Cache for unread total

lib/connector/meshcore_connector.dart

@@ -150,6 +150,8 @@ class MeshCoreConnector extends ChangeNotifier {
   final Set<String> _knownContactKeys = {};
   final Map<String, int> _contactUnreadCount = {};
   bool _unreadStateLoaded = false;
+  int _cachedContactsUnreadTotal = 0;
+  int _cachedChannelsUnreadTotal = 0;
   final Map<String, _RepeaterAckContext> _pendingRepeaterAcks = {};
   String? _activeContactKey;
   int? _activeChannelIndex;
@@ -342,22 +344,28 @@ class MeshCoreConnector extends ChangeNotifier {
 
   int getTotalContactsUnreadCount() {
     if (!_unreadStateLoaded) return 0;
-    var total = 0;
-    for (final contact in _contacts) {
-      total += getUnreadCountForContact(contact);
-    }
-    return total;
+    return _cachedContactsUnreadTotal;
   }
 
   int getTotalChannelsUnreadCount() {
     if (!_unreadStateLoaded) return 0;
-    var total = 0;
-    // Check all channels (from _channels or _cachedChannels)
+    return _cachedChannelsUnreadTotal;
+  }
+
+  /// Recalculates both cached unread totals from scratch.
+  /// Called when unread state is first loaded.
+  void _recalculateCachedUnreadTotals() {
+    _recalculateCachedContactsUnreadTotal();
+    _recalculateCachedChannelsUnreadTotal();
+  }
+
+  void _recalculateCachedContactsUnreadTotal() {
+    _cachedContactsUnreadTotal = _contactUnreadCount.values.fold(0, (a, b) => a + b);
+  }
+
+  void _recalculateCachedChannelsUnreadTotal() {
     final allChannels = _channels.isNotEmpty ? _channels : _cachedChannels;
-    for (final channel in allChannels) {
-      total += channel.unreadCount;
-    }
-    return total;
+    _cachedChannelsUnreadTotal = allChannels.fold(0, (total, ch) => total + ch.unreadCount);
   }
 
   bool isChannelSmazEnabled(int channelIndex) {
@@ -377,11 +385,13 @@ class MeshCoreConnector extends ChangeNotifier {
       ..clear()
       ..addAll(await _unreadStore.loadContactUnreadCount());
     _unreadStateLoaded = true;
+    _recalculateCachedUnreadTotals();
     notifyListeners();
   }
 
   Future<void> loadCachedChannels() async {
     _cachedChannels = await _channelStore.loadChannels();
+    _recalculateCachedChannelsUnreadTotal();
   }
 
   void setActiveContact(String? contactKeyHex) {
@@ -408,6 +418,7 @@ class MeshCoreConnector extends ChangeNotifier {
     final previousCount = _contactUnreadCount[contactKeyHex] ?? 0;
     if (previousCount > 0) {
       _contactUnreadCount[contactKeyHex] = 0;
+      _cachedContactsUnreadTotal -= previousCount;
       _appDebugLogService?.info(
         'Contact $contactKeyHex marked as read (was $previousCount unread)',
         tag: 'Unread',
@@ -424,6 +435,7 @@ class MeshCoreConnector extends ChangeNotifier {
     if (channel != null && channel.unreadCount > 0) {
       final previousCount = channel.unreadCount;
       channel.unreadCount = 0;
+      _cachedChannelsUnreadTotal -= previousCount;
       _appDebugLogService?.info(
         'Channel ${channel.name.isNotEmpty ? channel.name : channelIndex} marked as read (was $previousCount unread)',
         tag: 'Unread',
@@ -1656,6 +1668,7 @@ class MeshCoreConnector extends ChangeNotifier {
     if (completed) {
       _hasLoadedChannels = true;
       _previousChannelsCache.clear();
+      _recalculateCachedChannelsUnreadTotal();
     }
     // Keep cache on failure/disconnection for future attempts
   }
@@ -2703,6 +2716,7 @@ class MeshCoreConnector extends ChangeNotifier {
     final channel = _findChannelByIndex(channelIndex);
     if (channel != null) {
       channel.unreadCount++;
+      _cachedChannelsUnreadTotal++;
       _appDebugLogService?.info(
         'Channel ${channel.name.isNotEmpty ? channel.name : channelIndex} unread count incremented to ${channel.unreadCount}',
         tag: 'Unread',
@@ -2747,6 +2761,7 @@ class MeshCoreConnector extends ChangeNotifier {
 
     final currentCount = _contactUnreadCount[contactKey] ?? 0;
     _contactUnreadCount[contactKey] = currentCount + 1;
+    _cachedContactsUnreadTotal++;
     _appDebugLogService?.info(
       'Contact $contactKey unread count incremented to ${currentCount + 1}',
       tag: 'Unread',