samples/poppopwin: upgrade to first-class sample

samples/third_party/pop-pop-win/lib/src/poppopwin/game.dart

-part of ppw;
-
-class Game {
-  final Field field;
-  final Array2d<SquareState> _states;
-  final EventHandle<EventArgs> _updatedEvent = new EventHandle<EventArgs>();
-  final EventHandle<GameState> _gameStateEvent = new EventHandle<GameState>();
-
-  GameState _state;
-  int _bombsLeft;
-  int _revealsLeft;
-  DateTime _startTime;
-  DateTime _endTime;
-
-  Game(Field field) :
-    this.field = field,
-    _state = GameState.reset,
-    _states = new Array2d<SquareState>(field.width, field.height, SquareState.hidden) {
-    assert(field != null);
-    _bombsLeft = field.bombCount;
-    _revealsLeft = field.length - field.bombCount;
-  }
-
-  int get bombsLeft => _bombsLeft;
-
-  int get revealsLeft => _revealsLeft;
-
-  GameState get state => _state;
-
-  Stream get updated => _updatedEvent.stream;
-
-  Stream get stateChanged => _gameStateEvent.stream;
-
-  SquareState getSquareState(int x, int y) => _states.get(x,y);
-
-  bool get gameEnded => _state == GameState.won || _state == GameState.lost;
-
-  Duration get duration {
-    if(_startTime == null) {
-      assert(state == GameState.reset);
-      return null;
-    } else {
-      assert((state == GameState.started) == (_endTime == null));
-      final end = (_endTime == null) ? new DateTime.now() : _endTime;
-      return end.difference(_startTime);
-    }
-  }
-
-  bool canToggleFlag(int x, int y) {
-    final currentSS = _states.get(x,y);
-    return currentSS == SquareState.hidden ||
-        currentSS == SquareState.flagged;
-  }
-
-  void setFlag(int x, int y, bool value) {
-    _ensureStarted();
-    assert(value != null);
-
-    final currentSS = _states.get(x,y);
-    if(value) {
-      require(currentSS == SquareState.hidden);
-      _states.set(x,y,SquareState.flagged);
-      _bombsLeft--;
-    } else {
-      require(currentSS == SquareState.flagged);
-      _states.set(x,y,SquareState.hidden);
-      _bombsLeft++;
-    }
-    _update();
-  }
-
-  bool canReveal(int x, int y) {
-    final currentSS = _states.get(x,y);
-    if(currentSS == SquareState.hidden) {
-      return true;
-    } else if(_canChord(x, y)) {
-      return true;
-    }
-    return false;
-  }
-
-  List<Coordinate> reveal(int x, int y) {
-    _ensureStarted();
-    require(canReveal(x, y), "Item cannot be revealed.");
-    final currentSS = _states.get(x,y);
-
-    List<Coordinate> reveals;
-
-    // normal reveal
-    if(currentSS == SquareState.hidden) {
-      if(field.get(x, y)) {
-        _setLost();
-        reveals = <Coordinate>[];
-      } else {
-        reveals = _doReveal(x, y);
-      }
-    } else if(_canChord(x, y)) {
-      reveals = _doChord(x, y);
-    }
-    _update();
-
-    if(_state == GameState.lost) {
-      return null;
-    } else {
-      return reveals;
-    }
-  }
-
-  String toBoardString() {
-    final buffer = new StringBuffer();
-    for(var y = -2; y < field.height; y++) {
-      if(y > -2) {
-        buffer.write('\n');
-      }
-      for(var x = -2; x < field.width; x++) {
-        var char = null;
-        if(y == -2) {
-          if(x == -2) {
-            char = ' ';
-          } else if(x == -1) {
-            char = '|';
-          } else {
-            char = (x % 10).toString();
-          }
-        } else if(y == -1) {
-          if(x == -1) {
-            char = '+';
-          } else {
-            char = '-';
-          }
-        } else {
-          if(x == -2) {
-            char = (y % 10).toString();
-          } else if(x == -1) {
-            char = '|';
-          } else {
-            switch(getSquareState(x, y)) {
-              case SquareState.flagged:
-                char = '\u2611';
-                break;
-              case SquareState.revealed:
-                var count = field.getAdjacentCount(x, y);
-                char = count.toString();
-                break;
-              case SquareState.hidden:
-                char = '?';
-                break;
-            }
-          }
-        }
-        assert(char != null);
-        buffer.write(char);
-      }
-    }
-    return buffer.toString();
-  }
-
-  bool _canChord(int x, int y) {
-    final currentSS = _states.get(x,y);
-    if(currentSS == SquareState.revealed) {
-      // might be a 'chord' reveal
-      final adjCount = field.getAdjacentCount(x, y);
-      if(adjCount > 0) {
-        final adjHidden = _getAdjacentCount(x, y, SquareState.hidden);
-        if(adjHidden > 0) {
-          final adjFlags = _getAdjacentCount(x, y, SquareState.flagged);
-          if(adjFlags == adjCount) {
-            return true;
-          }
-        }
-      }
-    }
-    return false;
-  }
-
-  List<Coordinate> _doChord(int x, int y) {
-    // this does not repeat a bunch of validations that have already happened
-    // be careful
-    final currentSS = _states.get(x,y);
-    assert(currentSS == SquareState.revealed);
-
-    final flagged = new List<int>();
-    final hidden = new List<int>();
-    final adjCount = field.getAdjacentCount(x, y);
-    assert(adjCount > 0);
-
-    bool failed = false;
-
-    for(final i in field.getAdjacentIndices(x, y)) {
-      if(_states[i] == SquareState.hidden) {
-        hidden.add(i);
-        if(field[i]) {
-          failed = true;
-        }
-      } else if(_states[i] == SquareState.flagged) {
-        flagged.add(i);
-      }
-    }
-
-    // for now we assume counts have been checked
-    assert(flagged.length == adjCount);
-
-    var reveals = <Coordinate>[];
-
-    // if any of the hidden are bombs, we've failed
-    if(failed) {
-      // TODO: assert one of the flags must be wrong, right?
-      _setLost();
-    } else {
-      for(final i in hidden) {
-        final c = field.getCoordinate(i);
-        if(canReveal(c.item1, c.item2)) {
-          reveals.addAll(reveal(c.item1, c.item2));
-        }
-      }
-    }
-
-    return reveals;
-  }
-
-  List<Coordinate> _doReveal(int x, int y) {
-    assert(_states.get(x,y) == SquareState.hidden);
-    _states.set(x,y,SquareState.revealed);
-    _revealsLeft--;
-    assert(_revealsLeft >= 0);
-    var reveals = [new Coordinate(x, y)];
-    if(_revealsLeft == 0) {
-      _setWon();
-    } else if (field.getAdjacentCount(x, y) == 0) {
-      for(final i in field.getAdjacentIndices(x, y)) {
-        if(_states[i] == SquareState.hidden) {
-          final c = field.getCoordinate(i);
-          reveals.addAll(_doReveal(c.item1, c.item2));
-          assert(state == GameState.started || state == GameState.won);
-        }
-      }
-    }
-    return reveals;
-  }
-
-  void _setWon() {
-    assert(state == GameState.started);
-    for(int i = 0; i < field.length; i++) {
-      if(field[i]) {
-        _states[i] = SquareState.safe;
-      }
-    }
-    _setState(GameState.won);
-  }
-
-  void _setLost() {
-    assert(state == GameState.started);
-    for(int i = 0; i < field.length; i++) {
-      if(field[i]) {
-        _states[i] = SquareState.bomb;
-      }
-    }
-    _setState(GameState.lost);
-  }
-
-  void _update() => _updatedEvent.add(EventArgs.empty);
-
-  void _setState(GameState value) {
-    assert(value != null);
-    assert(_state != null);
-    assert((_state == GameState.reset) == (_startTime == null));
-    if(_state != value) {
-      _state = value;
-      if(_state == GameState.started) {
-        _startTime = new DateTime.now();
-      } else if(gameEnded) {
-        _endTime = new DateTime.now();
-      }
-      _gameStateEvent.add(_state);
-    }
-  }
-
-  void _ensureStarted() {
-    if(state == GameState.reset) {
-      assert(_startTime == null);
-      _setState(GameState.started);
-    }
-    assert(state == GameState.started);
-    assert(_startTime != null);
-  }
-
-  int _getAdjacentCount(int x, int y, SquareState state) {
-    int val = 0;
-    for(final i in field.getAdjacentIndices(x, y)) {
-      if(_states[i] == state) {
-        val++;
-      }
-    }
-    return val;
-  }
-}