/*******************************************************************************
 * 
 * TRIQS: a Toolbox for Research in Interacting Quantum Systems
 *
 * Copyright (C) 2012 by M. Ferrero, O. Parcollet
 *
 * TRIQS 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 3 of the License, or (at your option) any later
 * version.
 *
 * TRIQS 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
 * TRIQS. If not, see <http://www.gnu.org/licenses/>.
 *
 ******************************************************************************/
#ifndef TRIQS_GF_IMTIME_REFREQ_TIMES_H
#define TRIQS_GF_IMTIME_REFREQ_TIMES_H
#include "./tools.hpp"
#include "./gf.hpp"
#include "./imtime.hpp"
#include "./refreq.hpp"
#include "./meshes/product.hpp"

namespace triqs { namespace gfs {
  
  struct refreq_imtime {};
  
  namespace gfs_implementation { 
    
    // the mesh
    template<typename Opt> struct mesh<refreq_imtime,Opt>  {
      typedef typename mesh<refreq,Opt>::type m1_t; 
      typedef typename mesh<imtime,Opt>::type m2_t; 
      typedef mesh_product<m1_t,m2_t> type;
      static type make (double wmin, double wmax, size_t n_freq, double beta, statistic_enum S, size_t nt, mesh_kind mk=full_bins ) { 
        return {make_gf_mesh<refreq,Opt>(wmin,wmax,n_freq), make_gf_mesh<imtime,Opt>(beta,S,nt,mk)};
      }
    };
    
    // singularity
    //template<typename Opt> struct singularity<refreq_imtime,scalar_valued,Opt>  { typedef gf<retime,scalar_valued> type;};
    
    // h5 name
    template<typename Opt> struct h5_name<refreq_imtime,scalar_valued,Opt> { static std::string invoke(){ return  "GfReFreqImTime";}};
    
    /// ---------------------------  data access  ---------------------------------
    
    template<typename Opt> struct data_proxy<refreq_imtime,scalar_valued,Opt> : data_proxy_array<std::complex<double>,1> {};
    
    /// ---------------------------  evaluator ---------------------------------
    
    template<typename Opt>
    struct evaluator<refreq_imtime,scalar_valued,Opt> {
      static constexpr int arity = 2;
      template<typename G>
      std::complex<double> operator() (G const * g, double omega, double tau)  const {
       double beta = std::get<1>(g->mesh().components()).domain().beta;
       int p = std::floor(tau/beta);
       tau -= p*beta;
       size_t n1,n2; double w1,w2; bool in;
       std::tie(in, n1, w1) = windowing( std::get<0>(g->mesh().components()),omega);
       if (!in) TRIQS_RUNTIME_ERROR <<" Evaluation out of bounds";
       std::tie(in, n2, w2) = windowing( std::get<1>(g->mesh().components()),tau);
       if (!in) TRIQS_RUNTIME_ERROR <<" Evaluation out of bounds";
       auto gg = on_mesh(*g); //[g]( size_t n1, size_t n2) {return g->on_mesh(n1,n2);};
       auto res =  w1 *( w2*gg(n1,n2) + (1-w2)*gg(n1,n2+1)) + (1-w1) * ( w2*gg(n1+1,n2) + (1-w2)*gg(n1+1,n2+1));
   
       //std::cout  << "eval reref imtim"<< n1 << " "<< n2 << " "<< w1 << " " << w2 << " "<< omega << " "<< tau<<  std::endl;

       return ((std::get<1>(g->mesh().components()).domain().statistic == Fermion) && (p%2==1) ? -res : res);
      } 
    };

    // -------------------------------   Factories  --------------------------------------------------

    template<typename Opt> struct factories<refreq_imtime, scalar_valued,Opt> {
     typedef gf<refreq_imtime, scalar_valued,Opt> gf_t;
     
     template<typename MeshType>
     static gf_t make_gf(MeshType && m) {
      typename gf_t::data_non_view_t A(m.size());
      A() =0;
      return gf_t (m, std::move(A), nothing(), nothing() ) ;
     }
     
     static gf_t make_gf(double wmin, double wmax, size_t n_freq, double beta, statistic_enum S, size_t nt, mesh_kind mk=full_bins) { 
      auto m =  make_gf_mesh<refreq_imtime,Opt>(wmin, wmax, n_freq, beta,S, nt, mk);
      typename gf_t::data_non_view_t A(m.size()); 
      A() =0;
      return gf_t (m, std::move(A), nothing(), nothing() ) ;
     }
    };

  } // gfs_implementation

  //slices
 inline gf_view<refreq,scalar_valued> slice_mesh_imtime (gf_view<refreq_imtime,scalar_valued> g, size_t index) { 
  auto arr = reinterpret_linear_array(g.mesh(),g.data()); // view it as a 2d array
  return { std::get<0>(g.mesh().components()), arr(arrays::range(),index), local::tail(1,1), nothing() };
 }

}}
#endif