/*=========================================================================
 *
 *  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 itkHMinimaImageFilter_hxx
#define itkHMinimaImageFilter_hxx

#include "itkImageRegionIterator.h"
#include "itkReconstructionByErosionImageFilter.h"
#include "itkShiftScaleImageFilter.h"
#include "itkCastImageFilter.h"
#include "itkProgressAccumulator.h"

namespace itk
{
template <typename TInputImage, typename TOutputImage>
HMinimaImageFilter<TInputImage, TOutputImage>::HMinimaImageFilter()
  : m_Height(2)

{}

template <typename TInputImage, typename TOutputImage>
void
HMinimaImageFilter<TInputImage, TOutputImage>::GenerateInputRequestedRegion()
{
  // Call the superclass' implementation of this method
  Superclass::GenerateInputRequestedRegion();

  // We need all the input.
  InputImagePointer input = const_cast<InputImageType *>(this->GetInput());
  if (input)
  {
    input->SetRequestedRegion(input->GetLargestPossibleRegion());
  }
}

template <typename TInputImage, typename TOutputImage>
void
HMinimaImageFilter<TInputImage, TOutputImage>::EnlargeOutputRequestedRegion(DataObject *)
{
  this->GetOutput()->SetRequestedRegion(this->GetOutput()->GetLargestPossibleRegion());
}

template <typename TInputImage, typename TOutputImage>
void
HMinimaImageFilter<TInputImage, TOutputImage>::GenerateData()
{
  // Allocate the output
  this->AllocateOutputs();

  // Construct a marker image to manipulate using reconstruction by
  // erosion. the marker image is the input image minus the height
  // parameter.
  using ShiftFilterType = ShiftScaleImageFilter<TInputImage, TInputImage>;
  auto shift = ShiftFilterType::New();
  shift->SetInput(this->GetInput());
  shift->SetShift(static_cast<typename ShiftFilterType::RealType>(m_Height));

  // Delegate to a geodesic erosion filter.
  //
  //
  typename ReconstructionByErosionImageFilter<TInputImage, TInputImage>::Pointer erode =
    ReconstructionByErosionImageFilter<TInputImage, TInputImage>::New();

  // Create a process accumulator for tracking the progress of this minipipeline
  auto progress = ProgressAccumulator::New();
  progress->SetMiniPipelineFilter(this);
  progress->RegisterInternalFilter(erode, 1.0f);

  // Set up the erode filter
  // erode->RunOneIterationOff();             // run to convergence
  erode->SetMarkerImage(shift->GetOutput());
  erode->SetMaskImage(this->GetInput());
  erode->SetFullyConnected(m_FullyConnected);

  // Must cast to the output type
  typename CastImageFilter<TInputImage, TOutputImage>::Pointer cast = CastImageFilter<TInputImage, TOutputImage>::New();
  cast->SetInput(erode->GetOutput());
  cast->InPlaceOn();

  // Graft our output to the cast filter to force the proper regions
  // to be generated
  cast->GraftOutput(this->GetOutput());

  // Reconstruction by erosion
  cast->Update();

  // Graft the output of the erode filter back onto this filter's
  // output. this is needed to get the appropriate regions passed
  // back.
  this->GraftOutput(cast->GetOutput());
}

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

  os << indent << "Depth of local maxima (contrast): "
     << static_cast<typename NumericTraits<InputImagePixelType>::PrintType>(m_Height) << std::endl;
  os << indent << "Number of iterations used to produce current output: " << m_NumberOfIterationsUsed << std::endl;
  os << indent << "FullyConnected: " << (m_FullyConnected ? "On" : "Off") << std::endl;
}
} // end namespace itk
#endif
