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#pragma once

#include "hytlass/core_io.h"
#include "hytlass/tensor_view.h"
#include "hytlass/complex.h"

namespace hytlass {

///////////////////////////////////////////////////////////////////////////////////////////////////

namespace detail {

/// Helper to write the least significant rank of a TensorView
template <
  typename Element,
  typename Layout
>
inline std::ostream & TensorView_WriteLeastSignificantRank(
  std::ostream& out, 
  TensorView<Element, Layout> const& view,
  Coord<Layout::kRank> const &start_coord,
  int rank,
  std::streamsize width) {

  for (int idx = 0; idx < view.extent(rank); ++idx) {

    Coord<Layout::kRank> coord(start_coord);
    coord[rank] = idx;

    if (idx) {
      out.width(0);
      out << ", ";
    }
    if (idx || coord) {
      out.width(width);
    }
    out << ScalarIO<Element>(view.at(coord));
  }

  return out;
}

/// Helper to write a rank of a TensorView
template <
  typename Element,
  typename Layout
>
inline std::ostream & TensorView_WriteRank(
  std::ostream& out, 
  TensorView<Element, Layout> const& view,
  Coord<Layout::kRank> const &start_coord,
  int rank,
  std::streamsize width) {

  // If called on the least significant rank, write the result as a row
  if (rank + 1 == Layout::kRank) {
    return TensorView_WriteLeastSignificantRank(out, view, start_coord, rank, width);
  }

  // Otherwise, write a sequence of rows and newlines
  for (int idx = 0; idx < view.extent(rank); ++idx) {

    Coord<Layout::kRank> coord(start_coord);
    coord[rank] = idx;

    if (rank + 2 == Layout::kRank) {
      // Write least significant ranks asa matrix with rows delimited by "\n"
      if (idx) {
        out << ",\n";
      }
      TensorView_WriteLeastSignificantRank(out, view, coord, rank + 1, width);
    }
    else {
      // Higher ranks are separated by newlines
      if (idx) {
        out << ",\n\n";
      }
      TensorView_WriteRank(out, view, coord, rank + 1, width);
    }
  }

  return out;
}

} // namespace detail

///////////////////////////////////////////////////////////////////////////////////////////////////

/// Prints human-readable representation of a TensorView to an ostream
template <
  typename Element,
  typename Layout
>
inline std::ostream& TensorViewWrite(
  std::ostream& out, 
  TensorView<Element, Layout> const& view) {

  // Prints a TensorView according to the following conventions:
  //   - least significant rank is printed as rows separated by ";\n"
  //   - all greater ranks are delimited with newlines
  //
  // The result is effectively a whitespace-delimited series of 2D matrices.

  return detail::TensorView_WriteRank(out, view, Coord<Layout::kRank>(), 0, out.width());
}

/// Prints human-readable representation of a TensorView to an ostream
template <
  typename Element,
  typename Layout
>
inline std::ostream& operator<<(
  std::ostream& out, 
  TensorView<Element, Layout> const& view) {

  // Prints a TensorView according to the following conventions:
  //   - least significant rank is printed as rows separated by ";\n"
  //   - all greater ranks are delimited with newlines
  //
  // The result is effectively a whitespace-delimited series of 2D matrices.

  return TensorViewWrite(out, view);
}

///////////////////////////////////////////////////////////////////////////////////////////////////

} // namespace hytlass
