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/*! \internal \file
 * \brief Implements a force calculator based on GROMACS data structures.
 *
 * \author Victor Holanda <victor.holanda@cscs.ch>
 * \author Joe Jordan <ejjordan@kth.se>
 * \author Prashanth Kanduri <kanduri@cscs.ch>
 * \author Sebastian Keller <keller@cscs.ch>
 */
#include "nblib/gmxcalculator.h"
#include "gromacs/ewald/ewald_utils.h"
#include "gromacs/gmxlib/nrnb.h"
#include "gromacs/mdlib/rf_util.h"
#include "gromacs/mdtypes/enerdata.h"
#include "gromacs/mdtypes/forcerec.h"
#include "gromacs/mdtypes/interaction_const.h"
#include "gromacs/mdtypes/simulation_workload.h"
#include "gromacs/nbnxm/nbnxm.h"
#include "gromacs/utility/range.h"
#include "nblib/exception.h"
#include "nblib/simulationstate.h"

namespace nblib
{

GmxForceCalculator::GmxForceCalculator()
{
    enerd_            = std::make_unique<gmx_enerdata_t>(1, 0);
    forcerec_         = std::make_unique<t_forcerec>();
    interactionConst_ = std::make_unique<interaction_const_t>();
    stepWork_         = std::make_unique<gmx::StepWorkload>();
    nrnb_             = std::make_unique<t_nrnb>();
}

GmxForceCalculator::~GmxForceCalculator() = default;

void GmxForceCalculator::compute(gmx::ArrayRef<const gmx::RVec> coordinateInput,
                                 gmx::ArrayRef<gmx::RVec>       forceOutput)
{
    // update the coordinates in the backend
    nbv_->convertCoordinates(gmx::AtomLocality::Local, false, coordinateInput);

    nbv_->dispatchNonbondedKernel(gmx::InteractionLocality::Local, *interactionConst_, *stepWork_,
                                  enbvClearFYes, *forcerec_, enerd_.get(), nrnb_.get());

    nbv_->atomdata_add_nbat_f_to_f(gmx::AtomLocality::All, forceOutput);
}

void GmxForceCalculator::setParticlesOnGrid(gmx::ArrayRef<const int>       particleInfoAllVdw,
                                            gmx::ArrayRef<const gmx::RVec> coordinates,
                                            const Box&                     box)
{
    auto legacyBox = box.legacyMatrix();

    if (TRICLINIC(legacyBox))
    {
        throw InputException("Only rectangular unit-cells are supported here");
    }
    const rvec lowerCorner = { 0, 0, 0 };
    const rvec upperCorner = { legacyBox[dimX][dimX], legacyBox[dimY][dimY], legacyBox[dimZ][dimZ] };

    const real particleDensity = coordinates.size() / det(legacyBox);

    nbnxn_put_on_grid(nbv_.get(), legacyBox, 0, lowerCorner, upperCorner, nullptr,
                      { 0, int(coordinates.size()) }, particleDensity, particleInfoAllVdw,
                      coordinates, 0, nullptr);
}

} // namespace nblib
