read method

Implementation

Future<void> read(ChatItemId untilId) async {
  Log.debug('read($untilId)', '$runtimeType($id)');

  int firstUnreadIndex = 0;

  if (firstUnread != null) {
    firstUnreadIndex = messages.indexOf(firstUnread!);
  }

  int lastReadIndex = messages.indexWhere(
    (m) => m.value.id == untilId,
    firstUnreadIndex,
  );

  if (lastReadIndex != -1 && firstUnreadIndex != -1) {
    int read =
        messages
            .skip(firstUnreadIndex)
            .take(lastReadIndex - firstUnreadIndex + 1)
            .where((e) => !e.value.id.isLocal && e.value.author.id != me)
            .length;
    unreadCount.value = chat.value.unreadCount - read;
  }

  final ChatItemId? lastReadItem = chat.value.lastReadItem;
  if (lastReadItem != untilId) {
    chat.update((e) => e?..lastReadItem = untilId);

    _readTimer?.cancel();
    _readTimer = AwaitableTimer(
      chat.value.lastItem?.id == untilId
          ? Duration.zero
          : const Duration(seconds: 1),
      () async {
        try {
          await _chatRepository.readUntil(id, untilId);

          final DtoChatItem? item = await _driftItems.read(untilId);
          _lastReadItemCursor =
              item?.cursor ?? _lastReadItemCursor ?? dto.lastReadItemCursor;
          dto.lastReadItemCursor = _lastReadItemCursor;
        } catch (_) {
          chat.update((e) => e?..lastReadItem = lastReadItem);
          unreadCount.value = chat.value.unreadCount;
          rethrow;
        } finally {
          _readTimer = null;
        }
      },
    );

    await _readTimer?.future;
  }
}