flutter-samples/chatty/lib/ui/home/chat/selection/friends_selection_cubit.dart

import 'package:stream_chatter/data/stream_api_repository.dart';
import 'package:stream_chatter/domain/models/chat_user.dart';
import 'package:flutter_bloc/flutter_bloc.dart';
import 'package:stream_chat_flutter/stream_chat_flutter.dart';

class ChatUserState {
  const ChatUserState(this.chatUser, {this.selected = false});
  final ChatUser chatUser;
  final bool selected;
}

class FriendsSelectionCubit extends Cubit<List<ChatUserState>> {
  FriendsSelectionCubit(this._streamApiRepository) : super([]);
  final StreamApiRepository _streamApiRepository;

  List<ChatUserState> get selectedUsers => state.where((element) => element.selected).toList();

  Future<void> init() async {
    final chatUsers = (await _streamApiRepository.getChatUsers()).map((e) => ChatUserState(e)).toList();
    emit(chatUsers);
  }

  void selectUser(ChatUserState chatUser) {
    final index = state.indexWhere((element) => element.chatUser.id == chatUser.chatUser.id);
    state[index] = ChatUserState(state[index].chatUser, selected: !chatUser.selected);
    emit(List<ChatUserState>.from(state));
  }

  Future<Channel> createFriendChannel(ChatUserState chatUserState) async {
    return await _streamApiRepository.createSimpleChat(chatUserState.chatUser.id);
  }
}

class FriendsGroupCubit extends Cubit<bool> {
  FriendsGroupCubit() : super(false);

  void changeToGroup() => emit(!state);
}