RuleBasedControl.java

/*
 * The MIT License (MIT)
 *
 * FXGL - JavaFX Game Library
 *
 * Copyright (c) 2015-2017 AlmasB (almaslvl@gmail.com)
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the "Software"), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

package com.almasb.fxglgames.tictactoe.control.enemy;

import com.almasb.fxgl.app.FXGL;
import com.almasb.fxglgames.tictactoe.TicTacToeApp;
import com.almasb.fxglgames.tictactoe.TileCombo;
import com.almasb.fxglgames.tictactoe.TileEntity;
import com.almasb.fxglgames.tictactoe.TileValue;

import java.util.Arrays;
import java.util.List;
import java.util.function.Predicate;

/**
 * A decent AI but can be easily defeated by analyzing the pattern.
 *
 * @author Almas Baimagambetov (almaslvl@gmail.com)
 */
public class RuleBasedControl extends EnemyControl {

    private List<Predicate<TileCombo>> aiPredicates = Arrays.asList(
            c -> c.isTwoThirds(TileValue.O),
            c -> c.isTwoThirds(TileValue.X),
            c -> c.isOneThird(TileValue.O),
            c -> c.isOpen(),
            c -> c.getFirstEmpty() != null
    );

    @Override
    public void makeMove() {
        List<TileCombo> combos = FXGL.<TicTacToeApp>getAppCast().getCombos();

        TileEntity tile = aiPredicates.stream()
                .map(predicate -> {
                    return combos.stream()
                            .filter(predicate)
                            .findAny()
                            .map(TileCombo::getFirstEmpty)
                            .orElse(null);
                })
                .filter(t -> t != null)
                .findFirst()
                // should not happen
                .orElseThrow(() -> new IllegalStateException("No empty tiles"));

        tile.getControl().mark(TileValue.O);
    }
}