feat(llc): mark unread feature - core (#1880)

* mark message as unread feature

* jump to last read message

* changelog

* error handling

* tweak

* changelog

* fixed changelog

packages/stream_chat/CHANGELOG.md

@@ -1,3 +1,8 @@
+## Unreleased
+
+✅ Added
+- Added `markUnread` method to `Channel` that marks messages from the provided message id onwards as unread
+
 ## 7.1.0
 
 🐞 Fixed

packages/stream_chat/lib/src/client/channel.dart

@@ -1341,8 +1341,8 @@ class Channel {
 
   /// Mark all messages as read.
   ///
-  /// Optionally provide a [messageId] if you want to mark a
-  /// particular message as read.
+  /// Optionally provide a [messageId] if you want to mark channel as
+  /// read from a particular message onwards.
   Future<EmptyResponse> markRead({String? messageId}) async {
     _checkInitialized();
     client.state.totalUnreadCount =
@@ -1351,6 +1351,37 @@ class Channel {
     return _client.markChannelRead(id!, type, messageId: messageId);
   }
 
+  /// Mark message as unread.
+  ///
+  /// You have to provide a [messageId] from which you want the channel
+  /// to be marked as unread.
+  Future<EmptyResponse> markUnread(String messageId) async {
+    _checkInitialized();
+
+    final response = await _client.markChannelUnread(id!, type, messageId);
+
+    final lastReadDate = state!.currentUserRead?.lastRead;
+    final currentUnread = state!.currentUserRead?.unreadMessages ?? 0;
+
+    final messagesFromMarked = state!.messages
+        .where((message) => message.user?.id != client.state.currentUser?.id)
+        .skipWhile((message) => message.id != messageId)
+        .toList();
+    final channelUnreadCount = max(currentUnread, messagesFromMarked.length);
+    final additionalTotalUnreadCount = currentUnread > 0
+        ? messagesFromMarked
+            .takeWhile((message) =>
+                lastReadDate == null ||
+                message.createdAt.isBefore(lastReadDate))
+            .length
+        : messagesFromMarked.length;
+
+    client.state.totalUnreadCount += additionalTotalUnreadCount;
+    state!.unreadCount = channelUnreadCount;
+
+    return response;
+  }
+
   void _initState(ChannelState channelState) {
     state = ChannelClientState(this, channelState);
 
@@ -1761,6 +1792,8 @@ class ChannelClientState {
 
     _listenReadEvents();
 
+    _listenUnreadEvents();
+
     _listenChannelTruncated();
 
     _listenChannelUpdated();
@@ -2242,6 +2275,31 @@ class ChannelClientState {
     return updateMessage(message);
   }
 
+  void _listenUnreadEvents() {
+    if (_channelState.channel?.config.readEvents == false) {
+      return;
+    }
+
+    _subscriptions.add(
+        _channel.on(EventType.notificationMarkUnread).listen((Event event) {
+      if (event.user?.id != _channel._client.state.currentUser!.id) return;
+
+      final readList = <Read>[
+        ..._channelState.read?.where((r) => r.user.id != event.user!.id) ??
+            <Read>[],
+        if (event.lastReadAt != null)
+          Read(
+            user: event.user!,
+            lastRead: event.lastReadAt!,
+            unreadMessages: event.unreadMessages ?? 0,
+            lastReadMessageId: event.lastReadMessageId,
+          )
+      ];
+
+      _channelState = _channelState.copyWith(read: readList);
+    }));
+  }
+
   void _listenReadEvents() {
     if (_channelState.channel?.config.readEvents == false) {
       return;
@@ -2262,6 +2320,7 @@ class ChannelClientState {
             readList.add(Read(
               user: event.user!,
               lastRead: event.createdAt,
+              lastReadMessageId: messages.lastOrNull?.id,
             ));
             _channelState = _channelState.copyWith(read: readList);
           }

packages/stream_chat/lib/src/client/client.dart

@@ -1184,6 +1184,20 @@ class StreamChatClient {
         messageId: messageId,
       );
 
+  /// Mark [channelId] of type [channelType] all messages as read
+  /// Optionally provide a [messageId] if you want to mark a
+  /// particular message as read
+  Future<EmptyResponse> markChannelUnread(
+    String channelId,
+    String channelType,
+    String messageId,
+  ) =>
+      _chatApi.channel.markUnread(
+        channelId,
+        channelType,
+        messageId,
+      );
+
   /// Update or Create the given user object.
   Future<UpdateUsersResponse> updateUser(User user) => updateUsers([user]);
 

packages/stream_chat/lib/src/core/api/channel_api.dart

@@ -310,8 +310,8 @@ class ChannelApi {
   }
 
   /// Mark [channelId] of type [channelType] all messages as read
-  /// Optionally provide a [messageId] if you want to mark a
-  /// particular message as read
+  /// Optionally provide a [messageId] if you want to mark channel as
+  /// read from particular message onwards
   Future<EmptyResponse> markRead(
     String channelId,
     String channelType, {
@@ -324,6 +324,19 @@ class ChannelApi {
     return EmptyResponse.fromJson(response.data);
   }
 
+  /// Marks all messages from the provided [messageId] onwards as unread
+  Future<EmptyResponse> markUnread(
+    String channelId,
+    String channelType,
+    String? messageId,
+  ) async {
+    final response = await _client.post(
+      '${_getChannelUrl(channelId, channelType)}/unread',
+      data: {'message_id': messageId},
+    );
+    return EmptyResponse.fromJson(response.data);
+  }
+
   /// Stop watching the channel
   Future<EmptyResponse> stopWatching(
     String channelId,

packages/stream_chat/lib/src/core/models/event.dart

@@ -97,6 +97,24 @@ class Event {
   /// Map of custom channel extraData
   final Map<String, Object?> extraData;
 
+  /// Create date of the last read message (notification.mark_unread)
+  @JsonKey(includeToJson: false, includeFromJson: false)
+  DateTime? get lastReadAt {
+    if (extraData.containsKey('last_read_at')) {
+      return DateTime.parse(extraData['last_read_at']! as String);
+    }
+
+    return null;
+  }
+
+  /// The number of unread messages (notification.mark_unread)
+  @JsonKey(includeToJson: false, includeFromJson: false)
+  int? get unreadMessages => extraData['unread_messages'] as int?;
+
+  /// The id of the last read message (notification.mark_read)
+  @JsonKey(includeToJson: false, includeFromJson: false)
+  String? get lastReadMessageId => extraData['last_read_message_id'] as String?;
+
   /// Known top level fields.
   /// Useful for [Serializer] methods.
   static final topLevelFields = [

packages/stream_chat/lib/src/core/models/read.dart

@@ -11,6 +11,7 @@ class Read extends Equatable {
   const Read({
     required this.lastRead,
     required this.user,
+    this.lastReadMessageId,
     this.unreadMessages = 0,
   });
 
@@ -26,24 +27,30 @@ class Read extends Equatable {
   /// Number of unread messages
   final int unreadMessages;
 
+  /// The id of the last read message
+  final String? lastReadMessageId;
+
   /// Serialize to json
   Map<String, dynamic> toJson() => _$ReadToJson(this);
 
   /// Creates a copy of [Read] with specified attributes overridden.
   Read copyWith({
     DateTime? lastRead,
+    String? lastReadMessageId,
     User? user,
     int? unreadMessages,
   }) =>
       Read(
         lastRead: lastRead ?? this.lastRead,
+        lastReadMessageId: lastReadMessageId ?? this.lastReadMessageId,
         user: user ?? this.user,
         unreadMessages: unreadMessages ?? this.unreadMessages,
       );
 
   @override
   List<Object?> get props => [
         lastRead,
+        lastReadMessageId,
         user,
         unreadMessages,
       ];

packages/stream_chat/lib/src/event_type.dart

@@ -21,6 +21,9 @@ class EventType {
   /// Event sent when the unread count changes
   static const String notificationMarkRead = 'notification.mark_read';
 
+  /// Event sent when the unread count changes
+  static const String notificationMarkUnread = 'notification.mark_unread';
+
   /// Event sent when deleting a new message
   static const String messageDeleted = 'message.deleted';
 

packages/stream_chat/test/fixtures/read.json

@@ -3,5 +3,6 @@
     "id": "bbb19d9a-ee50-45bc-84e5-0584e79d0c9e"
   },
   "last_read": "2020-01-28T22:17:30.966485504Z",
-  "unread_messages": 10
+  "unread_messages": 10,
+  "last_read_message_id": "8cc1301d-2d47-4305-945a-cd8e19b736d6"
 }

packages/stream_chat/test/src/core/api/channel_api_test.dart

@@ -33,6 +33,7 @@ void main() {
       (index) => Read(
         lastRead: DateTime.now(),
         user: User(id: 'test-user-id-$index'),
+        lastReadMessageId: 'last-message-id-$index',
       ),
     );
     final watchers = List.generate(