// Included by octree.h

/**\var  template<typename T_, int d_=3, class A_> typedef octree<T_,d_,A_>*
 *octree_node<T_,d_,A_>::octree_pointer \brief Shorthand for a pointer to an octree.
 */

/**\var  template<typename T_, int d_=3, class A_> typedef octree_node<T_,d_,A_>*
 *octree_node<T_,d_,A_>::octree_node_pointer \brief Shorthand for a pointer to an octree node (this
 *class).
 */

/**\var  template<typename T_, int d_=3, class A_> typedef const octree_node<T_,d_,A_>*
 *octree_node<T_,d_,A_>::const_octree_node_pointer \brief Shorthand for a pointer to an immutable
 *octree node (this class).
 */

/**\var  template<typename T_, int d_=3, class A_> typedef octree_node<T_,d_,A_>&
 *octree_node<T_,d_,A_>::octree_node_reference \brief Shorthand for a reference to an octree node
 *(this class).
 */

/**\var  template<typename T_, int d_=3, class A_> typedef const octree_node<T_,d_,A_>&
 *octree_node<T_,d_,A_>::const_octree_node_reference \brief Shorthand for a reference to an
 *immutable octree node (this class).
 */

/**\var  template<typename T_, int d_=3, class A_> typedef T_ octree_node<T_,d_,A_>::value_type
 *\brief Shorthand for application data.
 */

/**\var  template<typename T_, int d_=3, class A_> typedef T_* octree_node<T_,d_,A_>::pointer
 *\brief Shorthand for a pointer to application data.
 */

/**\var  template<typename T_, int d_=3, class A_> typedef T_& octree_node<T_,d_,A_>::reference
 *\brief Shorthand for a reference to application data.
 */

/**\var  template<typename T_, int d_=3, class A_> typedef const T_*
 *octree_node<T_,d_,A_>::const_pointer \brief Shorthand for a pointer to immutable application data.
 */

/**\var  template<typename T_, int d_=3, class A_> typedef const T_&
 *octree_node<T_,d_,A_>::const_reference \brief Shorthand for a reference to immutable application
 *data.
 */

/**\var  template<typename T_, int d_=3, class A_> octree_node_pointer
 *octree_node<T_,d_,A_>::_M_parent \brief The parent octree node that owns this node.
 */

/**\var  template<typename T_, int d_=3, class A_> octree_node_pointer
 *octree_node<T_,d_,A_>::_M_children \brief A pointer to an array of \f$2^{\mathrm{\texttt{\d_}}}\f$
 *children, or NULL if the node is a leaf node.
 */

/**\var  template<typename T_, int d_=3, class A_> value_type octree_node<T_,d_,A_>::_M_data
 *\brief Application-specific data.
 */

/**\brief Default constructor.
 *
 * The node will be a leaf node (i.e. have no children).
 * The node's application-specific data will not be initialized by this constructor.
 * The node will not have an owning octree -- which means that this constructor should never be used
 * except possibly for serialization.
 */
template <typename T_, int d_, typename A_>
octree_node<T_, d_, A_>::octree_node()
{
  this->_M_parent = nullptr;
  this->_M_children = nullptr;
}

/**\brief Root node constructor.
 *
 * The node will be a leaf node (i.e. have no children).
 * The node's application-specific data will be initialized to the value you pass.
 * This form of the constructor is used by the octree to create the root node of the tree.
 *
 * @param[in] parent The octree node owning this node
 * @param[in] data   Application-specific data to copy and store at this node.
 */
template <typename T_, int d_, typename A_>
octree_node<T_, d_, A_>::octree_node(octree_node_pointer parent, const value_type& data)
  : _M_parent(parent)
  , _M_data(data)
{
  this->_M_children = nullptr;
}

/**\brief Destructor.
 */
template <typename T_, int d_, typename A_>
octree_node<T_, d_, A_>::~octree_node()
{
  if (this->_M_children)
    this->remove_children();
}

/**\fn template< typename T_, int d_, typename A_ > bool octree_node<T_,d_,A_>::is_leaf_node()
 *\brief Test whether the node has any children.
 *
 * @retval True if the node is a leaf node (no children), false if the node has children.
 */

/**\fn template< typename T_, int d_, typename A_ > int octree_node<T_,d_,A_>::num_children()
 *\brief Return the number of direct children of this node.
 *
 * For leaf nodes, this returns 0. Otherwise it will return \f$2^{\mathrm{\texttt{\d_}}}\f$.
 *
 * @retval The number of children.
 */

/**\brief Create children of this node if they did not already exist.
 *
 * Note that the application-specific data is not initialized by this call; you are responsible for
 * any initialization. Use this variant when the default constructor of your application-specific
 * data does some meaningful initialization.
 * @retval     True if children were created, false if they already existed.
 */
template <typename T_, int d_, typename A_>
bool octree_node<T_, d_, A_>::add_children()
{
  if (this->_M_children)
  {
    return false;
  }
  this->_M_children = new octree_node<T_, d_, A_>[1 << d_];
  for (int i = 0; i < (1 << d_); ++i)
  {
    octree_node_pointer child = this->_M_children + i;
    child->_M_parent = this;
  }
  return true;
}

/**\brief Create children of this node if they did not already exist.
 *
 * Note that the application-specific data is not initialized by this call; you are responsible for
 * any initialization. Use this variant when you need to provide a default value for the children's
 * application-specific data. This is useful when the application-specific data is a pointer or some
 * other basic type that does not normally get initialized.
 * @retval     True if children were created, false if they already existed.
 */
template <typename T_, int d_, typename A_>
bool octree_node<T_, d_, A_>::add_children(const T_& child_initializer)
{
  if (this->_M_children)
  {
    return false;
  }
  this->_M_children = new octree_node<T_, d_, A_>[1 << d_];
  for (int i = 0; i < (1 << d_); ++i)
  {
    octree_node_pointer child = this->_M_children + i;
    child->_M_parent = this->_M_parent;
    child->_M_data = child_initializer;
  }
  return true;
}

/**\brief Remove any child nodes from this node (if any existed to begin with).
 *
 * @retval     True if children were removed, false if the node had none to begin with.
 */
template <typename T_, int d_, typename A_>
bool octree_node<T_, d_, A_>::remove_children()
{
  if (this->_M_children)
  {
    int i;
    for (i = 0; i < (1 << d_); ++i)
    {
      this->_M_children[i]._M_parent =
        nullptr; // prevent updates from propagating up the portion of the tree being deleted.
      this->_M_children[i].remove_children();
    }
    delete[] this->_M_children;
    this->_M_children = nullptr;
    return true;
  }
  return false;
}

/**\fn template< typename T_, int d_, typename A_ > reference octree_node<T_,d_,A_>::value()
 *\brief Retrieve the application-specific data stored at a node.
 *
 * @retval A reference to the application-specific data.
 */

/**\fn template< typename T_, int d_, typename A_ > const reference octree_node<T_,d_,A_>::value()
 *const \brief Retrieve a reference to immutable application-specific data stored at a node.
 *
 * @retval A reference to immutable application-specific data.
 */

/**\brief Return a (const) reference to a child node.
 *
 * @param child An integer in \f$[0,2^{\mathrm{\texttt{\d_}}}]\f$ indicating which child node to
 * return.
 */
template <typename T_, int d_, typename A_>
const octree_node<T_, d_, A_>& octree_node<T_, d_, A_>::operator[](int child) const
{
  if (!this->_M_children)
  {
    throw std::domain_error("Attempt to access children of an octree leaf node.");
  }
  return this->_M_chilren[child];
}

/**\brief Return a reference to a child node.
 *
 * @param child An integer in \f$[0,2^{\mathrm{\texttt{\d_}}}]\f$ indicating which child node to
 * return.
 */
template <typename T_, int d_, typename A_>
octree_node<T_, d_, A_>& octree_node<T_, d_, A_>::operator[](int child)
{
  if (!this->_M_children)
  {
    throw std::domain_error("Attempt to access children of an octree leaf node.");
  }
  return this->_M_children[child];
}

/**\fn  template<typename T_, int d_=3, class A_> reference octree_node<T_,d_,A_>::operator * ()
 *\brief Provide access to the application-specific data.
 */

/**\fn  template<typename T_, int d_=3, class A_> const_reference octree_node<T_,d_,A_>::operator *
 *() const \brief Provide read-only access to the application-specific data.
 */