m8chat-app2/lib/features/chat/data/chat_repository.dart

// Version: 1.0.1 | Created: 2026-04-01
// Chat repository. Bridges Matrix SDK timeline to app domain models.
// Uses room.getTimeline() — timeline is async in matrix 0.33.0.

import 'package:matrix/matrix.dart';
import 'package:riverpod_annotation/riverpod_annotation.dart';

import '../../../core/network/matrix_client.dart';
import '../domain/message_model.dart';

part 'chat_repository.g.dart';

@riverpod
ChatRepository chatRepository(Ref ref) {
  return ChatRepository(client: ref.watch(matrixClientProvider));
}

class ChatRepository {
  ChatRepository({required Client client}) : _client = client;

  final Client _client;

  Room? _getRoom(String roomId) => _client.getRoomById(roomId);

  /// Returns a stream of message lists for [roomId].
  ///
  /// Opens the room's timeline once and then emits on every update.
  /// The timeline object is closed when the stream subscription is cancelled.
  Stream<List<MessageModel>> watchTimeline(String roomId) async* {
    final room = _getRoom(roomId);
    if (room == null) return;

    final timeline = await room.getTimeline(
      onUpdate: () {
        // Handled by the stream controller below.
      },
    );

    // Emit the initial state.
    yield _mapTimeline(timeline, room);

    // Emit on subsequent sync events that affect this room.
    await for (final update in _client.onSync.stream) {
      final updatesThisRoom = update.rooms?.join?.containsKey(roomId) ?? false;
      if (updatesThisRoom) {
        yield _mapTimeline(timeline, room);
      }
    }

    // Clean up timeline subscriptions when the stream is cancelled.
    timeline.cancelSubscriptions();
  }

  /// Sends a plain text message to [roomId].
  Future<void> sendTextMessage(String roomId, String text) async {
    final room = _getRoom(roomId);
    if (room == null) return;
    await room.sendTextEvent(text);
  }

  /// Sends a read receipt for the latest event in [roomId].
  Future<void> markAsRead(String roomId) async {
    final room = _getRoom(roomId);
    if (room == null) return;
    final lastEventId = room.lastEvent?.eventId ?? '';
    if (lastEventId.isEmpty) return;
    await room.setReadMarker(lastEventId, mRead: lastEventId);
  }

  /// Requests older messages be loaded (pagination).
  Future<void> loadMoreMessages(String roomId) async {
    final room = _getRoom(roomId);
    if (room == null) return;
    await room.requestHistory();
  }

  List<MessageModel> _mapTimeline(Timeline timeline, Room room) {
    final myUserId = _client.userID ?? '';
    return timeline.events
        .map((e) => _toModel(e, timeline, myUserId))
        .toList()
        .reversed
        .toList();
  }

  MessageModel _toModel(Event event, Timeline timeline, String myUserId) {
    final senderProfile = event.room.unsafeGetUserFromMemoryOrFallback(
      event.senderId,
    );

    return MessageModel(
      eventId: event.eventId,
      roomId: event.roomId ?? '',
      senderId: event.senderId,
      senderDisplayName:
          senderProfile.displayName ?? event.senderId.split(':').first,
      senderAvatarUrl: senderProfile.avatarUrl?.toString(),
      timestamp: event.originServerTs,
      type: _messageType(event),
      body: event.redacted ? null : event.body,
      mxcUrl: _extractMxcUrl(event),
      inReplyToEventId: event.relationshipEventId,
      isMine: event.senderId == myUserId,
      isEdited: event.hasAggregatedEvents(timeline, RelationshipTypes.edit),
    );
  }

  MessageType _messageType(Event event) {
    if (event.redacted) return MessageType.redacted;

    return switch (event.messageType) {
      MessageTypes.Text => MessageType.text,
      MessageTypes.Image => MessageType.image,
      MessageTypes.File => MessageType.file,
      MessageTypes.Audio => MessageType.audio,
      MessageTypes.Video => MessageType.video,
      MessageTypes.Sticker => MessageType.sticker,
      _ => MessageType.unsupported,
    };
  }

  String? _extractMxcUrl(Event event) {
    final content = event.content;
    if (content.containsKey('url')) {
      return content['url'] as String?;
    }
    return null;
  }
}