/*
 Copyright 2008-2010 Gephi
 Authors : Mathieu Jacomy
 Website : http://www.gephi.org

 This file is part of Gephi.

 DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS HEADER.

 Copyright 2011 Gephi Consortium. All rights reserved.

 The contents of this file are subject to the terms of either the GNU
 General Public License Version 3 only ("GPL") or the Common
 Development and Distribution License("CDDL") (collectively, the
 "License"). You may not use this file except in compliance with the
 License. You can obtain a copy of the License at
 http://gephi.org/about/legal/license-notice/
 or /cddl-1.0.txt and /gpl-3.0.txt. See the License for the
 specific language governing permissions and limitations under the
 License.  When distributing the software, include this License Header
 Notice in each file and include the License files at
 /cddl-1.0.txt and /gpl-3.0.txt. If applicable, add the following below the
 License Header, with the fields enclosed by brackets [] replaced by
 your own identifying information:
 "Portions Copyrighted [year] [name of copyright owner]"

 If you wish your version of this file to be governed by only the CDDL
 or only the GPL Version 3, indicate your decision by adding
 "[Contributor] elects to include this software in this distribution
 under the [CDDL or GPL Version 3] license." If you do not indicate a
 single choice of license, a recipient has the option to distribute
 your version of this file under either the CDDL, the GPL Version 3 or
 to extend the choice of license to its licensees as provided above.
 However, if you add GPL Version 3 code and therefore, elected the GPL
 Version 3 license, then the option applies only if the new code is
 made subject to such option by the copyright holder.

 Contributor(s):

 Portions Copyrighted 2011 Gephi Consortium.
 */
package org.gephi.layout.plugin;

import org.gephi.graph.api.Node;

/**
 *
 * @author Mathieu Jacomy
 */
public class ForceVectorUtils {

    public static float distance(Node n1, Node n2) {
        return (float) Math.hypot(n1.x() - n2.x(), n1.y() - n2.y());
    }

    public static void fcBiRepulsor(Node N1, Node N2, double c) {
        double xDist = N1.x() - N2.x();	// distance en x entre les deux noeuds
        double yDist = N1.y() - N2.y();
        double dist = (float) Math.sqrt(xDist * xDist + yDist * yDist);	// distance tout court

        if (dist > 0) {
            double f = repulsion(c, dist);

            ForceVectorNodeLayoutData N1L = N1.getLayoutData();
            ForceVectorNodeLayoutData N2L = N2.getLayoutData();

            N1L.dx += xDist / dist * f;
            N1L.dy += yDist / dist * f;

            N2L.dx -= xDist / dist * f;
            N2L.dy -= yDist / dist * f;
        }
    }

    public static void fcBiRepulsor_y(Node N1, Node N2, double c, double verticalization) {
        double xDist = N1.x() - N2.x();	// distance en x entre les deux noeuds
        double yDist = N1.y() - N2.y();
        double dist = (float) Math.sqrt(xDist * xDist + yDist * yDist);	// distance tout court

        if (dist > 0) {
            double f = repulsion(c, dist);

            ForceVectorNodeLayoutData N1L = N1.getLayoutData();
            ForceVectorNodeLayoutData N2L = N2.getLayoutData();

            N1L.dx += xDist / dist * f;
            N1L.dy += verticalization * yDist / dist * f;

            N2L.dx -= xDist / dist * f;
            N2L.dy -= verticalization * yDist / dist * f;
        }
    }

    public static void fcBiRepulsor_noCollide(Node N1, Node N2, double c) {
        double xDist = N1.x() - N2.x();	// distance en x entre les deux noeuds
        double yDist = N1.y() - N2.y();
        double dist = (float) Math.sqrt(xDist * xDist + yDist * yDist) - N1.size() - N2.size();	// distance (from the border of each node)

        if (dist > 0) {
            double f = repulsion(c, dist);

            ForceVectorNodeLayoutData N1L = N1.getLayoutData();
            ForceVectorNodeLayoutData N2L = N2.getLayoutData();

            N1L.dx += xDist / dist * f;
            N1L.dy += yDist / dist * f;

            N2L.dx -= xDist / dist * f;
            N2L.dy -= yDist / dist * f;
        } else if (dist != 0) {
            double f = -c;	//flat repulsion

            ForceVectorNodeLayoutData N1L = N1.getLayoutData();
            ForceVectorNodeLayoutData N2L = N2.getLayoutData();

            N1L.dx += xDist / dist * f;
            N1L.dy += yDist / dist * f;

            N2L.dx -= xDist / dist * f;
            N2L.dy -= yDist / dist * f;
        }
    }

    public static void fcUniRepulsor(Node N1, Node N2, double c) {
        double xDist = N1.x() - N2.x();	// distance en x entre les deux noeuds
        double yDist = N1.y() - N2.y();
        double dist = (float) Math.sqrt(xDist * xDist + yDist * yDist);	// distance tout court

        if (dist > 0) {
            double f = repulsion(c, dist);

            ForceVectorNodeLayoutData N2L = N2.getLayoutData();

            N2L.dx -= xDist / dist * f;
            N2L.dy -= yDist / dist * f;
        }
    }

    public static void fcBiAttractor(Node N1, Node N2, double c) {
        double xDist = N1.x() - N2.x();	// distance en x entre les deux noeuds
        double yDist = N1.y() - N2.y();
        double dist = (float) Math.sqrt(xDist * xDist + yDist * yDist);	// distance tout court

        if (dist > 0) {
            double f = attraction(c, dist);

            ForceVectorNodeLayoutData N1L = N1.getLayoutData();
            ForceVectorNodeLayoutData N2L = N2.getLayoutData();

            N1L.dx += xDist / dist * f;
            N1L.dy += yDist / dist * f;

            N2L.dx -= xDist / dist * f;
            N2L.dy -= yDist / dist * f;
        }
    }

    public static void fcBiAttractor_noCollide(Node N1, Node N2, double c) {
        double xDist = N1.x() - N2.x();	// distance en x entre les deux noeuds
        double yDist = N1.y() - N2.y();
        double dist = (float) Math.sqrt(xDist * xDist + yDist * yDist) - N1.size() - N2.size();	// distance (from the border of each node)

        if (dist > 0) {
            double f = attraction(c, dist);

            ForceVectorNodeLayoutData N1L = N1.getLayoutData();
            ForceVectorNodeLayoutData N2L = N2.getLayoutData();

            N1L.dx += xDist / dist * f;
            N1L.dy += yDist / dist * f;

            N2L.dx -= xDist / dist * f;
            N2L.dy -= yDist / dist * f;
        }
    }

    public static void fcBiFlatAttractor(Node N1, Node N2, double c) {
        double xDist = N1.x() - N2.x();	// distance en x entre les deux noeuds
        double yDist = N1.y() - N2.y();
        double dist = (float) Math.sqrt(xDist * xDist + yDist * yDist);	// distance tout court

        if (dist > 0) {
            double f = -c;

            ForceVectorNodeLayoutData N1L = N1.getLayoutData();
            ForceVectorNodeLayoutData N2L = N2.getLayoutData();

            N1L.dx += xDist / dist * f;
            N1L.dy += yDist / dist * f;

            N2L.dx -= xDist / dist * f;
            N2L.dy -= yDist / dist * f;
        }
    }

    public static void fcUniAttractor(Node N1, Node N2, float c) {
        double xDist = N1.x() - N2.x();	// distance en x entre les deux noeuds
        double yDist = N1.y() - N2.y();
        double dist = (float) Math.sqrt(xDist * xDist + yDist * yDist);	// distance tout court

        if (dist > 0) {
            double f = attraction(c, dist);

            ForceVectorNodeLayoutData N2L = N2.getLayoutData();

            N2L.dx -= xDist / dist * f;
            N2L.dy -= yDist / dist * f;
        }
    }

    protected static double attraction(double c, double dist) {
        return 0.01 * -c * dist;
    }

    protected static double repulsion(double c, double dist) {
        return 0.001 * c / dist;
    }
}
