private void CheckCardinalDirections(Board board)
{
foreach (int fileOffset in new[] { -1, 0, 1 })
{
foreach (int rankOffset in Math.Abs(fileOffset) == 1 ? new[] { 0 } : new[] { -1, 1 })
{
Square testSquare = new Square(Position, fileOffset, rankOffset);
Movement testMove = new Movement(Position, testSquare);
while (testSquare.IsValid)
{
Square enemyKingPosition = Color == Side.White ? board.BlackKing.Position : board.WhiteKing.Position;
if (board.IsOccupied(testSquare))
{
if (!board.IsOccupiedBySide(testSquare, Color) && Rules.MoveObeysRules(board, testMove, Color) && testSquare != enemyKingPosition)
{
LegalMoves.Add(new Movement(testMove));
}
break;
}
if (Rules.MoveObeysRules(board, testMove, Color) && testSquare != enemyKingPosition)
{
LegalMoves.Add(new Movement(testMove));
}
testSquare = new Square(testSquare, fileOffset, rankOffset);
testMove = new Movement(Position, testSquare);
}
}
}
}
public bool canCastleQueenside() //returns true if the king can castle queenside (from E file to C file)
{
Piece rook = new Piece();
Coordinate pTmp = new Coordinate(Position);
pTmp.changeFile(-4); //moves from E file to A file
rook = board.board[pTmp.Rank, pTmp.File];
if (rook == null) //there is no piece where rook should be
{
return(false);
}
if (!(rook is Rook)) //the piece there is not a rook
{
return(false);
}
if (rook.hasMoved == true) //the rook there has already moved
{
return(false);
}
//figure out if the squares between the rook and king are empty MOVE TO POSSIBLE/LEGAL MOVES
pTmp.changeFile(1);
if (board.isTherePiece(pTmp) == true) //if there is a piece on B file
{
return(false);
}
pTmp.changeFile(1);
if (board.isTherePiece(pTmp) == true) //if there is a piece on C file
{
return(false);
}
if (IntoCheck(pTmp)) //if being on C file would cause check
{
return(false);
}
pTmp.changeFile(1);
if (board.isTherePiece(pTmp) == true) //if there is a piece on the D file
{
return(false);
}
if (IntoCheck(pTmp)) //if being on the D file would cause check
{
return(false);
}
if (board.inCheck(Color)) //if the king is already in check
{
return(false);
}
//if all of these are false and it has reached here, castling kingside is legal
pTmp.changeFile(-1); //moves pTmp from D file to C file
LegalMoves.Add(pTmp);
return(true);
}
private void CheckAttackingSquares(Board board)
{
foreach (int fileOffset in new[] { -1, 1 })
{
int rankOffset = Color == Side.White ? 1 : -1;
Square testSquare = new Square(Position, fileOffset, rankOffset);
Movement testMove = new Movement(Position, testSquare);
Square enemyKingPosition = Color == Side.White ? board.BlackKing.Position : board.WhiteKing.Position;
if (testSquare.IsValid && board.IsOccupiedBySide(testSquare, Color.Complement()) && Rules.MoveObeysRules(board, testMove, Color) && testSquare != enemyKingPosition)
{
bool pawnAtSecondToLastRank = Position.Rank == (Color == Side.White ? 7 : 2);
Movement move = pawnAtSecondToLastRank ? new PromotionMove(Position, testSquare) : new Movement(testMove);
LegalMoves.Add(move);
}
}
}
private void CheckSurroundingSquares(Board board)
{
for (int fileOffset = -1; fileOffset <= 1; fileOffset++)
{
for (int rankOffset = -1; rankOffset <= 1; rankOffset++)
{
if (fileOffset == 0 && rankOffset == 0)
{
continue;
}
Square testSquare = new Square(Position, fileOffset, rankOffset);
Movement testMove = new Movement(Position, testSquare);
Square enemyKingPosition = Color == Side.White ? board.BlackKing.Position : board.WhiteKing.Position;
if (testSquare.IsValid && !board.IsOccupiedBySide(testSquare, Color) && Rules.MoveObeysRules(board, testMove, Color) && testSquare != enemyKingPosition)
{
LegalMoves.Add(new Movement(testMove));
}
}
}
}
private void CheckCastlingMoves(Board board)
{
if (!HasMoved && !Rules.IsPlayerInCheck(board, Color))
{
int castlingRank = Color == Side.White ? 1 : 8;
List <Square> rookSquares = new List <Square> {
new Square(1, castlingRank), new Square(8, castlingRank)
};
List <Square> inBetweenSquares = new List <Square>();
List <Movement> inBetweenMoves = new List <Movement>();
for (int rookSquareIndex = 0; rookSquareIndex < rookSquares.Count; rookSquareIndex++)
{
if (board[rookSquares[rookSquareIndex]] is Rook rook && !rook.HasMoved && rook.Color == Color)
{
bool checkingQueensideCastle = rookSquareIndex == 0;
inBetweenSquares.Add(new Square(checkingQueensideCastle ? 4 : 6, castlingRank));
inBetweenSquares.Add(new Square(checkingQueensideCastle ? 3 : 7, castlingRank));
if (checkingQueensideCastle)
{
inBetweenSquares.Add(new Square(2, castlingRank));
}
if (!board.IsOccupied(inBetweenSquares[0]) && !board.IsOccupied(inBetweenSquares[1]) && (!checkingQueensideCastle || !board.IsOccupied(inBetweenSquares[2])))
{
inBetweenMoves.Add(new Movement(Position, inBetweenSquares[0]));
inBetweenMoves.Add(new Movement(Position, inBetweenSquares[1]));
if (Rules.MoveObeysRules(board, inBetweenMoves[0], Color) && Rules.MoveObeysRules(board, inBetweenMoves[1], Color))
{
LegalMoves.Add(new CastlingMove(Position, inBetweenSquares[1], rook));
}
}
inBetweenSquares.Clear();
inBetweenMoves.Clear();
}
}
}
}
private void CheckKnightCircleSquares(Board board)
{
for (int fileOffset = -2; fileOffset <= 2; fileOffset++)
{
if (fileOffset == 0)
{
continue;
}
foreach (int rankOffset in Math.Abs(fileOffset) == 2 ? new[] { -1, 1 } : new[] { -2, 2 })
{
Square testSquare = new Square(Position, fileOffset, rankOffset);
Movement testMove = new Movement(Position, testSquare);
Square enemyKingPosition = Color == Side.White ? board.BlackKing.Position : board.WhiteKing.Position;
if (testSquare.IsValid && !board.IsOccupiedBySide(testSquare, Color) && Rules.MoveObeysRules(board, testMove, Color) && testSquare != enemyKingPosition)
{
LegalMoves.Add(new Movement(testMove));
}
}
}
}
private void CheckForwardMovingSquares(Board board)
{
int advancingDirection = Color == Side.White ? 1 : -1;
Square testSquare = new Square(Position, 0, advancingDirection);
Movement testMove = new Movement(Position, testSquare);
if (!board.IsOccupied(testSquare) && Rules.MoveObeysRules(board, testMove, Color))
{
bool amOnSecondToLastRank = Position.Rank == (Color == Side.White ? 7 : 2);
LegalMoves.Add(amOnSecondToLastRank ? new PromotionMove(Position, testSquare) : new Movement(testMove));
}
if (!HasMoved)
{
testSquare = new Square(testSquare, 0, advancingDirection);
testMove = new Movement(Position, testSquare);
if (!board.IsOccupied(testSquare) && Rules.MoveObeysRules(board, testMove, Color))
{
LegalMoves.Add(new Movement(testMove));
}
}
}
private void CheckEnPassantCaptures(Board board, Square enPassantEligibleSquare)
{
if (Color == Side.White ? Position.Rank == 5 : Position.Rank == 4)
{
foreach (int fileOffset in new[] { -1, 1 })
{
Square lateralSquare = new Square(Position, fileOffset, 0);
if (lateralSquare.IsValid && board[lateralSquare] is Pawn enemyLateralPawn && enemyLateralPawn.Color != Color)
{
Square squareToCheckWithEligibleSquare = new Square(enemyLateralPawn.Position, 0, enemyLateralPawn.Color == Side.White ? -1 : 1);
if (squareToCheckWithEligibleSquare.Equals(enPassantEligibleSquare))
{
EnPassantMove testMove = new EnPassantMove(Position, enPassantEligibleSquare, enemyLateralPawn);
if (Rules.MoveObeysRules(board, testMove, Color))
{
LegalMoves.Add(new EnPassantMove(Position, enPassantEligibleSquare, enemyLateralPawn));
}
}
}
}
}
}
