/*
 * ScalarVP.hpp, part of Hadrons (https://github.com/aportelli/Hadrons)
 *
 * Copyright (C) 2015 - 2023
 *
 * Author: Antonin Portelli <antonin.portelli@me.com>
 * Author: James Harrison <jch1g10@soton.ac.uk>
 *
 * 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_MScalar_ScalarVP_hpp_
#define Hadrons_MScalar_ScalarVP_hpp_

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

BEGIN_HADRONS_NAMESPACE

/******************************************************************************
 *                         Scalar vacuum polarisation                         *
 ******************************************************************************/
BEGIN_MODULE_NAMESPACE(MScalar)

class ScalarVPPar: Serializable
{
public:
    GRID_SERIALIZABLE_CLASS_MEMBERS(ScalarVPPar,
                                    std::string, emField,
                                    std::string, scalarProp,
                                    std::string, output,
                                    std::vector<std::string>, outputMom);
};

class TScalarVP: public Module<ScalarVPPar>
{
public:
    BASIC_TYPE_ALIASES(SIMPL,);
    typedef PhotonR::GaugeField     EmField;
    typedef PhotonR::GaugeLinkField EmComp;
    class Result: Serializable
    {
    public:
        class Projection: Serializable
        {
        public:
            GRID_SERIALIZABLE_CLASS_MEMBERS(Projection,
                                            std::vector<int>,     momentum,
                                            std::vector<std::vector<std::vector<Complex>>>, pi,
                                            std::vector<std::vector<std::vector<Complex>>>, pi_free,
                                            std::vector<std::vector<std::vector<Complex>>>, pi_2E,
                                            std::vector<std::vector<std::vector<Complex>>>, pi_2T,
                                            std::vector<std::vector<std::vector<Complex>>>, pi_S,
                                            std::vector<std::vector<std::vector<Complex>>>, pi_4C,
                                            std::vector<std::vector<std::vector<Complex>>>, pi_X,
                                            std::vector<std::vector<std::vector<Complex>>>, pi_srcT,
                                            std::vector<std::vector<std::vector<Complex>>>, pi_snkT);
        };
        GRID_SERIALIZABLE_CLASS_MEMBERS(Result,
                                        std::vector<int>,        lattice_size,
                                        double,                  mass,
                                        double,                  charge,
                                        std::vector<Projection>, projection);
    };
public:
    // constructor
    TScalarVP(const std::string name);
    // destructor
    virtual ~TScalarVP(void) {};
    // dependency relation
    virtual std::vector<std::string> getInput(void);
    virtual std::vector<std::string> getOutput(void);
protected:
    // setup
    virtual void setup(void);
    // execution
    virtual void execute(void);
private:
    void makeCaches(void);
    // conserved vector two-point contraction
    void vpContraction(ScalarField &vp,
                       ScalarField &prop_0_x, ScalarField &prop_nu_x,
                       TComplex u_src, ScalarField &u_snk, int mu);
    // conserved vector two-point contraction with unit gauge link at sink
    void vpContraction(ScalarField &vp,
                       ScalarField &prop_0_x, ScalarField &prop_nu_x,
                       TComplex u_src, int mu);
    // write momentum-projected vacuum polarisation to file(s)
    void project(std::vector<Complex> &projection, const ScalarField &vp,
                 int i_p);
    // momentum-space Delta_1 insertion
    void momD1(ScalarField &s, FFT &fft);
private:
    bool                                        momPhasesDone_;
    std::string                                 freeMomPropName_, GFSrcName_,
                                                prop0Name_, propQName_,
                                                propSunName_, propTadName_,
                                                fftName_;
    std::vector<std::string>                    phaseName_, muPropQName_,
                                                momPhaseName_;
    std::vector<std::vector<std::string> >      vpTensorName_;
    std::vector<ScalarField *>                  phase_, momPhase_;
};

MODULE_REGISTER(ScalarVP, TScalarVP, MScalar);

END_MODULE_NAMESPACE

END_HADRONS_NAMESPACE

#endif // Hadrons_MScalar_ScalarVP_hpp_