private static string CreateStringFromCastlingRights(CastlingRights castlingRights)
{
string output = "";
if (castlingRights.HasFlag(CastlingRights.WhiteKingSide))
{
output += 'K';
}
if (castlingRights.HasFlag(CastlingRights.WhiteQueenSide))
{
output += 'Q';
}
if (castlingRights.HasFlag(CastlingRights.BlackKingSide))
{
output += 'k';
}
if (castlingRights.HasFlag(CastlingRights.BlackQueenSide))
{
output += 'q';
}
if (string.IsNullOrEmpty(output))
{
return("-");
}
else
{
return(output);
}
}
public FEN(string piecePlacement, Side activeSide, CastlingRights castlingAvailability, Square?enpassantTargetSquare, int halfmoveClock, int fullmoveNumber)
{
PiecePlacement = piecePlacement;
ActiveSide = activeSide;
CastlingAvailability = castlingAvailability;
EnpassantTargetSquare = enpassantTargetSquare;
HalfmoveClock = halfmoveClock;
FullmoveNumber = fullmoveNumber;
}
private static CastlingRights CreateCastlingRightsFromString(string castlingRightsString)
{
CastlingRights whiteKing = castlingRightsString.Contains('K') ? CastlingRights.WhiteKingSide : 0;
CastlingRights whiteQueen = castlingRightsString.Contains('Q') ? CastlingRights.WhiteQueenSide : 0;
CastlingRights blackKing = castlingRightsString.Contains('k') ? CastlingRights.BlackKingSide : 0;
CastlingRights blackQueen = castlingRightsString.Contains('q') ? CastlingRights.BlackQueenSide : 0;
return(whiteKing | whiteQueen | blackKing | blackQueen);
}
public static CastlingRights RemoveKingSide(this CastlingRights castlingRights, Side side)
{
castlingRights &= side switch
{
Side.White => ~CastlingRights.WhiteKingSide,
Side.Black => ~CastlingRights.BlackKingSide,
_ => throw new ArgumentOutOfRangeException(nameof(side))
};
return(castlingRights);
}
private void SetCastlingRights(CastlingRights rights)
{
if (SideToMove == Player.White)
{
WhiteCastlingRights &= rights;
}
else
{
BlackCastlingRights &= rights;
}
}
private static CastlingRights UpdateCastlingRightsForSide(CastlingRights castlingRights, Board newBoard, Side side)
{
if ((Castling.KingSideRookFrom(side) & newBoard[side, Piece.Rook]) == 0)
{
castlingRights = castlingRights.RemoveKingSide(side);
}
if ((Castling.QueenSideRookFrom(side) & newBoard[side, Piece.Rook]) == 0)
{
castlingRights = castlingRights.RemoveQueenSide(side);
}
return(castlingRights);
}
public static Position MakeMoveNoLegalCheck(this Position position, Move move)
{
Board board = position.Board;
ApplyMoveToBoard(board, move, out Piece fromPiece);
CastlingRights castlingRights = position.CastlingRights;
int halfMoveClock = position.HalfmoveClock;
Square? enPassantSquare = null;
if (move.Flags == MoveFlags.DoublePawnPush)
{
enPassantSquare = position.SideToMove switch
{
Side.White => move.From + 8,
Side.Black => move.From - 8,
_ => throw new IndexOutOfRangeException(nameof(position.SideToMove))
};
}
if (fromPiece == Piece.King)
{
castlingRights = castlingRights.RemoveBoth(position.SideToMove);
}
castlingRights = UpdateCastlingRightsForBothSides(board, castlingRights);
if (fromPiece == Piece.Pawn || move.IsCapture)
{
halfMoveClock = 0;
}
else
{
halfMoveClock++;
}
int fullMoveNumber = position.FullMoveNumber;
if (position.SideToMove == Side.Black)
{
fullMoveNumber++;
}
return(new Position(board, position.OpposingSide, enPassantSquare, castlingRights, halfMoveClock)
{
FullMoveNumber = fullMoveNumber
});
}
private static CastlingRights UpdateCastlingRightsForBothSides(Board newBoard, CastlingRights castlingRights)
{
castlingRights = UpdateCastlingRightsForSide(castlingRights, newBoard, Side.White);
castlingRights = UpdateCastlingRightsForSide(castlingRights, newBoard, Side.Black);
return(castlingRights);
}
public static ulong ForCastlingRights(CastlingRights castlingRights)
{
Debug.Assert(castlingRights.IsValid());
return(CastlingRightsKeys[(int)castlingRights]);
}
public static bool IsValid(this CastlingRights castlingRights) => castlingRights >= CastlingRights.None && castlingRights <= CastlingRights.All;
