/*=========================================================================
 *
 *  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 itkGrayscaleErodeImageFilter_h
#define itkGrayscaleErodeImageFilter_h

#include "itkKernelImageFilter.h"
#include "itkMovingHistogramErodeImageFilter.h"
#include "itkBasicErodeImageFilter.h"
#include "itkAnchorErodeImageFilter.h"
#include "itkVanHerkGilWermanErodeImageFilter.h"
#include "itkCastImageFilter.h"
#include "itkConstantBoundaryCondition.h"
#include "itkNeighborhood.h"

namespace itk
{
/**
 * \class GrayscaleErodeImageFilter
 * \brief Grayscale erosion of an image.
 *
 * Erode an image using grayscale morphology. Erosion 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, GrayscaleFunctionErodeImageFilter, BinaryErodeImageFilter
 * \ingroup ImageEnhancement  MathematicalMorphologyImageFilters
 * \ingroup ITKMathematicalMorphology
 *
 * \wiki
 * \wikiexample{Morphology/GrayscaleErodeImageFilter,Erode a grayscale image}
 * \endwiki
 */

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

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

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

  /** Runtime information support. */
  itkTypeMacro(GrayscaleErodeImageFilter,
               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;

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

  using HistogramFilterType =
      MovingHistogramErodeImageFilter< TInputImage, TOutputImage, TKernel >;
  using BasicFilterType =
      BasicErodeImageFilter< TInputImage, TOutputImage, TKernel >;

  using FlatKernelType = FlatStructuringElement< Self::ImageDimension >;

  using AnchorFilterType = AnchorErodeImageFilter< TInputImage, FlatKernelType >;
  using VHGWFilterType = VanHerkGilWermanErodeImageFilter< TInputImage, FlatKernelType >;
  using CastFilterType = CastImageFilter< TInputImage, TOutputImage >;

  /** Typedef for boundary conditions. */
  using ImageBoundaryConditionPointerType = ImageBoundaryCondition< InputImageType > *;
  using ImageBoundaryConditionConstPointerType = const ImageBoundaryCondition<InputImageType> *;
  using DefaultBoundaryConditionType = ConstantBoundaryCondition< InputImageType >;

  /** 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 boundary value. */
  void SetBoundary(const PixelType value);

  itkGetConstMacro(Boundary, PixelType);

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

  itkGetConstMacro(Algorithm, int);

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

  void SetNumberOfWorkUnits(ThreadIdType nb) override;

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

  void GenerateData() override;

private:
  PixelType m_Boundary;

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

  typename BasicFilterType::Pointer m_BasicFilter;

  typename AnchorFilterType::Pointer m_AnchorFilter;

  typename VHGWFilterType::Pointer m_VHGWFilter;

  // and the name of the filter
  int m_Algorithm;

  // the boundary condition need to be stored here
  DefaultBoundaryConditionType m_BoundaryCondition;
}; // end of class
} // end namespace itk

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

#endif
