsgContent
-  { content :: MsgContent,
-    -- the key used in mentions is a locally (per message) unique display name of member.
-    -- Suffixes _1, _2 should be appended to make names locally unique.
-    -- It should be done in the UI, as they will be part of the text, and validated in the API.
-    mentions :: Map MemberName MsgMention,
-    file :: Maybe FileInvitation,
-    ttl :: Maybe Int,
-    live :: Maybe Bool,
-    scope :: Maybe MsgScope,
-    asGroup :: Maybe Bool
-  }
-  deriving (Eq, Show)
-
 data MsgMention = MsgMention {memberId :: MemberId}
   deriving (Eq, Show)
 
@@ -851,9 +878,6 @@ parseMsgContainer v =
       asGroup <- v .:? "asGroup"
       pure ExtMsgContent {content, mentions, file, ttl, live, scope, asGroup}
 
-extMsgContent :: MsgContent -> Maybe FileInvitation -> ExtMsgContent
-extMsgContent mc file = ExtMsgContent mc M.empty file Nothing Nothing Nothing Nothing
-
 justTrue :: Bool -> Maybe Bool
 justTrue True = Just True
 justTrue False = Nothing
@@ -980,6 +1004,7 @@ data CMEventTag (e :: MsgEncoding) where
   XGrpDel_ :: CMEventTag 'Json
   XGrpInfo_ :: CMEventTag 'Json
   XGrpPrefs_ :: CMEventTag 'Json
+  XGrpCommentsDisabled_ :: CMEventTag 'Json
   XGrpDirectInv_ :: CMEventTag 'Json
   XGrpMsgForward_ :: CMEventTag 'Json
   XInfoProbe_ :: CMEventTag 'Json
@@ -1037,6 +1062,7 @@ instance MsgEncodingI e => StrEncoding (CMEventTag e) where
     XGrpDel_ -> "x.grp.del"
     XGrpInfo_ -> "x.grp.info"
     XGrpPrefs_ -> "x.grp.prefs"
+    XGrpCommentsDisabled_ -> "x.grp.cmnts.dsbl"
     XGrpDirectInv_ -> "x.grp.direct.inv"
     XGrpMsgForward_ -> "x.grp.msg.forward"
     XInfoProbe_ -> "x.info.probe"
@@ -1095,6 +1121,7 @@ instance StrEncoding ACMEventTag where
         "x.grp.del" -> XGrpDel_
         "x.grp.info" -> XGrpInfo_
         "x.grp.prefs" -> XGrpPrefs_
+        "x.grp.cmnts.dsbl" -> XGrpCommentsDisabled_
         "x.grp.direct.inv" -> XGrpDirectInv_
         "x.grp.msg.forward" -> XGrpMsgForward_
         "x.info.probe" -> XInfoProbe_
@@ -1149,6 +1176,7 @@ toCMEventTag msg = case msg of
   XGrpDel -> XGrpDel_
   XGrpInfo _ -> XGrpInfo_
   XGrpPrefs _ -> XGrpPrefs_
+  XGrpCommentsDisabled {} -> XGrpCommentsDisabled_
   XGrpDirectInv {} -> XGrpDirectInv_
   XGrpMsgForward {} -> XGrpMsgForward_
   XInfoProbe _ -> XInfoProbe_

src/Simplex/Chat/Store/Postgres/Migrations.hs

@@ -28,6 +28,7 @@ import Simplex.Chat.Store.Postgres.Migrations.M20260108_chat_indices
 import Simplex.Chat.Store.Postgres.Migrations.M20260122_has_link
 import Simplex.Chat.Store.Postgres.Migrations.M20260222_chat_relays
 import Simplex.Chat.Store.Postgres.Migrations.M20260403_item_viewed
+import Simplex.Chat.Store.Postgres.Migrations.M20260407_channel_comments
 import Simplex.Messaging.Agent.Store.Shared (Migration (..))
 
 schemaMigrations :: [(String, Text, Maybe Text)]
@@ -55,7 +56,8 @@ schemaMigrations =
     ("20260108_chat_indices", m20260108_chat_indices, Just down_m20260108_chat_indices),
     ("20260122_has_link", m20260122_has_link, Just down_m20260122_has_link),
     ("20260222_chat_relays", m20260222_chat_relays, Just down_m20260222_chat_relays),
-    ("20260403_item_viewed", m20260403_item_viewed, Just down_m20260403_item_viewed)
+    ("20260403_item_viewed", m20260403_item_viewed, Just down_m20260403_item_viewed),
+    ("20260407_channel_comments", m20260407_channel_comments, Just down_m20260407_channel_comments)
   ]
 
 -- | The list of migrations in ascending order by date

src/Simplex/Chat/Store/Postgres/Migrations/M20260407_channel_comments.hs

@@ -0,0 +1,30 @@
+{-# LANGUAGE OverloadedStrings #-}
+{-# LANGUAGE QuasiQuotes #-}
+
+module Simplex.Chat.Store.Postgres.Migrations.M20260407_channel_comments where
+
+import Data.Text (Text)
+import Text.RawString.QQ (r)
+
+m20260407_channel_comments :: Text
+m20260407_channel_comments =
+  [r|
+ALTER TABLE chat_items ADD COLUMN parent_chat_item_id BIGINT REFERENCES chat_items ON DELETE CASCADE;
+ALTER TABLE chat_items ADD COLUMN comments_total INTEGER NOT NULL DEFAULT 0;
+ALTER TABLE chat_items ADD COLUMN comments_disabled SMALLINT NOT NULL DEFAULT 0;
+
+CREATE INDEX idx_chat_items_parent_chat_item_id ON chat_items(parent_chat_item_id);
+CREATE INDEX idx_chat_items_parent_item_ts ON chat_items(user_id, group_id, parent_chat_item_id, item_ts);
+|]
+
+down_m20260407_channel_comments :: Text
+down_m20260407_channel_comments =
+  [r|
+DROP INDEX idx_chat_items_parent_chat_item_id;
+DROP INDEX idx_chat_items_parent_item_ts;
+ALTER TABLE chat_items DROP COLUMN parent_chat_item_id;
+ALTER TABLE chat_items DROP COLUMN comments_total;
+ALTER TABLE chat_items DROP COLUMN comments_disabled;
+
+UPDATE group_members SET member_role = 'observer' WHERE member_role = 'commenter';
+|]

src/Simplex/Chat/Store/SQLite/Migrations.hs

@@ -151,6 +151,7 @@ import Simplex.Chat.Store.SQLite.Migrations.M20260108_chat_indices
 import Simplex.Chat.Store.SQLite.Migrations.M20260122_has_link
 import Simplex.Chat.Store.SQLite.Migrations.M20260222_chat_relays
 import Simplex.Chat.Store.SQLite.Migrations.M20260403_item_viewed
+import Simplex.Chat.Store.SQLite.Migrations.M20260407_channel_comments
 import Simplex.Messaging.Agent.Store.Shared (Migration (..))
 
 schemaMigrations :: [(String, Query, Maybe Query)]
@@ -301,7 +302,8 @@ schemaMigrations =
     ("20260108_chat_indices", m20260108_chat_indices, Just down_m20260108_chat_indices),
     ("20260122_has_link", m20260122_has_link, Just down_m20260122_has_link),
     ("20260222_chat_relays", m20260222_chat_relays, Just down_m20260222_chat_relays),
-    ("20260403_item_viewed", m20260403_item_viewed, Just down_m20260403_item_viewed)
+    ("20260403_item_viewed", m20260403_item_viewed, Just down_m20260403_item_viewed),
+    ("20260407_channel_comments", m20260407_channel_comments, Just down_m20260407_channel_comments)
   ]
 
 -- | The list of migrations in ascending order by date

src/Simplex/Chat/Store/SQLite/Migrations/M20260407_channel_comments.hs

@@ -0,0 +1,29 @@
+{-# LANGUAGE QuasiQuotes #-}
+
+module Simplex.Chat.Store.SQLite.Migrations.M20260407_channel_comments where
+
+import Database.SQLite.Simple (Query)
+import Database.SQLite.Simple.QQ (sql)
+
+m20260407_channel_comments :: Query
+m20260407_channel_comments =
+  [sql|
+ALTER TABLE chat_items ADD COLUMN parent_chat_item_id INTEGER REFERENCES chat_items ON DELETE CASCADE;
+ALTER TABLE chat_items ADD COLUMN comments_total INTEGER NOT NULL DEFAULT 0;
+ALTER TABLE chat_items ADD COLUMN comments_disabled INTEGER NOT NULL DEFAULT 0;
+
+CREATE INDEX idx_chat_items_parent_chat_item_id ON chat_items(parent_chat_item_id);
+CREATE INDEX idx_chat_items_parent_item_ts ON chat_items(user_id, group_id, parent_chat_item_id, item_ts);
+|]
+
+down_m20260407_channel_comments :: Query
+down_m20260407_channel_comments =
+  [sql|
+DROP INDEX idx_chat_items_parent_chat_item_id;
+DROP INDEX idx_chat_items_parent_item_ts;
+ALTER TABLE chat_items DROP COLUMN parent_chat_item_id;
+ALTER TABLE chat_items DROP COLUMN comments_total;
+ALTER TABLE chat_items DROP COLUMN comments_disabled;
+
+UPDATE group_members SET member_role = 'observer' WHERE member_role = 'commenter';
+|]

src/Simplex/Chat/Types/Preferences.hs

@@ -177,6 +177,7 @@ data GroupFeature
   | GFReports
   | GFHistory
   | GFSessions
+  | GFComments
   deriving (Show)
 
 data SGroupFeature (f :: GroupFeature) where
@@ -190,6 +191,7 @@ data SGroupFeature (f :: GroupFeature) where
   SGFReports :: SGroupFeature 'GFReports
   SGFHistory :: SGroupFeature 'GFHistory
   SGFSessions :: SGroupFeature 'GFSessions
+  SGFComments :: SGroupFeature 'GFComments
 
 deriving instance Show (SGroupFeature f)
 
@@ -217,6 +219,7 @@ groupFeatureNameText = \case
   GFReports -> "Member reports"
   GFHistory -> "Recent history"
   GFSessions -> "Chat sessions"
+  GFComments -> "Comments"
 
 groupFeatureNameText' :: SGroupFeature f -> Text
 groupFeatureNameText' = groupFeatureNameText . toGroupFeature
@@ -240,11 +243,12 @@ allGroupFeatures =
     AGF SGFFiles,
     AGF SGFSimplexLinks,
     AGF SGFReports,
-    AGF SGFHistory
+    AGF SGFHistory,
+    AGF SGFComments
   ]
 
 groupPrefSel :: SGroupFeature f -> GroupPreferences -> Maybe (GroupFeaturePreference f)
-groupPrefSel f GroupPreferences {timedMessages, directMessages, fullDelete, reactions, voice, files, simplexLinks, reports, history, sessions} = case f of
+groupPrefSel f GroupPreferences {timedMessages, directMessages, fullDelete, reactions, voice, files, simplexLinks, reports, history, sessions, comments} = case f of
   SGFTimedMessages -> timedMessages
   SGFDirectMessages -> directMessages
   SGFFullDelete -> fullDelete
@@ -255,6 +259,7 @@ groupPrefSel f GroupPreferences {timedMessages, directMessages, fullDelete, reac
   SGFReports -> reports
   SGFHistory -> history
   SGFSessions -> sessions
+  SGFComments -> comments
 
 toGroupFeature :: SGroupFeature f -> GroupFeature
 toGroupFeature = \case
@@ -268,6 +273,7 @@ toGroupFeature = \case
   SGFReports -> GFReports
   SGFHistory -> GFHistory
   SGFSessions -> GFSessions
+  SGFComments -> GFComments
 
 class GroupPreferenceI p where
   getGroupPreference :: SGroupFeature f -> p -> GroupFeaturePreference f
@@ -279,7 +285,7 @@ instance GroupPreferenceI (Maybe GroupPreferences) where
   getGroupPreference pt prefs = fromMaybe (getGroupPreference pt defaultGroupPrefs) (groupPrefSel pt =<< prefs)
 
 instance GroupPreferenceI FullGroupPreferences where
-  getGroupPreference f FullGroupPreferences {timedMessages, directMessages, fullDelete, reactions, voice, files, simplexLinks, reports, history, sessions} = case f of
+  getGroupPreference f FullGroupPreferences {timedMessages, directMessages, fullDelete, reactions, voice, files, simplexLinks, reports, history, sessions, comments} = case f of
     SGFTimedMessages -> timedMessages
     SGFDirectMessages -> directMessages
     SGFFullDelete -> fullDelete
@@ -290,6 +296,7 @@ instance GroupPreferenceI FullGroupPreferences where
     SGFReports -> reports
     SGFHistory -> history
     SGFSessions -> sessions
+    SGFComments -> comments
   {-# INLINE getGroupPreference #-}
 
 -- collection of optional group preferences
@@ -304,6 +311,7 @@ data GroupPreferences = GroupPreferences
     reports :: Maybe ReportsGroupPreference,
     history :: Maybe HistoryGroupPreference,
     sessions :: Maybe SessionsGroupPreference,
+    comments :: Maybe CommentsGroupPreference,
     commands :: Maybe [ChatBotCommand]
   }
   deriving (Eq, Show)
@@ -354,6 +362,7 @@ setGroupPreference_ f pref prefs =
     SGFReports -> prefs {reports = pref}
     SGFHistory -> prefs {history = pref}
     SGFSessions -> prefs {sessions = pref}
+    SGFComments -> prefs {comments = pref}
 
 setGroupTimedMessagesPreference :: TimedMessagesGroupPreference -> Maybe GroupPreferences -> GroupPreferences
 setGroupTimedMessagesPreference pref prefs_ =
@@ -396,6 +405,7 @@ data FullGroupPreferences = FullGroupPreferences
     reports :: ReportsGroupPreference,
     history :: HistoryGroupPreference,
     sessions :: SessionsGroupPreference,
+    comments :: CommentsGroupPreference,
     commands :: ListDef ChatBotCommand
   }
   deriving (Eq, Show)
@@ -465,11 +475,12 @@ defaultGroupPrefs =
       reports = ReportsGroupPreference {enable = FEOn},
       history = HistoryGroupPreference {enable = FEOff},
       sessions = SessionsGroupPreference {enable = FEOff, role = Nothing},
+      comments = CommentsGroupPreference {enable = FEOff, closeAfter = Nothing},
       commands = ListDef []
     }
 
 emptyGroupPrefs :: GroupPreferences
-emptyGroupPrefs = GroupPreferences Nothing Nothing Nothing Nothing Nothing Nothing Nothing Nothing Nothing Nothing Nothing
+emptyGroupPrefs = GroupPreferences Nothing Nothing Nothing Nothing Nothing Nothing Nothing Nothing Nothing Nothing Nothing Nothing
 
 businessGroupPrefs :: Preferences -> GroupPreferences
 businessGroupPrefs Preferences {timedMessages, fullDelete, reactions, voice, files, sessions, commands} =
@@ -501,6 +512,7 @@ defaultBusinessGroupPrefs =
       reports = Just $ ReportsGroupPreference FEOff,
       history = Just $ HistoryGroupPreference FEOn,
       sessions = Just $ SessionsGroupPreference FEOn Nothing,
+      comments = Just $ CommentsGroupPreference FEOff Nothing,
       commands = Nothing
     }
 
@@ -635,6 +647,14 @@ data SessionsGroupPreference = SessionsGroupPreference
   {enable :: GroupFeatureEnabled, role :: Maybe GroupMemberRole}
   deriving (Eq, Show)
 
+-- Channel comments. `closeAfter` is the duration in seconds since post creation
+-- after which a channel post stops accepting new comments; `Nothing` means never close.
+data CommentsGroupPreference = CommentsGroupPreference
+  { enable :: GroupFeatureEnabled,
+    closeAfter :: Maybe Int
+  }
+  deriving (Eq, Show)
+
 class (Eq (GroupFeaturePreference f), HasField "enable" (GroupFeaturePreference f) GroupFeatureEnabled) => GroupFeatureI f where
   type GroupFeaturePreference (f :: GroupFeature) = p | p -> f
   sGroupFeature :: SGroupFeature f
@@ -678,6 +698,9 @@ instance HasField "enable" HistoryGroupPreference GroupFeatureEnabled where
 instance HasField "enable" SessionsGroupPreference GroupFeatureEnabled where
   hasField p@SessionsGroupPreference {enable} = (\e -> p {enable = e}, enable)
 
+instance HasField "enable" CommentsGroupPreference GroupFeatureEnabled where
+  hasField p@CommentsGroupPreference {enable} = (\e -> p {enable = e}, enable)
+
 instance GroupFeatureI 'GFTimedMessages where
   type GroupFeaturePreference 'GFTimedMessages = TimedMessagesGroupPreference
   sGroupFeature = SGFTimedMessages
@@ -738,6 +761,12 @@ instance GroupFeatureI 'GFSessions where
   groupPrefParam _ = Nothing
   groupPrefRole SessionsGroupPreference {role} = role
 
+instance GroupFeatureI 'GFComments where
+  type GroupFeaturePreference 'GFComments = CommentsGroupPreference
+  sGroupFeature = SGFComments
+  groupPrefParam CommentsGroupPreference {closeAfter} = closeAfter
+  groupPrefRole _ = Nothing
+
 instance GroupFeatureNoRoleI 'GFTimedMessages
 
 instance GroupFeatureNoRoleI 'GFFullDelete
@@ -748,6 +777,8 @@ instance GroupFeatureNoRoleI 'GFReports
 
 instance GroupFeatureNoRoleI 'GFHistory
 
+instance GroupFeatureNoRoleI 'GFComments
+
 instance HasField "role" DirectMessagesGroupPreference (Maybe GroupMemberRole) where
   hasField p@DirectMessagesGroupPreference {role} = (\r -> p {role = r}, role)
 
@@ -788,6 +819,7 @@ groupPrefStateText feature pref param role =
 groupParamText_ :: GroupFeature -> Maybe Int -> Text
 groupParamText_ feature param = case feature of
   GFTimedMessages -> maybe "" (\p -> " (" <> timedTTLText p <> ")") param
+  GFComments -> maybe "" (\p -> " (close after " <> timedTTLText p <> ")") param
   _ -> ""
 
 groupPreferenceText :: forall f. GroupFeatureI f => GroupFeaturePreference f -> Text
@@ -938,6 +970,7 @@ mergeGroupPreferences groupPreferences =
       reports = pref SGFReports,
       history = pref SGFHistory,
       sessions = pref SGFSessions,
+      comments = pref SGFComments,
       commands = ListDef $ fromMaybe [] $ groupPreferences >>= commands_
     }
   where
@@ -957,6 +990,7 @@ toGroupPreferences groupPreferences@FullGroupPreferences {commands = ListDef cmd
       reports = pref SGFReports,
       history = pref SGFHistory,
       sessions = pref SGFSessions,
+      comments = pref SGFComments,
       commands = Just cmds
     }
   where
@@ -1091,6 +1125,12 @@ instance FromJSON SessionsGroupPreference where
   parseJSON v = $(J.mkParseJSON defaultJSON ''SessionsGroupPreference) v
   omittedField = Just SessionsGroupPreference {enable = FEOff, role = Nothing}
 
+$(J.deriveToJSON defaultJSON ''CommentsGroupPreference)
+
+instance FromJSON CommentsGroupPreference where
+  parseJSON v = $(J.mkParseJSON defaultJSON ''CommentsGroupPreference) v
+  omittedField = Just CommentsGroupPreference {enable = FEOff, closeAfter = Nothing}
+
 $(J.deriveJSON defaultJSON ''GroupPreferences)
 
 instance ToField GroupPreferences where

src/Simplex/Chat/Types/Shared.hs

@@ -19,6 +19,7 @@ data GroupMemberRole
   = GRUnknown Text -- unknown role from a newer client
   | GRRelay -- chat relay: forwards messages, can't send its own messages
   | GRObserver -- connects to all group members and receives all messages, can't send messages
+  | GRCommenter -- + can comment on channel posts, can't send messages to the main channel
   | GRAuthor -- reserved, unused
   | GRMember -- + can send messages to all group members
   | GRModerator -- + moderate messages and block members (excl. Admins and Owners)
@@ -37,6 +38,7 @@ instance TextEncoding GroupMemberRole where
     GRModerator -> "moderator"
     GRMember -> "member"
     GRAuthor -> "author"
+    GRCommenter -> "commenter"
     GRObserver -> "observer"
     GRRelay -> "relay"
     GRUnknown t -> t
@@ -46,6 +48,7 @@ instance TextEncoding GroupMemberRole where
     "moderator" -> GRModerator
     "member" -> GRMember
     "author" -> GRAuthor
+    "commenter" -> GRCommenter
     "observer" -> GRObserver
     "relay" -> GRRelay
     t -> GRUnknown t