private void MakeNextMove()
{
Move bestMove = new Move()
{
Column = -1,
Row = -1
};
int bestScore = int.MinValue;
// check every valid move for this particular board, then select the one with the best 'score'
List<Move> moves = ValidMovesForBoard(_viewModel);
foreach (Move nextMove in moves)
{
// clone the current board and make this move
GameBoardViewModel testBoard = new GameBoardViewModel(_viewModel);
testBoard.MakeMove(nextMove.Row, nextMove.Column);
// determine the score for this move
int scoreForMove = ScoreForBoard(testBoard, 1);
// pick the best
if (scoreForMove > bestScore || bestScore == int.MinValue)
{
bestScore = scoreForMove;
bestMove.Row = nextMove.Row;
bestMove.Column = nextMove.Column;
}
}
if (bestMove.Column != -1 && bestMove.Row != -1)
{
_viewModel.MakeMove(bestMove.Row, bestMove.Column);
}
}
public GameBoardViewModel(GameBoardViewModel copy)
{
_squares = copy._squares.Select(s => new GameBoardSquareViewModel(s.Row, s.Column, this)
{
State = s.State
}).ToList();
_nextMove = copy._nextMove;
}
public ReversiView()
{
this.InitializeComponent();
var vm = new GameBoardViewModel();
var comp = new ComputerOpponent(vm, BoardSquareState.WHITE, 5);
DataContext = vm;
}
public ComputerOpponent(GameBoardViewModel viewModel, BoardSquareState computerColor, int maxDepth)
{
_maxDepth = maxDepth;
_computerColor = computerColor;
_viewModel = viewModel;
_viewModel.PropertyChanged += GameBoardViewModel_PropertyChanged;
MakeMoveIfCorrectTurn();
}
// Computes the score for the given board
private int ScoreForBoard(GameBoardViewModel board, int depth)
{
// if we have reached the maximum search depth, then just compute the score of the current
// board state
if (depth >= _maxDepth)
{
return(_computerColor == BoardSquareState.WHITE ?
board.WhiteScore - board.BlackScore :
board.BlackScore - board.WhiteScore);
}
int minMax = int.MinValue;
// check every valid next move for this particular board
List <Move> moves = ValidMovesForBoard(board);
foreach (Move nextMove in moves)
{
// clone the current board and make the move
GameBoardViewModel testBoard = new GameBoardViewModel(board);
testBoard.MakeMove(nextMove.Row, nextMove.Column);
// compute the score for this board
int score = ScoreForBoard(testBoard, depth + 1);
// pick the best score
if (depth % 2 == 0)
{
if (score > minMax || minMax == int.MinValue)
{
minMax = score;
}
}
else
{
if (score < minMax || minMax == int.MinValue)
{
minMax = score;
}
}
}
return(minMax);
}
// returns an array of valid next moves for the given board
private List <Move> ValidMovesForBoard(GameBoardViewModel viewModel)
{
List <Move> moves = new List <Move>();
for (int row = 0; row < 8; row++)
{
for (int col = 0; col < 8; col++)
{
if (viewModel.IsValidMove(row, col))
{
moves.Add(new Move()
{
Row = row,
Column = col
});
}
}
}
return(moves);
}
public GameBoardSquareViewModel(int row, int col, GameBoardViewModel parent)
{
Column = col;
Row = row;
_parent = parent;
}
public GameBoardSquareViewModel(int row, int col, GameBoardViewModel parent)
{
Column = col;
Row = row;
_parent = parent;
}
// Computes the score for the given board
private int ScoreForBoard(GameBoardViewModel board, int depth)
{
// if we have reached the maximum search depth, then just compute the score of the current
// board state
if (depth >= _maxDepth)
{
return _computerColor == BoardSquareState.WHITE ?
board.WhiteScore - board.BlackScore :
board.BlackScore - board.WhiteScore;
}
int minMax = int.MinValue;
// check every valid next move for this particular board
List<Move> moves = ValidMovesForBoard(board);
foreach (Move nextMove in moves)
{
// clone the current board and make the move
GameBoardViewModel testBoard = new GameBoardViewModel(board);
testBoard.MakeMove(nextMove.Row, nextMove.Column);
// compute the score for this board
int score = ScoreForBoard(testBoard, depth + 1);
// pick the best score
if (depth % 2 == 0)
{
if (score > minMax || minMax == int.MinValue)
{
minMax = score;
}
}
else
{
if (score < minMax || minMax == int.MinValue)
{
minMax = score;
}
}
}
return minMax;
}
// returns an array of valid next moves for the given board
private List<Move> ValidMovesForBoard(GameBoardViewModel viewModel)
{
List<Move> moves = new List<Move>();
for (int row = 0; row < 8; row++)
{
for (int col = 0; col < 8; col++)
{
if (viewModel.IsValidMove(row, col))
{
moves.Add(new Move()
{
Row = row,
Column = col
});
}
}
}
return moves;
}
