/*=========================================================================
 *
 *  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 itkWatershedBoundaryResolver_h
#define itkWatershedBoundaryResolver_h


#include "itkWatershedSegmenter.h"

namespace itk
{
namespace watershed
{
/**
 * \class BoundaryResolver
 *  This filter implements a piece of the streaming watershed
 *  segmentation algorithm.  It takes in pairs of itk::watershed::Boundary
 *  objects and connects the labeling of pixels across image chunk boundaries.
 *  Read the documentation found in itk::WatershedImageFilter and the other
 *  watershed segmentation component objects for more information.
 *
 * \par A note on terminology in itk watershed segmentation code
 * For streamed segmentation of images in the watershed framework, the
 * documentation refers to the complete data set at the "image volume."  The
 * image volume is assumed to be partitioned into pieces referred to as image
 * chunks. Each chunk is processed in sequence through the pipeline.  The
 * "face" of an image chunk is an N-1 dimensional boundary region of an N
 * dimensional chunk (the planar faces of a cube, for example).

 * \par Input
 * The input to this filter is a pair of itk::watershed::Boundary pointers
 * (BoundaryA and BoundaryB).
 * The algorithm assumes that these Boundaries come from facing chunks in the
 * image volume.  The faces that align need to be specified in the parameters
 * of the filter.
 *
 * \par Output
 * This filter outputs a table of equivalencies among labels.  See
 * itk::EquivalencyTable for more information.
 * \ingroup WatershedSegmentation
 *
 * \par Parameters
 * The only parameters to set on this filter are the indices of the faces that
 * align in the boundary object inputs.  See itk::Boundary for a description of
 * how boundary faces are indexed.
 * \sa itk::watershed::Boundary
 * \ingroup WatershedSegmentation
 * \ingroup ITKWatersheds
 */
template <typename TPixelType, unsigned int TDimension>
class ITK_TEMPLATE_EXPORT BoundaryResolver : public ProcessObject
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(BoundaryResolver);

  /** Set up smart pointer and object factory definitions.   */
  using Self = BoundaryResolver;
  using Superclass = ProcessObject;
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;
  itkNewMacro(Self);
  itkOverrideGetNameOfClassMacro(BoundaryResolver);

  /** Expose the image dimension at run time. */
  static constexpr unsigned int ImageDimension = TDimension;

  /** Some convenient type alias.   */
  using PixelType = TPixelType;
  using BoundaryType = Boundary<PixelType, TDimension>;
  using EquivalencyTableType = EquivalencyTable;
  using SegmenterType = Segmenter<Image<TPixelType, TDimension>>;
  using DataObjectPointer = DataObject::Pointer;

  /** Set/Get the first of two boundaries that are to be resolved.   */
  void
  SetBoundaryA(BoundaryType * bd)
  {
    this->ProcessObject::SetNthInput(0, bd);
  }
  typename BoundaryType::Pointer
  GetBoundaryA()
  {
    return static_cast<BoundaryType *>(this->GetInput(0));
  }

  /** Set/Get the second of two boundaries that are to be resolved.  */
  void
  SetBoundaryB(BoundaryType * bd)
  {
    this->ProcessObject::SetNthInput(1, bd);
  }
  typename BoundaryType::Pointer
  GetBoundaryB()
  {
    return static_cast<BoundaryType *>(this->GetInput(1));
  }

  /**  Set/Get the face of the boundary object that we are going to
   *  resolve. */
  itkSetMacro(Face, unsigned short);
  itkGetConstMacro(Face, unsigned short);

  /** This method sets/gets the equivalency table used to store equivalencies
   *  among segments that are generated from the boundary resolution
   *  algorithm.  */
  void
  SetEquivalencyTable(EquivalencyTableType::Pointer a)
  {
    this->ProcessObject::SetNthOutput(0, a.GetPointer());
  }
  EquivalencyTableType::Pointer
  GetEquivalencyTable()
  {
    return static_cast<EquivalencyTableType *>(this->ProcessObject::GetOutput(0));
  }

  /** Standard non-threaded pipeline method */
  void
  GenerateData() override;

  /** Standard itk::ProcessObject subclass method. */
  using DataObjectPointerArraySizeType = ProcessObject::DataObjectPointerArraySizeType;
  using Superclass::MakeOutput;
  DataObjectPointer
  MakeOutput(DataObjectPointerArraySizeType idx) override;

protected:
  BoundaryResolver()
  {
    EquivalencyTable::Pointer eq = static_cast<EquivalencyTable *>(this->MakeOutput(0).GetPointer());

    this->SetNumberOfRequiredOutputs(1);
    this->ProcessObject::SetNthOutput(0, eq.GetPointer());
  }

  ~BoundaryResolver() override = default;

  void
  PrintSelf(std::ostream & os, Indent indent) const override;

  unsigned short m_Face{ 0 };
  void
  GenerateOutputRequestedRegion(DataObject * output) override;
};
} // end namespace watershed
} // end namespace itk

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

#endif
