/*=========================================================================
 *
 *  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 itkWarpVectorImageFilter_hxx
#define itkWarpVectorImageFilter_hxx

#include "itkImageRegionIterator.h"
#include "itkImageRegionIteratorWithIndex.h"
#include "itkTotalProgressReporter.h"

namespace itk
{

template <typename TInputImage, typename TOutputImage, typename TDisplacementField>
WarpVectorImageFilter<TInputImage, TOutputImage, TDisplacementField>::WarpVectorImageFilter()
{
  this->SetNumberOfRequiredInputs(2);

  // Setup default values
  m_OutputSpacing.Fill(1.0);
  m_OutputOrigin.Fill(0.0);
  m_OutputDirection.SetIdentity();

  for (unsigned int i = 0; i < PixelDimension; ++i)
  {
    m_EdgePaddingValue[i] = 0;
  }

  // Setup default interpolator
  auto interp = DefaultInterpolatorType::New();

  m_Interpolator = static_cast<InterpolatorType *>(interp.GetPointer());
  this->DynamicMultiThreadingOn();
  this->ThreaderUpdateProgressOff();
}


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

  os << indent << "OutputSpacing: " << m_OutputSpacing << std::endl;
  os << indent << "OutputOrigin: " << m_OutputOrigin << std::endl;
  os << indent << "OutputDirection: " << m_OutputDirection << std::endl;
  os << indent << "EdgePaddingValue: " << static_cast<typename NumericTraits<PixelType>::PrintType>(m_EdgePaddingValue)
     << std::endl;
  os << indent << "Interpolator: " << m_Interpolator.GetPointer() << std::endl;
}

/** Set the output image spacing. */
template <typename TInputImage, typename TOutputImage, typename TDisplacementField>
void
WarpVectorImageFilter<TInputImage, TOutputImage, TDisplacementField>::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);
}

/** Set the output image origin. */
template <typename TInputImage, typename TOutputImage, typename TDisplacementField>
void
WarpVectorImageFilter<TInputImage, TOutputImage, TDisplacementField>::SetOutputOrigin(const double * origin)
{
  this->SetOutputOrigin(PointType(origin));
}

/** Set displacement field as Inputs[1] for this ProcessObject. */
template <typename TInputImage, typename TOutputImage, typename TDisplacementField>
void
WarpVectorImageFilter<TInputImage, TOutputImage, TDisplacementField>::SetDisplacementField(
  const DisplacementFieldType * field)
{
  // const cast is needed because the pipeline is not const-correct.
  auto * input = const_cast<DisplacementFieldType *>(field);

  this->ProcessObject::SetNthInput(1, input);
}

/**
 * Set displacement field as Inputs[1] for this ProcessObject
 * (non const for backward compatibility)
 */
template <typename TInputImage, typename TOutputImage, typename TDisplacementField>
void
WarpVectorImageFilter<TInputImage, TOutputImage, TDisplacementField>::SetDisplacementField(
  DisplacementFieldType * field)
{
  this->ProcessObject::SetNthInput(1, field);
}


template <typename TInputImage, typename TOutputImage, typename TDisplacementField>
auto
WarpVectorImageFilter<TInputImage, TOutputImage, TDisplacementField>::GetDisplacementField() -> DisplacementFieldType *
{
  return itkDynamicCastInDebugMode<DisplacementFieldType *>(this->ProcessObject::GetInput(1));
}

/**
 * Setup state of filter before multi-threading.
 * InterpolatorType::SetInputImage is not thread-safe and hence
 * has to be setup before DynamicThreadedGenerateData
 */
template <typename TInputImage, typename TOutputImage, typename TDisplacementField>
void
WarpVectorImageFilter<TInputImage, TOutputImage, TDisplacementField>::BeforeThreadedGenerateData()
{
  if (!m_Interpolator)
  {
    itkExceptionMacro("Interpolator not set");
  }

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


template <typename TInputImage, typename TOutputImage, typename TDisplacementField>
void
WarpVectorImageFilter<TInputImage, TOutputImage, TDisplacementField>::DynamicThreadedGenerateData(
  const OutputImageRegionType & outputRegionForThread)
{
  InputImageConstPointer   inputPtr = this->GetInput();
  OutputImagePointer       outputPtr = this->GetOutput();
  DisplacementFieldPointer fieldPtr = this->GetDisplacementField();


  ImageRegionIteratorWithIndex<OutputImageType> outputIt(outputPtr, outputRegionForThread);
  TotalProgressReporter                         progress(this, outputPtr->GetRequestedRegion().GetNumberOfPixels());

  ImageRegionIterator<DisplacementFieldType> fieldIt(fieldPtr, outputRegionForThread);

  IndexType        index;
  PointType        point;
  DisplacementType displacement;
  PixelType        outputValue;

  while (!outputIt.IsAtEnd())
  {
    index = outputIt.GetIndex();
    outputPtr->TransformIndexToPhysicalPoint(index, point);
    displacement = fieldIt.Get();

    // compute the required input image point
    for (unsigned int j = 0; j < ImageDimension; ++j)
    {
      point[j] += displacement[j];
    }

    // get the interpolated value
    if (m_Interpolator->IsInsideBuffer(point))
    {
      using OutputType = typename InterpolatorType::OutputType;
      const OutputType interpolatedValue = m_Interpolator->Evaluate(point);

      for (unsigned int k = 0; k < PixelDimension; ++k)
      {
        outputValue[k] = static_cast<ValueType>(interpolatedValue[k]);
      }

      outputIt.Set(outputValue);
    }
    else
    {
      outputIt.Set(m_EdgePaddingValue);
    }
    ++outputIt;
    ++fieldIt;
    progress.CompletedPixel();
  }
}

template <typename TInputImage, typename TOutputImage, typename TDisplacementField>
void
WarpVectorImageFilter<TInputImage, TOutputImage, TDisplacementField>::GenerateInputRequestedRegion()
{
  // call the superclass's implementation
  Superclass::GenerateInputRequestedRegion();

  // request the largest possible region for the input image
  InputImagePointer inputPtr = const_cast<InputImageType *>(this->GetInput());

  if (inputPtr)
  {
    inputPtr->SetRequestedRegionToLargestPossibleRegion();
  }

  // just propagate up the output requested region for the
  // displacement field.
  DisplacementFieldPointer fieldPtr = this->GetDisplacementField();
  OutputImagePointer       outputPtr = this->GetOutput();
  if (fieldPtr)
  {
    fieldPtr->SetRequestedRegion(outputPtr->GetRequestedRegion());
  }
}

template <typename TInputImage, typename TOutputImage, typename TDisplacementField>
void
WarpVectorImageFilter<TInputImage, TOutputImage, TDisplacementField>::GenerateOutputInformation()
{
  // call the superclass's implementation of this method
  Superclass::GenerateOutputInformation();

  OutputImagePointer outputPtr = this->GetOutput();

  outputPtr->SetSpacing(m_OutputSpacing);
  outputPtr->SetOrigin(m_OutputOrigin);
  outputPtr->SetDirection(m_OutputDirection);

  DisplacementFieldPointer fieldPtr = this->GetDisplacementField();
  if (fieldPtr)
  {
    outputPtr->SetLargestPossibleRegion(fieldPtr->GetLargestPossibleRegion());
  }
}
} // end namespace itk

#endif
