/*******************************************************************************
 *
 * TRIQS: a Toolbox for Research in Interacting Quantum Systems
 *
 * Copyright (C) 2011-2014 by 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 "indexmaps/cuboid/map.hpp"
#include "indexmaps/cuboid/slice.hpp"
#include "impl/indexmap_storage_pair.hpp"
#include "impl/assignment.hpp"
#include "vector.hpp"
namespace triqs {
namespace arrays {

 template <typename ValueType, typename TraversalOrder = void, bool Borrowed = false, bool IsConst = false> class matrix_view;
 template <typename ValueType, typename TraversalOrder = void> class matrix;

// ---------------------- matrix --------------------------------
//
#define _IMPL_MATRIX_COMMON                                                                                                      \
 bool is_square() const { return this->shape()[0] == this->shape()[1]; }                                                         \
                                                                                                                                 \
 view_type transpose() const {                                                                                                   \
  typename indexmap_type::lengths_type l;                                                                                        \
  l[0] = this->indexmap().lengths()[1];                                                                                          \
  l[1] = this->indexmap().lengths()[0];                                                                                          \
  typename indexmap_type::strides_type s;                                                                                        \
  s[0] = this->indexmap().strides()[1];                                                                                          \
  s[1] = this->indexmap().strides()[0];                                                                                          \
  return view_type(indexmap_type(l, s, this->indexmap().start_shift()), this->storage());                                        \
 }                                                                                                                               \
 bool memory_layout_is_c() const { return this->indexmap().strides()[0] >= this->indexmap().strides()[1]; }                      \
 bool memory_layout_is_fortran() const { return this->indexmap().strides()[0] < this->indexmap().strides()[1]; }

#define IMPL_TYPE                                                                                                                \
 indexmap_storage_pair<indexmaps::cuboid::map<2,TraversalOrder>, storages::shared_block<ValueType, Borrowed>, TraversalOrder, IsConst, true,    \
                       Tag::matrix_view>

 template <typename ValueType, typename TraversalOrder, bool Borrowed, bool IsConst>
 class matrix_view : Tag::matrix_view, TRIQS_CONCEPT_TAG_NAME(MutableMatrix), public IMPL_TYPE {
  public:
  using regular_type = matrix<ValueType, TraversalOrder>;
  using view_type = matrix_view<ValueType, TraversalOrder>;
  using const_view_type = matrix_view<ValueType, TraversalOrder, false, true>;
  using weak_view_type = matrix_view<ValueType, TraversalOrder, true>;
  using indexmap_type = typename IMPL_TYPE::indexmap_type;
  using storage_type = typename IMPL_TYPE::storage_type;

  /// Build from an IndexMap and a storage
  template <typename S> matrix_view(typename IMPL_TYPE::indexmap_type const& Ind, S const& Mem) : IMPL_TYPE(Ind, Mem) {}

  /// Build from anything that has an indexmap and a storage compatible with this class
  template <typename ISP> matrix_view(const ISP& X) : IMPL_TYPE(X.indexmap(), X.storage()) {}

#ifdef TRIQS_WITH_PYTHON_SUPPORT
  /// Build from a numpy.array : throws if X is not a numpy.array
  explicit matrix_view(PyObject* X) : IMPL_TYPE(X, false, "matrix_view ") {}
#endif

  /// Copy construction
  matrix_view(matrix_view const& X) : IMPL_TYPE(X.indexmap(), X.storage()) {}

  matrix_view() = delete;

  // Move
  matrix_view(matrix_view&& X) { this->swap_me(X); }

  /// Swap
  friend void swap(matrix_view& A, matrix_view& B) { A.swap_me(B); }

  /// Rebind the view
  void rebind(matrix_view const& X) {
   this->indexmap_ = X.indexmap_;
   this->storage_ = X.storage_;
  }

  // rebind the other view, iif this is const, and the other is not.
  template <typename To2, bool C = IsConst> ENABLE_IFC(C) rebind(matrix_view<ValueType, To2, Borrowed, !IsConst> const& X) {
   this->indexmap_ = X.indexmap_;
   this->storage_ = X.storage_;
  }

  /** Assignement.  The size of the array MUST match exactly.  */
  template <typename RHS> matrix_view& operator=(const RHS& X) {
   triqs_arrays_assign_delegation(*this, X);
   return *this;
  }

  matrix_view& operator=(matrix_view const& X) {
   triqs_arrays_assign_delegation(*this, X);
   return *this;
  } // cf array_view class comment

  // Move assignment not defined : will use the copy = since view must copy data

  TRIQS_DEFINE_COMPOUND_OPERATORS(matrix_view);
  _IMPL_MATRIX_COMMON;
 };

 //---------------------------------------------------------------------
 // this traits is used by indexmap_storage_pair, when slicing to find the correct view type.
 template <class V, int R, typename TraversalOrder, bool Borrowed, bool IsConst>
 struct ISPViewType<V, R, TraversalOrder, Tag::matrix_view, Borrowed, IsConst> : std::conditional<R == 1, vector_view<V, Borrowed, IsConst>,
                                                                                  matrix_view<V, TraversalOrder, Borrowed, IsConst>> {};
#undef IMPL_TYPE

 template <typename ValueType, typename TraversalOrder = void, bool Borrowed = false>
 using matrix_const_view = matrix_view<ValueType, TraversalOrder, Borrowed, true>;

// ---------------------- matrix --------------------------------
#define IMPL_TYPE                                                                                                                \
 indexmap_storage_pair<indexmaps::cuboid::map<2, TraversalOrder>, storages::shared_block<ValueType>, TraversalOrder, false,      \
                       false, Tag::matrix_view>

 template <typename ValueType, typename TraversalOrder>
 class matrix : Tag::matrix, TRIQS_CONCEPT_TAG_NAME(MutableMatrix), public IMPL_TYPE {
  public:
  using value_type = typename IMPL_TYPE::value_type;
  using storage_type = typename IMPL_TYPE::storage_type;
  using indexmap_type = typename IMPL_TYPE::indexmap_type;
  using regular_type = matrix<ValueType, TraversalOrder>;
  using view_type = matrix_view<ValueType, TraversalOrder>;
  using const_view_type = matrix_view<ValueType, TraversalOrder, false, true>;
  using weak_view_type = matrix_view<ValueType, TraversalOrder, true>;

  /// Empty matrix.
  matrix(memory_layout<2> ml = memory_layout<2>{}) : IMPL_TYPE(indexmap_type(ml)) {}

  /// Move
  explicit matrix(matrix&& X) { this->swap_me(X); }

  ///
  matrix(size_t dim1, size_t dim2, memory_layout<2> ml = memory_layout<2>{})
     : IMPL_TYPE(indexmap_type(mini_vector<size_t, 2>(dim1, dim2), ml)) {}

  ///
  matrix(mini_vector<size_t, 2> const& sha, memory_layout<2> ml = memory_layout<2>{}) : IMPL_TYPE(indexmap_type(sha, ml)) {}

  /** Makes a true (deep) copy of the data. */
  matrix(const matrix& X) : IMPL_TYPE(X.indexmap(), X.storage().clone()) {}

  /// Build a new matrix from X.domain() and fill it with by evaluating X. X can be :
  template <typename T>
  matrix(const T& X, TYPE_ENABLE_IF(memory_layout<2>, ImmutableCuboidArray<T>) ml = memory_layout<2>{})
     : IMPL_TYPE(indexmap_type(X.domain(), ml)) {
   triqs_arrays_assign_delegation(*this, X);
  }

#ifdef TRIQS_WITH_PYTHON_SUPPORT
  /// Build from a numpy.array X (or any object from which numpy can make a numpy.array). Makes a copy.
  explicit matrix(PyObject* X) : IMPL_TYPE(X, true, "matrix ") {}
#endif

  // build from a init_list
  template <typename T> matrix(std::initializer_list<std::initializer_list<T>> const& l) : IMPL_TYPE(memory_layout<2>()) {
   size_t i = 0, j = 0;
   int s = -1;
   for (auto const& l1 : l) {
    if (s == -1)
     s = l1.size();
    else if (s != l1.size())
     TRIQS_RUNTIME_ERROR << "initializer list not rectangular !";
   }
   IMPL_TYPE::resize(typename IMPL_TYPE::domain_type(mini_vector<size_t, 2>(l.size(), s)));
   for (auto const& l1 : l) {
    for (auto const& x : l1) {
     (*this)(i, j++) = x;
    }
    j = 0;
    ++i;
   }
  }

  /**
   * Resizes the matrix. NB : all references to the storage is invalidated.
   * Does not initialize the matrix by default
   */
  matrix& resize(size_t n1, size_t n2) {
   IMPL_TYPE::resize(typename IMPL_TYPE::domain_type(mini_vector<size_t, 2>(n1, n2)));
   return *this;
  }

  /**
   * Resizes the matrix. NB : all references to the storage is invalidated.
   * Does not initialize the matrix by default
   */
  matrix& resize(const indexmaps::cuboid::domain_t<IMPL_TYPE::rank>& l) {
   IMPL_TYPE::resize(l);
   return *this;
  }

  /// Assignement resizes the matrix.  All references to the storage are therefore invalidated.
  matrix& operator=(const matrix& X) {
   IMPL_TYPE::resize_and_clone_data(X);
   return *this;
  }

  /// Move assignment
  matrix& operator=(matrix&& X) {
   this->swap_me(X);
   return *this;
  }

  /// Swap
  friend void swap(matrix& A, matrix& B) { A.swap_me(B); }

  /**
   * Assignement resizes the matrix.  All references to the storage are therefore invalidated.
   * NB : to avoid that, do make_view(A) = X instead of A = X
   */
  template <typename RHS> matrix& operator=(const RHS& X) {
   static_assert(ImmutableCuboidArray<RHS>::value, "Assignment : RHS not supported");
   IMPL_TYPE::resize(X.domain());
   triqs_arrays_assign_delegation(*this, X);
   return *this;
  }

  TRIQS_DEFINE_COMPOUND_OPERATORS(matrix);
  _IMPL_MATRIX_COMMON;
 }; // matrix class
#undef _IMPL_MATRIX_COMMON
#undef IMPL_TYPE


 template <typename V> matrix<V> make_unit_matrix(int dim) {
  matrix<V> r(dim, dim);
  r() = 1;
  return r;
 }

 template <typename ArrayType>
 matrix_view<typename ArrayType::value_type, typename ArrayType::traversal_order_t, true> make_matrix_view(ArrayType const& a) {
  static_assert(ArrayType::rank == 2, "make_matrix_view only works for array of rank 2");
  return a;
 }

 template <typename ArrayType> matrix<typename ArrayType::value_type> make_matrix(ArrayType const& a) {
  static_assert(ArrayType::domain_type::rank == 2, "make_matrix only works for array of rank 2");
  return a;
 }

 template <typename M> TYPE_ENABLE_IF(typename M::value_type, ImmutableMatrix<M>) trace(M const& m) {
  auto r = typename M::value_type{};
  if (first_dim(m) != second_dim(m)) TRIQS_RUNTIME_ERROR << " Trace of a non square matrix";
  auto d = first_dim(m);
  for (int i = 0; i < d; ++i) r += m(i, i);
  return r;
 }
}
} // namespace triqs::arrays

// The std::swap is WRONG for a view because of the copy/move semantics of view.
// Use swap instead (the correct one, found by ADL).
namespace std {
template <typename V, typename To1, typename To2, bool B1, bool B2, bool C1, bool C2>
void swap(triqs::arrays::matrix_view<V, To1, B1, C1>& a, triqs::arrays::matrix_view<V, To2, B2, C2>& b) = delete;
}
#include "./expression_template/matrix_algebra.hpp"