watch method

Stream<ChatMessage?> watch(
  1. ChatId id
)

Returns the Stream of real-time changes happening with the draft in the Chat identified by the provided id.

Implementation

Stream<ChatMessage?> watch(ChatId id) {
  return stream((db) {
    final stmt = db.select(db.drafts)..where((u) => u.chatId.equals(id.val));

    StreamController<ChatMessage?>? controller = _controllers[id];
    if (controller == null) {
      controller = StreamController<ChatMessage?>.broadcast(sync: true);
      _controllers[id] = controller;
    }

    ChatMessage? last;

    return StreamGroup.merge([
      controller.stream,
      stmt.watch().map((e) => e.isEmpty ? null : _DraftDb.fromDb(e.first)),
    ]).asyncExpand((e) async* {
      if (e != last) {
        last = e;
        yield e;
      }
    });
  });
}