98 lines
3.0 KiB
Java
98 lines
3.0 KiB
Java
package dev.kske.chess.board;
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import java.util.ArrayList;
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import java.util.List;
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/**
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* Project: <strong>Chess</strong><br>
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* File: <strong>Pawn.java</strong><br>
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* Created: <strong>01.07.2019</strong><br>
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* Author: <strong>Kai S. K. Engelbart</strong>
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*/
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public class Pawn extends Piece {
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public Pawn(Color color, Board board) {
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super(color, board);
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}
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@Override
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public boolean isValidMove(Move move) {
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boolean step = move.isVertical() && move.yDist == 1;
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boolean doubleStep = move.isVertical() && move.yDist == 2;
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boolean strafe = move.isDiagonal() && move.xDist == 1;
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boolean enPassant = false;
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if (getColor() == Color.WHITE) doubleStep &= move.pos.y == 6;
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else doubleStep &= move.pos.y == 1;
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// Mark move as pawn promotion if necessary
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if (move.ySign == 1 && move.pos.y == 6 || move.ySign == -1 && move.pos.y == 1)
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move.type = Move.Type.PAWN_PROMOTION;
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// Mark the move as en passant if necessary
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if (strafe && move.dest.equals(board.getEnPassantSquare())) {
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enPassant = true;
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move.type = Move.Type.EN_PASSANT;
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}
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return enPassant || (step ^ doubleStep ^ strafe) && move.ySign == (getColor() == Color.WHITE ? -1 : 1)
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&& isFreePath(move);
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}
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@Override
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protected boolean isFreePath(Move move) {
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// Two steps forward
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if (move.yDist == 2)
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return board.getBoardArr()[move.pos.x][move.dest.y - move.ySign] == null && board.getDest(move) == null;
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// One step forward
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else if (move.xDist == 0) return board.getDest(move) == null;
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// Capture move
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else return board.getDest(move) != null && board.getDest(move).getColor() != getColor();
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}
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@Override
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protected List<Move> getPseudolegalMoves(Position pos) {
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List<Move> moves = new ArrayList<>();
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int sign = getColor() == Color.WHITE ? -1 : 1;
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// Strafe left
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if (pos.x > 0) {
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Move move = new Move(pos, new Position(pos.x - 1, pos.y + sign));
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if (isFreePath(move)) moves.add(move);
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}
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// Strafe right
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if (pos.x < 7) {
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Move move = new Move(pos, new Position(pos.x + 1, pos.y + sign));
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if (isFreePath(move)) moves.add(move);
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}
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// Step forward
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if (sign == 1 && pos.y < 7 || sign == -1 && pos.y > 0) {
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Move move = new Move(pos, new Position(pos.x, pos.y + sign));
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if (isFreePath(move)) moves.add(move);
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}
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// Double step forward
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if (sign == 1 && pos.y == 1 || sign == -1 && pos.y == 6) {
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Move move = new Move(pos, new Position(pos.x, pos.y + 2 * sign));
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if (isFreePath(move)) moves.add(move);
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}
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// Mark moves as pawn promotion if necessary
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if (sign == 1 && pos.y == 6 || sign == -1 && pos.y == 1)
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moves.parallelStream().forEach(m -> m.type = Move.Type.PAWN_PROMOTION);
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// Add en passant move if necessary
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if (board.getEnPassantSquare() != null) {
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Move move = new Move(pos, board.getEnPassantSquare(), Move.Type.EN_PASSANT);
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if (move.isDiagonal() && move.xDist == 1) moves.add(move);
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}
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return moves;
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}
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@Override
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public Type getType() { return Type.PAWN; }
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}
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