/*=========================================================================
 *
 *  Copyright NumFOCUS
 *
 *  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
 *
 *         https://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 itkImageShapeModelEstimatorBase_h
#define itkImageShapeModelEstimatorBase_h

#include "itkImageToImageFilter.h"

namespace itk
{
/** \class ImageShapeModelEstimatorBase
 * \brief Base class for statistical shape model estimation.
 *
 * itkImageShapeModelEstimatorBase is the base class for the
 * ImageShapeModelEstimator objects. It provides the basic function
 * definitions that are inherent to a ImageShapeModelEstimator objects.
 *
 * This is the Superclass for the ImageShapeModelEstimator
 * framework. This is an abstract class defining an interface for all
 * such objects available through the ImageShapeModelEstimator
 * framework in the ITK toolkit.
 *
 * The basic functionality of the ImageShapeModelEstimator framework
 * base class is to generate the ShapeModels. It requires input image
 * to be provided by the user. EstimateShapeModels() is a pure virtual
 * function making this an abstract class. Classes deriving from this
 * class are required to implement the EstimateShapeModels function.
 *
 *  \ingroup ImageFeatureExtraction
 * \ingroup ITKImageStatistics
 */

template <typename TInputImage, typename TOutputImage = Image<double, TInputImage::ImageDimension>>
class ITK_TEMPLATE_EXPORT ImageShapeModelEstimatorBase : public ImageToImageFilter<TInputImage, TOutputImage>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(ImageShapeModelEstimatorBase);

  /** Standard class type aliases. */
  using Self = ImageShapeModelEstimatorBase;
  using Superclass = ImageToImageFilter<TInputImage, TOutputImage>;
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;

  /** \see LightObject::GetNameOfClass() */
  itkOverrideGetNameOfClassMacro(ImageShapeModelEstimatorBase);

  /** Type definitions for the training image. */
  using InputImageType = TInputImage;
  using InputImagePointer = typename TInputImage::Pointer;

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

  void
  GenerateData() override;

private:
  /** The core virtual function to perform ShapeModeling of the input data */
  virtual void
  EstimateShapeModels() = 0;

  /** Container for holding the training image. */
  InputImagePointer m_InputImage{};

}; // class ImageShapeModelEstimator
} // namespace itk

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

#endif
