public PolyglotBoard()
{
_state = new PieceType[8, 8];
_castlingFlags = CastlingFlags.Everything;
_colorToMove = ColorType.White;
_enPassantFile = -1;
}
public void MakeMove(string move)
{
var(fromFile, fromRank) = (move[0] - 'a', move[1] - '1');
var(toFile, toRank) = (move[2] - 'a', move[3] - '1');
var pieceType = _state[fromFile, fromRank];
var oldEnPassant = _enPassantFile;
// Pieces
_state[toFile, toRank] = _state[fromFile, fromRank];
_state[fromFile, fromRank] = PieceType.None;
_enPassantFile = -1;
// Castling
if (pieceType == PieceType.WhiteKing)
{
_castlingFlags &= ~CastlingFlags.WhiteCastling;
if (Math.Abs(fromFile - toFile) == 2)
{
// Short castling
if (fromFile < toFile)
{
_state[7, 0] = PieceType.None;
_state[5, 0] = PieceType.WhiteRook;
}
// Long castling
else
{
_state[0, 0] = PieceType.None;
_state[3, 0] = PieceType.WhiteRook;
}
}
}
else if (pieceType == PieceType.BlackKing)
{
_castlingFlags &= ~CastlingFlags.BlackCastling;
if (Math.Abs(fromFile - toFile) == 2)
{
// Short castling
if (fromFile < toFile)
{
_state[7, 7] = PieceType.None;
_state[5, 7] = PieceType.BlackRook;
}
// Long castling
else
{
_state[0, 7] = PieceType.None;
_state[3, 7] = PieceType.BlackRook;
}
}
}
else if (pieceType == PieceType.WhiteRook && fromFile == 0 && fromRank == 0)
{
_castlingFlags &= ~CastlingFlags.WhiteLong;
}
else if (pieceType == PieceType.WhiteRook && fromFile == 7 && fromRank == 0)
{
_castlingFlags &= ~CastlingFlags.WhiteShort;
}
else if (pieceType == PieceType.BlackRook && fromFile == 0 && fromRank == 7)
{
_castlingFlags &= ~CastlingFlags.BlackLong;
}
else if (pieceType == PieceType.BlackRook && fromFile == 7 && fromRank == 7)
{
_castlingFlags &= ~CastlingFlags.BlackShort;
}
// En passant
if (pieceType == PieceType.WhitePawn || pieceType == PieceType.BlackPawn)
{
if (Math.Abs(fromRank - toRank) == 2)
{
var targetPieceType = _colorToMove == ColorType.White ? PieceType.BlackPawn : PieceType.WhitePawn;
if (toFile > 0 && _state[toFile - 1, toRank] == targetPieceType ||
toFile < 7 && _state[toFile + 1, toRank] == targetPieceType)
{
_enPassantFile = toFile;
}
}
else if (Math.Abs(fromFile - toFile) == 1 && toFile == oldEnPassant)
{
if (_colorToMove == ColorType.White)
{
_state[toFile, toRank - 1] = PieceType.None;
}
else if (_colorToMove == ColorType.Black)
{
_state[toFile, toRank + 1] = PieceType.None;
}
}
}
// Color
_colorToMove = _colorToMove == ColorType.White ? ColorType.Black : ColorType.White;
}
