/*
 * A2AFourQuarkContraction.hpp, part of Hadrons (https://github.com/aportelli/Hadrons)
 *
 * Copyright (C) 2015 - 2023
 *
 * Author: Antonin Portelli <antonin.portelli@me.com>
 * Author: fionnoh <fionnoh@gmail.com>
 *
 * Hadrons is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 2 of the License, or
 * (at your option) any later version.
 *
 * Hadrons 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 General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with Hadrons.  If not, see <http://www.gnu.org/licenses/>.
 *
 * See the full license in the file "LICENSE" in the top level distribution 
 * directory.
 */

/*  END LEGAL */
#ifndef Hadrons_MContraction_A2AFourQuarkContraction_hpp_
#define Hadrons_MContraction_A2AFourQuarkContraction_hpp_

#include <Hadrons/Global.hpp>
#include <Hadrons/Module.hpp>
#include <Hadrons/ModuleFactory.hpp>
#include <Hadrons/DiskVector.hpp>

BEGIN_HADRONS_NAMESPACE

/******************************************************************************
 *                         A2AFourQuarkContraction                                 *
 ******************************************************************************/
BEGIN_MODULE_NAMESPACE(MContraction)

class A2AFourQuarkContractionPar: Serializable
{
public:
    GRID_SERIALIZABLE_CLASS_MEMBERS(A2AFourQuarkContractionPar,
                                    std::string,  v1,
                                    std::string,  v2,
                                    std::string,  mf12,
                                    bool,         allContr,
                                    unsigned int, dt);
};

template <typename FImpl>
class TA2AFourQuarkContraction: public Module<A2AFourQuarkContractionPar>
{
  public:
    FERM_TYPE_ALIASES(FImpl, );
    // constructor
    TA2AFourQuarkContraction(const std::string name);
    // destructor
    virtual ~TA2AFourQuarkContraction(void) {};
    // dependency relation
    virtual std::vector<std::string> getInput(void);
    virtual std::vector<std::string> getOutput(void);
    // setup
    virtual void setup(void);
    // execution
    virtual void execute(void);
  private:
    unsigned int nt_;
};

MODULE_REGISTER_TMP(A2AFourQuarkContraction, TA2AFourQuarkContraction<FIMPL>, MContraction);

/******************************************************************************
 *                 TA2AFourQuarkContraction implementation                             *
 ******************************************************************************/
// constructor /////////////////////////////////////////////////////////////////
template <typename FImpl>
TA2AFourQuarkContraction<FImpl>::TA2AFourQuarkContraction(const std::string name)
: Module<A2AFourQuarkContractionPar>(name)
{}

// dependencies/products ///////////////////////////////////////////////////////
template <typename FImpl>
std::vector<std::string> TA2AFourQuarkContraction<FImpl>::getInput(void)
{
    std::vector<std::string> in = {par().v1, par().v2, par().mf12};
    
    return in;
}

template <typename FImpl>
std::vector<std::string> TA2AFourQuarkContraction<FImpl>::getOutput(void)
{
    std::vector<std::string> out = {getName()};
    
    return out;
}

// setup ///////////////////////////////////////////////////////////////////////
template <typename FImpl>
void TA2AFourQuarkContraction<FImpl>::setup(void)
{
    if (par().allContr)
    {
        nt_ = env().getDim(Tp);
        envTmp(std::vector<PropagatorField>, "tmpWWVV", 1, nt_, envGetGrid(PropagatorField));
        envCreate(std::vector<PropagatorField>, getName(), 1, nt_, envGetGrid(PropagatorField));
    }
    else
    {
        envTmp(std::vector<PropagatorField>, "tmpWWVV", 1, 1, envGetGrid(PropagatorField));
        envCreate(PropagatorField, getName(), 1, envGetGrid(PropagatorField));
    }
}

// execution ///////////////////////////////////////////////////////////////////
template <typename FImpl>
void TA2AFourQuarkContraction<FImpl>::execute(void)
{
    auto &v1   = envGet(std::vector<FermionField>, par().v1);
    auto &v2   = envGet(std::vector<FermionField>, par().v2);
    auto &mf12 = envGet(EigenDiskVector<Complex>, par().mf12);

    envGetTmp(std::vector<PropagatorField>, tmpWWVV);

    unsigned int dt = par().dt;
    unsigned int nt = env().getDim(Tp);

    if (par().allContr)
    {
        LOG(Message) << "Computing 4 quark contraction for " << getName()
                     << " for all t0 time translations "
                     << "with nt = " << nt_ << " and dt = " << dt << std::endl;

        auto &WWVV = envGet(std::vector<PropagatorField>, getName());
        A2Autils<FImpl>::ContractWWVV(tmpWWVV, mf12, &v1[0], &v2[0]);
        for(unsigned int t = 0; t < nt_; t++){
            unsigned int t0 = (t + dt) % nt_;
            WWVV[t] = tmpWWVV[t0];
        }
    }
    else
    {
        LOG(Message) << "Computing 4 quark contraction for: " << getName()
                     << " for time dt = " << dt << std::endl;

        auto &WWVV = envGet(PropagatorField, getName());
        int ni = v1.size();
        int nj = v2.size();
        Eigen::Matrix<Complex, -1, -1, Eigen::RowMajor> mf;
        mf = mf12[dt];
        Eigen::TensorMap<Eigen::Tensor<Complex, 3, Eigen::RowMajor>> mfT(mf.data(), 1, ni, nj);
        A2Autils<FImpl>::ContractWWVV(tmpWWVV, mfT, &v1[0], &v2[0]);
        WWVV = tmpWWVV[0];
    }
}

END_MODULE_NAMESPACE

END_HADRONS_NAMESPACE

#endif // Hadrons_MContraction_A2AFourQuarkContraction_hpp_