/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  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
 *
 *         https://www.apache.org/licenses/LICENSE-2.0.txt
 *
 *  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.
 *
 *=========================================================================*/
#ifndef itkPeriodicBoundaryCondition_hxx
#define itkPeriodicBoundaryCondition_hxx

#include "itkConstNeighborhoodIterator.h"

namespace itk
{
template <typename TInputImage, typename TOutputImage>
auto
PeriodicBoundaryCondition<TInputImage, TOutputImage>::operator()(const OffsetType &       point_index,
                                                                 const OffsetType &       boundary_offset,
                                                                 const NeighborhoodType * data) const -> OutputPixelType
{
  // This is guaranteed to be called with an object that is using
  // PeriodicBoundaryCondition
  const auto * iterator = reinterpret_cast<const ConstNeighborhoodIterator<TInputImage, Self> *>(data);
  typename TInputImage::PixelType * ptr;
  int                               linear_index = 0;
  unsigned int                      i;

  // Find the pointer of the closest boundary pixel

  // Return the value of the pixel at the closest boundary point.
  for (i = 0; i < ImageDimension; ++i)
  {
    linear_index += (point_index[i] + boundary_offset[i]) * data->GetStride(i);
  }
  // (data->operator[](linear_index)) is guaranteed to be a pointer to
  // TInputImage::PixelType except for VectorImage, in which case, it will be a
  // pointer to TInputImage::InternalPixelType.
  ptr = reinterpret_cast<PixelType *>((data->operator[](linear_index)));

  // Wrap the pointer around the image in the necessary dimensions.  If we have
  // reached this point, we can assume that we are on the edge of the BUFFERED
  // region of the image.  Boundary conditions are only invoked if touching the
  // actual memory boundary.

  // These are the step sizes for increments in each dimension of the image.
  const typename TInputImage::OffsetValueType * offset_table = iterator->GetImagePointer()->GetOffsetTable();

  for (i = 0; i < ImageDimension; ++i)
  {
    if (boundary_offset[i] != 0)
    { // If the neighborhood overlaps on the low edge, then wrap from the
      // high edge of the image.
      if (point_index[i] < static_cast<OffsetValueType>(iterator->GetRadius(i)))
      {
        ptr += iterator->GetImagePointer()->GetBufferedRegion().GetSize()[i] * offset_table[i] -
               boundary_offset[i] * offset_table[i];
      }
      else // wrap from the low side of the image
      {
        ptr -= iterator->GetImagePointer()->GetBufferedRegion().GetSize()[i] * offset_table[i] +
               boundary_offset[i] * offset_table[i];
      }
    }
  }

  return static_cast<OutputPixelType>(*ptr);
}

template <typename TInputImage, typename TOutputImage>
auto
PeriodicBoundaryCondition<TInputImage, TOutputImage>::operator()(
  const OffsetType &                      point_index,
  const OffsetType &                      boundary_offset,
  const NeighborhoodType *                data,
  const NeighborhoodAccessorFunctorType & neighborhoodAccessorFunctor) const -> OutputPixelType
{
  // This is guaranteed to be called with an object that is using
  // PeriodicBoundaryCondition
  const auto * iterator = reinterpret_cast<const ConstNeighborhoodIterator<TInputImage, Self> *>(data);
  typename TInputImage::InternalPixelType * ptr;
  int                                       linear_index = 0;
  unsigned int                              i;

  // Find the pointer of the closest boundary pixel
  //  std::cout << "Boundary offset = " << boundary_offset << std::endl;
  // std::cout << "point index = " << point_index << std::endl;

  // Return the value of the pixel at the closest boundary point.
  for (i = 0; i < ImageDimension; ++i)
  {
    linear_index += (point_index[i] + boundary_offset[i]) * data->GetStride(i);
  }
  ptr = data->operator[](linear_index);

  // Wrap the pointer around the image in the necessary dimensions.  If we have
  // reached this point, we can assume that we are on the edge of the BUFFERED
  // region of the image.  Boundary conditions are only invoked if touching the
  // actual memory boundary.

  // These are the step sizes for increments in each dimension of the image.
  const typename TInputImage::OffsetValueType * offset_table = iterator->GetImagePointer()->GetOffsetTable();

  for (i = 0; i < ImageDimension; ++i)
  {
    if (boundary_offset[i] != 0)
    { // If the neighborhood overlaps on the low edge, then wrap from the
      // high edge of the image.
      if (point_index[i] < static_cast<OffsetValueType>(iterator->GetRadius(i)))
      {
        ptr += iterator->GetImagePointer()->GetBufferedRegion().GetSize()[i] * offset_table[i] -
               boundary_offset[i] * offset_table[i];
      }
      else // wrap from the low side of the image
      {
        ptr -= iterator->GetImagePointer()->GetBufferedRegion().GetSize()[i] * offset_table[i] +
               boundary_offset[i] * offset_table[i];
      }
    }
  }

  return static_cast<OutputPixelType>(neighborhoodAccessorFunctor.Get(ptr));
}


template <typename TInputImage, typename TOutputImage>
auto
PeriodicBoundaryCondition<TInputImage, TOutputImage>::GetInputRequestedRegion(
  const RegionType & inputLargestPossibleRegion,
  const RegionType & outputRequestedRegion) const -> RegionType
{
  IndexType imageIndex = inputLargestPossibleRegion.GetIndex();
  SizeType  imageSize = inputLargestPossibleRegion.GetSize();

  IndexType outputIndex = outputRequestedRegion.GetIndex();
  SizeType  outputSize = outputRequestedRegion.GetSize();

  IndexType inputRequestedIndex;
  SizeType  inputRequestedSize;

  for (unsigned int i = 0; i < ImageDimension; ++i)
  {
    // Check for image boundary overlap in the requested region
    IndexValueType lowIndex = ((outputIndex[i] - imageIndex[i]) % static_cast<IndexValueType>(imageSize[i]));
    if (lowIndex < 0)
    {
      lowIndex += static_cast<IndexValueType>(imageSize[i]);
    }
    IndexValueType highIndex = lowIndex + static_cast<IndexValueType>(outputSize[i]);

    bool overlap = (highIndex >= static_cast<IndexValueType>(imageSize[i]));

    if (overlap)
    {
      // Request the totality of the image in this dimension
      inputRequestedIndex[i] = imageIndex[i];
      inputRequestedSize[i] = imageSize[i];
    }
    else
    {
      // Remap the requested portion in this dimension into the image region.
      inputRequestedIndex[i] = lowIndex;
      inputRequestedSize[i] = outputSize[i];
    }
  }
  RegionType inputRequestedRegion(inputRequestedIndex, inputRequestedSize);

  return inputRequestedRegion;
}


template <typename TInputImage, typename TOutputImage>
auto
PeriodicBoundaryCondition<TInputImage, TOutputImage>::GetPixel(const IndexType & index, const TInputImage * image) const
  -> OutputPixelType
{
  RegionType imageRegion = image->GetLargestPossibleRegion();
  IndexType  imageIndex = imageRegion.GetIndex();
  SizeType   imageSize = imageRegion.GetSize();

  IndexType lookupIndex;

  for (unsigned int i = 0; i < ImageDimension; ++i)
  {
    IndexValueType modIndex = ((index[i] - imageIndex[i]) % static_cast<IndexValueType>(imageSize[i]));

    if (modIndex < 0)
    {
      modIndex += static_cast<IndexValueType>(imageSize[i]);
    }

    lookupIndex[i] = modIndex + imageIndex[i];
  }

  return static_cast<OutputPixelType>(image->GetPixel(lookupIndex));
}

} // end namespace itk

#endif
