/******************************************************************************
*       SOFA, Simulation Open-Framework Architecture, development version     *
*                (c) 2006-2017 INRIA, USTL, UJF, CNRS, MGH                    *
*                                                                             *
* This program 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; either version 2.1 of the License, or (at     *
* your option) any later version.                                             *
*                                                                             *
* This program 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.                                                           *
*                                                                             *
* You should have received a copy of the GNU Lesser General Public License    *
* along with this program. If not, see <http://www.gnu.org/licenses/>.        *
*******************************************************************************
* Authors: The SOFA Team and external contributors (see Authors.txt)          *
*                                                                             *
* Contact information: contact@sofa-framework.org                             *
******************************************************************************/
#ifndef SOFA_COMPONENT_FORCEFIELD_LENNARDJONESFORCEFIELD_H
#define SOFA_COMPONENT_FORCEFIELD_LENNARDJONESFORCEFIELD_H
#include "config.h"

#include <sofa/core/behavior/ForceField.h>
#include <sofa/core/behavior/MechanicalState.h>
#include <vector>


namespace sofa
{

namespace component
{

namespace forcefield
{

template<class DataTypes>
class LennardJonesForceField : public sofa::core::behavior::ForceField<DataTypes>
{
public:
    SOFA_CLASS(SOFA_TEMPLATE(LennardJonesForceField, DataTypes), SOFA_TEMPLATE(core::behavior::ForceField, DataTypes));

    typedef sofa::core::behavior::ForceField<DataTypes> Inherit;
    typedef typename DataTypes::VecCoord VecCoord;
    typedef typename DataTypes::VecDeriv VecDeriv;
    typedef typename DataTypes::Coord Coord;
    typedef typename DataTypes::Deriv Deriv;
    typedef typename Coord::value_type Real;

    typedef core::objectmodel::Data<VecDeriv>    DataVecDeriv;
    typedef core::objectmodel::Data<VecCoord>    DataVecCoord;

protected:
    Real a,b;
    Data<Real> aInit;
    Data<Real> alpha,beta,dmax,fmax;
    Data<Real> d0,p0;
    Data<Real> damping;

    struct DForce
    {
        unsigned int a,b;
        Real df;
    };

    sofa::helper::vector<DForce> dforces;

    LennardJonesForceField()
        : a(1)
        , b(1)
        , aInit  (initData(&aInit  ,Real(0), "aInit"  ,"a for Gravitational FF which corresponds to G*m1*m2 alpha should be equal to 1 and beta to 0."))
        , alpha  (initData(&alpha  ,Real(6), "alpha"  ,"Alpha"))
        , beta   (initData(&beta   ,Real(12),"beta"   ,"Beta"))
        , dmax   (initData(&dmax   ,Real(2), "dmax"   ,"DMax"))
        , fmax   (initData(&fmax   ,Real(1), "fmax"   ,"FMax"))
        , d0     (initData(&d0     ,Real(1), "d0"     ,"d0"))
        , p0     (initData(&p0     ,Real(1), "p0"     ,"p0"))
        , damping(initData(&damping,Real(0), "damping","Damping"))
    {
    }

public:

    void setAInit(Real v) { aInit.setValue(v); }
    void setAlpha(Real v) { alpha.setValue(v); }
    void setBeta(Real v) { beta.setValue(v); }
    void setFMax(Real v) { fmax.setValue(v); }
    void setDMax(Real v) { dmax.setValue(v); }
    void setD0(Real v) { d0.setValue(v); }
    void setP0(Real v) { p0.setValue(v); }
    void setDamping(Real v) { damping.setValue(v); }


    virtual void init();

    virtual void addForce(const core::MechanicalParams* mparams, DataVecDeriv& d_f, const DataVecCoord& d_x, const DataVecDeriv& d_v);
    virtual void addDForce(const core::MechanicalParams* mparams, DataVecDeriv& d_df, const DataVecDeriv& d_dx);
    virtual SReal getPotentialEnergy(const core::MechanicalParams*, const DataVecCoord& d_x) const;

    void draw(const core::visual::VisualParams* vparams);

};

#if defined(SOFA_EXTERN_TEMPLATE) && !defined(SOFA_COMPONENT_FORCEFIELD_LENNARDJONESFORCEFIELD_CPP)

#ifndef SOFA_FLOAT
extern template class SOFA_MISC_FORCEFIELD_API LennardJonesForceField<defaulttype::Vec3dTypes>;
#endif
#ifndef SOFA_DOUBLE
extern template class SOFA_MISC_FORCEFIELD_API LennardJonesForceField<defaulttype::Vec3fTypes>;
#endif

#endif // defined(SOFA_EXTERN_TEMPLATE) && !defined(SOFA_COMPONENT_FORCEFIELD_LENNARDJONESFORCEFIELD_CPP)

} // namespace forcefield

} // namespace component

} // namespace sofa

#endif // SOFA_COMPONENT_FORCEFIELD_LENNARDJONESFORCEFIELD_H
