/* -------------------------------------------------------------------------- *
 *                                   OpenMM                                   *
 * -------------------------------------------------------------------------- *
 * This is part of the OpenMM molecular simulation toolkit.                   *
 * See https://openmm.org/development.                                        *
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 * Portions copyright (c) 2015-2024 Stanford University and the Authors.      *
 * Authors: Peter Eastman                                                     *
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#include "openmm/CompoundIntegrator.h"
#include "openmm/Context.h"
#include "openmm/OpenMMException.h"
#include "openmm/internal/ContextImpl.h"
#include "openmm/internal/AssertionUtilities.h"
#include "openmm/kernels.h"
#include <string>

using namespace OpenMM;
using namespace std;

CompoundIntegrator::CompoundIntegrator() : currentIntegrator(0) {
}

CompoundIntegrator::~CompoundIntegrator() {
    for (int i = 0; i < integrators.size(); i++)
        delete integrators[i];
}

int CompoundIntegrator::getNumIntegrators() const {
    return integrators.size();
}

int CompoundIntegrator::addIntegrator(Integrator* integrator) {
    if (owner != NULL)
        throw OpenMMException("addIntegrator() cannot be called after a CustomIntegrator is already bound to a context");
    integrators.push_back(integrator);
    return integrators.size()-1;
}

Integrator& CompoundIntegrator::getIntegrator(int index) {
    ASSERT_VALID_INDEX(index, integrators);
    return *integrators[index];
}

const Integrator& CompoundIntegrator::getIntegrator(int index) const {
    ASSERT_VALID_INDEX(index, integrators);
    return *integrators[index];
}

int CompoundIntegrator::getCurrentIntegrator() const {
    return currentIntegrator;
}

void CompoundIntegrator::setCurrentIntegrator(int index) {
    if (index < 0 || index >= integrators.size())
        throw OpenMMException("Illegal index for setCurrentIntegrator()");
    currentIntegrator = index;
}

double CompoundIntegrator::getStepSize() const {
    return integrators[currentIntegrator]->getStepSize();
}

void CompoundIntegrator::setStepSize(double size) {
    integrators[currentIntegrator]->setStepSize(size);
}

double CompoundIntegrator::getConstraintTolerance() const {
    return integrators[currentIntegrator]->getConstraintTolerance();
}

void CompoundIntegrator::setConstraintTolerance(double tol) {
    integrators[currentIntegrator]->setConstraintTolerance(tol);
}

void CompoundIntegrator::step(int steps) {
    integrators[currentIntegrator]->step(steps);
}

int CompoundIntegrator::getIntegrationForceGroups() const {
    return integrators[currentIntegrator]->getIntegrationForceGroups();
}

void CompoundIntegrator::setIntegrationForceGroups(int groups) {
    for (int i = 0; i < integrators.size(); i++)
        integrators[i]->setIntegrationForceGroups(groups);
}

void CompoundIntegrator::initialize(ContextImpl& context) {
    if (integrators.size() == 0)
        throw OpenMMException("CompoundIntegrator must contain at least one Integrator");
    for (int i = 0; i < integrators.size(); i++)
        integrators[i]->initialize(context);
}

void CompoundIntegrator::cleanup() {
    for (int i = 0; i < integrators.size(); i++) {
        integrators[i]->cleanup();
        integrators[i]->context = nullptr;
    }
}

vector<string> CompoundIntegrator::getKernelNames() {
    vector<string> kernels;
    for (int i = 0; i < integrators.size(); i++) {
        vector<string> integratorKernels = integrators[i]->getKernelNames();
        kernels.insert(kernels.end(), integratorKernels.begin(), integratorKernels.end());
    }
    return kernels;
}

void CompoundIntegrator::stateChanged(State::DataType changed) {
    for (int i = 0; i < integrators.size(); i++)
        integrators[i]->stateChanged(changed);
}

double CompoundIntegrator::computeKineticEnergy() {
    return integrators[currentIntegrator]->computeKineticEnergy();
}

void CompoundIntegrator::createCheckpoint(std::ostream& stream) const {
    stream.write((char*) &currentIntegrator, sizeof(int));
    for (int i = 0; i < integrators.size(); i++)
        integrators[i]->createCheckpoint(stream);
}

void CompoundIntegrator::loadCheckpoint(std::istream& stream) {
    stream.read((char*) &currentIntegrator, sizeof(int));
    for (int i = 0; i < integrators.size(); i++)
        integrators[i]->loadCheckpoint(stream);
}

void CompoundIntegrator::serializeParameters(SerializationNode& node) const {
    node.setIntProperty("version", 1);
    node.setIntProperty("currentIntegrator", currentIntegrator);
    for (int i = 0; i < getNumIntegrators(); i++) {
        SerializationNode& child = node.createChildNode("IntegratorParameters");
        integrators[i]->serializeParameters(child);
    }
}

void CompoundIntegrator::deserializeParameters(const SerializationNode& node) {
    if (node.getIntProperty("version") != 1)
        throw OpenMMException("Unsupported version number");
    if (node.getChildren().size() != getNumIntegrators())
        throw OpenMMException("State has wrong number of integrators for CompoundIntegrator");
    setCurrentIntegrator(node.getIntProperty("currentIntegrator"));
    for (int i = 0; i < node.getChildren().size(); i++)
        integrators[i]->deserializeParameters(node.getChildren()[i]);
}
