/* -------------------------------------------------------------------------- *
 *                                   OpenMM                                   *
 * -------------------------------------------------------------------------- *
 * This is part of the OpenMM molecular simulation toolkit.                   *
 * See https://openmm.org/development.                                        *
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 * Portions copyright (c) 2008-2024 Stanford University and the Authors.      *
 * Authors: Peter Eastman                                                     *
 * Contributors:                                                              *
 *                                                                            *
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 * copy of this software and associated documentation files (the "Software"), *
 * to deal in the Software without restriction, including without limitation  *
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#ifdef WIN32
  #define _USE_MATH_DEFINES // Needed to get M_PI
#endif
#include "openmm/OpenMMException.h"
#include "openmm/internal/ContextImpl.h"
#include "openmm/internal/CustomGBForceImpl.h"
#include "openmm/internal/Messages.h"
#include "openmm/kernels.h"
#include <cmath>
#include <sstream>

using namespace OpenMM;
using namespace std;

CustomGBForceImpl::CustomGBForceImpl(const CustomGBForce& owner) : owner(owner) {
    forceGroup = owner.getForceGroup();
}

CustomGBForceImpl::~CustomGBForceImpl() {
}

void CustomGBForceImpl::initialize(ContextImpl& context) {
    kernel = context.getPlatform().createKernel(CalcCustomGBForceKernel::Name(), context);

    // Check for errors in the specification of parameters and exclusions.

    const System& system = context.getSystem();
    if (owner.getNumParticles() != system.getNumParticles())
        throw OpenMMException("CustomGBForce must have exactly as many particles as the System it belongs to.");
    vector<set<int> > exclusions(owner.getNumParticles());
    vector<double> parameters;
    int numParameters = owner.getNumPerParticleParameters();
    for (int i = 0; i < owner.getNumParticles(); i++) {
        owner.getParticleParameters(i, parameters);
        if (parameters.size() != numParameters) {
            stringstream msg;
            msg << "CustomGBForce: Wrong number of parameters for particle ";
            msg << i;
            throw OpenMMException(msg.str());
        }
    }
    for (int i = 0; i < owner.getNumExclusions(); i++) {
        int particle1, particle2;
        owner.getExclusionParticles(i, particle1, particle2);
        int minp = min(particle1, particle2);
        int maxp = max(particle1, particle2);
        if (particle1 < 0 || particle1 >= owner.getNumParticles()) {
            stringstream msg;
            msg << "CustomGBForce: Illegal particle index for an exclusion: ";
            msg << particle1;
            throw OpenMMException(msg.str());
        }
        if (particle2 < 0 || particle2 >= owner.getNumParticles()) {
            stringstream msg;
            msg << "CustomGBForce: Illegal particle index for an exclusion: ";
            msg << particle2;
            throw OpenMMException(msg.str());
        }
        if (exclusions[minp].count(maxp) > 0) {
            stringstream msg;
            msg << "CustomGBForce: Multiple exclusions are specified for particles ";
            msg << particle1;
            msg << " and ";
            msg << particle2;
            throw OpenMMException(msg.str());
        }
        exclusions[minp].insert(maxp);
    }
    if (owner.getNonbondedMethod() == CustomGBForce::CutoffPeriodic) {
        Vec3 boxVectors[3];
        system.getDefaultPeriodicBoxVectors(boxVectors[0], boxVectors[1], boxVectors[2]);
        double cutoff = owner.getCutoffDistance();
        if (cutoff > 0.5*boxVectors[0][0] || cutoff > 0.5*boxVectors[1][1] || cutoff > 0.5*boxVectors[2][2])
            throw OpenMMException("CustomGBForce: "+Messages::cutoffTooLarge);
    }
    kernel.getAs<CalcCustomGBForceKernel>().initialize(context.getSystem(), owner);
}

double CustomGBForceImpl::calcForcesAndEnergy(ContextImpl& context, bool includeForces, bool includeEnergy, int groups) {
    if ((groups&(1<<forceGroup)) != 0)
        return kernel.getAs<CalcCustomGBForceKernel>().execute(context, includeForces, includeEnergy);
    return 0.0;
}

vector<string> CustomGBForceImpl::getKernelNames() {
    return {CalcCustomGBForceKernel::Name()};
}

map<string, double> CustomGBForceImpl::getDefaultParameters() {
    map<string, double> parameters;
    for (int i = 0; i < owner.getNumGlobalParameters(); i++)
        parameters[owner.getGlobalParameterName(i)] = owner.getGlobalParameterDefaultValue(i);
    return parameters;
}

void CustomGBForceImpl::updateParametersInContext(ContextImpl& context) {
    kernel.getAs<CalcCustomGBForceKernel>().copyParametersToContext(context, owner);
    context.systemChanged();
}
