/*=========================================================================
 *
 *  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 itkCheckerBoardImageFilter_hxx
#define itkCheckerBoardImageFilter_hxx

#include "itkImageRegionIteratorWithIndex.h"
#include "itkObjectFactory.h"
#include "itkTotalProgressReporter.h"

namespace itk
{

template <typename TImage>
CheckerBoardImageFilter<TImage>::CheckerBoardImageFilter()
{
  m_CheckerPattern.Fill(4);
  this->DynamicMultiThreadingOn();
  this->ThreaderUpdateProgressOff();
}

template <typename TImage>
void
CheckerBoardImageFilter<TImage>::SetInput1(const InputImageType * image1)
{
  // Process object is not const-correct so the const casting is required.
  this->SetNthInput(0, const_cast<InputImageType *>(image1));
}

template <typename TImage>
void
CheckerBoardImageFilter<TImage>::SetInput2(const InputImageType * image2)
{
  // Process object is not const-correct so the const casting is required.
  this->SetNthInput(1, const_cast<InputImageType *>(image2));
}

template <typename TImage>
void
CheckerBoardImageFilter<TImage>::DynamicThreadedGenerateData(const ImageRegionType & outputRegionForThread)
{
  // Get the output pointers
  OutputImagePointer     outputPtr = this->GetOutput();
  InputImageConstPointer input1Ptr = this->GetInput(0);
  InputImageConstPointer input2Ptr = this->GetInput(1);

  // Create an iterator that will walk the output region for this thread.
  using OutputIterator = ImageRegionIteratorWithIndex<OutputImageType>;
  using InputIterator = ImageRegionConstIteratorWithIndex<InputImageType>;

  OutputIterator outItr(outputPtr, outputRegionForThread);
  InputIterator  in1Itr(input1Ptr, outputRegionForThread);
  InputIterator  in2Itr(input2Ptr, outputRegionForThread);

  TotalProgressReporter progress(this, outputPtr->GetRequestedRegion().GetNumberOfPixels());

  typename InputImageType::SizeType size = input2Ptr->GetLargestPossibleRegion().GetSize();

  PatternArrayType factors;

  for (unsigned int d = 0; d < ImageDimension; ++d)
  {
    factors[d] = size[d] / m_CheckerPattern[d];
  }

  using PixelType = typename InputImageType::PixelType;
  using IndexType = typename InputImageType::IndexType;

  PixelType pixval;

  // Walk the output region
  while (!outItr.IsAtEnd())
  {
    IndexType index = outItr.GetIndex();

    unsigned int sum = 0;

    for (unsigned int i = 0; i < ImageDimension; ++i)
    {
      sum += static_cast<unsigned int>(index[i] / factors[i]);
    }

    if (sum & 1)
    {
      pixval = in2Itr.Get();
    }
    else
    {
      pixval = in1Itr.Get();
    }

    outItr.Set(pixval);

    ++outItr;
    ++in1Itr;
    ++in2Itr;
    progress.CompletedPixel();
  }
}

template <typename TImage>
void
CheckerBoardImageFilter<TImage>::PrintSelf(std::ostream & os, Indent indent) const
{
  Superclass::PrintSelf(os, indent);

  os << indent << "Checker pattern: " << m_CheckerPattern << std::endl;
}
} // end namespace itk

#endif
