import 'package:flutter/foundation.dart';

/// Pending UI removals are scoped to an account as well as a chat.
class PendingMessageDeletions extends ChangeNotifier {
  PendingMessageDeletions();
  static final instance = PendingMessageDeletions();
  final Map<(int, int), Set<String>> _pending = {};

  bool contains(int accountId, int chatId, String id) =>
      _pending[(accountId, chatId)]?.contains(id) ?? false;

  void hold(int accountId, int chatId, Iterable<String> ids) {
    _pending.putIfAbsent((accountId, chatId), () => {}).addAll(ids);
    notifyListeners();
  }

  void release(int accountId, int chatId, Iterable<String> ids) {
    final pending = _pending[(accountId, chatId)];
    if (pending == null) return;
    pending.removeAll(ids);
    if (pending.isEmpty) _pending.remove((accountId, chatId));
    notifyListeners();
  }
}