/*
 *  sketcherMinimizerClashInteraction.h
 *
 *  Created by Nicola Zonta on 19/04/2010.
 *   Copyright Schrodinger, LLC. All rights reserved.
 *
 */

#ifndef sketcherMINIMIZERCLASHMINIMIZERINTERACTION
#define sketcherMINIMIZERCLASHMINIMIZERINTERACTION

#include "sketcherMinimizerInteraction.h"
#include <iostream>
#include "sketcherMinimizerMaths.h"

/* forcefield clash */
class sketcherMinimizerClashInteraction : public sketcherMinimizerInteraction
{
  public:
    sketcherMinimizerClashInteraction(sketcherMinimizerAtom* at1,
                                      sketcherMinimizerAtom* at2,
                                      sketcherMinimizerAtom* at3)
        : sketcherMinimizerInteraction(at1, at2)
    {
        atom3 = at3;
        restV = 900;

        k2 = 0.1f;
    };
    virtual ~sketcherMinimizerClashInteraction(){};

    /* calculate the energy of the clash */
    void energy(float& e) override
    {
        float squaredDistance =
            sketcherMinimizerMaths::squaredDistancePointSegment(
                atom2->coordinates, atom1->coordinates, atom3->coordinates);
        if (squaredDistance > restV)
            return;

        float dr = restV - squaredDistance;
        if (dr > 0)
            e += 0.5f * k * k2 * dr;
    };

    /* calculate the forces of the clash and apply them */
    void score(float& totalE, bool skipForce = false) override
    {
        energy(totalE);
        if (skipForce)
            return;
        sketcherMinimizerPointF atomP = atom2->coordinates;
        sketcherMinimizerPointF bondP1 = atom1->coordinates;
        sketcherMinimizerPointF bondP2 = atom3->coordinates;

        float squaredDistance =
            sketcherMinimizerMaths::squaredDistancePointSegment(atomP, bondP1,
                                                                bondP2);
        if (squaredDistance > restV)
            return;

        sketcherMinimizerPointF projection =
            sketcherMinimizerMaths::projectPointOnLine(atomP, bondP1, bondP2);
        sketcherMinimizerPointF f = atomP - projection;
        f.normalize();
        f *= (restV - squaredDistance) * k * k2;
        atom2->force += f;
        atom1->force -= f * 0.5;
        atom3->force -= f * 0.5;
    }
    bool isClash() override { return true; };

    float k2;
    sketcherMinimizerAtom* atom3;
};

#endif // sketcherMINIMIZERCLASHINTERACTION