/*=========================================================================
 *
 *  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 itkMultiResolutionImageRegistrationMethod_h
#define itkMultiResolutionImageRegistrationMethod_h

#include "itkProcessObject.h"
#include "itkImageToImageMetric.h"
#include "itkSingleValuedNonLinearOptimizer.h"
#include "itkMultiResolutionPyramidImageFilter.h"
#include "itkNumericTraits.h"
#include "itkDataObjectDecorator.h"

namespace itk
{
/** \class MultiResolutionImageRegistrationMethod
 * \brief Base class for multi-resolution image registration methods
 *
 * This class provides a generic interface for multi-resolution
 * registration using components of the registration framework.
 * See documentation for ImageRegistrationMethod for a description
 * of the registration framework components.
 *
 * The registration process is initiated by method Update().
 * The user must set the parameters of each component before calling
 * this method.
 *
 * The number of resolution level to process can be set via
 * SetNumberOfLevels(). At each resolution level, the user specified
 * registration components are used to register downsampled version of the
 * images by computing the transform parameters that will map one image onto
 * the other image.
 *
 * A user can specify schedules for the fixed and moving image using
 * SetSchedules() method.  However, SetNumberOfLevels() and SetSchedules()
 * should not be used together. An exception will be thrown if that happens.
 *
 * The downsampled images are provided by user specified
 * MultiResolutionPyramidImageFilters. User must specify the schedule
 * for each pyramid externally prior to calling Update().
 *
 * \warning If there is discrepancy between the number of level requested
 * and a pyramid schedule. The pyramid schedule will be overriden
 * with a default one.
 *
 * Before each resolution level an IterationEvent is invoked providing an
 * opportunity for a user interface to change any of the components,
 * change component parameters, or stop the registration.
 *
 * This class is templated over the fixed image type and the moving image
 * type.
 *
 * \sa ImageRegistrationMethod
 * \ingroup RegistrationFilters
 * \ingroup ITKRegistrationCommon
 */
template< typename TFixedImage, typename TMovingImage >
class ITK_TEMPLATE_EXPORT MultiResolutionImageRegistrationMethod:public ProcessObject
{
public:
  /** Standard class typedefs. */
  typedef MultiResolutionImageRegistrationMethod Self;
  typedef ProcessObject                          Superclass;
  typedef SmartPointer< Self >                   Pointer;
  typedef SmartPointer< const Self >             ConstPointer;

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

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

  /**  Type of the Fixed image. */
  typedef          TFixedImage                  FixedImageType;
  typedef typename FixedImageType::ConstPointer FixedImageConstPointer;
  typedef typename FixedImageType::RegionType   FixedImageRegionType;

  /**  Type of the Moving image. */
  typedef          TMovingImage                  MovingImageType;
  typedef typename MovingImageType::ConstPointer MovingImageConstPointer;

  /**  Type of the metric. */
  typedef ImageToImageMetric< FixedImageType, MovingImageType > MetricType;
  typedef typename MetricType::Pointer                          MetricPointer;

  /**  Type of the Transform . */
  typedef typename MetricType::TransformType TransformType;
  typedef typename TransformType::Pointer    TransformPointer;

  /** Type for the output: Using Decorator pattern for enabling
   *  the Transform to be passed in the data pipeline */
  typedef  DataObjectDecorator< TransformType >      TransformOutputType;
  typedef typename TransformOutputType::Pointer      TransformOutputPointer;
  typedef typename TransformOutputType::ConstPointer TransformOutputConstPointer;

  /**  Type of the Interpolator. */
  typedef typename MetricType::InterpolatorType InterpolatorType;
  typedef typename InterpolatorType::Pointer    InterpolatorPointer;

  /**  Type of the optimizer. */
  typedef SingleValuedNonLinearOptimizer OptimizerType;

  /** Type of the Fixed image multiresolution pyramid. */
  typedef MultiResolutionPyramidImageFilter< FixedImageType, FixedImageType > FixedImagePyramidType;
  typedef typename FixedImagePyramidType::Pointer                             FixedImagePyramidPointer;

  /** Type of pyramid schedule type */
  typedef typename FixedImagePyramidType::ScheduleType ScheduleType;

  /** Type of the moving image multiresolution pyramid. */
  typedef MultiResolutionPyramidImageFilter< MovingImageType, MovingImageType > MovingImagePyramidType;
  typedef typename MovingImagePyramidType::Pointer                              MovingImagePyramidPointer;

  /** Type of the Transformation parameters This is the same type used to
   *  represent the search space of the optimization algorithm */
  typedef  typename MetricType::TransformParametersType ParametersType;

  /** Smart Pointer type to a DataObject. */
  typedef typename DataObject::Pointer DataObjectPointer;

  /** Method to stop the registration. */
  void StopRegistration();

  /** Set/Get the Fixed image. */
  itkSetConstObjectMacro(FixedImage, FixedImageType);
  itkGetConstObjectMacro(FixedImage, FixedImageType);

  /** Set/Get the Moving image. */
  itkSetConstObjectMacro(MovingImage, MovingImageType);
  itkGetConstObjectMacro(MovingImage, MovingImageType);

  /** Set/Get the Optimizer. */
  itkSetObjectMacro(Optimizer,  OptimizerType);
  itkGetModifiableObjectMacro(Optimizer, OptimizerType);

  /** Set/Get the Metric. */
  itkSetObjectMacro(Metric, MetricType);
  itkGetModifiableObjectMacro(Metric, MetricType);

  /** Set/Get the Metric. */
  itkSetMacro(FixedImageRegion, FixedImageRegionType);
  itkGetConstReferenceMacro(FixedImageRegion, FixedImageRegionType);

  /** Set/Get the Transfrom. */
  itkSetObjectMacro(Transform, TransformType);
  itkGetModifiableObjectMacro(Transform, TransformType);

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

  /** Set/Get the Fixed image pyramid. */
  itkSetObjectMacro(FixedImagePyramid, FixedImagePyramidType);
  itkGetModifiableObjectMacro(FixedImagePyramid, FixedImagePyramidType);

  /** Set/Get the Moving image pyramid. */
  itkSetObjectMacro(MovingImagePyramid, MovingImagePyramidType);
  itkGetModifiableObjectMacro(MovingImagePyramid, MovingImagePyramidType);

  /** Set/Get the schedules . */
  void SetSchedules(const ScheduleType & fixedSchedule,
                    const ScheduleType & movingSchedule);

  itkGetConstMacro(FixedImagePyramidSchedule, ScheduleType);
  itkGetConstMacro(MovingImagePyramidSchedule, ScheduleType);

  /** Set/Get the number of multi-resolution levels. */
  void SetNumberOfLevels(SizeValueType numberOfLevels);

  itkGetConstMacro(NumberOfLevels, SizeValueType);

  /** Get the current resolution level being processed. */
  itkGetConstMacro(CurrentLevel, SizeValueType);

  /** Set/Get the initial transformation parameters. */
  itkSetMacro(InitialTransformParameters, ParametersType);
  itkGetConstReferenceMacro(InitialTransformParameters, ParametersType);

  /** Set/Get the initial transformation parameters of the next resolution
   level to be processed. The default is the last set of parameters of
   the last resolution level. */
  itkSetMacro(InitialTransformParametersOfNextLevel, ParametersType);
  itkGetConstReferenceMacro(InitialTransformParametersOfNextLevel, ParametersType);

  /** Get the last transformation parameters visited by
   * the optimizer. */
  itkGetConstReferenceMacro(LastTransformParameters, ParametersType);

  /** Returns the transform resulting from the registration process  */
  const TransformOutputType * GetOutput() const;

  /** Make a DataObject of the correct type to be used as the specified
   * output. */
  typedef ProcessObject::DataObjectPointerArraySizeType DataObjectPointerArraySizeType;
  using Superclass::MakeOutput;
  virtual DataObjectPointer MakeOutput(DataObjectPointerArraySizeType idx) ITK_OVERRIDE;

  /** Method to return the latest modified time of this object or
   * any of its cached ivars */
  virtual ModifiedTimeType GetMTime() const ITK_OVERRIDE;

#ifdef ITKV3_COMPATIBILITY
  // StartRegistration is an old API from before
  // this RegistrationMethod was a subclass of ProcessObject.
  // Historically, one could call StartRegistration() instead of
  // calling Update().  However, when called directly by the user, the
  // inputs to the RegistrationMethod may not be up to date.  This
  // may cause an unexpected behavior.
  //
  // Since we cannot eliminate StartRegistration for backward
  // compatibility reasons, we check whether StartRegistration was
  // called directly or whether Update() (which in turn called
  // StartRegistration()).
  void StartRegistration(void) { this->Update(); }
#endif

protected:
  MultiResolutionImageRegistrationMethod();
  virtual ~MultiResolutionImageRegistrationMethod() ITK_OVERRIDE {}
  virtual void PrintSelf(std::ostream & os, Indent indent) const ITK_OVERRIDE;

  /** Method invoked by the pipeline in order to trigger the computation of
   * the registration. */
  virtual void  GenerateData() ITK_OVERRIDE;

  /** Initialize by setting the interconnects between the components.
      This method is executed at every level of the pyramid with the
      values corresponding to this resolution
   */
  void Initialize();

  /** Compute the size of the fixed region for each level of the pyramid. */
  void PreparePyramids();

  /** Set the current level to be processed */
  itkSetMacro(CurrentLevel, SizeValueType);

private:
  ITK_DISALLOW_COPY_AND_ASSIGN(MultiResolutionImageRegistrationMethod);

  MetricPointer          m_Metric;
  OptimizerType::Pointer m_Optimizer;

  MovingImageConstPointer m_MovingImage;
  FixedImageConstPointer  m_FixedImage;

  TransformPointer    m_Transform;
  InterpolatorPointer m_Interpolator;

  MovingImagePyramidPointer m_MovingImagePyramid;
  FixedImagePyramidPointer  m_FixedImagePyramid;

  ParametersType m_InitialTransformParameters;
  ParametersType m_InitialTransformParametersOfNextLevel;
  ParametersType m_LastTransformParameters;

  FixedImageRegionType                m_FixedImageRegion;
  std::vector< FixedImageRegionType > m_FixedImageRegionPyramid;

  SizeValueType m_NumberOfLevels;
  SizeValueType m_CurrentLevel;

  bool m_Stop;

  ScheduleType m_FixedImagePyramidSchedule;
  ScheduleType m_MovingImagePyramidSchedule;

  bool m_ScheduleSpecified;
  bool m_NumberOfLevelsSpecified;
};
} // end namespace itk

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

#endif