/* 
GeoGebra - Dynamic Mathematics for Everyone
http://www.geogebra.org

This file is part of GeoGebra.

This program is free software; you can redistribute it and/or modify it 
under the terms of the GNU General Public License as published by 
the Free Software Foundation.

 */

/*
 * Random point in a conic
 *
 */

package org.geogebra.common.kernel.algos;

import org.geogebra.common.kernel.Construction;
import org.geogebra.common.kernel.commands.Commands;
import org.geogebra.common.kernel.geos.GeoElement;
import org.geogebra.common.kernel.geos.GeoPoint;
import org.geogebra.common.kernel.geos.GeoVec2D;
import org.geogebra.common.kernel.kernelND.GeoConicND;
import org.geogebra.common.kernel.kernelND.GeoConicNDConstants;

public class AlgoRandomPointInConic extends AlgoElement {

	protected GeoConicND conic; // input
	protected GeoPoint randomPoint; // output

	public AlgoRandomPointInConic(Construction cons, String label,
			GeoConicND c) {
		this(cons, c);
		randomPoint.setLabel(label);
	}

	AlgoRandomPointInConic(Construction cons, GeoConicND c) {
		super(cons);
		this.conic = c;
		createOutput(cons);
		setInputOutput(); // for AlgoElement

		// compute
		initCoords();
		compute();
	}

	/**
	 * init Coords values
	 */
	protected void initCoords() {
		// none here
	}

	protected void createOutput(Construction cons) {
		randomPoint = new GeoPoint(cons);
	}

	@Override
	public Commands getClassName() {
		return Commands.RandomPointIn;
	}

	// for AlgoElement
	@Override
	protected void setInputOutput() {
		input = new GeoElement[1];
		input[0] = conic;

		setOnlyOutput(randomPoint);
		setDependencies(); // done by AlgoElement
	}

	public GeoPoint getRandomPoint() {
		return randomPoint;
	}

	GeoConicND getConic() {
		return conic;
	}

	// find random point in the polygon P[0], ..., P[n]
	@Override
	public void compute() {

		if (!conic.isDefined()) {
			randomPoint.setUndefined();
			return;
		}

		int type = conic.getType();
		switch (type) {
		case GeoConicNDConstants.CONIC_CIRCLE:
			GeoVec2D center = conic.b;

			double r = conic.getHalfAxis(0)
					* cons.getApplication().getRandomNumber();
			double radians = 2 * Math.PI
					* cons.getApplication().getRandomNumber();

			double xRandom = r * Math.cos(radians);
			double yRandom = r * Math.sin(radians);

			randomPoint.setCoords(xRandom + center.getX(),
					yRandom + center.getY(), 1);
			break;

		case GeoConicNDConstants.CONIC_ELLIPSE:
			center = conic.b;

			double a = conic.getHalfAxis(0)
					* cons.getApplication().getRandomNumber();
			double b = conic.getHalfAxis(1)
					* cons.getApplication().getRandomNumber();

			radians = 2 * Math.PI * cons.getApplication().getRandomNumber();
			double angle = Math.atan2(conic.eigenvec[0].getY(),
					conic.eigenvec[0].getX());

			if (angle == 0) {
				xRandom = a * Math.cos(radians);
				yRandom = b * Math.sin(radians);
			} else {
				xRandom = b * Math.cos(radians);
				yRandom = a * Math.sin(radians);
			}

			randomPoint.setCoords(xRandom + center.getX(),
					yRandom + center.getY(), 1);
			break;

		default:
			randomPoint.setUndefined();
		}
	}

}