/*=========================================================================
 *
 *  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 itkJointDomainImageToListSampleAdaptor_h
#define itkJointDomainImageToListSampleAdaptor_h

#include "itkPoint.h"
#include "itkPixelTraits.h"
#include "itkImageRegionConstIteratorWithIndex.h"
#include "itkImageRegionIterator.h"
#include "itkListSample.h"

namespace itk
{
namespace Statistics
{
/** \class ImageJointDomainTraits
 *  \brief This class provides the type definition for the measurement
 *  vector in the joint domain (range domain -- pixel values + spatial
 *  domain -- pixel's physical coordinates).
 *
 * \sa JointDomainImageToListSampleAdaptor
 * \ingroup ITKStatistics
 */
template< typename TImage >
struct ImageJointDomainTraits {
  using Self = ImageJointDomainTraits;
  using PixelTraitsType = PixelTraits< typename TImage::PixelType >;
  using RangeDomainMeasurementType = typename PixelTraitsType::ValueType;

  static constexpr unsigned int ImageDimension = TImage::ImageDimension;
  static constexpr unsigned int Dimension = TImage::ImageDimension + PixelTraitsType::Dimension;

  using CoordinateRepType = float;
  using PointType = Point< CoordinateRepType, Self::ImageDimension >;
  using JoinTraitsType = JoinTraits< RangeDomainMeasurementType, CoordinateRepType >;
  using MeasurementType = typename JoinTraitsType::ValueType;

  using MeasurementVectorType =
      FixedArray< MeasurementType, Self::Dimension >;
};  // end of ImageJointDomainTraits

/** \class JointDomainImageToListSampleAdaptor
 *  \brief This adaptor returns measurement vectors composed of an
 *  image pixel's range domain value (pixel value) and spatial domain
 *  value (pixel's physical coordiantes).
 *
 * This class is a derived class of the ListSample class. This class
 * overrides the GetMeasurementVector method. The GetMeasurementVector
 * returns a measurement vector that consist of a pixel's physical
 * coordinates and intensity value. For example, if the image
 * dimension is 3, and the pixel value is two component vector, the
 * measurement vector is a 5 component vector. The first three
 * component will be x, y, z physical coordinates (not index) and the
 * rest two component is the pixel values. The type of component is
 * float or which is determined by the ImageJointDomainTraits
 * class. When the pixel value type is double, the component value
 * type of a measurement vector is double. In other case, the
 * component value type is float becase the physical coordinate value
 * type is float. Since the measurment vector is a composition of
 * spatial domain and range domain, for many statistical analysis, we
 * want to normalize the values from both domains. For this purpose,
 * there is the SetNormalizationFactors method. With the above example
 * (5 component measurement vector), you can specify a 5 component
 * normalization factor array. With such factors, the
 * GetMeasurementVector method returns a measurement vector whose each
 * component is divided by the corresponding component of the factor array.
 *
 * \sa Sample, ListSample, ImageToListSampleAdaptor
 * \ingroup ITKStatistics
 */

template< typename TImage >
class ITK_TEMPLATE_EXPORT JointDomainImageToListSampleAdaptor:
  public ListSample< typename ImageJointDomainTraits< TImage >::MeasurementVectorType >
{
public:
  ITK_DISALLOW_COPY_AND_ASSIGN(JointDomainImageToListSampleAdaptor);

  /** Standard class type aliases */
  using Self = JointDomainImageToListSampleAdaptor;

  using Superclass = ListSample<
    typename ImageJointDomainTraits< TImage >::MeasurementVectorType >;

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

  using ImageJointDomainTraitsType = ImageJointDomainTraits< TImage >;

  using MeasurementVectorType = typename ImageJointDomainTraitsType::MeasurementVectorType;
  using MeasurementType = typename ImageJointDomainTraitsType::MeasurementType;
  using RangeDomainMeasurementType = typename ImageJointDomainTraitsType::RangeDomainMeasurementType;
  using PointType = typename ImageJointDomainTraitsType::PointType;
  using CoordinateRepType = typename ImageJointDomainTraitsType::CoordinateRepType;

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

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

  /** the number of components in a measurement vector */
  static constexpr unsigned int MeasurementVectorSize = ImageJointDomainTraitsType::Dimension;

  using MeasurementVectorSizeType = typename Superclass::MeasurementVectorSizeType;

  /** type alias for Measurement vector, measurement,
   * Instance Identifier, frequency, size, size element value */
  using AbsoluteFrequencyType = typename Superclass::AbsoluteFrequencyType;
  using TotalAbsoluteFrequencyType = typename Superclass::TotalAbsoluteFrequencyType;
  using InstanceIdentifier = typename Superclass::InstanceIdentifier;

  /** Image type alias */
  using ImageType = TImage;
  using ImageIteratorType = ImageRegionIterator< ImageType >;
  using ImageConstIteratorType = ImageRegionConstIterator< ImageType >;

  using ImagePointer = typename ImageType::Pointer;
  using ImageConstPointer = typename ImageType::ConstPointer;
  using PixelType = typename ImageType::PixelType;
  using PixelContainerConstPointer = typename ImageType::PixelContainerConstPointer;
  using ImageIndexType = typename ImageType::IndexType;
  using ImageSizeType = typename ImageType::SizeType;
  using ImageRegionType = typename ImageType::RegionType;
  using ValueType = MeasurementVectorType;

  /** Method to set the image */
  void SetImage(const TImage *image);

  /** Method to get the image */
  const TImage * GetImage() const;

  /** returns the number of measurement vectors in this container */
  InstanceIdentifier Size() const override;

  /** Get frequency */
  AbsoluteFrequencyType GetFrequency(InstanceIdentifier id) const override;

  /** Get total frequency */
  TotalAbsoluteFrequencyType GetTotalFrequency() const override;

  static constexpr unsigned int RangeDomainDimension = itk::PixelTraits< typename TImage::PixelType >::Dimension;

  using RangeDomainMeasurementVectorType = FixedArray< RangeDomainMeasurementType,
                      Self::RangeDomainDimension >;

  using InstanceIdentifierVectorType = std::vector< InstanceIdentifier >;
  using NormalizationFactorsType = FixedArray< float, Self::MeasurementVectorSize >;

  /** Sets the normalization factors */
  void SetNormalizationFactors(NormalizationFactorsType & factors);

  /** Gets the measurement vector specified by the instance
   * identifier. This method overrides superclass method. */
  const MeasurementVectorType & GetMeasurementVector(InstanceIdentifier id) const override;

  /** Method to set UsePixelContainer flag */
  itkSetMacro(UsePixelContainer, bool);
  itkGetConstMacro(UsePixelContainer, bool);
  itkBooleanMacro(UsePixelContainer);

  //  void PrintSelf(std::ostream& os, Indent indent) const override;

  /** \class ConstIterator
   * \brief Const Iterator
   * \ingroup ITKStatistics
   */
  class ConstIterator
  {
    friend class JointDomainImageToListSampleAdaptor;

public:

    ConstIterator(const JointDomainImageToListSampleAdaptor *adaptor)
    {
      *this = adaptor->Begin();
    }

    ConstIterator(const ConstIterator & iter)
    {
      m_InstanceIdentifier = iter.m_InstanceIdentifier;
      m_Adaptor            = iter.m_Adaptor;
    }

    ConstIterator & operator=(const ConstIterator & iter)
    {
      m_InstanceIdentifier = iter.m_InstanceIdentifier;
      return *this;
    }

    AbsoluteFrequencyType GetFrequency() const
    {
      return 1;
    }

    const MeasurementVectorType & GetMeasurementVector() const
    {
      m_MeasurementVectorCache = m_Adaptor->GetMeasurementVector(m_InstanceIdentifier);
      return this->m_MeasurementVectorCache;
    }

    InstanceIdentifier GetInstanceIdentifier() const
    {
      return m_InstanceIdentifier;
    }

    ConstIterator & operator++()
    {
      ++m_InstanceIdentifier;
      return *this;
    }

    bool operator!=(const ConstIterator & it)
    {
      return ( m_InstanceIdentifier != it.m_InstanceIdentifier );
    }

    bool operator==(const ConstIterator & it)
    {
      return ( m_InstanceIdentifier == it.m_InstanceIdentifier );
    }

protected:
    // This method should only be available to the ListSample class
    ConstIterator(
      const JointDomainImageToListSampleAdaptor *adaptor,
      InstanceIdentifier iid)
    {
      m_Adaptor = adaptor;
      m_InstanceIdentifier = iid;
    }

private:
    ConstIterator() = delete;
    mutable MeasurementVectorType              m_MeasurementVectorCache;
    InstanceIdentifier                         m_InstanceIdentifier;
    const JointDomainImageToListSampleAdaptor *m_Adaptor;
  };

  /** \class Iterator
   * \brief Iterator
   * \ingroup ITKStatistics
   */
  class Iterator:public ConstIterator
  {
    friend class JointDomainImageToListSampleAdaptor;

public:

    Iterator(Self *adaptor):ConstIterator(adaptor)
    {}

    Iterator(const Iterator & iter):ConstIterator(iter)
    {}

    Iterator & operator=(const Iterator & iter)
    {
      this->ConstIterator::operator=(iter);
      return *this;
    }

protected:
    Iterator(
      const JointDomainImageToListSampleAdaptor *adaptor,
      InstanceIdentifier iid):ConstIterator(adaptor, iid)
    {}

private:
    // To ensure const-correctness these method must not be in the public API.
    // The are purposly not implemented, since they should never be called.
    Iterator() = delete;
    Iterator(const Self *adaptor) = delete;
    Iterator(const ConstIterator & it) = delete;
    ConstIterator & operator=(const ConstIterator & it) = delete;

  };

  /** returns an iterator that points to the beginning of the container */
  Iterator Begin()
  {
    Iterator iter(this, 0);

    return iter;
  }

  /** returns an iterator that points to the end of the container */
  Iterator End()
  {
    Iterator iter( this, m_Image->GetPixelContainer()->Size() );

    return iter;
  }

  /** returns an iterator that points to the beginning of the container */
  ConstIterator Begin() const
  {
    ConstIterator iter(this, 0);

    return iter;
  }

  /** returns an iterator that points to the end of the container */
  ConstIterator End() const
  {
    ConstIterator iter( this, m_Image->GetPixelContainer()->Size() );

    return iter;
  }

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

private:
  NormalizationFactorsType                 m_NormalizationFactors;
  mutable MeasurementVectorType            m_TempVector;
  mutable PointType                        m_TempPoint;
  mutable ImageIndexType                   m_TempIndex;
  mutable RangeDomainMeasurementVectorType m_TempRangeVector;
  ImageConstPointer                        m_Image;
  bool                                     m_UsePixelContainer;

  PixelContainerConstPointer m_PixelContainer;
};  // end of class JointDomainImageToListSampleAdaptor
} // end of namespace Statistics
} // end of namespace itk

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

#endif
