/*=========================================================================
 *
 *  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 itkCorrespondenceDataStructureIterator_h
#define itkCorrespondenceDataStructureIterator_h

#include "itkMacro.h"

namespace itk
{
/** \class CorrespondenceDataStructureIterator
 * \brief An iterator designed to easily traverse an
 *        CorrespondenceDataStructure.
 *
 * \ingroup ITKCommon
 */
template <typename TStructureType>
class ITK_TEMPLATE_EXPORT CorrespondenceDataStructureIterator
{
public:
  /** Standard class type aliases. */
  using Self = CorrespondenceDataStructureIterator;

  /** Get the dimension (size) of the index. */
  static unsigned int
  GetIteratorDimension()
  {
    return TStructureType::dim;
  }

  /** Is the iterator at the end of the region? */
  bool
  IsAtEnd() const;

  /** Walk forward one index. (prefix) */
  void
  operator++()
  {
    GoToNext();
  }

  /** Walk forward one index. (postfix) */
  void
  operator++(int)
  {
    GoToNext();
  }

  /** Goes to the next corresponding node clique in the structure,
   *  moving on to the next base node clique if necessary. */
  void
  GoToNext();

  /** Goes to the next base node clique. */
  void
  GoToNextBaseGroup();

  /** Resets the iterator. */
  void
  Reset();

  /** Constructor */
  CorrespondenceDataStructureIterator(TStructureType * StructurePtr);

  /** Destructor */
  virtual ~CorrespondenceDataStructureIterator() = default;

  using CorrespondingListType = typename TStructureType::CorrespondingListType;
  using ItemType = typename TStructureType::ItemType;
  using SecondaryNodeListType = typename TStructureType::SecondaryNodeListType;
  using NodeListType = typename TStructureType::NodeListType;

  using CorrespondingListIterator = typename CorrespondingListType::iterator;
  using SecondaryNodeListIterator = typename SecondaryNodeListType::iterator;
  using NodeListIterator = typename NodeListType::iterator;

  /** Get m_CorrespondingListPointer.  */
  CorrespondingListType *
  GetCorrespondingListPointer()
  {
    return m_CorrespondingListPointer;
  }

  CorrespondingListIterator m_CorrespondingListIterator{};
  SecondaryNodeListIterator m_SecondaryListIterator{};

  typename TStructureType::NodeListType::iterator m_NodeListIterator{};

protected:
  /** Is the iterator at the end of its walk? */
  bool                    m_IsAtEnd{};
  TStructureType *        m_Structure{};
  ItemType *              m_CorrespondingNodePointer{};
  CorrespondingListType * m_CorrespondingListPointer{};
  SecondaryNodeListType * m_SecondaryListPointer{};
  NodeListType *          m_NodeListPointer{};
};
} // end namespace itk

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

#endif
