156 lines
3.8 KiB
Java
156 lines
3.8 KiB
Java
package chess.model.rules;
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import chess.model.ChessBoard;
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import chess.model.Color;
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import chess.model.Coordinate;
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import chess.model.Direction;
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import chess.model.Move;
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import chess.model.Piece;
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import chess.model.PieceVisitor;
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import chess.model.pieces.Bishop;
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import chess.model.pieces.King;
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import chess.model.pieces.Knight;
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import chess.model.pieces.Pawn;
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import chess.model.pieces.Queen;
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import chess.model.pieces.Rook;
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/**
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* Check if there are pieces in the path of a move.
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*/
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public class PiecePathChecker implements PieceVisitor<Boolean> {
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private final ChessBoard board;
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private final Move move;
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public PiecePathChecker(ChessBoard board, Move move) {
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this.move = move;
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this.board = board;
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}
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public boolean isValid() {
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if (this.move.getStart().equals(this.move.getFinish()))
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return false;
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Piece piece = this.board.pieceAt(move.getStart());
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if (piece == null)
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return false;
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return visit(piece);
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}
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@Override
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public Boolean visitPiece(Bishop bishop) {
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return basicCheck(bishop);
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}
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@Override
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public Boolean visitPiece(King king) {
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return destCheck(king);
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}
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@Override
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public Boolean visitPiece(Knight knight) {
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return destCheck(knight);
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}
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@Override
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public Boolean visitPiece(Queen queen) {
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return basicCheck(queen);
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}
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@Override
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public Boolean visitPiece(Rook rook) {
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return basicCheck(rook);
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}
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@Override
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public Boolean visitPiece(Pawn pawn) {
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if (!new PermissiveRuleChecker(this.move).isValidFor(pawn))
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return false;
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Direction moveDirection = Direction.fromInt(Direction.findDirection(move).getIndexOffset() * pawn.multiplier());
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if (moveDirection == Direction.Front)
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return testPath(pawn.getColor()) && this.board.pieceAt(this.move.getFinish()) == null;
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assert moveDirection == Direction.FrontLeft || moveDirection == Direction.FrontRight;
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if (checkEnPassant())
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return true;
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Piece destPiece = this.board.pieceAt(this.move.getFinish());
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if (destPiece == null)
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return false;
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return destPiece.getColor() != pawn.getColor();
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}
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private boolean checkEnPassant() {
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Move lastMove = this.board.getLastMove();
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if (lastMove == null)
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return false;
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Piece pieceToEat = this.board.pieceAt(lastMove.getFinish());
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if (pieceToEat == null || !(pieceToEat instanceof Pawn))
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return false;
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Piece pawn = this.board.pieceAt(this.move.getStart());
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if (pieceToEat.getColor() == pawn.getColor())
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return false;
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Direction lastMoveDir = Direction.findDirection(lastMove);
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if ((lastMoveDir != Direction.Front && lastMoveDir != Direction.Back) || lastMove.traversedCells() != 2)
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return false;
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Coordinate middle = lastMove.getMiddle();
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if (middle.equals(this.move.getFinish())
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&& pieceToEat instanceof Pawn) {
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this.move.setDeadPieceCoords(lastMove.getFinish());
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return true;
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}
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return false;
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}
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private boolean destCheck(Piece piece) {
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if (!new PermissiveRuleChecker(this.move).isValidFor(piece))
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return false;
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Piece destPiece = board.pieceAt(this.move.getFinish());
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if (destPiece == null)
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return true;
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return destPiece.getColor() != piece.getColor();
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}
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private boolean basicCheck(Piece piece) {
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if (!new PermissiveRuleChecker(this.move).isValidFor(piece))
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return false;
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return testPath(piece.getColor());
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}
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private boolean testPath(Color color) {
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Direction moveDirection = Direction.findDirection(this.move);
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int distance = this.move.traversedCells();
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int stepIndex = move.getStart().toIndex();
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for (int step = 0; step < distance; step++) {
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stepIndex += moveDirection.getIndexOffset();
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if (Coordinate.fromIndex(stepIndex).equals(move.getFinish())) {
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Piece pieceDest = this.board.pieceAt(move.getFinish());
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if (pieceDest == null)
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return true;
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return pieceDest.getColor() != color;
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}
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if (!this.board.isCellEmpty(Coordinate.fromIndex(stepIndex)))
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return false;
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}
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return false;
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}
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}
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