// Copyright (c) 1997  INRIA Sophia-Antipolis (France).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
//
// $URL: https://github.com/CGAL/cgal/blob/v6.0.1/TDS_2/include/CGAL/Triangulation_ds_circulators_2.h $
// $Id: include/CGAL/Triangulation_ds_circulators_2.h 50cfbde3b84 $
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s)     : Mariette Yvinec
//                 Menelaos Karavelas <mkaravel@cse.nd.edu>

#ifndef CGAL_TRIANGULATION_DS_CIRCULATORS_2_H
#define CGAL_TRIANGULATION_DS_CIRCULATORS_2_H

#include <CGAL/license/TDS_2.h>


#include <utility>
#include <iterator>
#include <CGAL/circulator.h>
#include <CGAL/assertions.h>
#include <CGAL/Triangulation_utils_2.h>

namespace CGAL {

template < class Tds>
class Triangulation_ds_face_circulator_2
  : public Bidirectional_circulator_base< typename Tds::Face,
                                 std::ptrdiff_t,
                                 std::size_t>,
    public Triangulation_cw_ccw_2

{
private:
  typedef
  Bidirectional_circulator_base< typename Tds::Face,
                                 std::ptrdiff_t,
                                 std::size_t>  Base_circulator;

public:
  typedef Triangulation_ds_face_circulator_2<Tds> Face_circulator;
  typedef typename Tds::Face                      Face;
  typedef typename Tds::Vertex                    Vertex;
  typedef typename Tds::Face_handle               Face_handle;
  typedef typename Tds::Vertex_handle             Vertex_handle;


private:
  Vertex_handle _v;
  Face_handle    pos;

public:
  Triangulation_ds_face_circulator_2()
    : _v(), pos()
  {}

  Triangulation_ds_face_circulator_2(Vertex_handle v,
                                     Face_handle f = Face_handle());

  Face_circulator& operator++();
  Face_circulator operator++(int);
  Face_circulator& operator--();
  Face_circulator operator--(int);

  bool operator==(const Face_circulator &fc) const;
  bool operator!=(const Face_circulator &fc) const;

  bool operator==(const Face_handle &fh) const { return pos == fh; }
  bool operator!=(const Face_handle &fh) const { return pos != fh; }

  bool is_empty() const;
  bool operator==(std::nullptr_t /*CGAL_assertion_code(n)*/) const;
  bool operator!=(std::nullptr_t /*CGAL_assertion_code(n)*/) const;

  Face&
  operator*() const
  {
    CGAL_precondition(pos != Face_handle() &&
                      _v != Vertex_handle());
    return *pos;
  }

  Face*
  operator->() const
  {
    CGAL_precondition(pos != Face_handle() &&
                      _v != Vertex_handle());
    return &*pos;
  }

  Face_handle base()  const {return pos;}
  operator Face_handle()  const {return pos;}
};

template < class Tds_ >
bool
operator==(typename Tds_::Face_handle fh,
           Triangulation_ds_face_circulator_2<Tds_> fc)
{
  return (fc==fh);
}

template < class Tds_ >
bool
operator!=(typename Tds_::Face_handle fh,
           Triangulation_ds_face_circulator_2<Tds_> fc)
{
  return (fc!=fh);
}


template < class Tds >
class Triangulation_ds_vertex_circulator_2 :
  public Bidirectional_circulator_base< typename Tds::Vertex,
                                       std::ptrdiff_t,
                                       std::size_t>,
  public  Triangulation_cw_ccw_2
{
public:
  typedef Triangulation_ds_vertex_circulator_2<Tds> Vertex_circulator;
  typedef typename Tds::Face                      Face;
  typedef typename Tds::Vertex                    Vertex;
  typedef typename Tds::Face_handle               Face_handle;
  typedef typename Tds::Vertex_handle             Vertex_handle;

private:
  Vertex_handle _v;
  Face_handle   pos;
  int _ri;

public:
  Triangulation_ds_vertex_circulator_2()
    :  _v(), pos()
  {}

  Triangulation_ds_vertex_circulator_2(Vertex_handle v,
                                       Face_handle f = Face_handle());

  Vertex_circulator& operator++();
  Vertex_circulator  operator++(int);
  Vertex_circulator& operator--();
  Vertex_circulator  operator--(int);

  bool operator==(const Vertex_circulator &vc) const;
  bool operator!=(const Vertex_circulator &vc) const;

  bool operator==(const Vertex_handle &vh) const
  { return pos->vertex(_ri) == vh; }
  bool operator!=(const Vertex_handle &vh) const
  { return pos->vertex(_ri) != vh; }

  bool is_empty() const;
  bool operator==(std::nullptr_t /*CGAL_assertion_code(n)*/) const;
  bool operator!=(std::nullptr_t /*CGAL_assertion_code(n)*/) const;

  Vertex&
  operator*() const
  {
    CGAL_precondition(pos != Face_handle() &&
                      _v != Vertex_handle());
    return *(pos->vertex(_ri));
  }

  Vertex*
  operator->() const
  {
    CGAL_precondition(pos != Face_handle() &&
                      _v != Vertex_handle());
    return &*(pos->vertex(_ri));
  }

   Vertex_handle base() const {return pos->vertex(_ri);}
   operator Vertex_handle() const {return pos->vertex(_ri);}
};

template < class Tds_ >
inline
bool
operator==(typename Tds_::Vertex_handle vh,
           Triangulation_ds_vertex_circulator_2<Tds_> vc)
{
  return (vc==vh);
}

template < class Tds_ >
inline
bool
operator!=(typename Tds_::Vertex_handle vh,
           Triangulation_ds_vertex_circulator_2<Tds_> vc)
{
  return !(vc==vh);
}


template < class Tds >
class Triangulation_ds_edge_circulator_2 :
  public Bidirectional_circulator_base < typename Tds::Edge,
                                         std::ptrdiff_t,
                                         std::size_t>,
  public Triangulation_cw_ccw_2
{
public:
  typedef Triangulation_ds_edge_circulator_2<Tds>  Edge_circulator;
  typedef typename Tds::Face                       Face;
  typedef typename Tds::Vertex                     Vertex;
  typedef typename Tds::Edge                       Edge;
  typedef typename Tds::Face_handle                Face_handle;
  typedef typename Tds::Vertex_handle              Vertex_handle;

private:
  int _ri;
  Vertex_handle _v;
  Face_handle  pos;
  mutable Edge edge;

public:
  Triangulation_ds_edge_circulator_2()
    : _ri(0), _v(), pos()
  {}

  Triangulation_ds_edge_circulator_2( Vertex_handle v,
                                      Face_handle f = Face_handle());

  Edge_circulator& operator++();
  Edge_circulator operator++(int);
  Edge_circulator& operator--();
  Edge_circulator operator--(int);

  bool operator==(const Edge_circulator &vc) const;
  bool operator!=(const Edge_circulator &vc) const;
  bool is_empty() const;
  bool operator==(std::nullptr_t /*CGAL_assertion_code(n)*/) const;
  bool operator!=(std::nullptr_t /*CGAL_assertion_code(n)*/) const;

  Edge*  operator->() const {
    edge.first=pos;
    edge.second= _ri;
    return &edge;
  }

  Edge& operator*() const {
    edge.first=pos;
    edge.second= _ri;
    return edge;
  }

};


template < class Tds >
Triangulation_ds_face_circulator_2<Tds> ::
Triangulation_ds_face_circulator_2(Vertex_handle v, Face_handle f)
  : _v(v), pos(f)
{
  if (_v == Vertex_handle()) pos = Face_handle();
  else if ( pos == Face_handle()) pos = v->face();

  if (pos ==  Face_handle()|| pos->dimension() < 2) {
    _v =  Vertex_handle() ; pos = Face_handle(); return;}
  else CGAL_precondition( pos->has_vertex(v));
}


template < class Tds >
Triangulation_ds_face_circulator_2<Tds>&
Triangulation_ds_face_circulator_2<Tds> ::
operator++()
{
  CGAL_precondition( pos != Face_handle() &&
                     _v != Vertex_handle());
  int i = pos->index(_v);
  pos = pos->neighbor(ccw(i));
  return *this;
}

template < class Tds >
Triangulation_ds_face_circulator_2<Tds>
Triangulation_ds_face_circulator_2<Tds> ::
operator++(int)
{
  CGAL_precondition(pos != Face_handle() &&
                    _v != Vertex_handle());
  Face_circulator tmp(*this);
  ++(*this);
  return tmp;
}

template < class Tds >
Triangulation_ds_face_circulator_2<Tds>&
Triangulation_ds_face_circulator_2<Tds> ::
operator--()
{
   CGAL_precondition(pos != Face_handle() &&
                     _v != Vertex_handle());
   int i = pos->index(_v);
   pos = pos->neighbor(cw(i));
   return *this;
}

template < class Tds >
Triangulation_ds_face_circulator_2<Tds>
Triangulation_ds_face_circulator_2<Tds> ::
operator--(int)
{
  CGAL_precondition(pos != Face_handle() &&
                    _v != Vertex_handle());
  Face_circulator tmp(*this);
  --(*this);
  return tmp;
}

template < class Tds >
inline bool
Triangulation_ds_face_circulator_2<Tds> ::
operator==(const Face_circulator &fc) const
{
  return (_v == fc._v) &&  (pos == fc.pos);
}

template < class Tds >
inline bool
Triangulation_ds_face_circulator_2<Tds> ::
operator!=(const Face_circulator &fc) const
{
return ! (*this == fc);
}

template < class Tds >
inline bool
Triangulation_ds_face_circulator_2<Tds> ::
is_empty() const
{
return (_v == Vertex_handle() ||  pos == Face_handle() );
}

template < class Tds >
inline bool
Triangulation_ds_face_circulator_2<Tds> ::
operator==(std::nullptr_t /*CGAL_assertion_code(n)*/) const
{
  //CGAL_assertion( n == nullptr);
  return (_v == Vertex_handle() ||  pos == Face_handle() );
}

template < class Tds >
inline bool
Triangulation_ds_face_circulator_2<Tds> ::
operator!=(std::nullptr_t /*CGAL_assertion_code(n)*/) const
{
  //CGAL_assertion( n == nullptr);
  return ! (*this == nullptr);
}

template < class Tds >
Triangulation_ds_vertex_circulator_2<Tds> ::
Triangulation_ds_vertex_circulator_2 (Vertex_handle v,
                                      Face_handle f)
  : _v( v ), pos(f)
{
  if (_v == Vertex_handle()) { pos = Face_handle();}
  else if (pos == Face_handle()) {pos = v->face();}

  if (pos == Face_handle() || pos->dimension() < 1){
    _v = Vertex_handle(); pos = Face_handle(); return;}
  int i = pos->index(_v);
  if (pos->dimension() == 2) {_ri = ccw(i);}
  else {CGAL_assertion(i>=0 && i<=1);_ri = (i == 0) ? 1 : 0;}
  return;
}


template < class Tds >
Triangulation_ds_vertex_circulator_2<Tds>&
Triangulation_ds_vertex_circulator_2<Tds> ::
operator++()
{
  CGAL_precondition(pos != Face_handle() &&
                    _v != Vertex_handle());
  int i = pos->index(_v);

  if (pos->dimension() == 1) {
    CGAL_assertion(i>=0 && i<=1);
    pos = pos->neighbor((i == 0) ? 1 : 0);
    _ri = 1 - pos->index(_v);
  }
  else{
    pos = pos->neighbor(ccw(i));
    i = pos->index(_v);
    _ri = ccw(i);
  }
  return *this;
}

template < class Tds >
Triangulation_ds_vertex_circulator_2<Tds>
Triangulation_ds_vertex_circulator_2<Tds> ::
operator++(int)
{
  Vertex_circulator tmp(*this);
  ++(*this);
  return tmp;
}

template < class Tds >
Triangulation_ds_vertex_circulator_2<Tds>&
Triangulation_ds_vertex_circulator_2<Tds> ::
operator--()
{
  CGAL_precondition(pos != Face_handle() &&
                                  _v != Vertex_handle());
  int i = pos->index(_v);

  if (pos->dimension() == 1) {
    CGAL_assertion(i>=0 && i<=1);
    pos = pos->neighbor((i == 0) ? 1 : 0);
    _ri = 1 - pos->index(_v);
  }
  else{
    pos = pos->neighbor(cw(i));
    i = pos->index(_v);
    _ri = ccw(i);
  }
  return *this;
}

template < class Tds >
Triangulation_ds_vertex_circulator_2<Tds>
Triangulation_ds_vertex_circulator_2<Tds> ::
operator--(int)
{
  Vertex_circulator tmp(*this);
  --(*this);
  return tmp;
}

template < class Tds >
inline bool
Triangulation_ds_vertex_circulator_2<Tds> ::
operator==(const Vertex_circulator &vc) const
{
  return (_v == vc._v) &&  (_ri == vc._ri) && (pos == vc.pos);
}

template < class Tds >
inline bool
Triangulation_ds_vertex_circulator_2<Tds> ::
operator!=(const Vertex_circulator &vc) const
{
  return ! (*this == vc);
}

template < class Tds >
inline bool
Triangulation_ds_vertex_circulator_2<Tds> ::
is_empty() const
{
  return (_v == Vertex_handle() || pos == Face_handle());
}

template < class Tds >
inline bool
Triangulation_ds_vertex_circulator_2<Tds> ::
operator==(std::nullptr_t /*CGAL_assertion_code(n)*/) const
{
  //CGAL_assertion( n == nullptr);
  return (_v == Vertex_handle() || pos == Face_handle());
}

template < class Tds >
inline bool
Triangulation_ds_vertex_circulator_2<Tds> ::
operator!=(std::nullptr_t /*CGAL_assertion_code(n)*/) const
{
  //CGAL_assertion( n == nullptr);
  return !(*this == nullptr);
}


template < class Tds >
Triangulation_ds_edge_circulator_2<Tds> ::
Triangulation_ds_edge_circulator_2(Vertex_handle v, Face_handle f)
    : _v(v), pos(f)
{
  if (_v == Vertex_handle()) { pos = Face_handle();}
  else if (pos==Face_handle()) {pos = v->face();}

  if (pos == Face_handle() || pos->dimension() < 1){
    _ri = 0; _v = Vertex_handle(); pos = Face_handle();return;}
  int i = pos->index(_v);
  if (pos->dimension() == 2) {_ri = ccw(i);}
  else {_ri = 2;}
  return;
}

template < class Tds >
Triangulation_ds_edge_circulator_2<Tds>&
Triangulation_ds_edge_circulator_2<Tds> ::
operator++()
{
  CGAL_precondition(pos != Face_handle() &&
                                  _v != Vertex_handle());
  int i = pos->index(_v);
  if (pos->dimension() == 1) {
    CGAL_assertion(i>=0 && i<=1);
    pos = pos->neighbor(i == 0 ? 1 : 0);
    return *this;
  }
  else{
    pos = pos->neighbor(ccw(i));
    i = pos->index(_v);
    _ri = ccw(i);
  }
  return *this;
}

template < class Tds >
Triangulation_ds_edge_circulator_2<Tds>
Triangulation_ds_edge_circulator_2<Tds> ::
operator++(int)
{
  Edge_circulator tmp(*this);
  ++(*this);
  return tmp;
}

template < class Tds >
Triangulation_ds_edge_circulator_2<Tds>&
Triangulation_ds_edge_circulator_2<Tds> ::
operator--()
{
  CGAL_precondition(pos != Face_handle() &&
                    _v != Vertex_handle());
  int i = pos->index(_v);

  if (pos->dimension() == 1) {
    CGAL_assertion(i>=0 && i<=1);
    pos = pos->neighbor((i == 0) ? 1 : 0);
    return *this;
  }
  else{
    pos = pos->neighbor(cw(i));
    i = pos->index(_v);
    _ri = ccw(i);
  }
  return *this;
}

template < class Tds >
Triangulation_ds_edge_circulator_2<Tds>
Triangulation_ds_edge_circulator_2<Tds> ::
operator--(int)
{
  Edge_circulator tmp(*this);
  --(*this);
  return tmp;
}

template < class Tds >
inline bool
Triangulation_ds_edge_circulator_2<Tds> ::
operator==(const Edge_circulator &vc) const
{
  return (_v == vc._v) &&  (_ri == vc._ri) && (pos == vc.pos);
}

template < class Tds >
inline bool
Triangulation_ds_edge_circulator_2<Tds> ::
operator!=(const Edge_circulator &vc) const
{
  return ! (*this == vc);
}

template < class Tds >
inline bool
Triangulation_ds_edge_circulator_2<Tds> ::
is_empty() const
{
  return (_v == Vertex_handle() || pos == Face_handle());
}

template < class Tds >
inline bool
Triangulation_ds_edge_circulator_2<Tds> ::
operator==(std::nullptr_t /*CGAL_assertion_code(n)*/) const
{
  //CGAL_assertion( n == nullptr);
  return (_v == Vertex_handle() || pos == Face_handle());
}

template < class Tds >
inline bool
Triangulation_ds_edge_circulator_2<Tds> ::
operator!=(std::nullptr_t /*CGAL_assertion_code(n)*/) const
{
  //CGAL_assertion( n == nullptr);
  return !(*this == nullptr);
}


} //namespace CGAL

#endif //CGAL_TRIANGULATION_DS_CIRCULATORS_2_H

