/*=========================================================================
 *
 *  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 itkBinaryFunctorImageFilter_h
#define itkBinaryFunctorImageFilter_h

#include "itkInPlaceImageFilter.h"
#include "itkSimpleDataObjectDecorator.h"

namespace itk
{
/** \class BinaryFunctorImageFilter
 * \brief Implements pixel-wise generic operation of two images,
 * or of an image and a constant.
 *
 * This class is parameterized over the types of the two input images
 * and the type of the output image. It is also parameterized by the
 * operation to be applied. A Functor style is used.
 *
 * The constant must be of the same type than the pixel type of the corresponding
 * image. It is wrapped in a SimpleDataObjectDecorator so it can be updated through
 * the pipeline. The SetConstant() and GetConstant() methods are provided as shortcuts
 * to set or get the constant value without manipulating the decorator.
 *
 * \sa BinaryGeneratorImagFilter
 * \sa UnaryFunctorImageFilter TernaryFunctorImageFilter
 *
 * \ingroup IntensityImageFilters   MultiThreaded
 * \ingroup ITKImageFilterBase
 *
 * \wiki
 * \wikiexample{ImageProcessing/BinaryFunctorImageFilter,Apply a predefined operation to corresponding pixels in two images}
 * \wikiexample{ImageProcessing/BinaryFunctorImageFilterCustom,Apply a custom operation to corresponding pixels in two images}
 * \endwiki
 */
template< typename TInputImage1, typename TInputImage2,
          typename TOutputImage, typename TFunction    >
class ITK_TEMPLATE_EXPORT BinaryFunctorImageFilter:
  public InPlaceImageFilter< TInputImage1, TOutputImage >
{
public:
  ITK_DISALLOW_COPY_AND_ASSIGN(BinaryFunctorImageFilter);

  /** Standard class type aliases. */
  using Self = BinaryFunctorImageFilter;
  using Superclass = InPlaceImageFilter< TInputImage1, TOutputImage >;
  using Pointer = SmartPointer< Self >;
  using ConstPointer = SmartPointer< const Self >;

  /** Method for creation through the object factory. */
  itkNewMacro(Self);

  /** Run-time type information (and related methods). */
  itkTypeMacro(BinaryFunctorImageFilter, InPlaceImageFilter);

  /** Some convenient type alias. */
  using FunctorType = TFunction;
  using Input1ImageType = TInputImage1;
  using Input1ImagePointer = typename Input1ImageType::ConstPointer;
  using Input1ImageRegionType = typename Input1ImageType::RegionType;
  using Input1ImagePixelType = typename Input1ImageType::PixelType;
  using DecoratedInput1ImagePixelType = SimpleDataObjectDecorator<Input1ImagePixelType>;

  using Input2ImageType = TInputImage2;
  using Input2ImagePointer = typename Input2ImageType::ConstPointer;
  using Input2ImageRegionType = typename Input2ImageType::RegionType;
  using Input2ImagePixelType = typename Input2ImageType::PixelType;
  using DecoratedInput2ImagePixelType = SimpleDataObjectDecorator<Input2ImagePixelType>;

  using OutputImageType = TOutputImage;
  using OutputImagePointer = typename OutputImageType::Pointer;
  using OutputImageRegionType = typename OutputImageType::RegionType;
  using OutputImagePixelType = typename OutputImageType::PixelType;

  /** Connect the first operand for pixel-wise operation. */
  virtual void SetInput1(const TInputImage1 *image1);
  virtual void SetInput1(const DecoratedInput1ImagePixelType *input1);
  virtual void SetInput1(const Input1ImagePixelType &input1);

  /** Set the first operand as a constant. */
  virtual void SetConstant1(const Input1ImagePixelType &input1);

  /** Get the constant value of the first operand. An exception is sent if
   * the first operand is not a constant. */
  virtual const Input1ImagePixelType & GetConstant1() const;

  /** Connect the second operand for pixel-wise operation. */
  virtual void SetInput2(const TInputImage2 *image2);
  virtual void SetInput2(const DecoratedInput2ImagePixelType *input2);
  virtual void SetInput2(const Input2ImagePixelType &input2);

  /** Set the second operand as a constant. */
  virtual void SetConstant2(const Input2ImagePixelType &input2);
  void SetConstant(Input2ImagePixelType ct)
  {
    this->SetConstant2(ct);
  }
  const Input2ImagePixelType & GetConstant() const
  {
    return this->GetConstant2();
  }

  /** Get the constant value of the second operand. An exception is sent if
   * the second operand is not a constant. */
  virtual const Input2ImagePixelType & GetConstant2() const;

  /** Get the functor object. The functor is returned by reference.
   * (Functors do not have to derive from itk::LightObject, so they do
   * not necessarily have a reference count. So we cannot return a
   * SmartPointer.). */
  FunctorType & GetFunctor() { return m_Functor; }

  /** Get the functor object. The functor is returned by reference.
   * (Functors do not have to derive from itk::LightObject, so they do
   * not necessarily have a reference count. So we cannot return a
   * SmartPointer.). */
  const FunctorType & GetFunctor() const
  {
    return m_Functor;
  }

  /** Set the functor object. This replaces the current Functor with a
   * copy of the specified Functor. This allows the user to specify a
   * functor that has ivars set differently than the default functor.
   * This method requires an operator!=() be defined on the functor
   * (or the compiler's default implementation of operator!=() being
   * appropriate). */
  void SetFunctor(const FunctorType & functor)
  {
    if ( m_Functor != functor )
      {
      m_Functor = functor;
      this->Modified();
      }
  }

  /** ImageDimension constants */
  static constexpr unsigned int InputImage1Dimension = TInputImage1::ImageDimension;
  static constexpr unsigned int InputImage2Dimension = TInputImage2::ImageDimension;
  static constexpr unsigned int OutputImageDimension = TOutputImage::ImageDimension;

#ifdef ITK_USE_CONCEPT_CHECKING
  // Begin concept checking
  itkConceptMacro( SameDimensionCheck1,
                   ( Concept::SameDimension< Self::InputImage1Dimension,
                                             Self::InputImage2Dimension > ) );
  itkConceptMacro( SameDimensionCheck2,
                   ( Concept::SameDimension< Self::InputImage1Dimension,
                                             Self::OutputImageDimension > ) );
  // End concept checking
#endif

protected:
  BinaryFunctorImageFilter();
  ~BinaryFunctorImageFilter() override = default;

  /** BinaryFunctorImageFilter can be implemented as a multithreaded filter.
   * Therefore, this implementation provides a DynamicThreadedGenerateData() routine
   * which is called for each processing thread. The output image data is
   * allocated automatically by the superclass prior to calling
   * DynamicThreadedGenerateData(). DynamicThreadedGenerateData can only write to the
   * portion of the output image specified by the parameter
   * "outputRegionForThread".
   *
   * \sa ImageToImageFilter::ThreadedGenerateData(),
   *     ImageToImageFilter::GenerateData()  */
  void DynamicThreadedGenerateData(const OutputImageRegionType & outputRegionForThread) override;


  // Needed to take the image information from the 2nd input, if the first one is
  // a simple decorated object.
  void GenerateOutputInformation() override;

private:
  FunctorType m_Functor;
};
} // end namespace itk

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

#endif
