/*******************************************************************************
 *
 * 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/>.
 *
 ******************************************************************************/
#pragma once
#include "./mesh_tools.hpp"
#include "../domains/discrete.hpp"

namespace triqs {
namespace gfs {

 template <typename Domain> struct discrete_mesh {

  using domain_t = Domain;
  using index_t = long;

  discrete_mesh(domain_t dom) : _dom(std::move(dom)) {}
  discrete_mesh() = default;

  domain_t const &domain() const { return _dom; }
  long size() const { return _dom.size(); }

  /// Conversions point <-> index <-> discrete_index
  long index_to_point(index_t ind) const { return ind; }
  long index_to_linear(index_t ind) const { return ind; }

  /// The wrapper for the mesh point
  class mesh_point_t : tag::mesh_point, public utility::arithmetic_ops_by_cast<mesh_point_t, long> {
   discrete_mesh const *m;
   index_t _index;
   public:
   mesh_point_t() = default;
   mesh_point_t(discrete_mesh const &mesh, index_t const &index_) : m(&mesh), _index(index_) {}
   mesh_point_t(discrete_mesh const &mesh) : mesh_point_t(mesh, 0){}
   void advance() { ++_index; }
   using cast_t = long;
   operator cast_t() const { return m->index_to_point(_index); }
   long linear_index() const { return _index; }
   long index() const { return _index; }
   bool at_end() const { return (_index == m->size()); }
   void reset() { _index = 0; }
  };

  /// Accessing a point of the mesh
  mesh_point_t operator[](index_t i) const { return mesh_point_t(*this, i); }
  mesh_point_t operator[](std::string const &s) const { return mesh_point_t(*this, _dom.index_from_name(s)); }

  /// Iterating on all the points...
  using const_iterator = mesh_pt_generator<discrete_mesh>;
  const_iterator begin() const { return const_iterator(this); }
  const_iterator end() const { return const_iterator(this, true); }
  const_iterator cbegin() const { return const_iterator(this); }
  const_iterator cend() const { return const_iterator(this, true); }

  /// Mesh comparison
  bool operator==(discrete_mesh const &M) const { return (_dom == M._dom); }
  bool operator!=(discrete_mesh const &M) const { return !(operator==(M)); }

  /// Write into HDF5
  friend void h5_write(h5::group fg, std::string subgroup_name, discrete_mesh const &m) {
   h5::group gr = fg.create_group(subgroup_name);
   h5_write(gr, "domain", m.domain());
  }

  /// Read from HDF5
  friend void h5_read(h5::group fg, std::string subgroup_name, discrete_mesh &m) {
   h5::group gr = fg.open_group(subgroup_name);
   typename discrete_mesh::domain_t dom;
   h5_read(gr, "domain", dom);
   m = discrete_mesh(std::move(dom));
  }

  //  BOOST Serialization
  friend class boost::serialization::access;
  template <class Archive> void serialize(Archive &ar, const unsigned int version) {
   ar &boost::serialization::make_nvp("domain", _dom);
  }

  friend std::ostream &operator<<(std::ostream &sout, discrete_mesh const &m) { return sout << "Discrete Mesh"; }

  private:
  domain_t _dom;
 };
}
}