/*=========================================================================
 *
 *  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 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:
  /** 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);
  itkTypeMacro(WatershedBoundaryResolver, ProcessObject);

  /** 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;
  BoundaryResolver(const Self &) {}
  void operator=(const Self &) {}
  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
