/*=========================================================================

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkConstrainedValueMultiplicationImageFilter.h,v $
  Language:  C++
  Date:      $Date: 2007-09-27 11:36:40 $
  Version:   $Revision: 1.7 $

  Copyright (c) Insight Software Consortium. All rights reserved.
  See ITKCopyright.txt or https://www.itk.org/HTML/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notices for more information.

=========================================================================*/
#ifndef itkConstrainedValueMultiplicationImageFilter_h
#define itkConstrainedValueMultiplicationImageFilter_h

#include "itkBinaryFunctorImageFilter.h"
#include "itkNumericTraits.h"

namespace itk
{

/** \class ConstrainedValueMultiplicationImageFilter
 * \brief Implements pixel-wise the computation of constrained value addition.
 *
 * This filter is parameterized over the types of the two
 * input images and the type of the output image.
 *
 * Numeric conversions (castings) are done by the C++ defaults.
 *
 * The filter will walk over all the pixels in the two input images, and for
 * each one of them it will do the following:
 *
 * - cast the input 1 pixel value to \c double
 * - cast the input 2 pixel value to \c double
 * - compute the addition of the two pixel values
 * - compute the constrained value (constrained to be between the
 *   NonpositiveMin and max of the output pixel type)
 * - cast the \c double value resulting from \c the constrained value
 *   to the pixel type of the output image
 * - store the cast value into the output image.
 *
 * The filter expects all images to have the same dimension
 * (e.g. all 2D, or all 3D, or all ND)
 *
 * \author Lino Ramirez. Dept. of Electrical and Computer
 * Engineering. University of Alberta. Canada
 */
namespace Functor
{

template <class TInput1, class TInput2, class TOutput>
class ConstrainedValueMultiplication
{
public:
  ConstrainedValueMultiplication() = default;
  ~ConstrainedValueMultiplication() = default;
  bool operator!=(const ConstrainedValueMultiplication&) const { return false; }
  bool operator==(const ConstrainedValueMultiplication& other) const { return !(*this != other); }
  inline TOutput operator()(const TInput1& A, const TInput2& B)
  {
    const double dA = static_cast<double>(A);
    const double dB = static_cast<double>(B);
    const double add = dA * dB;
    // IEEE‑754 double can exactly represent all integers in the range [–2^53, 2^53], but beyond that,
    // only some integer numbers are representable.
    //  18446744073709551615 (2^64−1) must be rounded to the nearest representable double: 18446744073709551616
    constexpr double max_closest_representable = static_cast<double>(NumericTraits<TOutput>::max());

    const double cadd1 = (add < max_closest_representable) ? add : max_closest_representable;
    const double cadd2 = (cadd1 > NumericTraits<TOutput>::NonpositiveMin()) ? cadd1 : NumericTraits<TOutput>::NonpositiveMin();
    return static_cast<TOutput>(cadd2);
  }
};
} // namespace Functor

template <class TInputImage1, class TInputImage2, class TOutputImage>
class ConstrainedValueMultiplicationImageFilter
  : public BinaryFunctorImageFilter<TInputImage1,
                                    TInputImage2,
                                    TOutputImage,
                                    Functor::ConstrainedValueMultiplication<typename TInputImage1::PixelType, typename TInputImage2::PixelType, typename TOutputImage::PixelType>>
{
public:
  /** Standard class typedefs. */
  typedef ConstrainedValueMultiplicationImageFilter Self;
  typedef BinaryFunctorImageFilter<TInputImage1,
                                   TInputImage2,
                                   TOutputImage,
                                   Functor::ConstrainedValueMultiplication<typename TInputImage1::PixelType, typename TInputImage2::PixelType, typename TOutputImage::PixelType>>
    Superclass;
  typedef SmartPointer<Self> Pointer;
  typedef SmartPointer<const Self> ConstPointer;

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

  /** Runtime information support. */
  itkTypeMacro(ConstrainedValueMultiplicationImageFilter, BinaryFunctorImageFilter);

#ifdef ITK_USE_CONCEPT_CHECKING
  /** Begin concept checking */
  itkConceptMacro(Input1ConvertibleToDoubleCheck, (Concept::Convertible<typename TInputImage1::PixelType, double>));
  itkConceptMacro(Input2ConvertibleToDoubleCheck, (Concept::Convertible<typename TInputImage2::PixelType, double>));
  itkConceptMacro(DoubleConvertibleToOutputCastCheck, (Concept::Convertible<double, typename TOutputImage::PixelType>));
  itkConceptMacro(DoubleLessThanOutputCheck, (Concept::LessThanComparable<double, typename TOutputImage::PixelType>));
  /** End concept checking */
#endif

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

private:
  ConstrainedValueMultiplicationImageFilter(const Self&) = delete;
  void operator=(const Self&) = delete;
};

} // namespace itk

#endif
