/*=========================================================================
 *
 *  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 itkMatrixIndexSelectionImageFilter_h
#define itkMatrixIndexSelectionImageFilter_h

#include "itkUnaryFunctorImageFilter.h"

namespace itk
{
namespace Functor
{
template <typename TInput, typename TOutput>
class MatrixIndexSelection
{
public:
  MatrixIndexSelection() { m_I = m_J = 0; }
  ~MatrixIndexSelection() = default;

  void
  GetIndices(unsigned int & i, unsigned int & j) const
  {
    i = m_I;
    j = m_J;
  }
  void
  SetIndices(unsigned int i, unsigned int j)
  {
    m_I = i;
    m_J = j;
  }

  bool
  operator==(const MatrixIndexSelection & other) const
  {
    return m_I == other.m_I && m_J == other.m_J;
  }

  ITK_UNEQUAL_OPERATOR_MEMBER_FUNCTION(MatrixIndexSelection);

  inline TOutput
  operator()(const TInput & A) const
  {
    return static_cast<TOutput>(A[m_I][m_J]);
  }

private:
  unsigned int m_I;
  unsigned int m_J;
};
} // namespace Functor

/** \class MatrixIndexSelectionImageFilter
 *
 * \brief Extracts the selected indices of a matrix image that is the input
 * pixel type
 *
 * This filter is templated over the input image type and
 * output image type.
 *
 * The filter expect the input image pixel type to be a matrix and
 * the output image pixel type to be a scalar. The only requirement on
 * the type used for representing the vector is that it must provide an
 * operator(i,j).
 *
 * \ingroup IntensityImageFilters  MultiThreaded
 * \ingroup ITKImageIntensity
 */

template <typename TInputImage, typename TOutputImage>
class MatrixIndexSelectionImageFilter
  : public UnaryFunctorImageFilter<
      TInputImage,
      TOutputImage,
      Functor::MatrixIndexSelection<typename TInputImage::PixelType, typename TOutputImage::PixelType>>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(MatrixIndexSelectionImageFilter);

  /** Standard class type aliases. */
  using Self = MatrixIndexSelectionImageFilter<Image<Matrix<unsigned short, 2, 2>, 2>, Image<unsigned char, 2>>;
  using Superclass = UnaryFunctorImageFilter<
    TInputImage,
    TOutputImage,
    Functor::MatrixIndexSelection<typename TInputImage::PixelType, typename TOutputImage::PixelType>>;
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;

  /** \see LightObject::GetNameOfClass() */
  itkOverrideGetNameOfClassMacro(MatrixIndexSelectionImageFilter);

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

  /** Get/Set methods for the index */
  void
  SetIndices(unsigned int i, unsigned int j)
  {
    this->GetFunctor().SetIndices(i, j);
    this->Modified();
  }

  void
  GetIndices(unsigned int & i, unsigned int & j) const
  {
    return this->GetFunctor().GetIndices(i, j);
  }

  itkConceptMacro(InputHasNumericTraitsCheck, (Concept::HasNumericTraits<typename TInputImage::PixelType::ValueType>));

protected:
  MatrixIndexSelectionImageFilter() = default;
  ~MatrixIndexSelectionImageFilter() override = default;
};
} // end namespace itk

#endif
