/*=========================================================================

  Program:   Advanced Normalization Tools

  Copyright (c) ConsortiumOfANTS. All rights reserved.
  See accompanying COPYING.txt or
  https://github.com/stnava/ANTs/blob/master/ANTSCopyright.txt
  for details.

  This software is distributed WITHOUT ANY WARRANTY; without even
  the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
  PURPOSE.  See the above copyright notices for more information.

=========================================================================*/
#ifndef __antsListSampleFunction_h
#define __antsListSampleFunction_h

#include "itkFunctionBase.h"

#include "itkArray.h"

namespace itk
{
namespace ants
{
namespace Statistics
{
/** \class ListSampleFunction
 * \brief Evaluates a function of an image at specified position.
 *
 * ListSampleFunction is a baseclass for all objects that evaluates
 * a function of a list sample at a measurement
 * This class is templated over the input list type, the type
 * of the function output and the coordinate representation type
 * (e.g. float or double).
 *
 * The input list sample is set via method SetInputListSample().
 * The methods Evaluate() evaluates the function at a measurement vector.
 *
 * \ingroup ListSampleFunctions
 */
template <typename TInputListSample, typename TOutput, typename TCoordRep = float>
class ListSampleFunction : public FunctionBase<typename TInputListSample::MeasurementVectorType, TOutput>
{
public:
  /** Standard class typedefs. */
  typedef ListSampleFunction                      Self;
  typedef FunctionBase<TInputListSample, TOutput> Superclass;
  typedef SmartPointer<Self>                      Pointer;
  typedef SmartPointer<const Self>                ConstPointer;

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

  /** InputListSampleType typedef support. */
  typedef TInputListSample InputListSampleType;

  /** Array typedef for weights */
  typedef Array<double> ListSampleWeightArrayType;

  /** InputPixel typedef support */
  typedef typename InputListSampleType::MeasurementVectorType InputMeasurementVectorType;
  typedef typename InputListSampleType::MeasurementType       InputMeasurementType;

  /** OutputType typedef support. */
  typedef TOutput OutputType;

  /** CoordRepType typedef support. */
  typedef TCoordRep CoordRepType;

  /** Set the input point set.
   * \warning this method caches BufferedRegion information.
   * If the BufferedRegion has changed, user must call
   * SetInputListSample again to update cached values. */
  virtual void
  SetInputListSample(const InputListSampleType * ptr)
  {
    this->SetIndexedInputListSample(0, ptr);
  }

  virtual void
  SetIndexedInputListSample(const unsigned int d, const InputListSampleType * ptr);

  /** Sets the weights using an array */
  virtual void
  SetListSampleWeights(ListSampleWeightArrayType * array)
  {
    this->SetListSampleWeights(0, array);
  }

  virtual void
  SetListSampleWeights(const unsigned int, ListSampleWeightArrayType *);

  /** Get the input image. */
  virtual const InputListSampleType *
  GetInputListSample(const unsigned int idx = 0) const;

  /** Clear the input list sample to free memory */
  virtual void
  ClearInputListSample(const unsigned int idx = 0)
  {
    this->SetIndexedInputListSample(idx, nullptr);
  }

  /** Gets the weights array */
  virtual ListSampleWeightArrayType *
  GetListSampleWeights(const unsigned int idx = 0);

  /** Evaluate the function at specified Point position.
   * Subclasses must provide this method. */
  TOutput
  Evaluate(const InputMeasurementVectorType & measurement) const override = 0;

protected:
  ListSampleFunction();
  ~ListSampleFunction() override = default;

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

  /** Const pointer to the input image. */
  std::vector<typename InputListSampleType::ConstPointer> m_ListSamples;
  std::vector<ListSampleWeightArrayType *>                m_ListSampleWeights;

private:
  ListSampleFunction(const Self &) = delete;
  void
  operator=(const Self &) = delete;
};
} // end of namespace Statistics
} // end of namespace ants
} // end of namespace itk

// Define instantiation macro for this template.
#define ITK_TEMPLATE_ListSampleFunction(_, EXPORT, x, y)              \
  namespace itk                                                       \
  {                                                                   \
  _(3(class EXPORT ListSampleFunction<ITK_TEMPLATE_3 x>))             \
  namespace Templates                                                 \
  {                                                                   \
  typedef ListSampleFunction<ITK_TEMPLATE_3 x> ListSampleFunction##y; \
  }                                                                   \
  }

#if ITK_TEMPLATE_EXPLICIT
#  include "Templates/antsListSampleFunction+-.h"
#endif

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

#endif
