/*
 * Copyright (c) 2018, Adam <Adam@sigterm.info>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * 1. Redistributions of source code must retain the above copyright notice, this
 *    list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright notice,
 *    this list of conditions and the following disclaimer in the documentation
 *    and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
 * DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR
 * ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
 * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
 * ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
package net.runelite.client.plugins.puzzlesolver.lightbox;

public class LightboxSolver
{
	private LightboxState initial;
	private final LightboxState[] switches = new LightboxState[LightBox.COMBINATIONS_POWER];

	static boolean isBitSet(int num, int bit)
	{
		return ((num >>> bit) & 1) != 0;
	}

	private static boolean isSolved(LightboxState s)
	{
		for (int i = 0; i < LightBox.WIDTH; ++i)
		{
			for (int j = 0; j < LightBox.HEIGHT; ++j)
			{
				if (!s.getState(i, j))
				{
					return false;
				}
			}
		}
		return true;
	}

	public LightboxSolution solve()
	{
		LightboxSolution solution = null;
		outer:
		for (int i = 0; i < Math.pow(2, LightBox.COMBINATIONS_POWER); ++i)
		{
			LightboxState s = initial;

			for (int bit = 0; bit < LightBox.COMBINATIONS_POWER; ++bit)
			{
				if (isBitSet(i, bit))
				{
					// this switch is unknown, so this can't be a valid answer
					if (switches[bit] == null)
					{
						continue outer;
					}

					s = s.diff(switches[bit]);
				}
			}

			if (isSolved(s))
			{
				LightboxSolution sol = new LightboxSolution(i);
				if (solution == null || sol.numMoves() < solution.numMoves())
				{
					solution = sol;
				}
			}
		}

		return solution;
	}

	public void setInitial(LightboxState initial)
	{
		this.initial = initial;
	}

	public void setSwitchChange(Combination combination, LightboxState newState)
	{
		switches[combination.ordinal()] = newState;
	}
}
