/*=========================================================================
 *
 *  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 itkVectorResampleImageFilter_hxx
#define itkVectorResampleImageFilter_hxx

#include "itkIdentityTransform.h"
#include "itkVectorLinearInterpolateImageFunction.h"
#include "itkTotalProgressReporter.h"
#include "itkImageRegionIteratorWithIndex.h"
#include <algorithm> // For max.

namespace itk
{

template <typename TInputImage, typename TOutputImage, typename TInterpolatorPrecisionType>
VectorResampleImageFilter<TInputImage, TOutputImage, TInterpolatorPrecisionType>::VectorResampleImageFilter()
  : m_OutputSpacing(1.0)
  , m_OutputOrigin(0.0)
{
  m_Size.Fill(0);
  m_OutputStartIndex.Fill(0);

  m_OutputDirection.SetIdentity();

  m_Transform = IdentityTransform<TInterpolatorPrecisionType, ImageDimension>::New();
  m_Interpolator = VectorLinearInterpolateImageFunction<InputImageType, TInterpolatorPrecisionType>::New();

  m_DefaultPixelValue = NumericTraits<PixelType>::ZeroValue(m_DefaultPixelValue);
  this->DynamicMultiThreadingOn();
  this->ThreaderUpdateProgressOff();
}

template <typename TInputImage, typename TOutputImage, typename TInterpolatorPrecisionType>
void
VectorResampleImageFilter<TInputImage, TOutputImage, TInterpolatorPrecisionType>::SetOutputSpacing(
  const double * spacing)
{
  SpacingType s;
  for (unsigned int i = 0; i < TInputImage::ImageDimension; ++i)
  {
    s[i] = static_cast<typename SpacingType::ValueType>(spacing[i]);
  }
  this->SetOutputSpacing(s);
}

template <typename TInputImage, typename TOutputImage, typename TInterpolatorPrecisionType>
void
VectorResampleImageFilter<TInputImage, TOutputImage, TInterpolatorPrecisionType>::SetOutputOrigin(const double * origin)
{
  OriginPointType p(origin);

  this->SetOutputOrigin(p);
}

template <typename TInputImage, typename TOutputImage, typename TInterpolatorPrecisionType>
void
VectorResampleImageFilter<TInputImage, TOutputImage, TInterpolatorPrecisionType>::BeforeThreadedGenerateData()
{
  if (!m_Interpolator)
  {
    itkExceptionMacro("Interpolator not set");
  }

  // Connect input image to interpolator
  m_Interpolator->SetInputImage(this->GetInput());

  if (m_DefaultPixelValue.Size() == 0)
  {
    NumericTraits<PixelType>::SetLength(m_DefaultPixelValue, this->GetInput()->GetNumberOfComponentsPerPixel());
    m_DefaultPixelValue.Fill(0);
  }
}

template <typename TInputImage, typename TOutputImage, typename TInterpolatorPrecisionType>
void
VectorResampleImageFilter<TInputImage, TOutputImage, TInterpolatorPrecisionType>::AfterThreadedGenerateData()
{
  // Disconnect input image from the interpolator
  m_Interpolator->SetInputImage(nullptr);
}

template <typename TInputImage, typename TOutputImage, typename TInterpolatorPrecisionType>
void
VectorResampleImageFilter<TInputImage, TOutputImage, TInterpolatorPrecisionType>::DynamicThreadedGenerateData(
  const OutputImageRegionType & outputRegionForThread)
{
  OutputImagePointer     outputPtr = this->GetOutput();
  InputImageConstPointer inputPtr = this->GetInput();

  TotalProgressReporter progress(this, outputPtr->GetRequestedRegion().GetNumberOfPixels());

  // Create an iterator that will walk the output region for this thread.
  using OutputIterator = ImageRegionIteratorWithIndex<TOutputImage>;

  OutputIterator outIt(outputPtr, outputRegionForThread);

  // Define a few indices that will be used to translate from an input pixel
  // to an output pixel
  PointType outputPoint; // Coordinates of current output pixel
  PointType inputPoint;  // Coordinates of current input pixel

  using ContinuousIndexType = ContinuousIndex<TInterpolatorPrecisionType, ImageDimension>;

  // Doc says this only works for VectorImage, but Image implementation says otherwise...
  const unsigned int numberOfComponents = this->GetInput()->GetNumberOfComponentsPerPixel();

  using OutputType = typename InterpolatorType::OutputType;

  // Walk the output region
  outIt.GoToBegin();

  while (!outIt.IsAtEnd())
  {
    // Determine the index of the current output pixel
    outputPtr->TransformIndexToPhysicalPoint(outIt.GetIndex(), outputPoint);

    // Compute corresponding input pixel position
    inputPoint = m_Transform->TransformPoint(outputPoint);
    const ContinuousIndexType inputIndex =
      inputPtr->template TransformPhysicalPointToContinuousIndex<TInterpolatorPrecisionType>(inputPoint);

    // Evaluate input at right position and copy to the output
    if (m_Interpolator->IsInsideBuffer(inputIndex))
    {
      PixelType pixval;
      NumericTraits<PixelType>::SetLength(pixval, numberOfComponents);

      const OutputType value = m_Interpolator->EvaluateAtContinuousIndex(inputIndex);
      for (unsigned int i = 0; i < numberOfComponents; ++i)
      {
        pixval[i] = static_cast<PixelComponentType>(value[i]);
      }

      outIt.Set(pixval);
    }
    else
    {
      outIt.Set(m_DefaultPixelValue); // default background value
    }

    ++outIt;
    progress.CompletedPixel();
  }
}

template <typename TInputImage, typename TOutputImage, typename TInterpolatorPrecisionType>
void
VectorResampleImageFilter<TInputImage, TOutputImage, TInterpolatorPrecisionType>::GenerateInputRequestedRegion()
{
  // Call the superclass's implementation of this method
  Superclass::GenerateInputRequestedRegion();

  if (!this->GetInput())
  {
    return;
  }

  // Get the pointer to the input image
  InputImagePointer inputPtr = const_cast<TInputImage *>(this->GetInput());

  // Determining the actual input region is non-trivial, especially
  // when we cannot assume anything about the transform being used.
  // So we do the easy thing and request the entire input image.
  //
  InputImageRegionType inputRegion;
  inputRegion = inputPtr->GetLargestPossibleRegion();
  inputPtr->SetRequestedRegion(inputRegion);
}

template <typename TInputImage, typename TOutputImage, typename TInterpolatorPrecisionType>
void
VectorResampleImageFilter<TInputImage, TOutputImage, TInterpolatorPrecisionType>::GenerateOutputInformation()
{
  // Call the superclass' implementation of this method
  Superclass::GenerateOutputInformation();

  // Get the pointer to the output image
  OutputImagePointer outputPtr = this->GetOutput();
  if (!outputPtr)
  {
    return;
  }

  // Set the size of the output region
  typename TOutputImage::RegionType outputLargestPossibleRegion;
  outputLargestPossibleRegion.SetSize(m_Size);
  outputLargestPossibleRegion.SetIndex(m_OutputStartIndex);
  outputPtr->SetLargestPossibleRegion(outputLargestPossibleRegion);

  // Set spacing and origin
  outputPtr->SetSpacing(m_OutputSpacing);
  outputPtr->SetOrigin(m_OutputOrigin);
  outputPtr->SetDirection(m_OutputDirection);
}

template <typename TInputImage, typename TOutputImage, typename TInterpolatorPrecisionType>
ModifiedTimeType
VectorResampleImageFilter<TInputImage, TOutputImage, TInterpolatorPrecisionType>::GetMTime() const
{
  ModifiedTimeType latestTime = Object::GetMTime();

  if (m_Transform)
  {
    latestTime = std::max(latestTime, m_Transform->GetMTime());
  }

  if (m_Interpolator)
  {
    latestTime = std::max(latestTime, m_Interpolator->GetMTime());
  }

  return latestTime;
}

template <typename TInputImage, typename TOutputImage, typename TInterpolatorPrecisionType>
void
VectorResampleImageFilter<TInputImage, TOutputImage, TInterpolatorPrecisionType>::PrintSelf(std::ostream & os,
                                                                                            Indent         indent) const
{
  Superclass::PrintSelf(os, indent);

  os << indent
     << "DefaultPixelValue: " << static_cast<typename NumericTraits<PixelType>::PrintType>(m_DefaultPixelValue)
     << std::endl;
  os << indent << "Size: " << m_Size << std::endl;
  os << indent << "OutputStartIndex: " << m_OutputStartIndex << std::endl;
  os << indent << "OutputSpacing: " << m_OutputSpacing << std::endl;
  os << indent << "OutputOrigin: " << m_OutputOrigin << std::endl;
  os << indent << "OutputDirection: " << m_OutputDirection << std::endl;
  os << indent << "Transform: " << m_Transform.GetPointer() << std::endl;
  os << indent << "Interpolator: " << m_Interpolator.GetPointer() << std::endl;
}
} // end namespace itk

#endif
