// Copyright (c) 1999-2005  INRIA Sophia-Antipolis (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org); you may redistribute it under
// the terms of the Q Public License version 1.0.
// See the file LICENSE.QPL distributed with CGAL.
//
// Licensees holding a valid commercial license may use this file in
// accordance with the commercial license agreement provided with the software.
//
// This file is provided AS IS with NO WARRANTY OF ANY KIND, INCLUDING THE
// WARRANTY OF DESIGN, MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
//
// $URL: svn+ssh://scm.gforge.inria.fr/svn/cgal/branches/CGAL-3.6-branch/Triangulation_3/include/CGAL/Triangulation_ds_cell_base_3.h $
// $Id: Triangulation_ds_cell_base_3.h 51517 2009-08-26 12:52:38Z spion $
//
// Author(s)     : Monique Teillaud <Monique.Teillaud@sophia.inria.fr>
//                 Sylvain Pion

// cell of a triangulation data structure of any dimension <=3

#ifndef CGAL_TRIANGULATION_DS_CELL_BASE_3_H
#define CGAL_TRIANGULATION_DS_CELL_BASE_3_H

#include <CGAL/basic.h>
#include <CGAL/triangulation_assertions.h>
#include <CGAL/internal/Dummy_tds_3.h>

CGAL_BEGIN_NAMESPACE

template < typename TDS = void >
class Triangulation_ds_cell_base_3
{
public:
  typedef TDS                          Triangulation_data_structure;
  typedef typename TDS::Vertex_handle  Vertex_handle;
  typedef typename TDS::Cell_handle    Cell_handle;
  typedef typename TDS::Vertex         Vertex;
  typedef typename TDS::Cell           Cell;
  typedef typename TDS::Cell_data      TDS_data;

  template <typename TDS2>
  struct Rebind_TDS { typedef Triangulation_ds_cell_base_3<TDS2> Other; };

  Triangulation_ds_cell_base_3() {}

  Triangulation_ds_cell_base_3(Vertex_handle v0, Vertex_handle v1,
                               Vertex_handle v2, Vertex_handle v3)
#ifndef CGAL_CFG_ARRAY_MEMBER_INITIALIZATION_BUG
    : V((Vertex_handle[4]) {v0, v1, v2, v3} ) {}
#else
  { set_vertices(v0, v1, v2, v3); }
#endif

  Triangulation_ds_cell_base_3(Vertex_handle v0, Vertex_handle v1,
                               Vertex_handle v2, Vertex_handle v3,
                               Cell_handle   n0, Cell_handle   n1,
                               Cell_handle   n2, Cell_handle   n3)
#ifndef CGAL_CFG_ARRAY_MEMBER_INITIALIZATION_BUG
    : N((Cell_handle[4]) {n0, n1, n2, n3}), V((Vertex_handle[4]) {v0, v1, v2, v3} ) {}
#else
  {
    set_neighbors(n0, n1, n2, n3);
    set_vertices(v0, v1, v2, v3);
  }
#endif

  // ACCESS FUNCTIONS

  Vertex_handle vertex(int i) const
  {
    CGAL_triangulation_precondition( i >= 0 && i <= 3 );
    return V[i];
  }

  bool has_vertex(Vertex_handle v) const
  {
    return (V[0] == v) || (V[1] == v) || (V[2]== v) || (V[3]== v);
  }

  bool has_vertex(Vertex_handle v, int & i) const
    {
      if (v == V[0]) { i = 0; return true; }
      if (v == V[1]) { i = 1; return true; }
      if (v == V[2]) { i = 2; return true; }
      if (v == V[3]) { i = 3; return true; }
      return false;
    }

  int index(Vertex_handle v) const
  {
    if (v == V[0]) { return 0; }
    if (v == V[1]) { return 1; }
    if (v == V[2]) { return 2; }
    CGAL_triangulation_assertion( v == V[3] );
    return 3;
  }

  Cell_handle neighbor(int i) const
  {
    CGAL_triangulation_precondition( i >= 0 && i <= 3);
    return N[i];
  }

  bool has_neighbor(Cell_handle n) const
  {
    return (N[0] == n) || (N[1] == n) || (N[2] == n) || (N[3] == n);
  }

  bool has_neighbor(Cell_handle n, int & i) const
  {
    if(n == N[0]){ i = 0; return true; }
    if(n == N[1]){ i = 1; return true; }
    if(n == N[2]){ i = 2; return true; }
    if(n == N[3]){ i = 3; return true; }
    return false;
  }

  int index(Cell_handle n) const
  {
    if (n == N[0]) return 0;
    if (n == N[1]) return 1;
    if (n == N[2]) return 2;
    CGAL_triangulation_assertion( n == N[3] );
    return 3;
  }

  // SETTING

  void set_vertex(int i, Vertex_handle v)
  {
    CGAL_triangulation_precondition( i >= 0 && i <= 3);
    V[i] = v;
  }

  void set_neighbor(int i, Cell_handle n)
  {
    CGAL_triangulation_precondition( i >= 0 && i <= 3);
    CGAL_triangulation_precondition( this != &*n );
    N[i] = n;
  }

  void set_vertices()
  {
    V[0] = V[1] = V[2] = V[3] = Vertex_handle();
  }

  void set_vertices(Vertex_handle v0, Vertex_handle v1,
                    Vertex_handle v2, Vertex_handle v3)
  {
    V[0] = v0;
    V[1] = v1;
    V[2] = v2;
    V[3] = v3;
  }

  void set_neighbors()
  {
    N[0] = N[1] = N[2] = N[3] = Cell_handle();
  }

  void set_neighbors(Cell_handle n0, Cell_handle n1,
                     Cell_handle n2, Cell_handle n3)
  {
    CGAL_triangulation_precondition( this != &*n0 );
    CGAL_triangulation_precondition( this != &*n1 );
    CGAL_triangulation_precondition( this != &*n2 );
    CGAL_triangulation_precondition( this != &*n3 );
    N[0] = n0;
    N[1] = n1;
    N[2] = n2;
    N[3] = n3;
  }

  // CHECKING

  // the following trivial is_valid allows
  // the user of derived cell base classes
  // to add their own purpose checking
  bool is_valid(bool = false, int = 0) const
  { return true; }

  // This is here in the *ds*_cell_base to ease its use as default
  // template parameter, so that the .dual() functions of Delaunay_3
  // still work.
  template < typename Traits >
  typename Traits::Point_3
  circumcenter(const Traits& gt) const
  {
    return gt.construct_circumcenter_3_object()(this->vertex(0)->point(),
                                                this->vertex(1)->point(),
                                                this->vertex(2)->point(),
                                                this->vertex(3)->point());
  }

  // For use by Compact_container.
  void * for_compact_container() const { return N[0].for_compact_container(); }
  void * & for_compact_container()     { return N[0].for_compact_container(); }

  // TDS internal data access functions.
        TDS_data& tds_data()       { return _tds_data; }
  const TDS_data& tds_data() const { return _tds_data; }

private:

  Cell_handle   N[4];
  Vertex_handle V[4];
  TDS_data      _tds_data;
};

template < class TDS >
inline
std::istream&
operator>>(std::istream &is, Triangulation_ds_cell_base_3<TDS> &)
  // non combinatorial information. Default = nothing
{
  return is;
}

template < class TDS >
inline
std::ostream&
operator<<(std::ostream &os, const Triangulation_ds_cell_base_3<TDS> &)
  // non combinatorial information. Default = nothing
{
  return os;
}

// Specialization for void.
template <>
class Triangulation_ds_cell_base_3<void>
{
public:
  typedef internal::Dummy_tds_3                         Triangulation_data_structure;
  typedef Triangulation_data_structure::Vertex_handle   Vertex_handle;
  typedef Triangulation_data_structure::Cell_handle     Cell_handle;
  template <typename TDS2>
  struct Rebind_TDS { typedef Triangulation_ds_cell_base_3<TDS2> Other; };
};

CGAL_END_NAMESPACE

#endif // CGAL_TRIANGULATION_DS_CELL_BASE_3_H
