import 'package:gobang/bridge/chess_shape.dart';
import 'package:gobang/bridge/circle_shape.dart';
import 'package:gobang/bridge/rect_shape.dart';
import 'package:gobang/flyweight/chess.dart';
import 'package:gobang/flyweight/chess_flyweight_factory.dart';
import 'package:gobang/state/game_state.dart';
import 'package:gobang/state/user_context.dart';

class GameViewModel {
  GameViewModel._();

  static final GameViewModel instance = GameViewModel._();

  static GameViewModel getInstance() => instance;

  final UserContext _userContext = UserContext();

  Chess play() {
    _userContext.play();
    return ChessFlyweightFactory.getInstance().getChess('white');
  }

  ChessShape shapeFor(bool useCircle) =>
      useCircle ? CircleShape() : RectShape();

  bool undo() => _userContext.regretChess();

  String get state {
    final s = _userContext.state;
    if (s is StartState) {
      return '热身阶段,不能悔棋，不能投降';
    }
    if (s is MidState) {
      return '入神阶段,可以悔棋且剩余${3 - s.reg}次，可以投降';
    }
    if (s is EndState) {
      return '白热化阶段,悔棋次数已用完，但可以投降';
    }
    return '';
  }

  void reset() => _userContext.reset();

  bool surrender() => _userContext.surrender();
}