// Copyright (c) 2005-2008 Max-Planck-Institute Saarbruecken (Germany).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
//
// $URL: https://github.com/CGAL/cgal/blob/v5.6/Convex_decomposition_3/include/CGAL/Convex_decomposition_3/SFace_separator.h $
// $Id: SFace_separator.h e8b66f2 2023-01-18T22:41:52+00:00 Giles Bathgate
// SPDX-License-Identifier: GPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s)     :  Peter Hachenberger <hachenberger@mpi-sb.mpg.de>
#ifndef CGAL_CD3_SFACE_SEPARATOR_H
#define CGAL_CD3_SFACE_SEPARATOR_H

#include <CGAL/license/Convex_decomposition_3.h>

#include <CGAL/Modifier_base.h>
#include <CGAL/Nef_3/SNC_decorator.h>
#include <CGAL/Nef_3/SNC_point_locator.h>
#include <CGAL/Convex_decomposition_3/SM_walls.h>

namespace CGAL {

template<typename Nef_>
class SFace_separator : public Modifier_base<typename Nef_::SNC_structure> {

  typedef Nef_                                   Nef_polyhedron;
  typedef typename Nef_polyhedron::SNC_structure SNC_structure;
  typedef typename SNC_structure::Items          Items;
  typedef CGAL::SNC_decorator<SNC_structure>     Base;
  typedef CGAL::SNC_point_locator<Base>          SNC_point_locator;
  typedef CGAL::SNC_constructor<Items, SNC_structure>
    SNC_constructor;

  typedef typename SNC_structure::Sphere_map     Sphere_map;
  typedef CGAL::SM_decorator<Sphere_map>         SM_decorator;
  typedef CGAL::SM_point_locator<SM_decorator>   SM_point_locator;
  typedef CGAL::SM_walls<Sphere_map>             SM_walls;

  typedef typename Base::SHalfedge_handle        SHalfedge_handle;
  typedef typename Base::SHalfloop_handle        SHalfloop_handle;
  typedef typename Base::SFace_handle            SFace_handle;

  typedef typename Base::SFace_iterator          SFace_iterator;
  typedef typename Base::SFace_cycle_iterator    SFace_cycle_iterator;

 public:
  SFace_separator() {}

  void operator()(SNC_structure& snc) {

    SFace_iterator sf;
    CGAL_forall_sfaces(sf, snc) {
      if(!sf->mark() ||
         sf->sface_cycles_begin() ==
         sf->sface_cycles_end()) continue;

      SM_decorator SD(&*sf->center_vertex());

      SFace_cycle_iterator sfci
        (++sf->sface_cycles_begin());
      while(sfci != sf->sface_cycles_end()) {
        SFace_handle sf_new = SD.new_sface();
        sf_new->mark() = sf->mark();
        sf_new->volume() = sf->volume();
        if(sfci.is_shalfedge()) {
          SHalfedge_handle se = sfci;
          SD.unlink_as_face_cycle(se);
          SD.link_as_face_cycle(se,sf_new);
        } else if(sfci.is_shalfloop()) {
                 SHalfloop_handle sl = sfci;
          SD.unlink_as_loop(sl);
          SD.link_as_loop(sl, sf_new);
        } else
          CGAL_error_msg("there should be no isolated edges");
        sfci = ++sf->sface_cycles_begin();
      }
    }
  }
};

} //namespace CGAL
#endif //CGAL_CD3_SFACE_SEPARATOR_H

