public Panel bestMove(BoardGen board, double alpha, double beta)
{
Panel bestMove = null;
double bestVal = 100000;
bool removed = false;
Piece removedPiece = null;
board.setPanelsInUse();
allPossibleBMoves = board.getAllPossibleBMoves(board);
allPossibleWMoves = board.getAllPossibleWMoves(board);
possibleWPieces = board.getPossibleWPieces();
possibleBPieces = board.getPossibleBPieces();
for (var i = 0; i < allPossibleBMoves.Count(); i++)
{
Panel temp = possibleBPieces[i].getPanel();
if (board.getPanelsInUse().Contains(allPossibleBMoves[i]))
{
foreach (Piece y in board.getPieces().ToList())
{
if (y.getPanel() == allPossibleBMoves[i])
{
removedPiece = y;
removed = true;
board.RemovePiece(y);
//take piece if we're taking a piece
}
}
}
possibleBPieces[i].setPanel(allPossibleBMoves[i]);
board.setPanelsInUse();
board.getAllPossibleWMoves(board);
board.getPossibleWPieces();
double tempVal = minimax(board, true, 1, board.getAllPossibleWMoves(board),
board.getPossibleWPieces(), alpha, beta);
//start a search on this move to see where it leads
if (tempVal < bestVal)
{
bestVal = tempVal;
beta = tempVal;
bestMove = allPossibleBMoves[i];
piece = possibleBPieces[i];
//if this move leads to a good board value then tempVal will be small/more
//negative.If it is then we update bestVal, update beta and update the best
//move and the piece it moves to get there
}
possibleBPieces[i].setPanel(temp);
if (removed)
{
removed = false;
board.AddPiece(removedPiece);
//return the removed piece to its position
}
board.setPanelsInUse();
//update board
}
return(bestMove);
//returns the best move we found
}
public double minimax(BoardGen board, bool max, int depth, List <Panel>
possibleMoves, List <Piece> possiblePieces, double alpha,
double beta)
{
double bestValue;
bool removed = false;
Piece removedPiece = null;
board.setPanelsInUse();
if (depth == 0)
{
return(getBoardValue(board));
//We have searched as far as we need to and can return what the board value
//would be in this position
}
if (max) //if the player is trying to maximise score
{
double bestVal = -100000; //set bestVal to some very large negative number so
//that it easily beaten
for (var i = 0; i < possibleMoves.Count(); i++) //for every move possible from
//this position
{
Panel temp = possiblePieces[i].getPanel();
if (board.getPanelsInUse().Contains(possibleMoves[i]))
{
foreach (Piece y in board.getPieces().ToList())
{
if (y.getPanel() == possibleMoves[i])
{
removedPiece = y;
removed = true;
board.RemovePiece(y);
//take piece if we're taking a piece
}
}
}
possiblePieces[i].setPanel(possibleMoves[i]);
board.setPanelsInUse();
board.getAllPossibleWMoves(board);
board.getPossibleWPieces();
//update the board for one of the possible moves
double tempVal = minimax(board, !max, depth - 1,
board.getAllPossibleBMoves(board),
board.getPossibleBPieces(), alpha, beta);
//dive deeper into a search looking ahead by 1 furhter witht tempVal
if (tempVal > bestVal)
{
bestVal = tempVal;
alpha = tempVal;
//if tempVal is better than the current bestVal then this is the new
//tempVal and alpha is set to tempVal
}
possiblePieces[i].setPanel(temp);
if (removed)
{
removed = false;
board.AddPiece(removedPiece);
//put taken piece back
}
board.setPanelsInUse();
if (alpha >= beta)
{
return(bestVal);
//If alpha is greater or equal to beta we can prune the search
}
}
bestValue = bestVal;
}
else
{
double bestVal = 100000; //We're minimising so some large value will be easily
//beaten here
for (var i = 0; i < possibleMoves.Count(); i++)
{
Panel temp = possiblePieces[i].getPanel();
if (board.getPanelsInUse().Contains(possibleMoves[i]))
{
foreach (Piece y in board.getPieces().ToList())
{
if (y.getPanel() == possibleMoves[i])
{
removedPiece = y;
removed = true;
board.RemovePiece(y);
//take piece if we're taking a piece
}
}
}
possiblePieces[i].setPanel(possibleMoves[i]);
board.setPanelsInUse();
board.getAllPossibleBMoves(board);
board.getPossibleBPieces();
//update the board to do this move
double tempVal = minimax(board, !max, depth - 1,
board.getAllPossibleWMoves(board),
board.getPossibleWPieces(), alpha, beta);
//go deeper to see if this move will lead anywhere good
beta = Math.Min(beta, tempVal);
if (tempVal < bestVal)
{
bestVal = tempVal;
beta = tempVal;
//if this move leads somewhere good then tempVal will be less than bestVal
//as black tries to minimise, so this val is set to bestVal
}
possiblePieces[i].setPanel(temp);
if (removed)
{
removed = false;
board.AddPiece(removedPiece);
//return the piece that was taken
}
board.setPanelsInUse();
if (alpha >= beta)
{
return(bestVal);
//if alpha is greater than beta then we can prune the search a bit
}
}
bestValue = bestVal;
}
return(bestValue);
//return the best value we have found
}