public CheckersBoardView()
{
_selectedPositions = new JavaList <object>();
_boardGameEngine = new CheckersBoardGameEngine();
_checkersMinimax = new CheckersMinimax(_boardGameEngine);
ResetBoard();
}
private JavaList <object> GetComputerMinimaxMovements(CheckersBoardGameEngine boardGameEngine)
{
JavaList <object> bestMove = null;
int maxValue = int.MinValue;
var sucessors = boardGameEngine.FindAllLegalMovesForCurrentPlayer();
while (IsValidMove(sucessors))
{
var move = (JavaList <object>)sucessors.pop_front();
var nextBoard = boardGameEngine.Clone();
nextBoard.ApplyMove(move);
var value = PlayerMinMove(nextBoard, 1, maxValue, int.MaxValue);
if (value > maxValue)
{
Debug.WriteLine("Max value : " + value + " at depth : 0");
maxValue = value;
bestMove = move;
}
}
Debug.WriteLine("Move value selected : " + maxValue + " at depth : 0");
return(bestMove);
}
private int GetCurrentPlayerStrength(CheckersBoardGameEngine boardGameEngine)
{
var colorForce = 0;
var enemyForce = 0;
int colorKing = _computerPieceColor == CheckersBoardGameEngine.WhitePiece ? CheckersBoardGameEngine.WhiteKingPiece : CheckersBoardGameEngine.BlackKing;
try
{
for (var i = 0; i < 32; i++)
{
int piece = boardGameEngine.GetPieceAtPosition(i);
if (piece != CheckersBoardGameEngine.EmptyPiece)
{
if (piece == _computerPieceColor || piece == colorKing)
{
colorForce += GetPieceStrength(piece, i);
}
else
{
enemyForce += GetPieceStrength(piece, i);
}
}
}
}
catch (InvalidBoardCoordinateException ex)
{
Debug.WriteLine(ex.StackTrace);
Application.Exit();
}
return(colorForce - enemyForce);
}
private int PlayerMaxMove(CheckersBoardGameEngine boardGameEngine, int minimaxTreeDepth, int alphaCutOff, int betaCutOff)
{
if (TreeCutOffTest(boardGameEngine, minimaxTreeDepth))
{
return(GetCurrentPlayerStrength(boardGameEngine));
}
Debug.WriteLine("Max node at depth : " + minimaxTreeDepth + " with alpha : " + alphaCutOff +
" beta : " + betaCutOff);
var sucessors = boardGameEngine.FindAllLegalMovesForCurrentPlayer();
while (IsValidMove(sucessors))
{
var move = (JavaList <object>)sucessors.pop_front();
var nextBoard = boardGameEngine.Clone();
nextBoard.ApplyMove(move);
var value = PlayerMinMove(nextBoard, minimaxTreeDepth + 1, alphaCutOff, betaCutOff);
if (value > alphaCutOff)
{
alphaCutOff = value;
Debug.WriteLine("Max value : " + value + " at depth : " + minimaxTreeDepth);
}
if (alphaCutOff > betaCutOff)
{
Debug.WriteLine("Max value with prunning : " + betaCutOff + " at depth : " + minimaxTreeDepth);
Debug.WriteLine(sucessors.Count + " sucessors left");
return(betaCutOff);
}
}
Debug.WriteLine("Max value selected : " + alphaCutOff + " at depth : " + minimaxTreeDepth);
return(alphaCutOff);
}
public CheckersMinimax(CheckersBoardGameEngine gameBoardGameEngine)
{
_currentBoardGameEngine = gameBoardGameEngine;
_computerPieceColor = CheckersBoardGameEngine.BlackPiece;
}
private bool TreeCutOffTest(CheckersBoardGameEngine boardGameEngine, int minimaxTreeDepth)
{
return(minimaxTreeDepth > DefaultMinimaxTreeDepth || boardGameEngine.IsGameOver());
}