// Copyright (c) 2014 GeometryFactory
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
//
// $URL: https://github.com/CGAL/cgal/blob/v6.2-beta1/Surface_mesh_shortest_path/include/CGAL/Surface_mesh_shortest_path/internal/Cone_expansion_event.h $
// $Id: include/CGAL/Surface_mesh_shortest_path/internal/Cone_expansion_event.h 431cfb5357d $
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
// Author(s)     : Stephen Kiazyk

#ifndef CGAL_SURFACE_MESH_SHORTEST_PATH_INTERNAL_CONE_EXPANSION_EVENT_H
#define CGAL_SURFACE_MESH_SHORTEST_PATH_INTERNAL_CONE_EXPANSION_EVENT_H

#include <CGAL/license/Surface_mesh_shortest_path.h>

namespace CGAL {
namespace Surface_mesh_shortest_paths_3 {
namespace internal {

template<class Traits>
class Cone_tree_node;

template <class Traits>
struct Cone_expansion_event
{
public:
  typedef typename Traits::Segment_2 Segment_2;
  typedef typename Traits::FT FT;

public:
  enum Expansion_type
  {
    LEFT_CHILD,
    RIGHT_CHILD,
    PSEUDO_SOURCE
  };

public:
  Cone_tree_node<Traits>* m_parent;
  FT m_distanceEstimate;
  Expansion_type m_type;
  Segment_2 m_windowSegment;
  bool m_cancelled;

public:
  Cone_expansion_event(Cone_tree_node<Traits>* parent,
                       const FT& distanceEstimate,
                       Expansion_type type)
    : m_parent(parent)
    , m_distanceEstimate(distanceEstimate)
    , m_type(type)
    , m_cancelled(false)
  {
  }

  Cone_expansion_event(Cone_tree_node<Traits>* parent,
                       const FT& distanceEstimate,
                       Expansion_type type,
                       const Segment_2& windowSegment)
    : m_parent(parent)
    , m_distanceEstimate(distanceEstimate)
    , m_type(type)
    , m_windowSegment(windowSegment)
    , m_cancelled(false)
  {
  }
};

// Does the opposite of what you would expect in order to implement a min-priority queue
template <class Traits>
struct Cone_expansion_event_min_priority_queue_comparator
{
public:
  bool operator () (const Cone_expansion_event<Traits>* lhs,
                    const Cone_expansion_event<Traits>* rhs) const
  {
    return rhs->m_distanceEstimate < lhs->m_distanceEstimate;
  }
};

} // namespace internal
} // namespace Surface_mesh_shortest_paths_3
} // namespace CGAL

#endif // CGAL_SURFACE_MESH_SHORTEST_PATH_INTERNAL_CONE_EXPANSION_EVENT_H
