/*************************************************************************************

Grid physics library, www.github.com/paboyle/Grid 

Source file: extras/Hadrons/Modules/MSource/SeqConserved.hpp

Copyright (C) 2015-2018

Author: Antonin Portelli <antonin.portelli@me.com>
Author: Andrew Lawson    <andrew.lawson1991@gmail.com>
Author: Vera Guelpers    <v.m.guelpers@soton.ac.uk>

This program 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.

This program 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 this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

See the full license in the file "LICENSE" in the top level distribution directory
*************************************************************************************/
/*  END LEGAL */

#ifndef Hadrons_MSource_SeqConserved_hpp_
#define Hadrons_MSource_SeqConserved_hpp_

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

BEGIN_HADRONS_NAMESPACE

/*
 
 Sequential source with insertion of conserved current. 
 Additionally optional insertion of a photon field A_\mu(x).
 -----------------------------
 * src_x = sum_{mu=mu_min}^{mu_max} 
     q_x * theta(x_3 - tA) * theta(tB - x_3) * J_mu * exp(i x.mom) (* A_\mu(x))
 
 * options:
 - q: input propagator (string)
 - action: fermion action used for propagator q (string)
 - tA: begin timeslice (integer)
 - tB: end timesilce (integer)
 - curr_type: type of conserved current to insert (Current)
 - mu_min: begin Lorentz Index (integer)
 - mu_max: end Lorentz Index (integer)
 - mom: momentum insertion, space-separated float sequence (e.g ".1 .2 1. 0.")
 - photon: optional photon field (string)
 
 */

/******************************************************************************
 *                              SeqConserved                                  *
 ******************************************************************************/
BEGIN_MODULE_NAMESPACE(MSource)

class SeqConservedPar: Serializable
{
public:
    GRID_SERIALIZABLE_CLASS_MEMBERS(SeqConservedPar,
                                    std::string,  q,
                                    std::string,  action,
                                    unsigned int, tA,
                                    unsigned int, tB,
                                    Current,      curr_type,
                                    unsigned int, mu_min,
                                    unsigned int, mu_max,
                                    std::string,  mom,
                                    std::string,  photon);
};

template <typename FImpl>
class TSeqConserved: public Module<SeqConservedPar>
{
public:
    FERM_TYPE_ALIASES(FImpl,);
public:
    typedef PhotonR::GaugeField     EmField;
public:
    // constructor
    TSeqConserved(const std::string name);
    // destructor
    virtual ~TSeqConserved(void) = default;
    // 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:
    bool        SeqhasPhase_{false}; 
    std::string SeqmomphName_;
};

MODULE_REGISTER_NS(SeqConserved, TSeqConserved<FIMPL>, MSource);


/******************************************************************************
 *                      TSeqConserved implementation                          *
 ******************************************************************************/
// constructor /////////////////////////////////////////////////////////////////
template <typename FImpl>
TSeqConserved<FImpl>::TSeqConserved(const std::string name)
: Module<SeqConservedPar>(name)
, SeqmomphName_ (name + "_Seqmomph")
{}

// dependencies/products ///////////////////////////////////////////////////////
template <typename FImpl>
std::vector<std::string> TSeqConserved<FImpl>::getInput(void)
{
    std::vector<std::string> in = {par().q, par().action};
    if (!par().photon.empty()) in.push_back(par().photon);
        
    return in;
}

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

// setup ///////////////////////////////////////////////////////////////////////
template <typename FImpl>
void TSeqConserved<FImpl>::setup(void)
{
    auto Ls_ = env().getObjectLs(par().action);
    envCreateLat(PropagatorField, getName(), Ls_);
    envTmpLat(PropagatorField, "src_tmp");
    envCacheLat(LatticeComplex, SeqmomphName_);
    envTmpLat(LatticeComplex, "coor");
    envTmpLat(LatticeComplex, "latt_compl");
}

// execution ///////////////////////////////////////////////////////////////////
template <typename FImpl>
void TSeqConserved<FImpl>::execute(void)
{
    if (par().tA == par().tB)
    {
        LOG(Message) << "Generating sequential source with conserved "
                     << par().curr_type << " current at " 
		     << "t = " << par().tA << " summed over the indices " 
		     << par().mu_min << " <= mu <= " << par().mu_max 
		     << std::endl;
    }
    else
    {
        LOG(Message) << "Generating sequential source with conserved "
                     << par().curr_type << " current for " 
                     << par().tA << " <= t <= " 
                     << par().tB << " summed over the indices " 
		     << par().mu_min << " <= mu <= " << par().mu_max
	             << std::endl;
    }
    auto &src = envGet(PropagatorField, getName());
    envGetTmp(PropagatorField, src_tmp);
    src_tmp = src;
    auto &q   = envGet(PropagatorField, par().q);
    auto &mat = envGet(FMat, par().action);
    envGetTmp(LatticeComplex, latt_compl);

    src = zero;

    //exp(ipx)
    auto &mom_phase = envGet(LatticeComplex, SeqmomphName_);
    if (!SeqhasPhase_)
    {    
        std::vector<Real> mom = strToVec<Real>(par().mom);
        mom_phase = zero;
        Complex           i(0.0,1.0);
        envGetTmp(LatticeComplex, coor);
        for(unsigned int mu = 0; mu < env().getNd(); mu++)
        {
            LatticeCoordinate(coor, mu);
            mom_phase = mom_phase + (mom[mu]/env().getGrid()->_fdimensions[mu])*coor;
        }
        mom_phase = exp((Real)(2*M_PI)*i*mom_phase);
        SeqhasPhase_ = true;
    }
    LOG(Message) << "Inserting momentum " << strToVec<Real>(par().mom) << std::endl;



    if (!par().photon.empty())    	
    {
	 LOG(Message) << "Inserting the stochastic photon field " << par().photon << std::endl;
    }

    for(unsigned int mu=par().mu_min;mu<=par().mu_max;mu++)
    {
        if (!par().photon.empty())    	
        {
	    //Get the stochastic photon field, if required
            auto &stoch_photon = envGet(EmField,  par().photon);
    	    latt_compl =  PeekIndex<LorentzIndex>(stoch_photon, mu) * mom_phase;
        }
        else
        {
            latt_compl = mom_phase;
        } 

    	mat.SeqConservedCurrent(q, src_tmp, par().curr_type, mu, 
                             par().tA, par().tB, latt_compl);
	src += src_tmp;

    }	

 
}


END_MODULE_NAMESPACE

END_HADRONS_NAMESPACE

#endif // Hadrons_MSource_SeqConserved_hpp_