/*=========================================================================
 *
 *  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 itkMapContainer_h
#define itkMapContainer_h

#include "itkObject.h"
#include "itkObjectFactory.h"

#include <map>

namespace itk
{
/** \class MapContainer
 * \brief A wrapper of the STL "map" container.
 *
 * Define a front-end to the STL "map" container that conforms to the
 * IndexedContainerInterface.  This is a full-fledged Object, so
 * there are events, modification time, debug, and reference count
 * information.
 *
 * \tparam TElementIdentifier A type that shall be used to index the
 * container. It must have a < operator defined for ordering.
 *
 * \tparam TElement The element type stored in the container.
 *
 * \ingroup DataRepresentation
 * \ingroup ITKCommon
 */
template <typename TElementIdentifier, typename TElement>
class ITK_TEMPLATE_EXPORT MapContainer
  : public Object
  , private std::map<TElementIdentifier, TElement>
{
public:
  ITK_DISALLOW_COPY_AND_MOVE(MapContainer);

  /** Standard class type aliases. */
  using Self = MapContainer;
  using Superclass = Object;
  using Pointer = SmartPointer<Self>;
  using ConstPointer = SmartPointer<const Self>;

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

  /** Save the template parameters. */
  using ElementIdentifier = TElementIdentifier;
  using Element = TElement;

private:
  /** Quick access to the STL map type that was inherited. */
  using MapType = std::map<ElementIdentifier, Element>;
  using MapIterator = typename MapType::iterator;
  using MapConstIterator = typename MapType::const_iterator;
  using MapKeyCompareType = typename MapType::key_compare;

public:
  /** Provide pass-through constructors corresponding to all the STL
   * map constructors.  These are for internal use only since this is also
   * an Object which must be constructed through the "New()" routine. */
  MapContainer()
    : MapType()
  {}
  MapContainer(const MapKeyCompareType & comp)
    : MapType(comp)
  {}
  //  MapContainer(const Self& r):MapType(r) {}
  template <typename TInputIterator>
  MapContainer(TInputIterator first, TInputIterator last)
    : MapType(first, last)
  {}
  template <typename TInputIterator>
  MapContainer(TInputIterator first, TInputIterator last, const MapKeyCompareType & comp)
    : MapType(first, last, comp)
  {}

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

  /** This type is provided to adapt this container as an STL container */
  using STLContainerType = MapType;

  /** Cast the container to a STL container type */
  STLContainerType &
  CastToSTLContainer() noexcept
  {
    return *this;
  }

  /** Cast the container to a const STL container type */
  const STLContainerType &
  CastToSTLConstContainer() const noexcept
  {
    return *this;
  }

  using STLContainerType::begin;
  using STLContainerType::cbegin;
  using STLContainerType::end;
  using STLContainerType::cend;
  using STLContainerType::rbegin;
  using STLContainerType::crbegin;
  using STLContainerType::rend;
  using STLContainerType::crend;

  using STLContainerType::empty;
  using STLContainerType::size;
  using STLContainerType::max_size;

  using STLContainerType::operator[];

  using STLContainerType::insert;
  using STLContainerType::erase;
  using STLContainerType::swap;
  using STLContainerType::clear;

  using STLContainerType::key_comp;
  using STLContainerType::value_comp;

  using STLContainerType::find;
  using STLContainerType::count;
  using STLContainerType::lower_bound;
  using STLContainerType::upper_bound;
  using STLContainerType::equal_range;

  using STLContainerType::get_allocator;

  using typename STLContainerType::key_type;
  using typename STLContainerType::mapped_type;
  using typename STLContainerType::value_type;
  using typename STLContainerType::key_compare;
  using typename STLContainerType::value_compare;
  using typename STLContainerType::allocator_type;
  using typename STLContainerType::reference;
  using typename STLContainerType::const_reference;
  using typename STLContainerType::iterator;
  using typename STLContainerType::const_iterator;
  using typename STLContainerType::size_type;
  using typename STLContainerType::difference_type;
  using typename STLContainerType::pointer;
  using typename STLContainerType::const_pointer;
  using typename STLContainerType::reverse_iterator;
  using typename STLContainerType::const_reverse_iterator;

  /** Declare iterators to container. */
  class Iterator;
  class ConstIterator;
  friend class Iterator;
  friend class ConstIterator;

  /** \class Iterator
   * \brief The non-const iterator type for the map.
   * \ingroup ITKCommon
   */
  class Iterator
  {
  public:
    using iterator_category = typename MapIterator::iterator_category;
    using value_type = typename MapIterator::value_type;
    using difference_type = typename MapIterator::difference_type;
    using pointer = typename MapIterator::pointer;
    using reference = typename MapIterator::reference;

    Iterator() = default;
    Iterator(const MapIterator & i)
      : m_Iter(i)
    {}

    Iterator & operator*() { return *this; }
    Iterator * operator->() { return this; }
    Iterator &
    operator++()
    {
      ++m_Iter;
      return *this;
    }
    Iterator
    operator++(int)
    {
      Iterator temp(*this);
      ++m_Iter;
      return temp;
    }
    Iterator &
    operator--()
    {
      --m_Iter;
      return *this;
    }
    Iterator
    operator--(int)
    {
      Iterator temp(*this);
      --m_Iter;
      return temp;
    }

    bool
    operator==(const Iterator & r) const
    {
      return m_Iter == r.m_Iter;
    }

    ITK_UNEQUAL_OPERATOR_MEMBER_FUNCTION(Iterator);

    bool
    operator==(const ConstIterator & r) const
    {
      return m_Iter == r.m_Iter;
    }

    ITK_UNEQUAL_OPERATOR_MEMBER_FUNCTION(ConstIterator);

    /** Get the index into the MapContainer associated with this iterator.   */
    ElementIdentifier
    Index() const
    {
      return m_Iter->first;
    }

    /** Get the value at this iterator's location in the MapContainer.   */
    Element &
    Value()
    {
      return m_Iter->second;
    }

  private:
    MapIterator m_Iter;
    friend class ConstIterator;
  };

  /** \class ConstIterator
   * \brief The const iterator type for the map.
   * \ingroup ITKCommon
   */
  class ConstIterator
  {
  public:
    using iterator_category = typename MapConstIterator::iterator_category;
    using value_type = typename MapConstIterator::value_type;
    using difference_type = typename MapConstIterator::difference_type;
    using pointer = typename MapConstIterator::pointer;
    using reference = typename MapConstIterator::reference;

    ConstIterator() = default;
    ConstIterator(const MapConstIterator & ci)
      : m_Iter(ci)
    {}
    ConstIterator(const Iterator & r)
      : m_Iter(r.m_Iter)
    {}

    ConstIterator & operator*() { return *this; }
    ConstIterator * operator->() { return this; }
    ConstIterator &
    operator++()
    {
      ++m_Iter;
      return *this;
    }
    ConstIterator
    operator++(int)
    {
      ConstIterator temp(*this);
      ++m_Iter;
      return temp;
    }
    ConstIterator &
    operator--()
    {
      --m_Iter;
      return *this;
    }
    ConstIterator
    operator--(int)
    {
      ConstIterator temp(*this);
      --m_Iter;
      return temp;
    }

    bool
    operator==(const Iterator & r) const
    {
      return m_Iter == r.m_Iter;
    }

    ITK_UNEQUAL_OPERATOR_MEMBER_FUNCTION(Iterator);

    bool
    operator==(const ConstIterator & r) const
    {
      return m_Iter == r.m_Iter;
    }

    ITK_UNEQUAL_OPERATOR_MEMBER_FUNCTION(ConstIterator);

    /** Get the index into the MapContainer associated with this iterator.   */
    ElementIdentifier
    Index() const
    {
      return m_Iter->first;
    }

    /** Get the value at this iterator's location in the MapContainer.   */
    const Element &
    Value() const
    {
      return m_Iter->second;
    }

  private:
    MapConstIterator m_Iter;
    friend class Iterator;
  };

  /* Declare the public interface routines. */

  /**
   * Get a reference to the element at the given index.
   * If the index does not exist, it is created automatically.
   *
   * It is assumed that the value of the element is modified through the
   * reference.
   */
  Element & ElementAt(ElementIdentifier);

  /**
   * Get a reference to the element at the given index.
   *
   */
  const Element & ElementAt(ElementIdentifier) const;

  /**
   * Get a reference to the element at the given index.
   * If the index does not exist, it is created automatically.
   *
   * It is assumed that the value of the element is modified through the
   * reference.
   */
  Element & CreateElementAt(ElementIdentifier);

  /**
   * Get the element at the specified index.  There is no check for
   * existence performed.
   */
  Element GetElement(ElementIdentifier) const;

  /**
   * Set the given index value to the given element.  If the index doesn't
   * exist, it is automatically created.
   */
  void SetElement(ElementIdentifier, Element);

  /**
   * Set the given index value to the given element.  If the index doesn't
   * exist, it is automatically created.
   */
  void InsertElement(ElementIdentifier, Element);

  /**
   * Check if the STL map has an entry corresponding to the given index.
   * The count will be either 1 or 0.
   */
  bool IndexExists(ElementIdentifier) const;

  /**
   * If the given index doesn't exist in the map, return false.
   * Otherwise, set the element through the pointer (if it isn't null), and
   * return true.
   */
  bool
  GetElementIfIndexExists(ElementIdentifier, Element *) const;

  /**
   * The map will create an entry for a given index through the indexing
   * operator.  Whether or not it is created, it will be assigned to the
   * default element.
   */
  void CreateIndex(ElementIdentifier);

  /**
   * Delete the entry in the STL map corresponding to the given identifier.
   * If the entry does not exist, nothing happens.
   */
  void DeleteIndex(ElementIdentifier);

  /**
   * Get a begin const iterator for the map.
   */
  ConstIterator
  Begin() const;

  /**
   * Get an end const iterator for the map.
   */
  ConstIterator
  End() const;

  /**
   * Get a begin const iterator for the map.
   */
  Iterator
  Begin();

  /**
   * Get an end const iterator for the map.
   */
  Iterator
  End();

  /**
   * Get the number of elements currently stored in the map.
   */
  ElementIdentifier
  Size() const;

  /**
   * Tell the container to allocate enough memory to allow at least
   * as many elements as the size given to be stored.  This is NOT
   * guaranteed to actually allocate any memory, but is useful if the
   * implementation of the container allocates contiguous storage.
   */
  void Reserve(ElementIdentifier);

  /**
   * Tell the container to try to minimize its memory usage for storage of
   * the current number of elements.  This is NOT guaranteed to decrease
   * memory usage.
   */
  void
  Squeeze();

  /**
   * Tell the container to release any memory it may have allocated and
   * return itself to its initial state.
   */
  void
  Initialize();
};
} // end namespace itk

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

#endif