// Copyright (c) 2004  INRIA Sophia-Antipolis (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
//
// $URL: https://github.com/CGAL/cgal/blob/v6.1/Segment_Delaunay_graph_2/include/CGAL/Segment_Delaunay_graph_2/Triangulation_face_base_with_edges_2.h $
// $Id: include/CGAL/Segment_Delaunay_graph_2/Triangulation_face_base_with_edges_2.h b26b07a1242 $
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s)     : Menelaos Karavelas <mkaravel@iacm.forth.gr>



#ifndef CGAL_TRIANGULATION_FACE_BASE_WITH_EDGES_2_H
#define CGAL_TRIANGULATION_FACE_BASE_WITH_EDGES_2_H

#include <CGAL/license/Segment_Delaunay_graph_2.h>

#include <CGAL/Triangulation_ds_face_base_2.h>

namespace CGAL {


template < class Gt,
           class Fb = Triangulation_ds_face_base_2<> >
class Triangulation_face_base_with_edges_2
  : public Fb
{
protected:
  // local types
  typedef typename Fb::Triangulation_data_structure    TDS;

public:
  // TYPES
  //------
  typedef Gt                           Geom_traits;
  typedef Fb                           Base;
  typedef TDS                          Triangulation_data_structure_2;
  typedef typename TDS::Vertex_handle  Vertex_handle;
  typedef typename TDS::Face_handle    Face_handle;
  typedef typename TDS::Edge           Edge;


  template <typename TDS2>
  struct Rebind_TDS {
    typedef typename Fb::template Rebind_TDS<TDS2>::Other  Vb2;
    typedef Triangulation_face_base_with_edges_2<Gt,Vb2>   Other;
  };


public:
  // CREATION
  //---------
  Triangulation_face_base_with_edges_2() : Base()
  { init(); }

  Triangulation_face_base_with_edges_2(Vertex_handle v0,
                                       Vertex_handle v1,
                                       Vertex_handle v2)
    : Base(v0,v1,v2)
  { init(); }

  Triangulation_face_base_with_edges_2(Vertex_handle v0,
                                       Vertex_handle v1,
                                       Vertex_handle v2,
                                       Face_handle n0,
                                       Face_handle n1,
                                       Face_handle n2)
    : Base(v0,v1,v2,n0,n1,n2)
  { init(); }

public:
  // OPERATIONS
  //-----------
  bool is_in_list(int i) const
  {
    CGAL_precondition( i >= 0 && i <= 2 );
    return ( next_edge_in_list[i].first != Face_handle() ||
             prev_edge_in_list[i].first != Face_handle() );
  }

  void set_next(int i, const Edge& next)
  {
    CGAL_precondition( i >= 0 && i <= 2 );
    CGAL_precondition( next.first == Face_handle() ||
                       (next.second >= 0 && next.second <= 2) );
    next_edge_in_list[i] = next;
  }

  void set_previous(int i, const Edge&  prev)
  {
    CGAL_precondition( i >= 0 && i <= 2 );
    CGAL_precondition( prev.first == Face_handle() ||
                       (prev.second >= 0 && prev.second <= 2) );
    prev_edge_in_list[i] = prev;
  }

  Edge next(int i) const
  {
    CGAL_precondition( i >= 0 && i <= 2 );
    return next_edge_in_list[i];
  }

  Edge previous(int i) const
  {
    CGAL_precondition( i >= 0 && i <= 2 );
    return prev_edge_in_list[i];
  }


protected:
  // class variables
  Edge next_edge_in_list[3];
  Edge prev_edge_in_list[3];

protected:

  static int sentinel_index() { return -1; }

  static Edge sentinel_edge() {
    return Edge(Face_handle(), sentinel_index());
  }

  // initialization of in-place list pointers
  void init() {
    for (int i = 0; i < 3; i++) {
      next_edge_in_list[i] = sentinel_edge();
      prev_edge_in_list[i] = sentinel_edge();
    }
  }

};




} //namespace CGAL

#endif // CGAL_TRIANGULATION_FACE_BASE_WITH_EDGES_2_H

