/*=========================================================================
 *
 *  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 itkCenteredTransformInitializer_hxx
#define itkCenteredTransformInitializer_hxx


namespace itk
{
template <typename TTransform, typename TFixedImage, typename TMovingImage>
void
CenteredTransformInitializer<TTransform, TFixedImage, TMovingImage>::InitializeTransform()
{
  // Sanity check
  if (!m_FixedImage)
  {
    itkExceptionMacro("Fixed Image has not been set");
  }
  if (!m_MovingImage)
  {
    itkExceptionMacro("Moving Image has not been set");
  }
  if (!m_Transform)
  {
    itkExceptionMacro("Transform has not been set");
  }

  // If images come from filters, then update those filters.
  m_FixedImage->UpdateSource();
  m_MovingImage->UpdateSource();

  InputPointType   rotationCenter;
  OutputVectorType translationVector;

  if (m_UseMoments)
  {
    m_FixedCalculator->SetImage(m_FixedImage);
    m_FixedCalculator->Compute();

    m_MovingCalculator->SetImage(m_MovingImage);
    m_MovingCalculator->Compute();

    typename FixedImageCalculatorType::VectorType fixedCenter = m_FixedCalculator->GetCenterOfGravity();

    typename MovingImageCalculatorType::VectorType movingCenter = m_MovingCalculator->GetCenterOfGravity();

    for (unsigned int i = 0; i < InputSpaceDimension; ++i)
    {
      rotationCenter[i] = fixedCenter[i];
      translationVector[i] = movingCenter[i] - fixedCenter[i];
    }
  }
  else
  {
    // Here use the geometrical center of each image.

    const typename FixedImageType::RegionType & fixedRegion = m_FixedImage->GetLargestPossibleRegion();
    const typename FixedImageType::IndexType &  fixedIndex = fixedRegion.GetIndex();
    const typename FixedImageType::SizeType &   fixedSize = fixedRegion.GetSize();

    InputPointType centerFixedPoint;

    using CoordRepType = typename InputPointType::ValueType;

    using ContinuousIndexType = ContinuousIndex<CoordRepType, InputSpaceDimension>;

    using ContinuousIndexValueType = typename ContinuousIndexType::ValueType;

    ContinuousIndexType centerFixedIndex;

    for (unsigned int k = 0; k < InputSpaceDimension; ++k)
    {
      centerFixedIndex[k] = static_cast<ContinuousIndexValueType>(fixedIndex[k]) +
                            static_cast<ContinuousIndexValueType>(fixedSize[k] - 1) / 2.0;
    }

    m_FixedImage->TransformContinuousIndexToPhysicalPoint(centerFixedIndex, centerFixedPoint);

    const typename MovingImageType::RegionType & movingRegion = m_MovingImage->GetLargestPossibleRegion();
    const typename MovingImageType::IndexType &  movingIndex = movingRegion.GetIndex();
    const typename MovingImageType::SizeType &   movingSize = movingRegion.GetSize();

    InputPointType centerMovingPoint;

    ContinuousIndexType centerMovingIndex;

    for (unsigned int m = 0; m < InputSpaceDimension; ++m)
    {
      centerMovingIndex[m] = static_cast<ContinuousIndexValueType>(movingIndex[m]) +
                             static_cast<ContinuousIndexValueType>(movingSize[m] - 1) / 2.0;
    }

    m_MovingImage->TransformContinuousIndexToPhysicalPoint(centerMovingIndex, centerMovingPoint);

    for (unsigned int i = 0; i < InputSpaceDimension; ++i)
    {
      rotationCenter[i] = centerFixedPoint[i];
      translationVector[i] = centerMovingPoint[i] - centerFixedPoint[i];
    }
  }

  m_Transform->SetCenter(rotationCenter);

  m_Transform->SetTranslation(translationVector);
}

template <typename TTransform, typename TFixedImage, typename TMovingImage>
void
CenteredTransformInitializer<TTransform, TFixedImage, TMovingImage>::PrintSelf(std::ostream & os, Indent indent) const
{
  Superclass::PrintSelf(os, indent);

  itkPrintSelfObjectMacro(Transform);
  itkPrintSelfObjectMacro(FixedImage);
  itkPrintSelfObjectMacro(MovingImage);

  os << indent << "UseMoments: " << (m_UseMoments ? "On" : "Off") << std::endl;

  itkPrintSelfObjectMacro(MovingCalculator);
  itkPrintSelfObjectMacro(FixedCalculator);
}
} // namespace itk

#endif /* itkCenteredTransformInitializer_hxx */