/*=========================================================================
 *
 *  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 itkImageRegionExclusionConstIteratorWithIndex_hxx
#define itkImageRegionExclusionConstIteratorWithIndex_hxx


namespace itk
{

template <typename TImage>
ImageRegionExclusionConstIteratorWithIndex<TImage>::ImageRegionExclusionConstIteratorWithIndex(
  const ImageType *  ptr,
  const RegionType & region)
  : Superclass(ptr, region)
{}

template <typename TImage>
ImageRegionExclusionConstIteratorWithIndex<TImage>::ImageRegionExclusionConstIteratorWithIndex(const Superclass & it)
{
  Superclass::operator=(it);
}
//----------------------------------------------------------------------
//  Set the region to exclude from the walk
//----------------------------------------------------------------------
template <typename TImage>
void
ImageRegionExclusionConstIteratorWithIndex<TImage>::SetExclusionRegion(const RegionType & region)
{
  // Crop the exclusion region so that it lies entirely within the
  // iterator region.
  m_ExclusionRegion = region;
  m_ExclusionRegion.Crop(this->m_Region);

  m_ExclusionBegin = m_ExclusionRegion.GetIndex();
  SizeType exclusionSize = m_ExclusionRegion.GetSize();

  for (unsigned int i = 0; i < TImage::ImageDimension; ++i)
  {
    m_ExclusionEnd[i] = m_ExclusionBegin[i] + exclusionSize[i];
  }
}

//----------------------------------------------------------------------
//  Set the region to exclude from the walk to a region that is inset
//  one pixel from the boundary of the region
//----------------------------------------------------------------------
template <typename TImage>
void
ImageRegionExclusionConstIteratorWithIndex<TImage>::SetExclusionRegionToInsetRegion()
{
  RegionType excludeRegion;

  excludeRegion = this->m_Region;
  for (unsigned int i = 0; i < TImage::ImageDimension; ++i)
  {
    if (excludeRegion.GetSize()[i] >= 2)
    {
      // region is large enough to inset, adjust size and index
      excludeRegion.SetSize(i, excludeRegion.GetSize()[i] - 2);
      excludeRegion.SetIndex(i, excludeRegion.GetIndex()[i] + 1);
    }
    else
    {
      // region is not large enough to inset, set exclusion size to
      // zero and keep the index the same.
      excludeRegion.SetSize(i, 0);
    }
  }
  this->SetExclusionRegion(excludeRegion);
}

//----------------------------------------------------------------------
// Move to beginning of region
//----------------------------------------------------------------------
template <typename TImage>
void
ImageRegionExclusionConstIteratorWithIndex<TImage>::GoToBegin()
{
  // Check whether exclusion region covers the entire region
  if (m_ExclusionRegion == this->m_Region)
  {
    this->m_Position = this->m_End;
    this->m_Remaining = false;
    return;
  }

  this->Superclass::GoToBegin();

  // If inside the exclusion region to begin with, jump past it.
  for (unsigned int in = 0; in < TImage::ImageDimension; ++in)
  {
    if (m_ExclusionRegion.IsInside(this->m_PositionIndex))
    {
      if (m_ExclusionRegion.GetSize()[in] == this->m_Region.GetSize()[in])
      {
        this->m_PositionIndex[in] = this->m_BeginIndex[in];
      }
      else
      {
        this->m_PositionIndex[in] = m_ExclusionEnd[in];
        this->m_Position += this->m_OffsetTable[in] * m_ExclusionRegion.GetSize()[in];
      }
    }
  }
}

//----------------------------------------------------------------------
// Move to the end of the region
//----------------------------------------------------------------------
template <typename TImage>
void
ImageRegionExclusionConstIteratorWithIndex<TImage>::GoToReverseBegin()
{
  // Check whether exclusion region covers the entire region
  if (m_ExclusionRegion == this->m_Region)
  {
    this->m_Position = this->m_End;
    this->m_Remaining = false;
    return;
  }

  this->Superclass::GoToReverseBegin();

  // If inside the exclusion region to begin with, jump past it.
  for (unsigned int in = 0; in < TImage::ImageDimension; ++in)
  {
    if (m_ExclusionRegion.IsInside(this->m_PositionIndex))
    {
      if (m_ExclusionRegion.GetSize()[in] == this->m_Region.GetSize()[in])
      {
        // The line will be skipped entirely.
        this->m_PositionIndex[in] = this->m_EndIndex[in] - 1;
      }
      else
      {
        this->m_PositionIndex[in] = m_ExclusionBegin[in] - 1;
        this->m_Position -= this->m_OffsetTable[in] * m_ExclusionRegion.GetSize()[in];
      }
    }
  }
}

//----------------------------------------------------------------------
//  Advance along the line, skipping the exclusion region
//----------------------------------------------------------------------
template <typename TImage>
ImageRegionExclusionConstIteratorWithIndex<TImage> &
ImageRegionExclusionConstIteratorWithIndex<TImage>::operator++()
{
  this->Superclass::operator++();

  while (m_ExclusionRegion.IsInside(this->m_PositionIndex) && this->m_Remaining)
  {
    // Entered the exclusion region, so jump across it
    this->m_Position += this->m_OffsetTable[0] * (static_cast<OffsetValueType>(m_ExclusionRegion.GetSize()[0]));
    this->m_PositionIndex[0] = m_ExclusionEnd[0];
    if (this->m_PositionIndex[0] == this->m_EndIndex[0])
    {
      this->m_Position -= this->m_OffsetTable[0];
      this->Superclass::operator++();
    }
  }

  return *this;
}

//----------------------------------------------------------------------
//  Advance along the line in reverse direction, skipping exclusion region
//----------------------------------------------------------------------
template <typename TImage>
ImageRegionExclusionConstIteratorWithIndex<TImage> &
ImageRegionExclusionConstIteratorWithIndex<TImage>::operator--()
{
  this->Superclass::operator--();

  while (m_ExclusionRegion.IsInside(this->m_PositionIndex) && this->m_Remaining)
  {
    // Entered the exclusion region, so jump across it
    this->m_Position -= this->m_OffsetTable[0] * (static_cast<OffsetValueType>(m_ExclusionRegion.GetSize()[0]));
    this->m_PositionIndex[0] = m_ExclusionBegin[0] - 1;
    if (this->m_PositionIndex[0] < this->m_BeginIndex[0])
    {
      this->m_Position += this->m_OffsetTable[0];
      this->Superclass::operator--();
    }
  }

  return *this;
}


} // end namespace itk

#endif
