/**
 * Copyright © CENRA (2016)
 *
 * remi.clement@espaces-naturels.fr
 * 
 * This software is a multi-platform and portable application based on 
 * the scientifical toolbox to monitor wetlands. With this toolbox it’s 
 * possible to calculate indicators «RhoMéO» to monitor quality, 
 * fonctionalities and urban and agricultural pressures of wetlands. 
 * Indicators are calculated using naturalist data entered and/or imported,
 * and geographic data downloaded from a geographic server.
 * 
 * This software is governed by the CeCILL license under French law and
 * abiding by the rules of distribution of free software.  You can  use, 
 * modify and/ or redistribute the software under the terms of the CeCILL
 * license as circulated by CEA, CNRS and INRIA at the following URL
 * "http://www.cecill.info". 
 * 
 * As a counterpart to the access to the source code and  rights to copy,
 * modify and redistribute granted by the license, users are provided only
 * with a limited warranty  and the software's author,  the holder of the
 * economic rights,  and the successive licensors  have only  limited
 * liability. 
 * 
 * In this respect, the user's attention is drawn to the risks associated
 * with loading,  using,  modifying and/or developing or reproducing the
 * software by the user in light of its specific status of free software,
 * that may mean  that it is complicated to manipulate,  and  that  also
 * therefore means  that it is reserved for developers  and  experienced
 * professionals having in-depth computer knowledge. Users are therefore
 * encouraged to load and test the software's suitability as regards their
 * requirements in conditions enabling the security of their systems and/or 
 * data to be ensured and,  more generally, to use and operate it in the 
 * same conditions as regards security. 
 * 
 * The fact that you are presently reading this means that you have had
 * knowledge of the CeCILL license and that you accept its terms.
*/
package fr.cenra.rhomeo.core.util;

import com.vividsolutions.jts.geom.Geometry;
import org.apache.commons.codec.digest.DigestUtils;

/**
 * @author Cédric Briançon (Geomatys)
 * @author Johann Sorel (Geomatys)
 */
public class GeometryUtils {
    /**
     * Get a SHA1 representation of a geometry.
     *
     * @param geometry Geometry to convert. Must not be {@code null}
     * @return SHA1 of the geometry, never {@code null}
     */
    public static String getSha1(Geometry geometry) {
        return DigestUtils.sha1Hex(geometry.toText());
    }

    /**
     * Compute geometry buffer.<br>
     * <br>
     * Java version of SQL :
     * <pre>
     * {@code
     * CREATE OR replace FUNCTION outils.calcul_geom_buffer()
     * returns TRIGGER AS $body$DECLARE surf_buff DOUBLE PRECISION;radius DOUBLE PRECISION;BEGIN
     *      surf_buff := st_area(new.geom);
     *      radius := ( |/ (surf_buff*2/pi()) ) - ( |/ (surf_buff/pi()) );
     *      new.geom_buffer := st_multi(st_difference(st_buffer(new.geom,radius,40),new.geom));
     *      return new;
     *  end;$BODY$ language plpgsql volatile cost 100;
     * }
     * </pre>
     *
     * @return buffer geometry
     */
    public static Geometry computeBuffer(Geometry geom){
        final double surfBuff = geom.getArea();
        final double radius = Math.sqrt(surfBuff*2.0/Math.PI) - Math.sqrt(surfBuff/Math.PI);
        Geometry g = geom.buffer(radius, 40);
        //.difference(geom);
        //note : by comparing result in database dump, the difference operator is not used anymore
        g.setSRID(geom.getSRID());
        g.setUserData(geom.getUserData());
        return g;
    }
}
