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

2026-05-10 15:47:55 +02:00
parent 6ae396e605
commit 1458d8ce49
15 changed files with 712 additions and 146 deletions
@@ -1,15 +1,54 @@
+import 'dart:async';
+import 'dart:developer';
+import 'dart:math' as math;
+
+import 'package:flutter/widgets.dart';
+
 import '../../../../../api/errors/error_mapper.dart';
+import '../../../../../api/marianumcloud/talk/chat/get_chat_response.dart';
+import '../../../../../api/marianumcloud/talk/chat/long_poll_chat.dart';
+import '../../../../../api/marianumcloud/talk/room/get_room_response.dart';
+import '../../../../../api/marianumcloud/talk/set_read_marker/set_read_marker.dart';
+import '../../../../../api/marianumcloud/talk/set_read_marker/set_read_marker_params.dart';
 import '../../../infrastructure/loadable_state/loading_error.dart';
 import '../../../infrastructure/utility_widgets/loadable_hydrated_bloc/loadable_hydrated_bloc.dart';
 import '../../../infrastructure/utility_widgets/loadable_hydrated_bloc/loadable_hydrated_bloc_event.dart';
+import '../../chat_list/bloc/chat_list_bloc.dart';
 import '../repository/chat_repository.dart';
 import 'chat_event.dart';
 import 'chat_state.dart';

 class ChatBloc
-    extends LoadableHydratedBloc<ChatEvent, ChatState, ChatRepository> {
+    extends LoadableHydratedBloc<ChatEvent, ChatState, ChatRepository>
+    with WidgetsBindingObserver {
+  final ChatListBloc? _chatListBloc;
+
+  String? _pollingToken;
+  int _backoffMs = 0;
+  int _lastKnownMessageId = 0;
+  bool _appResumed = true;
+
+  /// Distinguishes "the bloc tracks a chat the user has open" from "the
+  /// bloc remembers the last opened chat". App-resume only refreshes when
+  /// true — otherwise we'd silently mark a long-since-left chat as read
+  /// on the server. Can't reuse `currentToken` for this signal because
+  /// clearing it on leaveChat raced with setToken-from-didPopNext when
+  /// popping a stacked chat.
+  bool _chatViewActive = false;
+
  DateTime _lastTokenSet = DateTime.fromMillisecondsSinceEpoch(0);

+  ChatBloc({ChatListBloc? chatListBloc}) : _chatListBloc = chatListBloc {
+    WidgetsBinding.instance.addObserver(this);
+  }
+
+  @override
+  Future<void> close() {
+    WidgetsBinding.instance.removeObserver(this);
+    _stopLongPoll();
+    return super.close();
+  }
+
  @override
  ChatRepository repository() => ChatRepository();

@@ -33,24 +72,74 @@ class ChatBloc
  }

  void setToken(String token) {
+    _chatViewActive = true;
    if (token == (innerState?.currentToken ?? '')) {
      refresh();
      return;
    }
+    _stopLongPoll();
    add(Emit((s) => s.copyWith(currentToken: token, chatResponse: null)));
    add(RefetchStarted<ChatState>());
-    _loadChat(token);
-  }
-
-  void setReferenceMessageId(int? messageId) {
-    add(Emit((s) => s.copyWith(referenceMessageId: messageId)));
+    _scheduleLoad(token);
  }

  void refresh() {
    final token = innerState?.currentToken ?? '';
    if (token.isEmpty) return;
    add(RefetchStarted<ChatState>());
-    _loadChat(token);
+    _scheduleLoad(token);
+  }
+
+  void setReferenceMessageId(int? messageId) {
+    add(Emit((s) => s.copyWith(referenceMessageId: messageId)));
+  }
+
+  /// Token-aware: only acts when the bloc still points at [fromToken].
+  /// When popping a stacked chat (notification opened B over A), A's
+  /// didPopNext has already run setToken(A) by the time B's dispose
+  /// fires — at that point currentToken is A and we must leave it alone.
+  void leaveChat(String fromToken) {
+    if ((innerState?.currentToken ?? '') != fromToken) return;
+    _chatViewActive = false;
+    _stopLongPoll();
+  }
+
+  /// Fire-and-forget server-side read-marker. Exposed so view-side
+  /// callers (long-press menu, ChatView dispose) hit the same path.
+  Future<void> sendServerReadMarker(String token, int messageId) async {
+    try {
+      await SetReadMarker(
+        token,
+        true,
+        setReadMarkerParams: SetReadMarkerParams(lastReadMessage: messageId),
+      ).run();
+    } on Object catch (e) {
+      log('Server read-marker for $token failed: $e');
+    }
+  }
+
+  @override
+  void didChangeAppLifecycleState(AppLifecycleState state) {
+    final wasResumed = _appResumed;
+    _appResumed = state == AppLifecycleState.resumed;
+    if (!_appResumed) {
+      _stopLongPoll();
+      return;
+    }
+    if (wasResumed) return;
+    final token = innerState?.currentToken ?? '';
+    if (token.isNotEmpty && _chatViewActive) refresh();
+  }
+
+  /// Defer _loadChat by one microtask so the Bloc worker processes the
+  /// preceding Emit/RefetchStarted before any cache/network callback
+  /// fires — otherwise a quick cache hit can run with the previous
+  /// token in state, fail stillCurrent(), and never emit a DataGathered.
+  void _scheduleLoad(String token) {
+    Future<void>.microtask(() {
+      if (isClosed) return;
+      _loadChat(token).then((_) => _startLongPoll(token));
+    });
  }

  Future<void> _loadChat(String token) async {
@@ -69,14 +158,21 @@ class ChatBloc
        token: token,
        onCacheData: (data) {
          if (!stillCurrent()) return;
-          // Cache hit: show data immediately but preserve lastFetch — the
-          // cached payload may be stale and we don't want the UI to claim a
-          // fresh fetch just happened.
+          // Only paint cache when the state is empty — restoring a stale
+          // disk snapshot over already-merged long-poll data would visibly
+          // drop those messages until the network call resolves.
+          if (innerState?.chatResponse != null) return;
          add(Emit((s) => s.copyWith(chatResponse: data)));
        },
        onNetworkData: (data) {
+          // Server-side mark runs unconditionally with the freshly-fetched
+          // maxId. Skipping it on stillCurrent==false would leave the
+          // server cursor wherever a quick navigation away left it.
+          final maxId = _maxMessageId(data);
+          if (maxId > 0) unawaited(sendServerReadMarker(token, maxId));
          if (!stillCurrent()) return;
-          add(DataGathered((s) => s.copyWith(chatResponse: data)));
+          _applyChatResponse(data);
+          if (maxId > 0) _chatListBloc?.markRoomAsRead(token, maxId);
        },
        onError: (e) => capturedError = e,
      );
@@ -98,4 +194,115 @@ class ChatBloc
      );
    }
  }
+
+  // ---------------------------------------------------------------------------
+  // Long-poll loop
+  // ---------------------------------------------------------------------------
+
+  void _startLongPoll(String token) {
+    if (!_appResumed) return;
+    if (_pollingToken == token) return;
+    _stopLongPoll();
+    _pollingToken = token;
+    _backoffMs = 0;
+    _lastKnownMessageId = _maxMessageId(innerState?.chatResponse);
+    unawaited(_pollLoop(token));
+  }
+
+  void _stopLongPoll() {
+    _pollingToken = null;
+    _backoffMs = 0;
+  }
+
+  Future<void> _pollLoop(String token) async {
+    while (_pollingToken == token && !isClosed) {
+      try {
+        final response = await LongPollChat(
+          chatToken: token,
+          lastKnownMessageId: _lastKnownMessageId,
+        ).run();
+
+        if (_pollingToken != token || isClosed) return;
+        _backoffMs = 0;
+
+        if (response == null) continue;
+
+        final headerId = int.tryParse(
+          response.headers?[_kLongPollLastGivenHeader] ?? '',
+        );
+        if (headerId != null && headerId > _lastKnownMessageId) {
+          _lastKnownMessageId = headerId;
+        }
+
+        if (response.data.isEmpty) continue;
+        _applyChatResponse(response);
+        final maxId = _maxMessageId(response);
+        if (maxId > _lastKnownMessageId) _lastKnownMessageId = maxId;
+        // Long-poll's setReadMarker=on already moved the server cursor;
+        // mirror locally.
+        final preview = _pickDisplayMessage(response);
+        if (preview != null) {
+          _chatListBloc?.applyIncomingMessage(token, preview);
+        } else {
+          _chatListBloc?.markRoomAsRead(token, _lastKnownMessageId);
+        }
+      } on Object catch (e) {
+        if (_pollingToken != token || isClosed) return;
+        log('LongPoll error for $token: $e');
+        _backoffMs = _backoffMs == 0 ? 2000 : math.min(_backoffMs * 2, 30000);
+        await Future.delayed(Duration(milliseconds: _backoffMs));
+      }
+    }
+  }
+
+  /// Merges [incoming] into the existing chatResponse and emits as a
+  /// fresh fetch. Dedups by id (newer wins, so server edits/deletes
+  /// propagate). Shared by initial-load and long-poll so neither wipes
+  /// messages the other already committed.
+  void _applyChatResponse(GetChatResponse incoming) {
+    final current = innerState?.chatResponse;
+    if (current == null) {
+      add(DataGathered((s) => s.copyWith(chatResponse: incoming)));
+      return;
+    }
+    final byId = <int, GetChatResponseObject>{};
+    for (final m in current.data) {
+      byId[m.id] = m;
+    }
+    for (final m in incoming.data) {
+      byId[m.id] = m;
+    }
+    final merged = GetChatResponse(byId.values.toSet())
+      ..headers = incoming.headers;
+    add(DataGathered((s) => s.copyWith(chatResponse: merged)));
+  }
+
+  int _maxMessageId(GetChatResponse? response) {
+    if (response == null) return 0;
+    var max = 0;
+    for (final m in response.data) {
+      if (m.id > max) max = m.id;
+    }
+    return max;
+  }
+
+  /// Highest-id message worth showing as the room preview — comments
+  /// and voice messages, matching what the server picks for `lastMessage`.
+  GetChatResponseObject? _pickDisplayMessage(GetChatResponse response) {
+    GetChatResponseObject? best;
+    for (final m in response.data) {
+      switch (m.messageType) {
+        case GetRoomResponseObjectMessageType.comment:
+        case GetRoomResponseObjectMessageType.voiceMessage:
+          if (best == null || m.id > best.id) best = m;
+        case GetRoomResponseObjectMessageType.deletedComment:
+        case GetRoomResponseObjectMessageType.system:
+        case GetRoomResponseObjectMessageType.command:
+          break;
+      }
+    }
+    return best;
+  }
 }
+
+const _kLongPollLastGivenHeader = 'x-chat-last-given';