Refactor unread message tracking and implement channel caching (#126)

* Refactor unread message tracking and implement channel caching

* formatted files

lib/connector/meshcore_connector.dart

@@ -24,6 +24,7 @@ import '../services/notification_service.dart';
 import '../storage/channel_message_store.dart';
 import '../storage/channel_order_store.dart';
 import '../storage/channel_settings_store.dart';
+import '../storage/channel_store.dart';
 import '../storage/contact_settings_store.dart';
 import '../storage/contact_store.dart';
 import '../storage/message_store.dart';
@@ -139,14 +140,15 @@ class MeshCoreConnector extends ChangeNotifier {
   final ChannelSettingsStore _channelSettingsStore = ChannelSettingsStore();
   final ContactSettingsStore _contactSettingsStore = ContactSettingsStore();
   final ContactStore _contactStore = ContactStore();
+  final ChannelStore _channelStore = ChannelStore();
   final UnreadStore _unreadStore = UnreadStore();
+  List<Channel> _cachedChannels = [];
   final Map<int, bool> _channelSmazEnabled = {};
   bool _lastSentWasCliCommand =
       false; // Track if last sent message was a CLI command
   final Map<String, bool> _contactSmazEnabled = {};
   final Set<String> _knownContactKeys = {};
-  final Map<String, int> _contactLastReadMs = {};
-  final Map<int, int> _channelLastReadMs = {};
+  final Map<String, int> _contactUnreadCount = {};
   bool _unreadStateLoaded = false;
   final Map<String, _RepeaterAckContext> _pendingRepeaterAcks = {};
   String? _activeContactKey;
@@ -321,17 +323,7 @@ class MeshCoreConnector extends ChangeNotifier {
   int getUnreadCountForContactKey(String contactKeyHex) {
     if (!_unreadStateLoaded) return 0;
     if (!_shouldTrackUnreadForContactKey(contactKeyHex)) return 0;
-    final messages = _conversations[contactKeyHex];
-    if (messages == null || messages.isEmpty) return 0;
-    final lastReadMs = _contactLastReadMs[contactKeyHex] ?? 0;
-    var count = 0;
-    for (final message in messages) {
-      if (message.isOutgoing || message.isCli) continue;
-      if (message.timestamp.millisecondsSinceEpoch > lastReadMs) {
-        count++;
-      }
-    }
-    return count;
+    return _contactUnreadCount[contactKeyHex] ?? 0;
   }
 
   int getUnreadCountForChannel(Channel channel) {
@@ -340,17 +332,7 @@ class MeshCoreConnector extends ChangeNotifier {
 
   int getUnreadCountForChannelIndex(int channelIndex) {
     if (!_unreadStateLoaded) return 0;
-    final messages = _channelMessages[channelIndex];
-    if (messages == null || messages.isEmpty) return 0;
-    final lastReadMs = _channelLastReadMs[channelIndex] ?? 0;
-    var count = 0;
-    for (final message in messages) {
-      if (message.isOutgoing) continue;
-      if (message.timestamp.millisecondsSinceEpoch > lastReadMs) {
-        count++;
-      }
-    }
-    return count;
+    return _findChannelByIndex(channelIndex)?.unreadCount ?? 0;
   }
 
   int getTotalUnreadCount() {
@@ -380,16 +362,17 @@ class MeshCoreConnector extends ChangeNotifier {
   }
 
   Future<void> loadUnreadState() async {
-    _contactLastReadMs
-      ..clear()
-      ..addAll(await _unreadStore.loadContactLastRead());
-    _channelLastReadMs
+    _contactUnreadCount
       ..clear()
-      ..addAll(await _unreadStore.loadChannelLastRead());
+      ..addAll(await _unreadStore.loadContactUnreadCount());
     _unreadStateLoaded = true;
     notifyListeners();
   }
 
+  Future<void> loadCachedChannels() async {
+    _cachedChannels = await _channelStore.loadChannels();
+  }
+
   void setActiveContact(String? contactKeyHex) {
     if (contactKeyHex != null &&
         !_shouldTrackUnreadForContactKey(contactKeyHex)) {
@@ -411,17 +394,36 @@ class MeshCoreConnector extends ChangeNotifier {
 
   void markContactRead(String contactKeyHex) {
     if (!_shouldTrackUnreadForContactKey(contactKeyHex)) return;
-    final markMs = _calculateReadTimestampMs(
-      _conversations[contactKeyHex]?.map((m) => m.timestamp),
-    );
-    _setContactLastReadMs(contactKeyHex, markMs);
+    final previousCount = _contactUnreadCount[contactKeyHex] ?? 0;
+    if (previousCount > 0) {
+      _contactUnreadCount[contactKeyHex] = 0;
+      _appDebugLogService?.info(
+        'Contact $contactKeyHex marked as read (was $previousCount unread)',
+        tag: 'Unread',
+      );
+      _unreadStore.saveContactUnreadCount(
+        Map<String, int>.from(_contactUnreadCount),
+      );
+      notifyListeners();
+    }
   }
 
   void markChannelRead(int channelIndex) {
-    final markMs = _calculateReadTimestampMs(
-      _channelMessages[channelIndex]?.map((m) => m.timestamp),
-    );
-    _setChannelLastReadMs(channelIndex, markMs);
+    final channel = _findChannelByIndex(channelIndex);
+    if (channel != null && channel.unreadCount > 0) {
+      final previousCount = channel.unreadCount;
+      channel.unreadCount = 0;
+      _appDebugLogService?.info(
+        'Channel ${channel.name.isNotEmpty ? channel.name : channelIndex} marked as read (was $previousCount unread)',
+        tag: 'Unread',
+      );
+      unawaited(
+        _channelStore.saveChannels(
+          _channels.isNotEmpty ? _channels : _cachedChannels,
+        ),
+      );
+      notifyListeners();
+    }
   }
 
   Future<void> setChannelSmazEnabled(int channelIndex, bool enabled) async {
@@ -788,6 +790,9 @@ class MeshCoreConnector extends ChangeNotifier {
 
       // Keep device clock aligned on every connection.
       await syncTime();
+
+      // Fetch channels so we can track unread counts for incoming messages
+      unawaited(getChannels());
     } catch (e) {
       debugPrint("Connection error: $e");
       await disconnect(manual: false);
@@ -1341,8 +1346,10 @@ class MeshCoreConnector extends ChangeNotifier {
     unawaited(_persistContacts());
     _conversations.remove(contact.publicKeyHex);
     _loadedConversationKeys.remove(contact.publicKeyHex);
-    _contactLastReadMs.remove(contact.publicKeyHex);
-    _unreadStore.saveContactLastRead(Map<String, int>.from(_contactLastReadMs));
+    _contactUnreadCount.remove(contact.publicKeyHex);
+    _unreadStore.saveContactUnreadCount(
+      Map<String, int>.from(_contactUnreadCount),
+    );
     _messageStore.clearMessages(contact.publicKeyHex);
     notifyListeners();
   }
@@ -1617,6 +1624,10 @@ class MeshCoreConnector extends ChangeNotifier {
 
     _cleanupChannelSync(completed: true);
 
+    // Cache channels for offline use
+    _cachedChannels = List<Channel>.from(_channels);
+    unawaited(_channelStore.saveChannels(_channels));
+
     // Apply ordering and notify UI
     _applyChannelOrder();
     notifyListeners();
@@ -1651,8 +1662,6 @@ class MeshCoreConnector extends ChangeNotifier {
 
     // Delete by setting empty name and zero PSK
     await sendFrame(buildSetChannelFrame(index, '', Uint8List(16)));
-    _channelLastReadMs.remove(index);
-    _unreadStore.saveChannelLastRead(Map<int, int>.from(_channelLastReadMs));
     // Clear stored messages for this channel
     await _channelMessageStore.clearChannelMessages(index);
     // Clear in-memory messages for this channel
@@ -1930,9 +1939,9 @@ class MeshCoreConnector extends ChangeNotifier {
     final contact = Contact.fromFrame(frame);
     if (contact != null) {
       if (contact.type == advTypeRepeater) {
-        _contactLastReadMs.remove(contact.publicKeyHex);
-        _unreadStore.saveContactLastRead(
-          Map<String, int>.from(_contactLastReadMs),
+        _contactUnreadCount.remove(contact.publicKeyHex);
+        _unreadStore.saveContactUnreadCount(
+          Map<String, int>.from(_contactUnreadCount),
         );
       }
       // Check if this is a new contact
@@ -2157,7 +2166,7 @@ class MeshCoreConnector extends ChangeNotifier {
         }
       }
       _addMessage(message.senderKeyHex, message);
-      _maybeMarkActiveContactRead(message);
+      _maybeIncrementContactUnread(message);
       notifyListeners();
 
       // Show notification for new incoming message
@@ -2348,7 +2357,7 @@ class MeshCoreConnector extends ChangeNotifier {
         pathBytes: message.pathBytes,
       );
       final isNew = _addChannelMessage(message.channelIndex!, message);
-      _maybeMarkActiveChannelRead(message);
+      _maybeIncrementChannelUnread(message, isNew: isNew);
       notifyListeners();
       if (isNew) {
         _maybeNotifyChannelMessage(message);
@@ -2370,7 +2379,9 @@ class MeshCoreConnector extends ChangeNotifier {
     final channelHash = payload[0];
     final encrypted = Uint8List.fromList(payload.sublist(1));
 
-    for (final channel in _channels) {
+    // Use cached channels as fallback if live channels not yet loaded
+    final channelsToSearch = _channels.isNotEmpty ? _channels : _cachedChannels;
+    for (final channel in channelsToSearch) {
       if (channel.isEmpty) continue;
       final hash = _computeChannelHash(channel.psk);
       if (hash != channelHash) continue;
@@ -2409,7 +2420,7 @@ class MeshCoreConnector extends ChangeNotifier {
         pathBytes: message.pathBytes,
       );
       final isNew = _addChannelMessage(channel.index, message);
-      _maybeMarkActiveChannelRead(message);
+      _maybeIncrementChannelUnread(message, isNew: isNew);
       notifyListeners();
       if (isNew) {
         final label = channel.name.isEmpty
@@ -2539,6 +2550,15 @@ class MeshCoreConnector extends ChangeNotifier {
       '[ChannelSync] Received channel ${channel.index}: ${channel.isEmpty ? "empty" : channel.name}',
     );
 
+    // Preserve unread count from cached channel
+    final cachedChannel = _cachedChannels.cast<Channel?>().firstWhere(
+      (c) => c?.index == channel.index,
+      orElse: () => null,
+    );
+    if (cachedChannel != null) {
+      channel.unreadCount = cachedChannel.unreadCount;
+    }
+
     // If we're syncing and this is the channel we're waiting for
     if (_isSyncingChannels && _channelSyncInFlight) {
       if (channel.index == _nextChannelIndexToRequest) {
@@ -2578,6 +2598,8 @@ class MeshCoreConnector extends ChangeNotifier {
         (c) => c.index == channel.index,
       );
       if (existingIndex >= 0) {
+        // Preserve unread count from existing channel
+        channel.unreadCount = _channels[existingIndex].unreadCount;
         _channels[existingIndex] = channel;
       } else {
         _channels.add(channel);
@@ -2628,67 +2650,98 @@ class MeshCoreConnector extends ChangeNotifier {
     return contact.type != advTypeRepeater;
   }
 
-  int _calculateReadTimestampMs(Iterable<DateTime>? timestamps) {
-    var latestMs = 0;
-    if (timestamps != null) {
-      for (final timestamp in timestamps) {
-        final ms = timestamp.millisecondsSinceEpoch;
-        if (ms > latestMs) {
-          latestMs = ms;
-        }
-      }
-    }
-    return latestMs;
+  Channel? _findChannelByIndex(int index) {
+    return _channels.cast<Channel?>().firstWhere(
+          (c) => c?.index == index,
+          orElse: () => null,
+        ) ??
+        _cachedChannels.cast<Channel?>().firstWhere(
+          (c) => c?.index == index,
+          orElse: () => null,
+        );
   }
 
-  void _setContactLastReadMs(
-    String contactKeyHex,
-    int timestampMs, {
-    bool notify = true,
+  void _maybeIncrementChannelUnread(
+    ChannelMessage message, {
+    required bool isNew,
   }) {
-    if (!_shouldTrackUnreadForContactKey(contactKeyHex)) return;
-    final existing = _contactLastReadMs[contactKeyHex] ?? 0;
-    if (timestampMs <= existing) return;
-    _contactLastReadMs[contactKeyHex] = timestampMs;
-    _unreadStore.saveContactLastRead(Map<String, int>.from(_contactLastReadMs));
-    if (notify) {
-      notifyListeners();
+    if (!isNew || message.isOutgoing) {
+      _appDebugLogService?.info(
+        'Skip unread increment: isNew=$isNew, isOutgoing=${message.isOutgoing}',
+        tag: 'Unread',
+      );
+      return;
+    }
+    final channelIndex = message.channelIndex;
+    if (channelIndex == null) {
+      _appDebugLogService?.info(
+        'Skip unread increment: channelIndex is null',
+        tag: 'Unread',
+      );
+      return;
+    }
+    // Don't increment if user is viewing this channel
+    if (_activeChannelIndex == channelIndex) {
+      _appDebugLogService?.info(
+        'Skip unread increment: channel $channelIndex is active',
+        tag: 'Unread',
+      );
+      return;
     }
-  }
 
-  void _setChannelLastReadMs(
-    int channelIndex,
-    int timestampMs, {
-    bool notify = true,
-  }) {
-    final existing = _channelLastReadMs[channelIndex] ?? 0;
-    if (timestampMs <= existing) return;
-    _channelLastReadMs[channelIndex] = timestampMs;
-    _unreadStore.saveChannelLastRead(Map<int, int>.from(_channelLastReadMs));
-    if (notify) {
-      notifyListeners();
+    final channel = _findChannelByIndex(channelIndex);
+    if (channel != null) {
+      channel.unreadCount++;
+      _appDebugLogService?.info(
+        'Channel ${channel.name.isNotEmpty ? channel.name : channelIndex} unread count incremented to ${channel.unreadCount}',
+        tag: 'Unread',
+      );
+      unawaited(
+        _channelStore.saveChannels(
+          _channels.isNotEmpty ? _channels : _cachedChannels,
+        ),
+      );
+    } else {
+      _appDebugLogService?.info(
+        'Channel $channelIndex not found in _channels (${_channels.length}) or _cachedChannels (${_cachedChannels.length})',
+        tag: 'Unread',
+      );
     }
   }
 
-  void _maybeMarkActiveContactRead(Message message) {
-    if (message.isOutgoing || message.isCli) return;
-    if (_activeContactKey != message.senderKeyHex) return;
-    if (!_shouldTrackUnreadForContactKey(message.senderKeyHex)) return;
-    _setContactLastReadMs(
-      message.senderKeyHex,
-      message.timestamp.millisecondsSinceEpoch,
-      notify: false,
-    );
-  }
+  void _maybeIncrementContactUnread(Message message) {
+    if (message.isOutgoing || message.isCli) {
+      _appDebugLogService?.info(
+        'Skip contact unread increment: isOutgoing=${message.isOutgoing}, isCli=${message.isCli}',
+        tag: 'Unread',
+      );
+      return;
+    }
+    final contactKey = message.senderKeyHex;
+    if (!_shouldTrackUnreadForContactKey(contactKey)) {
+      _appDebugLogService?.info(
+        'Skip contact unread increment: should not track for $contactKey',
+        tag: 'Unread',
+      );
+      return;
+    }
+    // Don't increment if user is viewing this contact
+    if (_activeContactKey == contactKey) {
+      _appDebugLogService?.info(
+        'Skip contact unread increment: contact $contactKey is active',
+        tag: 'Unread',
+      );
+      return;
+    }
 
-  void _maybeMarkActiveChannelRead(ChannelMessage message) {
-    if (message.isOutgoing) return;
-    final channelIndex = message.channelIndex;
-    if (channelIndex == null || _activeChannelIndex != channelIndex) return;
-    _setChannelLastReadMs(
-      channelIndex,
-      message.timestamp.millisecondsSinceEpoch,
-      notify: false,
+    final currentCount = _contactUnreadCount[contactKey] ?? 0;
+    _contactUnreadCount[contactKey] = currentCount + 1;
+    _appDebugLogService?.info(
+      'Contact $contactKey unread count incremented to ${currentCount + 1}',
+      tag: 'Unread',
+    );
+    _unreadStore.saveContactUnreadCount(
+      Map<String, int>.from(_contactUnreadCount),
     );
   }
 

lib/main.dart

@@ -60,6 +60,7 @@ void main() async {
 
   await connector.loadContactCache();
   await connector.loadChannelSettings();
+  await connector.loadCachedChannels();
 
   // Load persisted channel messages
   await connector.loadAllChannelMessages();

lib/models/channel.dart

@@ -9,8 +9,14 @@ class Channel {
   final int index;
   final String name;
   final Uint8List psk; // 16 bytes
-
-  Channel({required this.index, required this.name, required this.psk});
+  int unreadCount;
+
+  Channel({
+    required this.index,
+    required this.name,
+    required this.psk,
+    this.unreadCount = 0,
+  });
 
   String get pskHex => _bytesToHex(psk);
 

lib/screens/channel_chat_screen.dart

@@ -41,6 +41,8 @@ class _ChannelChatScreenState extends State<ChannelChatScreen> {
   final Map<String, GlobalKey> _messageKeys = {};
   bool _isLoadingOlder = false;
 
+  MeshCoreConnector? _connector;
+
   @override
   void initState() {
     super.initState();
@@ -48,7 +50,8 @@ class _ChannelChatScreenState extends State<ChannelChatScreen> {
     _scrollController.onScrollNearTop = _loadOlderMessages;
     SchedulerBinding.instance.addPostFrameCallback((_) {
       if (!mounted) return;
-      context.read<MeshCoreConnector>().setActiveChannel(widget.channel.index);
+      _connector = context.read<MeshCoreConnector>();
+      _connector?.setActiveChannel(widget.channel.index);
     });
   }
 
@@ -72,7 +75,7 @@ class _ChannelChatScreenState extends State<ChannelChatScreen> {
 
   @override
   void dispose() {
-    context.read<MeshCoreConnector>().setActiveChannel(null);
+    _connector?.setActiveChannel(null);
     _textFieldFocusNode.removeListener(_onTextFieldFocusChange);
     _textFieldFocusNode.dispose();
     _textController.dispose();

lib/screens/chat_screen.dart

@@ -44,6 +44,7 @@ class _ChatScreenState extends State<ChatScreen> {
   final _scrollController = ChatScrollController();
   final _textFieldFocusNode = FocusNode();
   bool _isLoadingOlder = false;
+  MeshCoreConnector? _connector;
 
   @override
   void initState() {
@@ -52,9 +53,8 @@ class _ChatScreenState extends State<ChatScreen> {
     _scrollController.onScrollNearTop = _loadOlderMessages;
     SchedulerBinding.instance.addPostFrameCallback((_) {
       if (!mounted) return;
-      context.read<MeshCoreConnector>().setActiveContact(
-        widget.contact.publicKeyHex,
-      );
+      _connector = context.read<MeshCoreConnector>();
+      _connector?.setActiveContact(widget.contact.publicKeyHex);
     });
   }
 
@@ -78,7 +78,7 @@ class _ChatScreenState extends State<ChatScreen> {
 
   @override
   void dispose() {
-    context.read<MeshCoreConnector>().setActiveContact(null);
+    _connector?.setActiveContact(null);
     _textFieldFocusNode.removeListener(_onTextFieldFocusChange);
     _textFieldFocusNode.dispose();
     _textController.dispose();

lib/storage/channel_store.dart

@@ -0,0 +1,50 @@
+import 'dart:convert';
+import 'dart:typed_data';
+
+import '../models/channel.dart';
+import 'prefs_manager.dart';
+
+class ChannelStore {
+  static const String _key = 'channels';
+
+  Future<List<Channel>> loadChannels() async {
+    final prefs = PrefsManager.instance;
+    final jsonStr = prefs.getString(_key);
+    if (jsonStr == null) return [];
+
+    try {
+      final jsonList = jsonDecode(jsonStr) as List<dynamic>;
+      return jsonList
+          .map((entry) => _fromJson(entry as Map<String, dynamic>))
+          .toList();
+    } catch (_) {
+      return [];
+    }
+  }
+
+  Future<void> saveChannels(List<Channel> channels) async {
+    final prefs = PrefsManager.instance;
+    final jsonList = channels.map(_toJson).toList();
+    await prefs.setString(_key, jsonEncode(jsonList));
+  }
+
+  Map<String, dynamic> _toJson(Channel channel) {
+    return {
+      'index': channel.index,
+      'name': channel.name,
+      'psk': base64Encode(channel.psk),
+      'unreadCount': channel.unreadCount,
+    };
+  }
+
+  Channel _fromJson(Map<String, dynamic> json) {
+    return Channel(
+      index: json['index'] as int,
+      name: json['name'] as String? ?? '',
+      psk: json['psk'] != null
+          ? Uint8List.fromList(base64Decode(json['psk'] as String))
+          : Uint8List(16),
+      unreadCount: json['unreadCount'] as int? ?? 0,
+    );
+  }
+}

lib/storage/unread_store.dart

@@ -5,27 +5,23 @@ import 'prefs_manager.dart';
 
 /// Storage for unread message tracking with debounced writes to reduce I/O.
 class UnreadStore {
-  static const String _contactLastReadKey = 'contact_last_read';
-  static const String _channelLastReadKey = 'channel_last_read';
+  static const String _contactUnreadCountKey = 'contact_unread_count';
 
   // Debounce timers to batch rapid writes
-  Timer? _contactSaveTimer;
-  Timer? _channelSaveTimer;
+  Timer? _contactUnreadSaveTimer;
   static const Duration _saveDebounceDuration = Duration(milliseconds: 500);
 
   // Pending write data
-  Map<String, int>? _pendingContactLastRead;
-  Map<int, int>? _pendingChannelLastRead;
+  Map<String, int>? _pendingContactUnreadCount;
 
   /// Dispose timers when no longer needed
   void dispose() {
-    _contactSaveTimer?.cancel();
-    _channelSaveTimer?.cancel();
+    _contactUnreadSaveTimer?.cancel();
   }
 
-  Future<Map<String, int>> loadContactLastRead() async {
+  Future<Map<String, int>> loadContactUnreadCount() async {
     final prefs = PrefsManager.instance;
-    final jsonStr = prefs.getString(_contactLastReadKey);
+    final jsonStr = prefs.getString(_contactUnreadCountKey);
     if (jsonStr == null) return {};
 
     try {
@@ -36,75 +32,30 @@ class UnreadStore {
     }
   }
 
-  /// Save contact last read timestamps with debouncing.
-  /// Writes are delayed by 500ms and batched to reduce I/O operations.
-  void saveContactLastRead(Map<String, int> lastReadMs) {
-    _pendingContactLastRead = lastReadMs;
+  void saveContactUnreadCount(Map<String, int> counts) {
+    _pendingContactUnreadCount = counts;
 
-    // Cancel existing timer
-    _contactSaveTimer?.cancel();
+    _contactUnreadSaveTimer?.cancel();
 
-    // Schedule new write
-    _contactSaveTimer = Timer(_saveDebounceDuration, () async {
-      if (_pendingContactLastRead != null) {
-        await _flushContactLastRead();
+    _contactUnreadSaveTimer = Timer(_saveDebounceDuration, () async {
+      if (_pendingContactUnreadCount != null) {
+        await _flushContactUnreadCount();
       }
     });
   }
 
-  Future<Map<int, int>> loadChannelLastRead() async {
-    final prefs = PrefsManager.instance;
-    final jsonStr = prefs.getString(_channelLastReadKey);
-    if (jsonStr == null) return {};
-
-    try {
-      final json = jsonDecode(jsonStr) as Map<String, dynamic>;
-      return json.map((key, value) => MapEntry(int.parse(key), value as int));
-    } catch (_) {
-      return {};
-    }
-  }
-
-  /// Save channel last read timestamps with debouncing.
-  /// Writes are delayed by 500ms and batched to reduce I/O operations.
-  void saveChannelLastRead(Map<int, int> lastReadMs) {
-    _pendingChannelLastRead = lastReadMs;
-
-    _channelSaveTimer?.cancel();
-
-    _channelSaveTimer = Timer(_saveDebounceDuration, () async {
-      if (_pendingChannelLastRead != null) {
-        await _flushChannelLastRead();
-      }
-    });
-  }
-
-  Future<void> _flushContactLastRead() async {
-    if (_pendingContactLastRead == null) return;
+  Future<void> _flushContactUnreadCount() async {
+    if (_pendingContactUnreadCount == null) return;
 
     final prefs = PrefsManager.instance;
-    final jsonStr = jsonEncode(_pendingContactLastRead);
-    await prefs.setString(_contactLastReadKey, jsonStr);
-    _pendingContactLastRead = null;
-  }
-
-  Future<void> _flushChannelLastRead() async {
-    if (_pendingChannelLastRead == null) return;
-
-    final prefs = PrefsManager.instance;
-    final asString = _pendingChannelLastRead!.map(
-      (key, value) => MapEntry(key.toString(), value),
-    );
-    final jsonStr = jsonEncode(asString);
-    await prefs.setString(_channelLastReadKey, jsonStr);
-    _pendingChannelLastRead = null;
+    final jsonStr = jsonEncode(_pendingContactUnreadCount);
+    await prefs.setString(_contactUnreadCountKey, jsonStr);
+    _pendingContactUnreadCount = null;
   }
 
   /// Immediately flush pending writes (call before app termination or disposal)
   Future<void> flush() async {
-    _contactSaveTimer?.cancel();
-    _channelSaveTimer?.cancel();
-
-    await Future.wait([_flushContactLastRead(), _flushChannelLastRead()]);
+    _contactUnreadSaveTimer?.cancel();
+    await _flushContactUnreadCount();
   }
 }