/*=========================================================================
 *
 *  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 itkReflectiveImageRegionConstIterator_hxx
#define itkReflectiveImageRegionConstIterator_hxx


namespace itk
{
template <typename TImage>
ReflectiveImageRegionConstIterator<TImage>::ReflectiveImageRegionConstIterator()
  : ImageConstIteratorWithIndex<TImage>()
{
  for (unsigned int dim = 0; dim < TImage::ImageDimension; ++dim)
  {
    m_BeginOffset[dim] = 0;
    m_EndOffset[dim] = 0;
  }
  this->GoToBegin();
}

template <typename TImage>
ReflectiveImageRegionConstIterator<TImage>::ReflectiveImageRegionConstIterator(TImage * ptr, const RegionType & region)
  : ImageConstIteratorWithIndex<TImage>(ptr, region)
{
  for (unsigned int dim = 0; dim < TImage::ImageDimension; ++dim)
  {
    m_BeginOffset[dim] = 0;
    m_EndOffset[dim] = 0;
  }

  this->GoToBegin();
}

template <typename TImage>
ReflectiveImageRegionConstIterator<TImage>::ReflectiveImageRegionConstIterator(const Self & it)
{
  this->operator=(it);
  this->GoToBegin();
}

template <typename TImage>
ReflectiveImageRegionConstIterator<TImage>::ReflectiveImageRegionConstIterator(
  const ImageConstIteratorWithIndex<TImage> & it)
{
  this->ImageConstIteratorWithIndex<TImage>::operator=(it);

  for (unsigned int dim = 0; dim < TImage::ImageDimension; ++dim)
  {
    m_BeginOffset[dim] = 0;
    m_EndOffset[dim] = 0;
  }
}

template <typename TImage>
ReflectiveImageRegionConstIterator<TImage> &
ReflectiveImageRegionConstIterator<TImage>::operator=(const Self & it)
{
  if (this != &it)
  {
    this->ImageConstIteratorWithIndex<TImage>::operator=(it);

    for (unsigned int dim = 0; dim < TImage::ImageDimension; ++dim)
    {
      m_BeginOffset[dim] = it.m_BeginOffset[dim];
      m_EndOffset[dim] = it.m_EndOffset[dim];
    }
  }
  return *this;
}

template <typename TImage>
void
ReflectiveImageRegionConstIterator<TImage>::GoToBegin()
{
  this->m_PositionIndex = this->m_BeginIndex + this->m_BeginOffset;
  this->m_Position = this->m_Image->GetBufferPointer() + this->m_Image->ComputeOffset(this->m_PositionIndex);

  this->m_Remaining = false;
  SizeType size = this->m_Region.GetSize();
  for (unsigned int i = 0; i < TImage::ImageDimension; ++i)
  {
    m_IsFirstPass[i] = true;

    SizeValueType tempSize = size[i];
    if (tempSize > 0)
    {
      this->m_Remaining = true;
    }
  }
}

template <typename TImage>
bool
ReflectiveImageRegionConstIterator<TImage>::IsReflected(unsigned int dim) const
{
  return !m_IsFirstPass[dim];
}

template <typename TImage>
void
ReflectiveImageRegionConstIterator<TImage>::FillOffsets(const OffsetValueType & value)
{
  for (unsigned int dim = 0; dim < TImage::ImageDimension; ++dim)
  {
    m_BeginOffset[dim] = value;
    m_EndOffset[dim] = value;
  }
}

//----------------------------------------------------------------------
//  Advance along the line
//----------------------------------------------------------------------
template <typename TImage>
ReflectiveImageRegionConstIterator<TImage> &
ReflectiveImageRegionConstIterator<TImage>::operator++()
{
  this->m_Remaining = false;
  for (unsigned int in = 0; in < TImage::ImageDimension; ++in)
  {
    if (m_IsFirstPass[in])
    {
      if (this->m_PositionIndex[in] + 1 < this->m_EndIndex[in])
      {
        this->m_PositionIndex[in]++;
        this->m_Position += this->m_OffsetTable[in];
        this->m_Remaining = true;
        break;
      }
      else
      {
        this->m_PositionIndex[in] = this->m_EndIndex[in] - m_EndOffset[in] - 1;
        this->m_Position -= (this->m_EndOffset[in]) * (this->m_OffsetTable[in]);
        m_IsFirstPass[in] = false;
        this->m_Remaining = true;
        break;
      }
    }
    else
    {
      if (this->m_PositionIndex[in] - 1 >= this->m_BeginIndex[in])
      {
        this->m_PositionIndex[in]--;
        this->m_Position -= this->m_OffsetTable[in];
        this->m_Remaining = true;
        break;
      }
      else
      {
        this->m_PositionIndex[in] = this->m_BeginIndex[in] + m_BeginOffset[in];
        this->m_Position += (this->m_BeginOffset[in]) * (this->m_OffsetTable[in]);
        m_IsFirstPass[in] = true;
      }
    }
  }

  if (!this->m_Remaining) // It will not advance here otherwise
  {
    this->m_Position = this->m_End;
  }

  return *this;
}
} // end namespace itk

#endif
