/*=========================================================================
 *
 *  Copyright Insight Software Consortium
 *
 *  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
 *
 *         http://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 itkMorphologicalGradientImageFilter_h
#define itkMorphologicalGradientImageFilter_h

#include "itkKernelImageFilter.h"
#include "itkMovingHistogramMorphologicalGradientImageFilter.h"
#include "itkBasicDilateImageFilter.h"
#include "itkBasicErodeImageFilter.h"
#include "itkAnchorErodeImageFilter.h"
#include "itkAnchorDilateImageFilter.h"
#include "itkVanHerkGilWermanDilateImageFilter.h"
#include "itkVanHerkGilWermanErodeImageFilter.h"
#include "itkSubtractImageFilter.h"
#include "itkConstantBoundaryCondition.h"
#include "itkNeighborhood.h"

namespace itk
{
/**
 * \class MorphologicalGradientImageFilter
 * \brief gray scale dilation of an image
 *
 * Dilate an image using grayscale morphology. Dilation takes the
 * maximum of all the pixels identified by the structuring element.
 *
 * The structuring element is assumed to be composed of binary
 * values (zero or one). Only elements of the structuring element
 * having values > 0 are candidates for affecting the center pixel.
 *
 * \sa MorphologyImageFilter, GrayscaleFunctionDilateImageFilter, BinaryDilateImageFilter
 * \ingroup ImageEnhancement  MathematicalMorphologyImageFilters
 * \ingroup ITKMathematicalMorphology
 */

template< typename TInputImage, typename TOutputImage, typename TKernel >
class ITK_TEMPLATE_EXPORT MorphologicalGradientImageFilter:
  public KernelImageFilter< TInputImage, TOutputImage, TKernel >
{
public:
  ITK_DISALLOW_COPY_AND_ASSIGN(MorphologicalGradientImageFilter);

  /** Standard class type aliases. */
  using Self = MorphologicalGradientImageFilter;
  using Superclass = KernelImageFilter< TInputImage, TOutputImage, TKernel >;
  using Pointer = SmartPointer< Self >;
  using ConstPointer = SmartPointer< const Self >;

  /** Standard New method. */
  itkNewMacro(Self);

  /** Runtime information support. */
  itkTypeMacro(MorphologicalGradientImageFilter,
               KernelImageFilter);

  /** Image related type alias. */
  static constexpr unsigned int ImageDimension = TInputImage::ImageDimension;

  /** Image related type alias. */
  using InputImageType = TInputImage;
  using OutputImageType = TOutputImage;
  using RegionType = typename TInputImage::RegionType;
  using SizeType = typename TInputImage::SizeType;
  using IndexType = typename TInputImage::IndexType;
  using PixelType = typename TInputImage::PixelType;
  using OffsetType = typename TInputImage::OffsetType;
  using OutputImageRegionType = typename Superclass::OutputImageRegionType;

  using FlatKernelType =
      FlatStructuringElement< Self::ImageDimension >;
  using HistogramFilterType =
      MovingHistogramMorphologicalGradientImageFilter< TInputImage, TOutputImage, TKernel >;
  using BasicDilateFilterType =
      BasicDilateImageFilter< TInputImage, TInputImage, TKernel >;
  using BasicErodeFilterType =
      BasicErodeImageFilter< TInputImage, TInputImage, TKernel >;
  using AnchorDilateFilterType =
      AnchorDilateImageFilter< TInputImage, FlatKernelType >;
  using AnchorErodeFilterType = AnchorErodeImageFilter< TInputImage, FlatKernelType >;
  using VHGWDilateFilterType =
      VanHerkGilWermanDilateImageFilter< TInputImage, FlatKernelType >;
  using VHGWErodeFilterType =
      VanHerkGilWermanErodeImageFilter< TInputImage, FlatKernelType >;
  using SubtractFilterType =
      SubtractImageFilter< TInputImage, TInputImage, TOutputImage >;

  /** Kernel type alias. */
  using KernelType = TKernel;
//   using KernelSuperclass = typename KernelType::Superclass;
//   using KernelSuperclass = Neighborhood< typename KernelType::PixelType, ImageDimension >;

  /** Set kernel (structuring element). */
  void SetKernel(const KernelType & kernel) override;

  /** Set/Get the backend filter class. */
  void SetAlgorithm(int algo);

  itkGetConstMacro(Algorithm, int);

  /** MorphologicalGradientImageFilter need to set its internal filters as
    modified */
  void Modified() const override;

  /** define values used to determine which algorithm to use */
  enum AlgorithmType {
    BASIC = 0,
    HISTO = 1,
    ANCHOR = 2,
    VHGW = 3
    };

protected:
  MorphologicalGradientImageFilter();
  ~MorphologicalGradientImageFilter() override = default;
  void PrintSelf(std::ostream & os, Indent indent) const override;

  void GenerateData() override;

private:
  // the filters used internally
  typename HistogramFilterType::Pointer m_HistogramFilter;

  typename BasicDilateFilterType::Pointer m_BasicDilateFilter;

  typename BasicErodeFilterType::Pointer m_BasicErodeFilter;

  typename AnchorDilateFilterType::Pointer m_AnchorDilateFilter;

  typename AnchorErodeFilterType::Pointer m_AnchorErodeFilter;

  typename VHGWDilateFilterType::Pointer m_VanHerkGilWermanDilateFilter;

  typename VHGWErodeFilterType::Pointer m_VanHerkGilWermanErodeFilter;

  // and the name of the filter
  int m_Algorithm;
}; // end of class
} // end namespace itk

#ifndef ITK_MANUAL_INSTANTIATION
#include "itkMorphologicalGradientImageFilter.hxx"
#endif

#endif
