/*=========================================================================
 *
 *  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 itkFiniteDifferenceFunction_hxx
#define itkFiniteDifferenceFunction_hxx


namespace itk
{
template <typename TImageType>
FiniteDifferenceFunction<TImageType>::FiniteDifferenceFunction()
{
  // initialize variables
  m_Radius.Fill(0);
  for (unsigned int i = 0; i < ImageDimension; ++i)
  {
    m_ScaleCoefficients[i] = 1.0;
  }
}

template <typename TImageType>
void
FiniteDifferenceFunction<TImageType>::SetRadius(const RadiusType & r)
{
  m_Radius = r;
}

template <typename TImageType>
auto
FiniteDifferenceFunction<TImageType>::GetRadius() const -> const RadiusType &
{
  return m_Radius;
}

template <typename TImageType>
void
FiniteDifferenceFunction<TImageType>::SetScaleCoefficients(const PixelRealType vals[ImageDimension])
{
  for (unsigned int i = 0; i < ImageDimension; ++i)
  {
    m_ScaleCoefficients[i] = vals[i];
  }
}

template <typename TImageType>
void
FiniteDifferenceFunction<TImageType>::GetScaleCoefficients(PixelRealType vals[ImageDimension]) const
{
  for (unsigned int i = 0; i < ImageDimension; ++i)
  {
    vals[i] = m_ScaleCoefficients[i];
  }
}

template <typename TImageType>
void
FiniteDifferenceFunction<TImageType>::PrintSelf(std::ostream & os, Indent indent) const
{
  Superclass::PrintSelf(os, indent);
  os << indent << "Radius: " << m_Radius << std::endl;
  os << indent << "ScaleCoefficients: " << m_ScaleCoefficients;
}

template <typename TImageType>
auto
FiniteDifferenceFunction<TImageType>::ComputeNeighborhoodScales() const -> const NeighborhoodScalesType
{
  NeighborhoodScalesType neighborhoodScales;

  neighborhoodScales.Fill(0.0);
  for (unsigned int i = 0; i < ImageDimension; ++i)
  {
    if (this->m_Radius[i] > 0)
    {
      neighborhoodScales[i] = this->m_ScaleCoefficients[i] / this->m_Radius[i];
    }
  }
  return neighborhoodScales;
}
} // end namespace itk

#endif