/*=========================================================================
 *
 *  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 itkFastMarchingNumberOfElementsStoppingCriterion_h
#define itkFastMarchingNumberOfElementsStoppingCriterion_h

#include "itkFastMarchingStoppingCriterionBase.h"
#include "itkObjectFactory.h"

namespace itk
{
/**
 * \class FastMarchingNumberOfElementsStoppingCriterion
 * \brief Stopping Criterion is verified when Current Number of Elements is equal
 * to or greater than the provided Target Number Of Elements.
 *
 * \note For itk::Image, one element is one pixel. So the number of elements is directly
 * linked to the physical size of the object, i.e.
 * \f$ PhysicalSize = TargetNumberOfElements \cdot \prod_{i=1}{dim} Spacing_{i} \f$
 *
 * \note For itk::QuadEdgeMesh, one element is one vertex.
 *
 * \ingroup ITKFastMarching
 */
template< typename TInput, typename TOutput >
class FastMarchingNumberOfElementsStoppingCriterion :
public FastMarchingStoppingCriterionBase< TInput, TOutput >
{
public:
  ITK_DISALLOW_COPY_AND_ASSIGN(FastMarchingNumberOfElementsStoppingCriterion);

  using Self = FastMarchingNumberOfElementsStoppingCriterion;
  using Superclass = FastMarchingStoppingCriterionBase< TInput, TOutput >;
  using Pointer = SmartPointer< Self >;
  using ConstPointer = SmartPointer< const Self >;

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

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

  using OutputPixelType = typename Superclass::OutputPixelType;
  using NodeType = typename Superclass::NodeType;

  /** Get/set the threshold used by the stopping criteria. */
  itkSetMacro( TargetNumberOfElements, IdentifierType );
  itkGetMacro( TargetNumberOfElements, IdentifierType );

  bool IsSatisfied() const override
  {
    return ( this->m_CurrentNumberOfElements >= this->m_TargetNumberOfElements );
  }

  std::string GetDescription() const override
  {
    return "Current Number of Elements >= Target Number of Elements";
  }

protected:
  FastMarchingNumberOfElementsStoppingCriterion() : Superclass(),
    m_CurrentNumberOfElements( NumericTraits< IdentifierType >::ZeroValue() ),
    m_TargetNumberOfElements( NumericTraits< IdentifierType >::ZeroValue() )
  {}

  ~FastMarchingNumberOfElementsStoppingCriterion() override = default;

  IdentifierType  m_CurrentNumberOfElements;
  IdentifierType  m_TargetNumberOfElements;

  void SetCurrentNode( const NodeType& ) override
  {
    ++this->m_CurrentNumberOfElements;
  }

  void Reset() override
  {
    this->m_CurrentNumberOfElements = NumericTraits< IdentifierType >::ZeroValue();
  }
};

}
#endif // itkFastMarchingNumberOfElementsStoppingCriterion_h
