/*
 *    GeoTools - The Open Source Java GIS Toolkit
 *    http://geotools.org
 *    
 *    (C) 2001-2006  Vivid Solutions
 *    (C) 2001-2008, Open Source Geospatial Foundation (OSGeo)
 *    
 *    This library 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;
 *    version 2.1 of the License.
 *
 *    This library 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.
 */
package org.geotools.geometry.iso.util.algorithmND;

import java.util.Iterator;

import org.geotools.geometry.iso.aggregate.MultiPointImpl;
import org.geotools.geometry.iso.complex.CompositePointImpl;
import org.geotools.geometry.iso.coordinate.DirectPositionImpl;
import org.geotools.geometry.iso.primitive.PointImpl;
import org.geotools.geometry.iso.root.GeometryImpl;
import org.opengis.geometry.primitive.Point;
import org.opengis.referencing.crs.CoordinateReferenceSystem;

/**
 * Computes the centroid of a point geometry.
 * <h2>Algorithm</h2>
 * Compute the average of all points.
 *
 *
 *
 * @source $URL$
 */
public class CentroidPoint {
	
	//private FeatGeomFactoryImpl factory = null;	
	private CoordinateReferenceSystem crs = null;
	private int ptCount = 0;	
	DirectPositionImpl centSum = null;

	/**
	 * Creates a new Centroid operation
	 * 
	 * @param crs
	 */
	public CentroidPoint(CoordinateReferenceSystem crs) {
		this.crs = crs;
		this.centSum = new DirectPositionImpl(crs); //this.factory.getGeometryFactoryImpl().createDirectPosition();
	}

	/**
	 * Adds the point(s) defined by a Geometry to the centroid total. If the
	 * geometry is not of dimension 0 it does not contribute to the centroid.
	 * 
	 * @param geom
	 *            the geometry to add
	 */
	public void add(GeometryImpl geom) {
		if (geom instanceof PointImpl) {
			this.add(((PointImpl)geom).getDirectPosition());
		} else if (geom instanceof MultiPointImpl) {
			Iterator<Point> points = ((MultiPointImpl) geom).getElements().iterator();
			while (points.hasNext()) {
				this.add((DirectPositionImpl) points.next().getDirectPosition());
			}
		} else if (geom instanceof CompositePointImpl) {
			this.add((DirectPositionImpl) ((CompositePointImpl)geom).getGenerators().get(0));
		}
	}

	/**
	 * Adds the length defined by an array of coordinates.
	 * 
	 * @param pts
	 *            an array of {@link Coordinate}s
	 */
	private void add(DirectPositionImpl pt) {
		this.ptCount += 1;
		this.centSum.add(pt.getCoordinate());
	}

	/**
	 * Returns the centroid of the added points
	 * 
	 * @return Centroid position
	 */
	public DirectPositionImpl getCentroid() {
		this.centSum.divideBy(this.ptCount);
		return this.centSum;
//		DirectPositionImpl centroid = this.factory.getCoordinateFactory().createDirectPosition();
//		centroid.setCoordinate(thi);
//		centroid.setX(this.centSumX / this.ptCount);
//		centroid.setY(this.centSumY / this.ptCount);
//		return centroid;
	}

}