/*=========================================================================
 *
 *  Copyright UMC Utrecht and contributors
 *
 *  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
 *
 *        http://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.
 *
 *=========================================================================*/
/*=========================================================================

  Program:   Insight Segmentation & Registration Toolkit
  Module:    $RCSfile: itkGradientDifferenceImageToImageMetric2.h,v $
  Date:      $Date: 2011-29-04 14:33 $
  Version:   $Revision: 2.0 $

  Copyright (c) Insight Software Consortium. All rights reserved.
  See ITKCopyright.txt or http://www.itk.org/HTML/Copyright.htm for details.

     This software is distributed WITHOUT ANY WARRANTY; without even
     the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
     PURPOSE.  See the above copyright notices for more information.

=========================================================================*/
#ifndef itkGradientDifferenceImageToImageMetric2_h
#define itkGradientDifferenceImageToImageMetric2_h

#include "itkAdvancedImageToImageMetric.h"

#include "itkSobelOperator.h"
#include "itkNeighborhoodOperatorImageFilter.h"
#include "itkPoint.h"
#include "itkCastImageFilter.h"
#include "itkResampleImageFilter.h"
#include "itkOptimizer.h"
#include "itkAdvancedCombinationTransform.h"
#include "itkAdvancedRayCastInterpolateImageFunction.h"

namespace itk
{
/** \class GradientDifferenceImageToImageMetric
 * \brief Computes similarity between two objects to be registered
 *
 * This Class is templated over the type of the Images to be compared and
 * over the type of transformation and Iterpolator to be used.
 *
 * This metric computes the sum of squared differences between pixels in
 * the derivatives of the moving and fixed images after passing the squared
 * difference through a function of type \f$ \frac{1}{1+x} \f$.
 *
 *
 * Spatial correspondance between both images is established through a
 * Transform. Pixel values are taken from the Moving image. Their positions
 * are mapped to the Fixed image and result in general in non-grid position
 * on it. Values at these non-grid position of the Fixed image are
 * interpolated using a user-selected Interpolator.
 *
 * Implementation of this class is based on:
 * Hipwell, J. H., et. al. (2003), "Intensity-Based 2-D-3D Registration of
 * Cerebral Angiograms,", IEEE Transactions on Medical Imaging,
 * 22(11):1417-1426.
 *
 * \ingroup RegistrationMetrics
 */
template <class TFixedImage, class TMovingImage>
class ITK_TEMPLATE_EXPORT GradientDifferenceImageToImageMetric
  : public AdvancedImageToImageMetric<TFixedImage, TMovingImage>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(GradientDifferenceImageToImageMetric);

  /** Standard class typedefs. */
  using Self = GradientDifferenceImageToImageMetric;
  using Superclass = AdvancedImageToImageMetric<TFixedImage, TMovingImage>;

  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;

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

  /** Run-time type information (and related methods). */
  itkTypeMacro(GradientDifferenceImageToImageMetric, ImageToImageMetric);

/** Types transferred from the base class */
/** Work around a Visual Studio .NET bug */
#if defined(_MSC_VER) && (_MSC_VER == 1300)
  using RealType = double;
#else
  using typename Superclass::RealType;
#endif

  using typename Superclass::TransformType;
  using ScalarType = typename TransformType::ScalarType;
  using typename Superclass::TransformPointer;
  using typename Superclass::TransformParametersType;
  using typename Superclass::TransformJacobianType;
  using typename Superclass::InterpolatorType;
  using InterpolatorPointer = typename InterpolatorType::Pointer;
  using typename Superclass::MeasureType;
  using typename Superclass::DerivativeType;
  using typename Superclass::FixedImageType;
  using typename Superclass::MovingImageType;
  using typename Superclass::FixedImageConstPointer;
  using typename Superclass::MovingImageConstPointer;
  using FixedImagePixelType = typename TFixedImage::PixelType;
  using MovedImagePixelType = typename TMovingImage::PixelType;
  using MovingImageRegionType = typename MovingImageType::RegionType;
  using ScalesType = typename Optimizer::ScalesType;

  itkStaticConstMacro(FixedImageDimension, unsigned int, FixedImageType::ImageDimension);
  itkStaticConstMacro(MovedImageDimension, unsigned int, MovingImageType::ImageDimension);

  using CombinationTransformType = typename itk::AdvancedCombinationTransform<ScalarType, FixedImageDimension>;
  using CombinationTransformPointer = typename CombinationTransformType::Pointer;
  using TransformedMovingImageType = itk::Image<FixedImagePixelType, Self::FixedImageDimension>;
  using TransformMovingImageFilterType = itk::ResampleImageFilter<MovingImageType, TransformedMovingImageType>;
  using RayCastInterpolatorType = typename itk::AdvancedRayCastInterpolateImageFunction<MovingImageType, ScalarType>;
  using RayCastInterpolatorPointer = typename RayCastInterpolatorType::Pointer;
  using FixedGradientImageType = itk::Image<RealType, Self::FixedImageDimension>;
  using CastFixedImageFilterType = itk::CastImageFilter<FixedImageType, FixedGradientImageType>;
  using CastFixedImageFilterPointer = typename CastFixedImageFilterType::Pointer;
  using FixedGradientPixelType = typename FixedGradientImageType::PixelType;
  using MovedGradientImageType = itk::Image<RealType, Self::MovedImageDimension>;
  using CastMovedImageFilterType = itk::CastImageFilter<TransformedMovingImageType, MovedGradientImageType>;
  using CastMovedImageFilterPointer = typename CastMovedImageFilterType::Pointer;
  using MovedGradientPixelType = typename MovedGradientImageType::PixelType;

  /** Get the derivatives of the match measure. */
  void
  GetDerivative(const TransformParametersType & parameters, DerivativeType & derivative) const override;

  /**  Get the value for single valued optimizers. */
  MeasureType
  GetValue(const TransformParametersType & parameters) const override;

  /**  Get value and derivatives for multiple valued optimizers. */
  void
  GetValueAndDerivative(const TransformParametersType & parameters,
                        MeasureType &                   Value,
                        DerivativeType &                derivative) const override;

  void
  Initialize() override;

  /** Write gradient images to a files for debugging purposes. */
  void
  WriteGradientImagesToFiles() const;

  /** Set/Get Scales  */
  itkSetMacro(Scales, ScalesType);
  itkGetConstReferenceMacro(Scales, ScalesType);

  /** Set/Get the value of Delta used for computing derivatives by finite
   * differences in the GetDerivative() method */
  itkSetMacro(DerivativeDelta, double);
  itkGetConstReferenceMacro(DerivativeDelta, double);

protected:
  GradientDifferenceImageToImageMetric() = default;
  ~GradientDifferenceImageToImageMetric() override = default;
  void
  PrintSelf(std::ostream & os, Indent indent) const override;

  /** Compute the range of the moved image gradients. */
  void
  ComputeMovedGradientRange() const;

  /** Compute the variance and range of the moving image gradients. */
  void
  ComputeVariance() const;

  /** Compute the similarity measure using a specified subtraction factor. */
  MeasureType
  ComputeMeasure(const TransformParametersType & parameters, const double * subtractionFactor) const;

  using FixedSobelFilter = NeighborhoodOperatorImageFilter<FixedGradientImageType, FixedGradientImageType>;

  using MovedSobelFilter = NeighborhoodOperatorImageFilter<MovedGradientImageType, MovedGradientImageType>;

private:
  /** The variance of the moving image gradients. */
  mutable MovedGradientPixelType m_Variance[FixedImageDimension]{};

  /** The range of the moving image gradients. */
  mutable MovedGradientPixelType m_MinMovedGradient[MovedImageDimension]{};
  mutable MovedGradientPixelType m_MaxMovedGradient[MovedImageDimension]{};

  /** The range of the fixed image gradients. */
  mutable FixedGradientPixelType m_MinFixedGradient[FixedImageDimension]{};
  mutable FixedGradientPixelType m_MaxFixedGradient[FixedImageDimension]{};

  /** The filter for transforming the moving image. */
  typename TransformMovingImageFilterType::Pointer m_TransformMovingImageFilter{
    TransformMovingImageFilterType::New()
  };

  /** The Sobel gradients of the fixed image */
  CastFixedImageFilterPointer m_CastFixedImageFilter{ CastFixedImageFilterType::New() };

  SobelOperator<FixedGradientPixelType, Self::FixedImageDimension> m_FixedSobelOperators[FixedImageDimension]{};

  typename FixedSobelFilter::Pointer m_FixedSobelFilters[Self::FixedImageDimension]{};

  ZeroFluxNeumannBoundaryCondition<MovedGradientImageType> m_MovedBoundCond{};
  ZeroFluxNeumannBoundaryCondition<FixedGradientImageType> m_FixedBoundCond{};

  /** The Sobel gradients of the moving image */
  CastMovedImageFilterPointer m_CastMovedImageFilter{ CastMovedImageFilterType::New() };

  SobelOperator<MovedGradientPixelType, Self::MovedImageDimension> m_MovedSobelOperators[MovedImageDimension]{};

  typename MovedSobelFilter::Pointer m_MovedSobelFilters[Self::MovedImageDimension]{};

  ScalesType                  m_Scales{};
  double                      m_DerivativeDelta{ 0.001 };
  double                      m_Rescalingfactor{ 1.0 };
  CombinationTransformPointer m_CombinationTransform{ CombinationTransformType::New() };
};

} // end namespace itk

#ifndef ITK_MANUAL_INSTANTIATION
#  include "itkGradientDifferenceImageToImageMetric2.hxx"
#endif

#endif