/*=========================================================================
 *
 *  Copyright Insight Software Consortium
 *
 *  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.
 *
 *=========================================================================*/
#ifndef __itkInvertDisplacementFieldImageFilter_h
#define __itkInvertDisplacementFieldImageFilter_h

#include "itkImageToImageFilter.h"
#include "itkVectorInterpolateImageFunction.h"
#include "itkVectorLinearInterpolateImageFunction.h"
#include "itkSimpleFastMutexLock.h"

namespace itk
{

/**
 * \class InvertDisplacementFieldImageFilter
 *
 * \brief Iteratively estimate the inverse field of a displacement field.
 *
 * \author Nick Tustison
 * \author Brian Avants
 *
 * \ingroup ITKDisplacementField
 */

template <typename TInputImage, typename TOutputImage = TInputImage>
class InvertDisplacementFieldImageFilter
  : public ImageToImageFilter<TInputImage, TOutputImage>
{
public:
  typedef InvertDisplacementFieldImageFilter            Self;
  typedef ImageToImageFilter<TInputImage, TOutputImage> Superclass;
  typedef SmartPointer<Self>                            Pointer;
  typedef SmartPointer<const Self>                      ConstPointer;

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

  /** Extract dimension from input image. */
  itkStaticConstMacro( ImageDimension, unsigned int, TInputImage::ImageDimension );

  typedef TInputImage                          InputFieldType;
  typedef TOutputImage                         OutputFieldType;

  typedef InputFieldType                       DisplacementFieldType;
  typedef OutputFieldType                      InverseDisplacementFieldType;

  /** Image typedef support. */
  typedef typename OutputFieldType::PixelType     PixelType;
  typedef typename OutputFieldType::PixelType     VectorType;
  typedef typename OutputFieldType::RegionType    RegionType;
  typedef typename OutputFieldType::IndexType     IndexType;

  typedef typename OutputFieldType::PointType     PointType;
  typedef typename OutputFieldType::SpacingType   SpacingType;
  typedef typename OutputFieldType::PointType     OriginType;
  typedef typename OutputFieldType::SizeType      SizeType;
  typedef typename OutputFieldType::DirectionType DirectionType;

  /** Other typedef */
  typedef typename VectorType::ComponentType                        RealType;
  typedef Image<RealType, ImageDimension>                           RealImageType;
  typedef VectorInterpolateImageFunction<InputFieldType, RealType>  InterpolatorType;
  typedef VectorLinearInterpolateImageFunction <InputFieldType, RealType>
                                                                    DefaultInterpolatorType;

  /** Get the interpolator. */
  itkGetModifiableObjectMacro( Interpolator, InterpolatorType );

  /** Set the deformation field */
  void SetDisplacementField( const InputFieldType *field )
    {
    itkDebugMacro( "setting deformation field to " << field );
    if ( field != this->GetInput( 0 ) )
      {
      this->SetInput( 0, field );
      this->Modified();
      if( ! this->m_Interpolator.IsNull() )
        {
        this->m_Interpolator->SetInputImage( field );
        }
      }
    }

  /**
   * Get the deformation field.
   */
  const InputFieldType* GetDisplacementField() const
    {
    return this->GetInput( 0 );
    }

  /** Set/get the initial estimate for the inverse field (optional). */
  itkSetInputMacro( InverseFieldInitialEstimate, InverseDisplacementFieldType );
  itkGetInputMacro( InverseFieldInitialEstimate, InverseDisplacementFieldType );

  /* Set the interpolator. */
  virtual void SetInterpolator( InterpolatorType* interpolator );

  /* Set/Get the number of iterations */
  itkSetMacro( MaximumNumberOfIterations, unsigned int );
  itkGetConstMacro( MaximumNumberOfIterations, unsigned int );

  /* Set/Get the mean stopping criterion */
  itkSetMacro( MeanErrorToleranceThreshold, RealType );
  itkGetConstMacro( MeanErrorToleranceThreshold, RealType );

  /* Set/Get the max stopping criterion */
  itkSetMacro( MaxErrorToleranceThreshold, RealType );
  itkGetConstMacro( MaxErrorToleranceThreshold, RealType );

  /* Get the max norm */
  itkGetConstMacro( MaxErrorNorm, RealType );

  /* Get the mean norm */
  itkGetConstMacro( MeanErrorNorm, RealType );

/* Should we force the boundary to have zero displacement? */
  itkSetMacro( EnforceBoundaryCondition, bool );
  itkGetMacro( EnforceBoundaryCondition, bool );

protected:

  /** Constructor */
  InvertDisplacementFieldImageFilter();

  /** Deconstructor */
  virtual ~InvertDisplacementFieldImageFilter();

  /** Standard print self function **/
  void PrintSelf( std::ostream& os, Indent indent ) const;

  /** preprocessing function */
  void GenerateData();

  /** Multithreaded function which generates the output field. */
  void ThreadedGenerateData( const RegionType &, ThreadIdType );

private:
  InvertDisplacementFieldImageFilter( const Self& ); //purposely not implemented
  void operator=( const Self& );                 //purposely not implemented

  /** The interpolator. */
  typename InterpolatorType::Pointer                m_Interpolator;

  unsigned int                                      m_MaximumNumberOfIterations;

  RealType                                          m_MaxErrorToleranceThreshold;
  RealType                                          m_MeanErrorToleranceThreshold;

  // internal ivars necessary for multithreading basic operations

  typename DisplacementFieldType::Pointer           m_ComposedField;
  typename RealImageType::Pointer                   m_ScaledNormImage;

  RealType                                          m_MaxErrorNorm;
  RealType                                          m_MeanErrorNorm;
  RealType                                          m_Epsilon;
  SpacingType                                       m_DisplacementFieldSpacing;
  bool                                              m_DoThreadedEstimateInverse;
  bool                                              m_EnforceBoundaryCondition;
  SimpleFastMutexLock                               m_Mutex;

};

} // end namespace itk

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

#endif
