feat(llc): add pending messages for channels

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

@@ -3340,6 +3340,7 @@ class ChannelClientState {
       read: newReads,
       draft: updatedState.draft,
       pinnedMessages: updatedState.pinnedMessages,
+      pendingMessages: updatedState.pendingMessages,
       pushPreferences: updatedState.pushPreferences,
     );
   }

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

@@ -26,6 +26,7 @@ class ChannelConfig {
     this.urlEnrichment = false,
     this.skipLastMsgUpdateForSystemMsgs = false,
     this.userMessageReminders = false,
+    this.markMessagesPending = false,
   })  : createdAt = createdAt ?? DateTime.now(),
         updatedAt = updatedAt ?? DateTime.now();
 
@@ -91,6 +92,9 @@ class ChannelConfig {
   /// True if the user can set reminders for messages in this channel.
   final bool userMessageReminders;
 
+  /// Whether pending messages are enabled for this channel.
+  final bool markMessagesPending;
+
   /// Serialize to json
   Map<String, dynamic> toJson() => _$ChannelConfigToJson(this);
 }

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

@@ -30,6 +30,7 @@ class ChannelState implements ComparableFieldProvider {
     this.read,
     this.membership,
     this.draft,
+    this.pendingMessages,
     this.pushPreferences,
   });
 
@@ -60,6 +61,28 @@ class ChannelState implements ComparableFieldProvider {
   /// The draft message for this channel if it exists.
   final Draft? draft;
 
+  static Object? _pendingMessagesReadValue(
+    Map<Object?, Object?> json,
+    String key,
+  ) {
+    final pendingMessageResponse = json[key];
+    if (pendingMessageResponse is! List<Object?>) return null;
+
+    final value = pendingMessageResponse.map((it) {
+      if (it is! Map<String, Object?>) return null;
+      return it['message'];
+    }).nonNulls;
+
+    if (value.isEmpty) return null;
+    return value.toList(growable: false);
+  }
+
+  /// List of messages pending for moderation on this channel.
+  ///
+  /// These messages are only visible to the author until they are approved.
+  @JsonKey(readValue: _pendingMessagesReadValue)
+  final List<Message>? pendingMessages;
+
   /// The push preferences for this channel if it exists.
   final ChannelPushPreference? pushPreferences;
 
@@ -81,6 +104,7 @@ class ChannelState implements ComparableFieldProvider {
     List<Read>? read,
     Member? membership,
     Object? draft = _nullConst,
+    List<Message>? pendingMessages,
     ChannelPushPreference? pushPreferences,
   }) =>
       ChannelState(
@@ -93,6 +117,7 @@ class ChannelState implements ComparableFieldProvider {
         read: read ?? this.read,
         membership: membership ?? this.membership,
         draft: draft == _nullConst ? this.draft : draft as Draft?,
+        pendingMessages: pendingMessages ?? this.pendingMessages,
         pushPreferences: pushPreferences ?? this.pushPreferences,
       );
 

packages/stream_chat_flutter/lib/src/message_list_view/message_list_view.dart

@@ -1478,19 +1478,44 @@ class _StreamMessageListViewState extends State<StreamMessageListView> {
     if (_upToDate && lastFullyVisibleMessageChanged) {
       _lastFullyVisibleMessage = newLastFullyVisibleMessage;
 
-      if (streamChannel?.channel case final channel?) {
-        final hasUnread = (channel.state?.unreadCount ?? 0) > 0;
-        final allowMarkRead = channel.config?.readEvents == true;
-        final canMarkReadAtBottom = widget.markReadWhenAtTheBottom;
-
-        // Mark messages as read if it's allowed.
-        if (hasUnread && allowMarkRead && canMarkReadAtBottom) {
-          return _markMessagesAsRead().ignore();
-        }
-      }
+      // Mark messages as read if needed.
+      _maybeMarkMessagesAsRead().ignore();
     }
   }
 
+  // Marks messages as read if the conditions are met.
+  //
+  // The conditions are:
+  // 1. There are unread messages.
+  // 2. Marking messages as read is allowed in the channel config.
+  // 3. Marking messages as read when at the bottom is enabled.
+  // 4. Mark messages as pending is not enabled in the channel config.
+  //
+  // If any of the conditions are not met, the function returns early.
+  // Otherwise, it calls the _markMessagesAsRead function to mark the messages
+  // as read.
+  Future<void> _maybeMarkMessagesAsRead() async {
+    final channel = streamChannel?.channel;
+    if (channel == null) return;
+
+    final hasUnread = (channel.state?.unreadCount ?? 0) > 0;
+    if (!hasUnread) return;
+
+    final allowMarkRead = channel.config?.readEvents == true;
+    if (!allowMarkRead) return;
+
+    // When markMessagesPending is enabled, messages are held for moderation
+    // and should not be immediately marked as read.
+    final markPendingEnabled = channel.config?.markMessagesPending == true;
+    if (markPendingEnabled) return;
+
+    final canMarkReadAtBottom = widget.markReadWhenAtTheBottom;
+    if (!canMarkReadAtBottom) return;
+
+    // Mark messages as read if it's allowed.
+    return _markMessagesAsRead();
+  }
+
   void _getOnThreadTap() {
     if (widget.onThreadTap != null) {
       _onThreadTap = (Message message) {