class Contact { final int id; final String username; final String name; final String surname; final String? lastMessage; final String? avatarUrl; final DateTime? lastMessageTime; final bool isOnline; final int unreadCount; Contact({ required this.id, required this.username, required this.name, required this.surname, this.lastMessage, this.avatarUrl, this.lastMessageTime, this.isOnline = false, this.unreadCount = 0, }); factory Contact.fromJson(Map json) { return Contact( id: json['id'], username: json['username'] ?? 'Unknown', name: json['name'] ?? 'Unknown', surname: json['surname'] ?? 'Unknown', // Другие поля можно добавить позже ); } }