/* -------------------------------------------------------------------------- *
 *                                   OpenMMAmoeba                             *
 * -------------------------------------------------------------------------- *
 * This is part of the OpenMM molecular simulation toolkit originating from   *
 * Simbios, the NIH National Center for Physics-Based Simulation of           *
 * Biological Structures at Stanford, funded under the NIH Roadmap for        *
 * Medical Research, grant U54 GM072970. See https://simtk.org.               *
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 * Portions copyright (c) 2008-2012 Stanford University and the Authors.      *
 * Authors: Mark Friedrichs                                                   *
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/**
 * This tests the Reference implementation of CudaAmoebaWcaDispersionForce.
 */

#include "openmm/internal/AssertionUtilities.h"
#include "openmm/Context.h"
#include "OpenMMAmoeba.h"
#include "openmm/System.h"
#include "openmm/AmoebaWcaDispersionForce.h"
#include "openmm/LangevinIntegrator.h"
#include <iostream>
#include <vector>
#include <stdlib.h>
#include <stdio.h>

#define ASSERT_EQUAL_TOL_MOD(expected, found, tol, testname) {double _scale_ = std::abs(expected) > 1.0 ? std::abs(expected) : 1.0; if (!(std::abs((expected)-(found))/_scale_ <= (tol))) {std::stringstream details; details << testname << " Expected "<<(expected)<<", found "<<(found); throwException(__FILE__, __LINE__, details.str());}};

#define ASSERT_EQUAL_VEC_MOD(expected, found, tol,testname) {ASSERT_EQUAL_TOL_MOD((expected)[0], (found)[0], (tol),(testname)); ASSERT_EQUAL_TOL_MOD((expected)[1], (found)[1], (tol),(testname)); ASSERT_EQUAL_TOL_MOD((expected)[2], (found)[2], (tol),(testname));};


using namespace OpenMM;
const double TOL = 1e-4;

void setupAndGetForcesEnergyWcaDispersionAmmonia( std::vector<Vec3>& forces, double& energy, FILE* log ){

    // beginning of WcaDispersion setup

    System system;
    AmoebaWcaDispersionForce* amoebaWcaDispersionForce        = new AmoebaWcaDispersionForce();;
    int numberOfParticles                                     = 8;

    amoebaWcaDispersionForce->setEpso(    4.6024000e-01 );
    amoebaWcaDispersionForce->setEpsh(    5.6484000e-02 );
    amoebaWcaDispersionForce->setRmino(   1.7025000e-01 );
    amoebaWcaDispersionForce->setRminh(   1.3275000e-01 );
    amoebaWcaDispersionForce->setDispoff( 2.6000000e-02 );
    amoebaWcaDispersionForce->setAwater(  3.3428000e+01 );
    amoebaWcaDispersionForce->setSlevy(   1.0000000e+00 );
    amoebaWcaDispersionForce->setShctd(   8.1000000e-01 );

    // addParticle: radius, epsilon

    for( unsigned int ii = 0; ii < 2; ii++ ){
        system.addParticle(   1.4007000e+01 );
        amoebaWcaDispersionForce->addParticle(   1.8550000e-01,   4.3932000e-01 );
    
        system.addParticle(   1.0080000e+00 );
        amoebaWcaDispersionForce->addParticle(   1.3500000e-01,   8.3680000e-02 );
    
        system.addParticle(   1.0080000e+00 );
        amoebaWcaDispersionForce->addParticle(   1.3500000e-01,   8.3680000e-02 );
    
        system.addParticle(   1.0080000e+00 );
        amoebaWcaDispersionForce->addParticle(   1.3500000e-01,   8.3680000e-02 );
    }

    std::vector<Vec3> positions(numberOfParticles);

    positions[0]              = Vec3(   1.5927280e-01,   1.7000000e-06,    1.6491000e-03 );
    positions[1]              = Vec3(   2.0805540e-01,  -8.1258800e-02,    3.7282500e-02 );
    positions[2]              = Vec3(   2.0843610e-01,   8.0953200e-02,    3.7462200e-02 );
    positions[3]              = Vec3(   1.7280780e-01,   2.0730000e-04,   -9.8741700e-02 );
    positions[4]              = Vec3(  -1.6743680e-01,   1.5900000e-05,   -6.6149000e-03 );
    positions[5]              = Vec3(  -2.0428260e-01,   8.1071500e-02,    4.1343900e-02 );
    positions[6]              = Vec3(  -6.7308300e-02,   1.2800000e-05,    1.0623300e-02 );
    positions[7]              = Vec3(  -2.0426290e-01,  -8.1231400e-02,    4.1033500e-02 );

    system.addForce(amoebaWcaDispersionForce);

    std::string platformName;
    platformName = "Reference";
    LangevinIntegrator integrator(0.0, 0.1, 0.01);
    Context context(system, integrator, Platform::getPlatformByName( platformName ) );

    context.setPositions(positions);
    State state                      = context.getState(State::Forces | State::Energy);
    forces                           = state.getForces();
    energy                           = state.getPotentialEnergy();
}

void compareForcesEnergy( std::string& testName, double expectedEnergy, double energy,
                          std::vector<Vec3>& expectedForces,
                          std::vector<Vec3>& forces, double tolerance, FILE* log ) {

#ifdef AMOEBA_DEBUG
    if( log ){
        (void) fprintf( log, "%s: expected energy=%14.7e %14.7e\n", testName.c_str(), expectedEnergy, energy );
        for( unsigned int ii = 0; ii < forces.size(); ii++ ){
            (void) fprintf( log, "%6u [%14.7e %14.7e %14.7e]   [%14.7e %14.7e %14.7e]\n", ii,
                            expectedForces[ii][0], expectedForces[ii][1], expectedForces[ii][2], forces[ii][0], forces[ii][1], forces[ii][2] );
        }
        (void) fflush( log );
    }
#endif

    for( unsigned int ii = 0; ii < forces.size(); ii++ ){
        ASSERT_EQUAL_VEC_MOD( expectedForces[ii], forces[ii], tolerance, testName );
    }
    ASSERT_EQUAL_TOL_MOD( expectedEnergy, energy, tolerance, testName );
}

// test Wca dispersion

void testWcaDispersionAmmonia( FILE* log ) {

    std::string testName      = "testWcaDispersionAmmonia";

    int numberOfParticles     = 8;
    std::vector<Vec3> forces;
    double energy;

    setupAndGetForcesEnergyWcaDispersionAmmonia( forces, energy, log );
    std::vector<Vec3> expectedForces(numberOfParticles);

    // TINKER-computed values

    double expectedEnergy     =  -2.6981209e+01;

    expectedForces[0]         = Vec3(   4.7839388e+00,  -7.3510133e-04,  -5.0382764e-01 );
    expectedForces[1]         = Vec3(   1.4657758e+00,   1.2431003e+00,  -6.7075886e-01 );
    expectedForces[2]         = Vec3(   1.4563936e+00,  -1.2399917e+00,  -6.7443841e-01 );
    expectedForces[3]         = Vec3(   2.1116744e+00,  -2.7407512e-03,   1.3271245e+00 );
    expectedForces[4]         = Vec3(  -4.7528440e+00,  -1.5148066e-03,   1.2653813e+00 );
    expectedForces[5]         = Vec3(  -1.1875619e+00,  -1.2866678e+00,  -3.9109060e-01 );
    expectedForces[6]         = Vec3(  -2.6885679e+00,  -4.3038639e-04,   3.3763583e-02 );
    expectedForces[7]         = Vec3(  -1.1888087e+00,   1.2889802e+00,  -3.8615387e-01 );

    double tolerance          = 1.0e-04;
    compareForcesEnergy( testName, expectedEnergy, energy, expectedForces, forces, tolerance, log );
}

int main( int numberOfArguments, char* argv[] ) {

    try {
        std::cout << "TestCudaAmoebaWcaDispersionForce running test..." << std::endl;

        FILE* log = NULL;

        // test Wca dispersion force using two ammonia molecules

        testWcaDispersionAmmonia( log );


    } catch(const std::exception& e) {
        std::cout << "exception: " << e.what() << std::endl;
        std::cout << "FAIL - ERROR.  Test failed." << std::endl;
        return 1;
    }
    std::cout << "Done" << std::endl;
    return 0;
}
