implemented chat long-polling and optimistic updates, centralized notification management, optimized avatar caching

lib/view/pages/talk/chat_view.dart

@@ -1,3 +1,4 @@
+import 'dart:async';
 import 'dart:math' as math;
 
 import 'package:flutter/material.dart';
@@ -7,9 +8,12 @@ import 'package:scrollable_positioned_list/scrollable_positioned_list.dart';
 import '../../../api/marianumcloud/talk/chat/get_chat_response.dart';
 import '../../../api/marianumcloud/talk/room/get_room_response.dart';
 import '../../../extensions/date_time.dart';
+import '../../../notification/notification_tasks.dart';
+import '../../../routing/app_routes.dart';
 import '../../../state/app/infrastructure/loadable_state/view/loadable_state_consumer.dart';
 import '../../../state/app/modules/chat/bloc/chat_bloc.dart';
 import '../../../state/app/modules/chat/bloc/chat_state.dart';
+import '../../../state/app/modules/chat_list/bloc/chat_list_bloc.dart';
 import '../../../theming/app_theme.dart';
 import '../../../widget/clickable_app_bar.dart';
 import '../../../widget/user_avatar.dart';
@@ -36,7 +40,7 @@ class ChatView extends StatefulWidget {
   State<ChatView> createState() => _ChatViewState();
 }
 
-class _ChatViewState extends State<ChatView> {
+class _ChatViewState extends State<ChatView> with RouteAware {
   final ItemScrollController _itemScrollController = ItemScrollController();
   final TextEditingController _searchTextController = TextEditingController();
   final Map<int, int> _matchIndices = {};
@@ -48,12 +52,73 @@ class _ChatViewState extends State<ChatView> {
   GetChatResponse? _matchesComputedFor;
   String? _matchesComputedQuery;
 
+  // Captured in initState because the framework has unmounted us by the
+  // time dispose runs.
+  ChatBloc? _chatBlocRef;
+  ChatListBloc? _chatListBlocRef;
+  PageRoute<dynamic>? _subscribedRoute;
+
+  @override
+  void initState() {
+    super.initState();
+    _chatBlocRef = context.read<ChatBloc>();
+    _chatListBlocRef = context.read<ChatListBloc>();
+    NotificationTasks.clearNotificationsForChat(widget.room.token);
+  }
+
+  @override
+  void didChangeDependencies() {
+    super.didChangeDependencies();
+    final route = ModalRoute.of(context);
+    if (route is PageRoute && route != _subscribedRoute) {
+      if (_subscribedRoute != null) {
+        AppRoutes.chatRouteObserver.unsubscribe(this);
+      }
+      AppRoutes.chatRouteObserver.subscribe(this, route);
+      _subscribedRoute = route;
+    }
+  }
+
+  @override
+  void didPopNext() {
+    super.didPopNext();
+    // A stacked chat above us was just popped (typical: notification tap
+    // opened another chat). The global ChatBloc currently points at that
+    // other chat's token, so our isReady predicate fails until we re-claim.
+    _chatBlocRef?.setToken(widget.room.token);
+  }
+
   @override
   void dispose() {
+    if (_subscribedRoute != null) {
+      AppRoutes.chatRouteObserver.unsubscribe(this);
+    }
+    _markAsReadFinal();
+    _chatBlocRef?.leaveChat(widget.room.token);
     _searchTextController.dispose();
     super.dispose();
   }
 
+  /// Defensive final mark-as-read so a back-out before the long-poll
+  /// could fire doesn't leave the room as unread. Skipped when the bloc
+  /// has already moved on to another chat — the response data there
+  /// belongs to a different room, and writing its max-id as our marker
+  /// would regress our server cursor.
+  void _markAsReadFinal() {
+    final state = _chatBlocRef?.state.data;
+    if (state == null) return;
+    if (state.currentToken != widget.room.token) return;
+    final response = state.chatResponse;
+    if (response == null) return;
+    var maxId = 0;
+    for (final m in response.data) {
+      if (m.id > maxId) maxId = m.id;
+    }
+    if (maxId == 0) return;
+    _chatListBlocRef?.markRoomAsRead(widget.room.token, maxId);
+    unawaited(_chatBlocRef!.sendServerReadMarker(widget.room.token, maxId));
+  }
+
   @override
   void didUpdateWidget(covariant ChatView oldWidget) {
     super.didUpdateWidget(oldWidget);