/*
 * Copyright (C) 2005-2019 Centre National d'Etudes Spatiales (CNES)
 *
 * This file is part of Orfeo Toolbox
 *
 *     https://www.orfeo-toolbox.org/
 *
 * 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
 *
 * 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 otbShiftScaleImageAdaptor_h
#define otbShiftScaleImageAdaptor_h

#include "vnl/vnl_math.h"
#include "itkImageAdaptor.h"

namespace otb
{

namespace Accessor
{
/** \class ShiftScalePixelAccessor
 * \brief Apply a shift scale operation to the value
 *
 * ShiftScalePixelAccessor shifts the input pixel by Shift
 * and then scales the pixel by Scale. All computations
 * are performed in the precision of the input pixel's RealType
 *
 * ShiftScalePixelAccessor is templated over an internal type and an
 * external type representation. This class cast the input
 * applies the function to it and cast the result according
 * to the types defined as template parameters
 *
 * \ingroup ImageAdaptors
 *
 * \ingroup OTBImageManipulation
 */
template <class TPixelType, class TExternalType>
class ITK_EXPORT ShiftScalePixelAccessor
{
public:
  /** External typedef. It defines the external aspect
   * that this class will exhibit. */
  typedef TExternalType ExternalType;

  /** Internal typedef. It defines the internal real
   * representation of data. */
  typedef typename itk::NumericTraits<TPixelType>::RealType InternalType;

  InternalType GetShift() const
  {
    return m_Shift;
  }
  void SetShift(InternalType value)
  {
    m_Shift = value;
  }

  InternalType GetScale() const
  {
    return m_Scale;
  }
  void SetScale(InternalType value)
  {
    m_Scale = value;
  }

  inline void Set(InternalType& output, const ExternalType& input)
  {
    output = static_cast<InternalType>(m_Scale * (static_cast<InternalType>(input) + m_Shift));
  }

  inline const ExternalType Get(const InternalType& input) const
  {
    return static_cast<ExternalType>(m_Scale * (static_cast<InternalType>(input) + m_Shift));
  }

private:
  InternalType m_Shift;
  InternalType m_Scale;
};

} // end namespace Accessor

/** \class ShiftScaleImageAdaptor
 * \brief Presents an image as being composed of the shift scale operation of its pixels
 *
 * Additional casting is performed according to the input and output image
 * types following C++ default casting rules.
 *
 * \ingroup ImageAdaptors
 *
 * \ingroup OTBImageManipulation
 */
template <class TImage, class TOutputPixelType>
class ITK_EXPORT ShiftScaleImageAdaptor : public itk::ImageAdaptor<TImage, Accessor::ShiftScalePixelAccessor<typename TImage::PixelType, TOutputPixelType>>
{
public:
  /** Standard class typedefs. */
  typedef ShiftScaleImageAdaptor Self;
  typedef itk::ImageAdaptor<TImage, Accessor::ShiftScalePixelAccessor<typename TImage::PixelType, TOutputPixelType>> Superclass;
  typedef itk::SmartPointer<Self>        Pointer;
  typedef itk::SmartPointer<const Self>  ConstPointer;
  typedef typename TImage::PixelType     InternalType;
  typedef typename Superclass::IndexType IndexType;
  typedef typename Accessor::ShiftScalePixelAccessor<typename TImage::PixelType, TOutputPixelType> AccessorType;
  typedef typename AccessorType::ExternalType PixelType;

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

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

  typename TImage::PixelType GetShift() const
  {
    itkDebugMacro("returning "
                  << " m_Shift of " << this->GetPixelAccessor().GetShift());
    return this->GetPixelAccessor().GetShift();
  }

  virtual void SetShift(typename TImage::PixelType value)
  {
    itkDebugMacro("setting m_Shift to " << value);
    if (this->GetPixelAccessor().GetShift() != value)
    {
      this->GetPixelAccessor().SetShift(value);
      this->Modified();
    }
  }

  typename TImage::PixelType GetScale() const
  {
    itkDebugMacro("returning "
                  << " m_Scale of " << this->GetPixelAccessor().GetScale());
    return this->GetPixelAccessor().GetScale();
  }

  virtual void SetScale(typename TImage::PixelType value)
  {
    itkDebugMacro("setting m_Scale to " << value);
    if (this->GetPixelAccessor().GetScale() != value)
    {
      this->GetPixelAccessor().SetScale(value);
      this->Modified();
    }
  }

protected:
  ShiftScaleImageAdaptor()
  {
  }
  ~ShiftScaleImageAdaptor() override
  {
  }

private:
  ShiftScaleImageAdaptor(const Self&) = delete;
  void operator=(const Self&) = delete;
};

} // end namespace otb

#endif