// SPDX-License-Identifier: Apache-2.0
//
// Copyright 2008-2016 Conrad Sanderson (http://conradsanderson.id.au)
// Copyright 2008-2016 National ICT Australia (NICTA)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
// ------------------------------------------------------------------------

//! \addtogroup subview_cube
//! @{

//! Class for storing data required to construct or apply operations to a subcube
//! (ie. where the subcube starts and ends as well as a reference/pointer to the original
//! cube),
template <typename eT>
class subview_cube : public BaseCube<eT, subview_cube<eT> > {
 public:
  typedef eT elem_type;
  typedef typename get_pod_type<elem_type>::result pod_type;

  arma_aligned const Cube<eT>& m;

  const uword aux_row1;
  const uword aux_col1;
  const uword aux_slice1;

  const uword n_rows;
  const uword n_cols;
  const uword n_elem_slice;
  const uword n_slices;
  const uword n_elem;

 protected:
  arma_inline subview_cube(const Cube<eT>& in_m, const uword in_row1, const uword in_col1,
                           const uword in_slice1, const uword in_n_rows,
                           const uword in_n_cols, const uword in_n_slices);

 public:
  inline ~subview_cube();
  inline subview_cube() = delete;

  inline subview_cube(const subview_cube& in);
  inline subview_cube(subview_cube&& in);

  template <typename op_type>
  inline void inplace_op(const eT val);
  template <typename op_type, typename T1>
  inline void inplace_op(const BaseCube<eT, T1>& x, const char* identifier);
  template <typename op_type>
  inline void inplace_op(const subview_cube<eT>& x, const char* identifier);

  inline void operator=(const eT val);
  inline void operator+=(const eT val);
  inline void operator-=(const eT val);
  inline void operator*=(const eT val);
  inline void operator/=(const eT val);

  // deliberately returning void
  template <typename T1>
  inline void operator=(const BaseCube<eT, T1>& x);
  template <typename T1>
  inline void operator+=(const BaseCube<eT, T1>& x);
  template <typename T1>
  inline void operator-=(const BaseCube<eT, T1>& x);
  template <typename T1>
  inline void operator%=(const BaseCube<eT, T1>& x);
  template <typename T1>
  inline void operator/=(const BaseCube<eT, T1>& x);

  inline void operator=(const subview_cube& x);
  inline void operator+=(const subview_cube& x);
  inline void operator-=(const subview_cube& x);
  inline void operator%=(const subview_cube& x);
  inline void operator/=(const subview_cube& x);

  template <typename T1>
  inline void operator=(const Base<eT, T1>& x);
  template <typename T1>
  inline void operator+=(const Base<eT, T1>& x);
  template <typename T1>
  inline void operator-=(const Base<eT, T1>& x);
  template <typename T1>
  inline void operator%=(const Base<eT, T1>& x);
  template <typename T1>
  inline void operator/=(const Base<eT, T1>& x);

  template <typename gen_type>
  inline void operator=(const GenCube<eT, gen_type>& x);

  inline static void extract(Cube<eT>& out, const subview_cube& in);
  inline static void plus_inplace(Cube<eT>& out, const subview_cube& in);
  inline static void minus_inplace(Cube<eT>& out, const subview_cube& in);
  inline static void schur_inplace(Cube<eT>& out, const subview_cube& in);
  inline static void div_inplace(Cube<eT>& out, const subview_cube& in);

  inline static void extract(Mat<eT>& out, const subview_cube& in);
  inline static void plus_inplace(Mat<eT>& out, const subview_cube& in);
  inline static void minus_inplace(Mat<eT>& out, const subview_cube& in);
  inline static void schur_inplace(Mat<eT>& out, const subview_cube& in);
  inline static void div_inplace(Mat<eT>& out, const subview_cube& in);

  template <typename functor>
  inline void for_each(functor F);
  template <typename functor>
  inline void for_each(functor F) const;

  template <typename functor>
  inline void transform(functor F);
  template <typename functor>
  inline void imbue(functor F);

  inline void each_slice(const std::function<void(Mat<eT>&)>& F);
  inline void each_slice(const std::function<void(const Mat<eT>&)>& F) const;

  inline void replace(const eT old_val, const eT new_val);

  inline void clean(const pod_type threshold);

  inline void clamp(const eT min_val, const eT max_val);

  inline void fill(const eT val);
  inline void zeros();
  inline void ones();
  inline void randu();
  inline void randn();

  arma_warn_unused inline bool is_finite() const;
  arma_warn_unused inline bool is_zero(const pod_type tol = 0) const;

  arma_warn_unused inline bool has_inf() const;
  arma_warn_unused inline bool has_nan() const;
  arma_warn_unused inline bool has_nonfinite() const;

  inline eT at_alt(const uword i) const;

  inline eT& operator[](const uword i);
  inline eT operator[](const uword i) const;

  inline eT& operator()(const uword i);
  inline eT operator()(const uword i) const;

  arma_inline eT& operator()(const uword in_row, const uword in_col,
                             const uword in_slice);
  arma_inline eT operator()(const uword in_row, const uword in_col,
                            const uword in_slice) const;

  arma_inline eT& at(const uword in_row, const uword in_col, const uword in_slice);
  arma_inline eT at(const uword in_row, const uword in_col, const uword in_slice) const;

  arma_inline eT* slice_colptr(const uword in_slice, const uword in_col);
  arma_inline const eT* slice_colptr(const uword in_slice, const uword in_col) const;

  template <typename eT2>
  inline bool check_overlap(const subview_cube<eT2>& x) const;

  inline bool check_overlap(const Mat<eT>& x) const;

  class const_iterator;

  class iterator {
   public:
    inline iterator();
    inline iterator(const iterator& X);
    inline iterator(subview_cube<eT>& in_sv, const uword in_row, const uword in_col,
                    const uword in_slice);

    arma_warn_unused inline eT& operator*();

    inline iterator& operator++();
    arma_warn_unused inline iterator operator++(int);

    arma_warn_unused inline bool operator==(const iterator& rhs) const;
    arma_warn_unused inline bool operator!=(const iterator& rhs) const;
    arma_warn_unused inline bool operator==(const const_iterator& rhs) const;
    arma_warn_unused inline bool operator!=(const const_iterator& rhs) const;

    typedef std::forward_iterator_tag iterator_category;
    typedef eT value_type;
    typedef std::ptrdiff_t difference_type;  // TODO: not certain on this one
    typedef eT* pointer;
    typedef eT& reference;

    arma_aligned Cube<eT>* M;
    arma_aligned eT* current_ptr;
    arma_aligned uword current_row;
    arma_aligned uword current_col;
    arma_aligned uword current_slice;

    arma_aligned const uword aux_row1;
    arma_aligned const uword aux_col1;

    arma_aligned const uword aux_row2_p1;
    arma_aligned const uword aux_col2_p1;
  };

  class const_iterator {
   public:
    inline const_iterator();
    inline const_iterator(const iterator& X);
    inline const_iterator(const const_iterator& X);
    inline const_iterator(const subview_cube<eT>& in_sv, const uword in_row,
                          const uword in_col, const uword in_slice);

    arma_warn_unused inline const eT& operator*();

    inline const_iterator& operator++();
    arma_warn_unused inline const_iterator operator++(int);

    arma_warn_unused inline bool operator==(const iterator& rhs) const;
    arma_warn_unused inline bool operator!=(const iterator& rhs) const;
    arma_warn_unused inline bool operator==(const const_iterator& rhs) const;
    arma_warn_unused inline bool operator!=(const const_iterator& rhs) const;

    // So that we satisfy the STL iterator types.
    typedef std::forward_iterator_tag iterator_category;
    typedef eT value_type;
    typedef std::ptrdiff_t difference_type;  // TODO: not certain on this one
    typedef const eT* pointer;
    typedef const eT& reference;

    arma_aligned const Cube<eT>* M;
    arma_aligned const eT* current_ptr;
    arma_aligned uword current_row;
    arma_aligned uword current_col;
    arma_aligned uword current_slice;

    arma_aligned const uword aux_row1;
    arma_aligned const uword aux_col1;

    arma_aligned const uword aux_row2_p1;
    arma_aligned const uword aux_col2_p1;
  };

  inline iterator begin();
  inline const_iterator begin() const;
  inline const_iterator cbegin() const;

  inline iterator end();
  inline const_iterator end() const;
  inline const_iterator cend() const;

  friend class Mat<eT>;
  friend class Cube<eT>;
};

//! @}
