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);
}
internal static void AddCastlingMoves(Position position, List <Move> allMoves)
{
Side side = position.SideToMove;
Board board = position.Board;
if (board[side, Piece.King] == 0)
{
return;
}
if (Castling.CanCastleKingside(position.CastlingRights, side))
{
var kingsideBetween = Castling.KingSideBetween(side);
bool spaceAvailable = BitUtils.IsASubsetOfB(kingsideBetween, board.EmptySquares);
var kingsideChecks = Castling.KingSideChecks(side);
Bitboard enemyAttacks = board.AttacksBy(position.OpposingSide);
bool avoidsChecks = (kingsideChecks & enemyAttacks) == 0;
if (spaceAvailable && avoidsChecks)
{
Bitboard king = board[side, Piece.King];
Bitboard castleTarget = king.EastOne().EastOne();
Square from = (Square)king.Serialize()[0];
Square to = (Square)castleTarget.Serialize()[0];
allMoves.Add(new Move(from, to, MoveFlags.KingCastle));
}
}
if (Castling.CanCastleQueenside(position.CastlingRights, side))
{
var queensideBetween = Castling.QueenSideBetween(side);
bool spaceAvailable = BitUtils.IsASubsetOfB(queensideBetween, board.EmptySquares);
var queensideChecks = Castling.QueenSideChecks(side);
Bitboard enemyAttacks = board.AttacksBy(position.OpposingSide);
bool avoidsChecks = (queensideChecks & enemyAttacks) == 0;
if (spaceAvailable && avoidsChecks)
{
Bitboard king = board[side, Piece.King];
Bitboard castleTarget = king.WestOne().WestOne();
Square from = (Square)king.Serialize()[0];
Square to = (Square)castleTarget.Serialize()[0];
allMoves.Add(new Move(from, to, MoveFlags.QueenCastle));
}
}
}
public static void ApplyMoveToBoard(Board board, Move move, out Piece fromPiece)
{
(Side fromSide, Piece fromPiece_) = board.GetPieceOnSquare(move.From);
fromPiece = fromPiece_;
Bitboard from = Bitboard.FromSquare(move.From);
Bitboard to = Bitboard.FromSquare(move.To);
Bitboard fromTo = from | to;
if (move.Flags == MoveFlags.EnPassantCapture)
{
Bitboard capturedPawn = fromSide switch
{
Side.White => to.SoutOne(),
Side.Black => to.NortOne(),
_ => throw new IndexOutOfRangeException(nameof(fromSide))
};
board[fromSide.OpposingSide(), Piece.Pawn] ^= capturedPawn;
}
else if (move.IsCapture)
{
(Side toSide, Piece toPiece) = board.GetPieceOnSquare(move.To);
board[toSide, toPiece] ^= to;
}
else if (move.Flags == MoveFlags.KingCastle)
{
board[fromSide, Piece.Rook] ^= Castling.KingSideRookToFrom(fromSide);
}
else if (move.Flags == MoveFlags.QueenCastle)
{
board[fromSide, Piece.Rook] ^= Castling.QueenSideRookToFrom(fromSide);
}
board[fromSide, fromPiece] ^= fromTo;
if (move.IsPromotion)
{
board[fromSide, fromPiece] ^= to;
board[fromSide, move.PromotionPiece !.Value] ^= to;