/*
* Remove castling flags that arent valid
*/
private static void removeInvalidCastleFlags(Position position)
{
int castleMask = position.getCastleMask();
int validCastle = 0;
if (position.getPiece(4) == PieceType.K)
{
if (position.getPiece(0) == PieceType.R) validCastle |= (1 << Position.A1_CASTLE);
if (position.getPiece(7) == PieceType.R) validCastle |= (1 << Position.H1_CASTLE);
}
if (position.getPiece(60) == PieceType.k)
{
if (position.getPiece(56) == PieceType.r) validCastle |= (1 << Position.A8_CASTLE);
if (position.getPiece(63) == PieceType.r) validCastle |= (1 << Position.H8_CASTLE);
}
castleMask &= validCastle;
position.setCastleMask(castleMask);
}
/*
* Generate and return a list of psuedo-legal moves.
* Pseudo-legal moves are those that don't necessarily defend
* from check threats.
*/
public ArrayList psuedoLegalMoves(Position position)
{
ArrayList moveList = getMoveListObject();
Boolean whiteToMove = position.whiteMove;
for (int file = 0; file < 8; file++)
{
for (int rank = 0; rank < 8; rank++)
{
int square = Position.getSquare(file, rank);
PieceType piece = position.getPiece(square);
if ((piece == PieceType.Empty) || (((int)piece < 6) != whiteToMove))
{
continue;
}
if ((piece == PieceType.R) || (piece == PieceType.r) || (piece == PieceType.Q) || (piece == PieceType.q))
{
if (addDirection(moveList, position, square, 7 - file, 1)) return moveList;
if (addDirection(moveList, position, square, 7 - rank, 8)) return moveList;
if (addDirection(moveList, position, square, file, -1)) return moveList;
if (addDirection(moveList, position, square, rank, -8)) return moveList;
}
if ((piece == PieceType.B) || (piece == PieceType.b) || (piece == PieceType.Q) || (piece == PieceType.q))
{
if (addDirection(moveList, position, square, Math.Min(7 - file, 7 - rank), 9)) return moveList;
if (addDirection(moveList, position, square, Math.Min(file, 7 - rank), 7)) return moveList;
if (addDirection(moveList, position, square, Math.Min(file, rank), -9)) return moveList;
if (addDirection(moveList, position, square, Math.Min(7 - file, rank), -7)) return moveList;
}
if ((piece == PieceType.N) || (piece == PieceType.n))
{
if (file < 6 && rank < 7 && addDirection(moveList, position, square, 1, 10)) return moveList;
if (file < 7 && rank < 6 && addDirection(moveList, position, square, 1, 17)) return moveList;
if (file > 0 && rank < 6 && addDirection(moveList, position, square, 1, 15)) return moveList;
if (file > 1 && rank < 7 && addDirection(moveList, position, square, 1, 6)) return moveList;
if (file > 1 && rank > 0 && addDirection(moveList, position, square, 1, -10)) return moveList;
if (file > 0 && rank > 1 && addDirection(moveList, position, square, 1, -17)) return moveList;
if (file < 7 && rank > 1 && addDirection(moveList, position, square, 1, -15)) return moveList;
if (file < 6 && rank > 0 && addDirection(moveList, position, square, 1, -6)) return moveList;
}
if ((piece == PieceType.K) || (piece == PieceType.k))
{
if (file < 7 && addDirection(moveList, position, square, 1, 1)) return moveList;
if (file < 7 && rank < 7 && addDirection(moveList, position, square, 1, 9)) return moveList;
if (rank < 7 && addDirection(moveList, position, square, 1, 8)) return moveList;
if (file > 0 && rank < 7 && addDirection(moveList, position, square, 1, 7)) return moveList;
if (file > 0 && addDirection(moveList, position, square, 1, -1)) return moveList;
if (file > 0 && rank > 0 && addDirection(moveList, position, square, 1, -9)) return moveList;
if (rank > 0 && addDirection(moveList, position, square, 1, -8)) return moveList;
if (file < 7 && rank > 0 && addDirection(moveList, position, square, 1, -7)) return moveList;
int kingOrigin = whiteToMove ? Position.getSquare(4, 0) : Position.getSquare(4, 7);
if (Position.getSquare(file, rank) == kingOrigin)
{
int aCastle = whiteToMove ? Position.A1_CASTLE : Position.A8_CASTLE;
int hCastle = whiteToMove ? Position.H1_CASTLE : Position.H8_CASTLE;
PieceType rook = whiteToMove ? PieceType.R : PieceType.r;
if (((position.getCastleMask() & (1 << hCastle)) != 0) &&
(position.getPiece(kingOrigin + 1) == PieceType.Empty) &&
(position.getPiece(kingOrigin + 2) == PieceType.Empty) &&
(position.getPiece(kingOrigin + 3) == rook) &&
!squareAttacked(position, kingOrigin) &&
!squareAttacked(position, kingOrigin + 1) &&
!squareAttacked(position, kingOrigin + 2))
{
moveList.Add(getMoveObject(kingOrigin, kingOrigin + 2, PieceType.Empty));
}
if (((position.getCastleMask() & (1 << aCastle)) != 0) &&
(position.getPiece(kingOrigin - 1) == PieceType.Empty) &&
(position.getPiece(kingOrigin - 2) == PieceType.Empty) &&
(position.getPiece(kingOrigin - 3) == PieceType.Empty) &&
(position.getPiece(kingOrigin - 4) == rook) &&
!squareAttacked(position, kingOrigin) &&
!squareAttacked(position, kingOrigin - 1) &&
!squareAttacked(position, kingOrigin - 2))
{
moveList.Add(getMoveObject(kingOrigin, kingOrigin - 2, PieceType.Empty));
}
}
}
if ((piece == PieceType.P) || (piece == PieceType.p))
{
int rankDir = whiteToMove ? 8 : -8;
if (position.getPiece(square + rankDir) == PieceType.Empty)
{
//non capture moves
addPawnMoves(moveList, square, square + rankDir);
if ((rank == (whiteToMove ? 1 : 6)) &&
(position.getPiece(square + 2 * rankDir) == PieceType.Empty))
{
//double step moves
addPawnMoves(moveList, square, square + rankDir * 2);
}
}
//Capture to the left
if (file > 0)
{
int toSquare = square + rankDir - 1;
PieceType captured = position.getPiece(toSquare);
if (captured != PieceType.Empty)
{
if (((int)captured < 6) != whiteToMove)
{
if (captured == (whiteToMove ? PieceType.k : PieceType.K))
{
returnMoveList(moveList);
moveList = getMoveListObject();
moveList.Add(getMoveObject(square, toSquare, PieceType.Empty));
return moveList;
}
else
{
addPawnMoves(moveList, square, toSquare);
}
}
}
else if (toSquare == position.getEpSquare())
{
addPawnMoves(moveList, square, toSquare);
}
}
//Capture to the right
if (file < 7)
{
int toSquare = square + rankDir + 1;
PieceType captured = position.getPiece(toSquare);
if (captured != PieceType.Empty)
{
if (((int)captured < 6) != whiteToMove)
{
if (captured == (whiteToMove ? PieceType.k : PieceType.K))
{
returnMoveList(moveList);
moveList = getMoveListObject();
moveList.Add(getMoveObject(square, toSquare, PieceType.Empty));
return moveList;
}
else
{
addPawnMoves(moveList, square, toSquare);
}
}
}
else if (toSquare == position.getEpSquare())
{
addPawnMoves(moveList, square, toSquare);
}
}
}
}
}
return moveList;
}
