/*
 * This file is part of aion-emu <aion-emu.com>.
 *
 * aion-emu 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, either version 3 of the License, or
 * (at your option) any later version.
 *
 * aion-emu 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with aion-emu.  If not, see <http://www.gnu.org/licenses/>.
 */

package com.aionemu.gameserver.model.geometry;

import java.awt.Point;
import java.awt.Polygon;
import java.util.Collection;

import com.aionemu.gameserver.utils.MathUtil;

/**
 * Area of free form
 * 
 * @author SoulKeeper
 */
public class PolyArea extends AbstractArea
{

	/**
	 * Collection of x points
	 */
	private final int[]		xPoints;

	/**
	 * Collection of y points
	 */
	private final int[]		yPoints;

	/**
	 * Polygon used to calculate isInside()
	 */
	private final Polygon	poly;

	/**
	 * Creates new area from given points
	 * 
	 * @param points
	 *            list of points
	 * @param zMin
	 *            minimal z
	 * @param zMax
	 *            maximal z
	 */
	public PolyArea(Collection<Point> points, int zMin, int zMax)
	{
		this(points.toArray(new Point[points.size()]), zMin, zMax);
	}

	/**
	 * Creates new area from given points
	 * 
	 * @param points
	 *            list of points
	 * @param zMin
	 *            minimal z
	 * @param zMax
	 *            maximal z
	 */
	public PolyArea(Point[] points, int zMin, int zMax)
	{
		super(zMin, zMax);

		if(points.length < 3)
		{
			throw new IllegalArgumentException("Not enough points, needed at least 3 but got " + points.length);
		}

		this.xPoints = new int[points.length];
		this.yPoints = new int[points.length];

		Polygon polygon = new Polygon();
		for(int i = 0, n = points.length; i < n; i++)
		{
			Point p = points[i];
			polygon.addPoint(p.x, p.y);
			xPoints[i] = p.x;
			yPoints[i] = p.y;
		}
		this.poly = polygon;
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public boolean isInside2D(int x, int y)
	{
		return poly.contains(x, y);
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public double getDistance2D(int x, int y)
	{
		if(isInside2D(x, y))
		{
			return 0;
		}
		else
		{
			Point cp = getClosestPoint(x, y);
			return MathUtil.getDistance(cp.x, cp.y, x, y);
		}
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public double getDistance3D(int x, int y, int z)
	{
		if(isInside3D(x, y, z))
		{
			return 0;
		}
		else if(isInsideZ(z))
		{
			return getDistance2D(x, y);
		}
		else
		{
			Point3D cp = getClosestPoint(x, y, z);
			return MathUtil.getDistance(cp.getX(), cp.getY(), cp.getZ(), x, y, z);
		}
	}

	/**
	 * {@inheritDoc}
	 */
	@Override
	public Point getClosestPoint(int x, int y)
	{

		Point closestPoint = null;
		double closestDistance = 0;

		for(int i = 0; i < xPoints.length; i++)
		{
			int nextIndex = i + 1;
			if(nextIndex == xPoints.length)
			{
				nextIndex = 0;
			}

			int p1x = xPoints[i];
			int p1y = yPoints[i];
			int p2x = xPoints[nextIndex];
			int p2y = yPoints[nextIndex];

			Point point = MathUtil.getClosestPointOnSegment(p1x, p1y, p2x, p2y, x, y);

			if(closestPoint == null)
			{
				closestPoint = point;
				closestDistance = MathUtil.getDistance(closestPoint.x, closestPoint.y, x, y);
			}
			else
			{
				double newDistance = MathUtil.getDistance(point.x, point.y, x, y);
				if(newDistance < closestDistance)
				{
					closestPoint = point;
					closestDistance = newDistance;
				}
			}
		}

		return closestPoint;
	}
}