/*=========================================================================
 *
 *  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 itkOtsuMultipleThresholdsImageFilter_hxx
#define itkOtsuMultipleThresholdsImageFilter_hxx

#include "itkThresholdLabelerImageFilter.h"
#include "itkProgressAccumulator.h"

namespace itk
{
template <typename TInputImage, typename TOutputImage>
OtsuMultipleThresholdsImageFilter<TInputImage, TOutputImage>::OtsuMultipleThresholdsImageFilter()
  : m_LabelOffset(OutputPixelType{})

{
  m_Thresholds.clear();
}

template <typename TInputImage, typename TOutputImage>
void
OtsuMultipleThresholdsImageFilter<TInputImage, TOutputImage>::GenerateData()
{
  auto progress = ProgressAccumulator::New();
  progress->SetMiniPipelineFilter(this);

  // Create a histogram of the image intensities
  auto histogramGenerator = HistogramGeneratorType::New();
  histogramGenerator->SetInput(this->GetInput());
  histogramGenerator->SetNumberOfBins(m_NumberOfHistogramBins);
  histogramGenerator->Compute();

  // Compute the multiple Otsu Thresholds for the input image
  auto otsuHistogramThresholdCalculator = OtsuCalculatorType::New();
  otsuHistogramThresholdCalculator->SetInputHistogram(histogramGenerator->GetOutput());
  otsuHistogramThresholdCalculator->SetNumberOfThresholds(m_NumberOfThresholds);
  otsuHistogramThresholdCalculator->SetValleyEmphasis(m_ValleyEmphasis);
  otsuHistogramThresholdCalculator->SetReturnBinMidpoint(m_ReturnBinMidpoint);
  otsuHistogramThresholdCalculator->Compute();

  m_Thresholds = otsuHistogramThresholdCalculator->GetOutput();

  typename ThresholdLabelerImageFilter<TInputImage, TOutputImage>::Pointer threshold =
    ThresholdLabelerImageFilter<TInputImage, TOutputImage>::New();

  progress->RegisterInternalFilter(threshold, 1.0f);
  threshold->GraftOutput(this->GetOutput());
  threshold->SetInput(this->GetInput());
  threshold->SetRealThresholds(m_Thresholds);
  threshold->SetLabelOffset(m_LabelOffset);
  threshold->Update();

  this->GraftOutput(threshold->GetOutput());
}

template <typename TInputImage, typename TOutputImage>
void
OtsuMultipleThresholdsImageFilter<TInputImage, TOutputImage>::GenerateInputRequestedRegion()
{
  auto * input = const_cast<TInputImage *>(this->GetInput());

  if (input)
  {
    input->SetRequestedRegionToLargestPossibleRegion();
  }
}

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

  os << indent << "NumberOfHistogramBins: " << m_NumberOfHistogramBins << std::endl;
  os << indent << "NumberOfThresholds: " << m_NumberOfThresholds << std::endl;
  os << indent << "LabelOffset: " << m_LabelOffset << std::endl;
  os << indent << "Thresholds: " << std::endl;
  for (SizeValueType j = 0; j < m_Thresholds.size(); ++j)
  {
    os << indent << "\tThreshold #" << j << ": "
       << static_cast<typename NumericTraits<InputPixelType>::PrintType>(m_Thresholds[j]) << std::endl;
  }
}
} // end namespace itk
#endif
