es.udc.pfc.gamelib.chess.MiniChessGame.java Source code

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Here is the source code for es.udc.pfc.gamelib.chess.MiniChessGame.java

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/**
 * Copyright 2011 Jos Martnez
 * 
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 * 
 *     http://www.apache.org/licenses/LICENSE-2.0
 * 
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package es.udc.pfc.gamelib.chess;

import static com.google.common.base.Preconditions.checkNotNull;
import static com.google.common.base.Preconditions.checkState;

import java.util.EnumSet;

import javax.annotation.Nullable;

import com.google.common.collect.ImmutableSet;

import es.udc.pfc.gamelib.board.Position;
import es.udc.pfc.gamelib.chess.ChessMovement.Special;
import es.udc.pfc.gamelib.chess.pieces.ChessBishop;
import es.udc.pfc.gamelib.chess.pieces.ChessKing;
import es.udc.pfc.gamelib.chess.pieces.ChessPawn;
import es.udc.pfc.gamelib.chess.pieces.ChessQueen;

public final class MiniChessGame extends AbstractChessGame {

    @Nullable
    private ImmutableSet<ChessMovement> possibleMovementsCache;

    public MiniChessGame() {
        super(ChessBoard.fromString(ChessBoard.CHESSBOARD_MINI));
    }

    private final ChessMovement checkMovement(final Position from, final Position to) {
        final EnumSet<ChessMovement.Special> special = EnumSet.noneOf(ChessMovement.Special.class);
        if (chessBoard.getPieceAt(to) instanceof ChessKing) {
            special.add(Special.CHECK);
            special.add(Special.MATE);
        }

        return new ChessMovement(from, to, chessBoard.getPieceAt(from), chessBoard.getPieceAt(to), special);
    }

    private final ImmutableSet<ChessMovement> getPossibleMovements(final ChessBoard board, final ChessColor turn) {
        final ImmutableSet.Builder<ChessMovement> moves = ImmutableSet.builder();

        for (final ChessPiece piece : board.getAllPieces()) {
            if (!currentTurn.equals(piece.getColor()))
                continue;

            final Position from = board.getPositionFor(piece);

            if (piece instanceof ChessBishop) {
                for (final Position to : ((ChessBishop) piece).getMiniMoves(board)) {
                    moves.add(checkMovement(from, to));
                }
            } else {
                for (final Position to : piece.getStandardMoves(board)) {
                    moves.add(checkMovement(from, to));
                }
            }
        }

        return moves.build();
    }

    @Override
    public final ImmutableSet<ChessMovement> getPossibleMovements() {
        if (isFinished())
            return ImmutableSet.of();

        if (possibleMovementsCache == null) {
            possibleMovementsCache = getPossibleMovements(chessBoard, currentTurn);
        }

        return possibleMovementsCache;
    }

    @Override
    @Nullable
    public final ChessMovement movePiece(final Position from, final Position to) {
        checkState(!isFinished());
        checkNotNull(from);
        checkNotNull(to);

        for (final ChessMovement movement : getPossibleMovements()) {
            if (!from.equals(movement.getFrom()) || !to.equals(movement.getTo()))
                continue;

            chessBoard.setPieceAt(to, chessBoard.setPieceAt(from, null));

            if (chessBoard.getPieceAt(to) instanceof ChessPawn
                    && (to.getRow() == 1 || to.getRow() == chessBoard.getNumberOfRows())) {
                chessBoard.setPieceAt(to, new ChessQueen(currentTurn));
            }

            currentTurn = currentTurn.other();
            possibleMovementsCache = null;

            if (movement.is(Special.MATE)) {
                setWinner(movement.getSourcePiece().getColor());
            }

            movements.add(movement);

            return movement;
        }

        return null;
    }

}