/*
 * This file is part of the GROMACS molecular simulation package.
 *
 * Copyright 2020- The GROMACS Authors
 * and the project initiators Erik Lindahl, Berk Hess and David van der Spoel.
 * Consult the AUTHORS/COPYING files and https://www.gromacs.org for details.
 *
 * GROMACS 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.
 *
 * GROMACS 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 GROMACS; if not, see
 * https://www.gnu.org/licenses, or write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA.
 *
 * If you want to redistribute modifications to GROMACS, please
 * consider that scientific software is very special. Version
 * control is crucial - bugs must be traceable. We will be happy to
 * consider code for inclusion in the official distribution, but
 * derived work must not be called official GROMACS. Details are found
 * in the README & COPYING files - if they are missing, get the
 * official version at https://www.gromacs.org.
 *
 * To help us fund GROMACS development, we humbly ask that you cite
 * the research papers on the package. Check out https://www.gromacs.org.
 */
/*! \internal \file
 * \brief
 * This implements topology setup tests
 *
 * \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>
 * \author Artem Zhmurov <zhmurov@gmail.com>
 */
#include <gtest/gtest.h>

#include "gromacs/topology/exclusionblocks.h"

#include "nblib/gmxcalculatorcpu.h"
#include "nblib/integrator.h"
#include "nblib/topology.h"
#include "nblib/util/setup.h"

#include "testhelpers.h"
#include "testsystems.h"

namespace nblib
{
namespace test
{
namespace
{

TEST(NBlibTest, SpcMethanolForcesAreCorrect)
{
    auto options        = NBKernelOptions();
    options.nbnxmSimd   = SimdKernels::SimdNo;
    options.coulombType = CoulombType::Cutoff;

    SpcMethanolSimulationStateBuilder spcMethanolSystemBuilder;

    auto simState = spcMethanolSystemBuilder.setupSimulationState();

    auto forceCalculator = setupGmxForceCalculatorCpu(simState.topology(), options);

    forceCalculator->updatePairlist(simState.coordinates(), simState.box());

    gmx::ArrayRef<Vec3> forces(simState.forces());
    ASSERT_NO_THROW(forceCalculator->compute(simState.coordinates(), simState.box(), forces));

    RefDataChecker forcesOutputTest(5e-5);
    forcesOutputTest.testArrays<Vec3>(forces, "SPC-methanol forces");
}

TEST(NBlibTest, ExpectedNumberOfForces)
{
    auto options      = NBKernelOptions();
    options.nbnxmSimd = SimdKernels::SimdNo;

    SpcMethanolSimulationStateBuilder spcMethanolSystemBuilder;

    auto simState = spcMethanolSystemBuilder.setupSimulationState();

    auto forceCalculator = setupGmxForceCalculatorCpu(simState.topology(), options);

    forceCalculator->updatePairlist(simState.coordinates(), simState.box());

    gmx::ArrayRef<Vec3> forces(simState.forces());
    forceCalculator->compute(simState.coordinates(), simState.box(), forces);
    EXPECT_EQ(simState.topology().numParticles(), forces.size());
}

TEST(NBlibTest, CanIntegrateSystem)
{
    auto options          = NBKernelOptions();
    options.nbnxmSimd     = SimdKernels::SimdNo;
    options.numIterations = 1;

    SpcMethanolSimulationStateBuilder spcMethanolSystemBuilder;

    auto simState = spcMethanolSystemBuilder.setupSimulationState();

    auto forceCalculator = setupGmxForceCalculatorCpu(simState.topology(), options);

    forceCalculator->updatePairlist(simState.coordinates(), simState.box());

    LeapFrog integrator(simState.topology(), simState.box());

    for (int iter = 0; iter < options.numIterations; iter++)
    {
        gmx::ArrayRef<Vec3> forces(simState.forces());
        forceCalculator->compute(simState.coordinates(), simState.box(), forces);
        EXPECT_NO_THROW(integrator.integrate(1.0, simState.coordinates(), simState.velocities(), forces));
    }
}

/*!
 * Check if the following aspects of the ForceCalculator and
 * LeapFrog (integrator) work as expected:
 *
 * 1. Calling the ForceCalculator::compute() function makes no change
 *    to the internal representation of the system. Calling it repeatedly
 *    without update should return the same vector of forces.
 *
 * 2. Once the LeapFrog objects integrates for the given time using the
 *    forces, there the coordinates in SimulationState must change.
 *    Calling the compute() function must now generate a new set of forces.
 *
 */
TEST(NBlibTest, UpdateChangesForces)
{
    auto options          = NBKernelOptions();
    options.nbnxmSimd     = SimdKernels::SimdNo;
    options.numIterations = 1;

    SpcMethanolSimulationStateBuilder spcMethanolSystemBuilder;

    auto simState = spcMethanolSystemBuilder.setupSimulationState();

    auto forceCalculator = setupGmxForceCalculatorCpu(simState.topology(), options);

    forceCalculator->updatePairlist(simState.coordinates(), simState.box());

    LeapFrog integrator(simState.topology(), simState.box());

    // step 1
    gmx::ArrayRef<Vec3> forces(simState.forces());

    forceCalculator->compute(simState.coordinates(), simState.box(), simState.forces());

    // copy computed forces to another array
    std::vector<Vec3> forces_1(forces.size());
    std::copy(forces.begin(), forces.end(), begin(forces_1));

    // zero original force buffer
    zeroCartesianArray(forces);

    // check if forces change without update step
    forceCalculator->compute(simState.coordinates(), simState.box(), forces);

    // check if forces change without update
    for (size_t i = 0; i < forces_1.size(); i++)
    {
        for (int j = 0; j < dimSize; j++)
        {
            EXPECT_EQ(forces[i][j], forces_1[i][j]);
        }
    }

    // update
    integrator.integrate(1.0, simState.coordinates(), simState.velocities(), simState.forces());

    // zero original force buffer
    zeroCartesianArray(forces);

    // step 2
    forceCalculator->compute(simState.coordinates(), simState.box(), forces);

    std::vector<Vec3> forces_2(forces.size());
    std::copy(forces.begin(), forces.end(), begin(forces_2));

    // check if forces change after update
    for (size_t i = 0; i < forces_1.size(); i++)
    {
        for (int j = 0; j < dimSize; j++)
        {
            EXPECT_NE(forces_1[i][j], forces_2[i][j]);
        }
    }
}

TEST(NBlibTest, ArgonOplsaForcesAreCorrect)
{
    auto options        = NBKernelOptions();
    options.nbnxmSimd   = SimdKernels::SimdNo;
    options.coulombType = CoulombType::Cutoff;

    ArgonSimulationStateBuilder argonSystemBuilder(fftypes::OPLSA);

    auto simState = argonSystemBuilder.setupSimulationState();

    auto forceCalculator = setupGmxForceCalculatorCpu(simState.topology(), options);

    forceCalculator->updatePairlist(simState.coordinates(), simState.box());

    gmx::ArrayRef<Vec3> testForces(simState.forces());
    forceCalculator->compute(simState.coordinates(), simState.box(), simState.forces());

    RefDataChecker forcesOutputTest(1e-7);
    forcesOutputTest.testArrays<Vec3>(testForces, "Argon forces");
}

TEST(NBlibTest, ArgonGromos43A1ForcesAreCorrect)
{
    auto options        = NBKernelOptions();
    options.nbnxmSimd   = SimdKernels::SimdNo;
    options.coulombType = CoulombType::Cutoff;

    ArgonSimulationStateBuilder argonSystemBuilder(fftypes::GROMOS43A1);

    auto simState = argonSystemBuilder.setupSimulationState();

    auto forceCalculator = setupGmxForceCalculatorCpu(simState.topology(), options);

    forceCalculator->updatePairlist(simState.coordinates(), simState.box());

    gmx::ArrayRef<Vec3> testForces(simState.forces());
    forceCalculator->compute(simState.coordinates(), simState.box(), simState.forces());

    RefDataChecker forcesOutputTest;
    forcesOutputTest.testArrays<Vec3>(testForces, "Argon forces");
}

} // namespace
} // namespace test
} // namespace nblib
