/*=========================================================================
 *
 *  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 itkVotingBinaryHoleFillingImageFilter_hxx
#define itkVotingBinaryHoleFillingImageFilter_hxx

#include "itkConstNeighborhoodIterator.h"
#include "itkNeighborhoodInnerProduct.h"
#include "itkImageRegionIterator.h"
#include "itkNeighborhoodAlgorithm.h"
#include "itkProgressReporter.h"

#include <vector>
#include <algorithm>

namespace itk
{
template <typename TInputImage, typename TOutputImage>
VotingBinaryHoleFillingImageFilter<TInputImage, TOutputImage>::VotingBinaryHoleFillingImageFilter()
{
  this->SetSurvivalThreshold(0);
  this->m_MajorityThreshold = 1;
  this->m_NumberOfPixelsChanged = 0;
  this->DynamicMultiThreadingOff();
}

template <typename TInputImage, typename TOutputImage>
void
VotingBinaryHoleFillingImageFilter<TInputImage, TOutputImage>::BeforeThreadedGenerateData()
{
  unsigned int threshold = 1;

  InputSizeType radius = this->GetRadius();

  for (unsigned int i = 0; i < InputImageDimension; ++i)
  {
    threshold *= (2 * radius[i] + 1);
  }

  // remove central pixel and take 50%
  threshold = static_cast<unsigned int>((threshold - 1) / 2.0);

  // add the majority threshold.
  threshold += this->GetMajorityThreshold();

  this->SetBirthThreshold(threshold);
  this->SetSurvivalThreshold(0);

  this->m_NumberOfPixelsChanged = 0;

  unsigned int numberOfWorkUnits = this->GetNumberOfWorkUnits();
  this->m_Count.SetSize(numberOfWorkUnits);
  for (unsigned int i = 0; i < numberOfWorkUnits; ++i)
  {
    this->m_Count[i] = 0;
  }
}

template <typename TInputImage, typename TOutputImage>
void
VotingBinaryHoleFillingImageFilter<TInputImage, TOutputImage>::ThreadedGenerateData(
  const OutputImageRegionType & outputRegionForThread,
  ThreadIdType                  threadId)
{
  ZeroFluxNeumannBoundaryCondition<InputImageType> nbc;

  ConstNeighborhoodIterator<InputImageType> bit;
  ImageRegionIterator<OutputImageType>      it;

  // Allocate output
  typename OutputImageType::Pointer     output = this->GetOutput();
  typename InputImageType::ConstPointer input = this->GetInput();

  // Find the data-set boundary "faces"
  NeighborhoodAlgorithm::ImageBoundaryFacesCalculator<InputImageType>                        bC;
  typename NeighborhoodAlgorithm::ImageBoundaryFacesCalculator<InputImageType>::FaceListType faceList =
    bC(input, outputRegionForThread, this->GetRadius());

  ProgressReporter progress(this, threadId, outputRegionForThread.GetNumberOfPixels());

  const InputPixelType backgroundValue = this->GetBackgroundValue();
  const InputPixelType foregroundValue = this->GetForegroundValue();
  const auto           birthThreshold = static_cast<unsigned int>(this->GetBirthThreshold());

  unsigned int numberOfPixelsChanged = 0;

  // Process each of the boundary faces.  These are N-d regions which border
  // the edge of the buffer.
  for (const auto & face : faceList)
  {
    bit = ConstNeighborhoodIterator<InputImageType>(this->GetRadius(), input, face);
    it = ImageRegionIterator<OutputImageType>(output, face);
    bit.OverrideBoundaryCondition(&nbc);
    bit.GoToBegin();

    unsigned int neighborhoodSize = bit.Size();

    while (!bit.IsAtEnd())
    {
      const InputPixelType inpixel = bit.GetCenterPixel();

      if (inpixel == backgroundValue)
      {
        // count the pixels ON in the neighborhood
        unsigned int count = 0;
        for (unsigned int i = 0; i < neighborhoodSize; ++i)
        {
          InputPixelType value = bit.GetPixel(i);
          if (value == foregroundValue)
          {
            ++count;
          }
        }

        if (count >= birthThreshold)
        {
          it.Set(static_cast<OutputPixelType>(foregroundValue));
          ++numberOfPixelsChanged;
        }
        else
        {
          it.Set(static_cast<OutputPixelType>(backgroundValue));
        }
      }
      else
      {
        it.Set(static_cast<OutputPixelType>(foregroundValue));
      }
      ++bit;
      ++it;
      progress.CompletedPixel();
    }
  }
  this->m_Count[threadId] = numberOfPixelsChanged;
}

template <typename TInputImage, typename TOutputImage>
void
VotingBinaryHoleFillingImageFilter<TInputImage, TOutputImage>::AfterThreadedGenerateData()
{
  this->m_NumberOfPixelsChanged = SizeValueType{};

  unsigned int numberOfWorkUnits = this->GetNumberOfWorkUnits();
  this->m_Count.SetSize(numberOfWorkUnits);
  for (unsigned int t = 0; t < numberOfWorkUnits; ++t)
  {
    this->m_NumberOfPixelsChanged += this->m_Count[t];
  }
}


template <typename TInputImage, typename TOutput>
void
VotingBinaryHoleFillingImageFilter<TInputImage, TOutput>::PrintSelf(std::ostream & os, Indent indent) const
{
  Superclass::PrintSelf(os, indent);
  os << indent << "Majority Threshold           : " << m_MajorityThreshold << std::endl;
  os << indent << "Number of Pixels Changed     : " << m_NumberOfPixelsChanged << std::endl;
}
} // end namespace itk

#endif
