/*
 * Created on Oct 12, 2003
 *
 */
package kareltherobot;

import java.awt.Color;

/** A robot that can use a Compute Strategy to compute the function y=2x;
 * @author jbergin
 *
 */
public class TwoXRobot extends UrRobot
{

	/** These robots always start at the origin so there is no need for
	 * the parameters
	 * @param badge the color badge that the robot wears
	 */
	public TwoXRobot( Color badge)
	{
		super(1, 1, East, 0, badge);
	}

	public TwoXRobot()
	{
		super(1, 1, East, 0);
	}
	
	/**  Do an ordinary move, by also remember the new y 
	 * coordinate.
	 * 
	 */
	public void moveAndLearn()
	{	move();
		computeStrategy = new TwoX(computeStrategy);
	}
	
	/** The robot world's origin is (1,1) not (0,0) so we adjust
	 * at the end of a computation. 
	 */
	private void adjust()
	{	turnLeft();
		move();
		turnLeft();
		move();
	}
	
	/** After executing moveAndLearn zero or more times execute this once
	 * to compute the y coordinate by moving there.
	 *  
	 * PostCondition: The robot has turned off. 
	 */
	public void compute()
	{	turnLeft();
		computeStrategy.compute(this);
		adjust();
		turnOff();
	}
	
	/**  This class is used to decorate a strategy by adding 
	 * two moves to whatever else is known to do. 
	 * @author jbergin
	 *
	 */
	private class TwoX implements ComputeStrategy
	{	public TwoX(ComputeStrategy decorated)
		{	this.decorated = decorated;
		}
		
		public void compute(UrRobot who)
		{	who.move();
			who.move();
			decorated.compute(who);
		}
		
		ComputeStrategy decorated = null;
	}
	
	private ComputeStrategy computeStrategy = ComputeStrategy.NULL;

}