GoNStepsBackBrick.java

/**
 * Catroid: An on-device visual programming system for Android devices
 * Copyright (C) 2010-2014 The Catrobat Team
 * (<http://developer.catrobat.org/credits>)
 *
 * This program is free software: you can redistribute it and/or modify
 * it under the terms of the GNU Affero General Public License as
 * published by the Free Software Foundation, either version 3 of the
 * License, or (at your option) any later version.
 *
 * An additional term exception under section 7 of the GNU Affero
 * General Public License, version 3, is available at
 * http://developer.catrobat.org/license_additional_term
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU Affero General Public License for more details.
 *
 * You should have received a copy of the GNU Affero General Public License
 * along with this program. If not, see <http://www.gnu.org/licenses/>.
 */
package org.catrobat.html5player.client.bricks;

import java.util.Collection;

import org.catrobat.html5player.client.Sprite;
import org.catrobat.html5player.client.Stage;
import org.catrobat.html5player.client.common.Look;
import org.catrobat.html5player.client.formulaeditor.Formula;

public class GoNStepsBackBrick extends Brick {

	Formula steps;

	public GoNStepsBackBrick(String sprite, Formula steps) {
		super(sprite);
		this.steps = steps;
	}

	@Override
	public boolean execute(Sprite sprite) {
		Look look = sprite.getLook();
		int steps = this.steps.interpretInteger(sprite);
		Collection<Sprite> sprites = Stage.getInstance().getSpriteManager().getSpriteList();

		if (sprite.isBackground()) //background not allowed to use go n steps back brick
		{
			return false;
		}

		int last_layer = 0;

		for (Sprite sp : sprites) {
			if(sp.getLook().getZPosition() < last_layer
				&& !(sp.isBackground()))
				last_layer = sp.getLook().getZPosition();
		}

		if(steps < 0) //go forward
		{
			steps = Math.abs(steps);
			if(look.getZPosition() < 0) //not already at front
			{
				for (Sprite sp : sprites) { //send all other sprites between sprite and specific position back
					if(sp.getLook().getZPosition() > sprite.getLook().getZPosition()
						&& sp.getLook().getZPosition() <= sprite.getLook().getZPosition()+steps)
					{
						sp.getLook().setZPosition(sp.getLook().getZPosition()-1);
					}
				}
				if(look.getZPosition()+steps >= 0) //go to front because over max
				{
					sprite.getLook().setZPosition(0);
				}
				else //go forward
				{
					sprite.getLook().setZPosition(sprite.getLook().getZPosition()+steps);
				}
			}
		}
		else if(steps > 0) //go backward
		{
			steps = Math.abs(steps);
			if(look.getZPosition() != Integer.MIN_VALUE+1) //TODO what if at last possible layer, throw exception?
			{
				for (Sprite sp : sprites) {
					if(sp.getLook().getZPosition() < sprite.getLook().getZPosition()
						&& sp.getLook().getZPosition() >=  sprite.getLook().getZPosition() - steps
						&& !(sp.getName().equals(sprite.getName())))
					{
						sp.getLook().setZPosition(sp.getLook().getZPosition()+1);
					}
				}
				if(look.getZPosition()-steps < last_layer)
				{
					sprite.getLook().setZPosition(last_layer);
				}
				else
				{
					sprite.getLook().setZPosition(sprite.getLook().getZPosition()-steps);
				}
			}
		}

		return true;
	}

}