/* -------------------------------------------------------------------------- *
 *                                   OpenMM                                   *
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 * This is part of the OpenMM molecular simulation toolkit.                   *
 * See https://openmm.org/development.                                        *
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 * Authors: Peter Eastman                                                     *
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#include "openmm/Force.h"
#include "openmm/OpenMMException.h"
#include "openmm/CustomExternalForce.h"
#include "openmm/internal/AssertionUtilities.h"
#include "openmm/internal/CustomExternalForceImpl.h"
#include <cmath>
#include <map>
#include <sstream>
#include <utility>

using namespace OpenMM;
using namespace std;

CustomExternalForce::CustomExternalForce(const string& energy) : energyExpression(energy), numContexts(0) {
}

const string& CustomExternalForce::getEnergyFunction() const {
    return energyExpression;
}

void CustomExternalForce::setEnergyFunction(const std::string& energy) {
    energyExpression = energy;
}

int CustomExternalForce::addPerParticleParameter(const string& name) {
    parameters.push_back(ParticleParameterInfo(name));
    return parameters.size()-1;
}

const string& CustomExternalForce::getPerParticleParameterName(int index) const {
    ASSERT_VALID_INDEX(index, parameters);
    return parameters[index].name;
}

void CustomExternalForce::setPerParticleParameterName(int index, const string& name) {
    ASSERT_VALID_INDEX(index, parameters);
    parameters[index].name = name;
}

int CustomExternalForce::addGlobalParameter(const string& name, double defaultValue) {
    globalParameters.push_back(GlobalParameterInfo(name, defaultValue));
    return globalParameters.size()-1;
}

const string& CustomExternalForce::getGlobalParameterName(int index) const {
    ASSERT_VALID_INDEX(index, globalParameters);
    return globalParameters[index].name;
}

void CustomExternalForce::setGlobalParameterName(int index, const string& name) {
    ASSERT_VALID_INDEX(index, globalParameters);
    globalParameters[index].name = name;
}

double CustomExternalForce::getGlobalParameterDefaultValue(int index) const {
    ASSERT_VALID_INDEX(index, globalParameters);
    return globalParameters[index].defaultValue;
}

void CustomExternalForce::setGlobalParameterDefaultValue(int index, double defaultValue) {
    ASSERT_VALID_INDEX(index, globalParameters);
    globalParameters[index].defaultValue = defaultValue;
}

int CustomExternalForce::addParticle(int particle, const vector<double>& parameters) {
    particles.push_back(ParticleInfo(particle, parameters));
    return particles.size()-1;
}

void CustomExternalForce::getParticleParameters(int index, int& particle, std::vector<double>& parameters) const {
    ASSERT_VALID_INDEX(index, particles);
    particle = particles[index].particle;
    parameters = particles[index].parameters;
}

void CustomExternalForce::setParticleParameters(int index, int particle, const vector<double>& parameters) {
    ASSERT_VALID_INDEX(index, particles);
    particles[index].parameters = parameters;
    particles[index].particle = particle;
    if (numContexts > 0) {
        firstChangedParticle = min(index, firstChangedParticle);
        lastChangedParticle = max(index, lastChangedParticle);
    }
}

ForceImpl* CustomExternalForce::createImpl() const {
    if (numContexts == 0) {
        // Begin tracking changes to particles.
        firstChangedParticle = particles.size();
        lastChangedParticle = -1;
    }
    numContexts++;    return new CustomExternalForceImpl(*this);
}

void CustomExternalForce::updateParametersInContext(Context& context) {
    dynamic_cast<CustomExternalForceImpl&>(getImplInContext(context)).updateParametersInContext(getContextImpl(context), firstChangedParticle, lastChangedParticle);
    if (numContexts == 1) {
        // We just updated the only existing context for this force, so we can reset
        // the tracking of changed particles.
        firstChangedParticle = particles.size();
        lastChangedParticle = -1;
    }
}

bool CustomExternalForce::usesPeriodicBoundaryConditions() const {
    return (energyExpression.find("periodicdistance") != string::npos);
}

int CustomExternalForce::getNumParticles() const {
    return particles.size();
}

int CustomExternalForce::getNumPerParticleParameters() const {
    return parameters.size();
}

int CustomExternalForce::getNumGlobalParameters() const {
    return globalParameters.size();
}
