/*
 * Encog(tm) Examples v2.4
 * http://www.heatonresearch.com/encog/
 * http://code.google.com/p/encog-java/
 * 
 * Copyright 2008-2010 by Heaton Research Inc.
 * 
 * Released under the LGPL.
 *
 * This is free software; you can redistribute it and/or modify it
 * under the terms of the GNU Lesser General Public License as
 * published by the Free Software Foundation; either version 2.1 of
 * the License, or (at your option) any later version.
 *
 * This software 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
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this software; if not, write to the Free
 * Software Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 * 02110-1301 USA, or see the FSF site: http://www.fsf.org.
 * 
 * Encog and Heaton Research are Trademarks of Heaton Research, Inc.
 * For information on Heaton Research trademarks, visit:
 * 
 * http://www.heatonresearch.com/copyright.html
 */

package org.encog.examples.neural.lunar;

import java.text.NumberFormat;

public class LanderSimulator {

	public static final double GRAVITY = 1.62;
	public static final double THRUST = 10;
	public static final double TERMINAL_VELOCITY = 40;

	private int fuel;
	private int seconds;
	private double altitude;
	private double velocity;

	public LanderSimulator() {
		this.fuel = 200;
		this.seconds = 0;
		this.altitude = 10000;
		this.velocity = 0;
	}

	public void turn(boolean thrust) {
		this.seconds++;
		this.velocity -= GRAVITY;
		this.altitude += this.velocity;

		if (thrust && this.fuel > 0) {
			this.fuel--;
			this.velocity += THRUST;
		}

		this.velocity = Math.max(-TERMINAL_VELOCITY, this.velocity);
		this.velocity = Math.min(TERMINAL_VELOCITY, this.velocity);

		if (this.altitude < 0)
			this.altitude = 0;
	}

	public String telemetry() {
		NumberFormat nf = NumberFormat.getNumberInstance();
		nf.setMinimumFractionDigits(4);
		nf.setMaximumFractionDigits(4);
		StringBuilder result = new StringBuilder();
		result.append("Elapsed: ");
		result.append(seconds);
		result.append(" s, Fuel: ");
		result.append(this.fuel);
		result.append(" l, Velocity: ");
		result.append(nf.format(velocity));
		result.append(" m/s, ");
		result.append((int) altitude);
		result.append(" m");
		return result.toString();
	}

	public int score() {
		return (int) ((this.fuel * 10) + this.seconds + (this.velocity * 1000));
	}

	public int getFuel() {
		return fuel;
	}

	public int getSeconds() {
		return seconds;
	}

	public double getAltitude() {
		return altitude;
	}

	public double getVelocity() {
		return velocity;
	}

	public boolean flying() {
		return (this.altitude > 0);
	}
}