// Copyright (c) 1997-2002  Max-Planck-Institute Saarbruecken (Germany).
// All rights reserved.
//
// This file is part of CGAL (www.cgal.org).
// You can redistribute it and/or modify it under the terms of the GNU
// General Public License as published by the Free Software Foundation,
// either version 3 of the License, or (at your option) any later version.
//
// 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.
//
// $URL$
// $Id$
// 
//
// Author(s)     : Michael Seel        <seel@mpi-sb.mpg.de>
//                 Miguel Granados     <granados@mpi-sb.mpg.de>
//                 Susan Hert          <hert@mpi-sb.mpg.de>
//                 Lutz Kettner        <kettner@mpi-sb.mpg.de>
//                 Peter Hachenberger  <hachenberger@mpi-sb.mpg.de>
#ifndef CGAL_NEF_SHALFLOOP_H
#define CGAL_NEF_SHALFLOOP_H

#include <string>
#include <sstream>
#include <CGAL/IO/Verbose_ostream.h>
#include <CGAL/Nef_3/SNC_iteration.h>

#undef CGAL_NEF_DEBUG
#define CGAL_NEF_DEBUG 83
#include <CGAL/Nef_2/debug.h>

namespace CGAL {

template <typename Refs> 
class SHalfloop_base {

  typedef typename Refs::Mark  Mark;
  typedef typename Refs::Sphere_circle  Sphere_circle;
  typedef typename Refs::SHalfloop_handle SHalfloop_handle;
  typedef typename Refs::SHalfloop_const_handle SHalfloop_const_handle;
  typedef typename Refs::SFace_handle SFace_handle;
  typedef typename Refs::SFace_const_handle SFace_const_handle;
  typedef typename Refs::Halffacet_handle Halffacet_handle;
  typedef typename Refs::Halffacet_const_handle Halffacet_const_handle;

  SHalfloop_handle   twin_;
  SFace_handle       incident_sface_;
  Halffacet_handle   facet_;

  // temporary needed:
  Mark               mark_;
  Sphere_circle      circle_;

 public:

  SHalfloop_base() : twin_(), incident_sface_(), facet_(), 
    mark_(), circle_() {}

    ~SHalfloop_base() {
      CGAL_NEF_TRACEN("  destroying SHalfloop_base item "<<&*this);
    }
    SHalfloop_base(const SHalfloop_base<Refs>& l)
      { twin_ = l.twin_;
	incident_sface_ = l.incident_sface_;
	facet_ = l.facet_;
	mark_ = l.mark_;
	circle_ = l.circle_;
      }

    SHalfloop_base<Refs>& operator=(const SHalfloop_base<Refs>& l)
      { twin_ = l.twin_;
	incident_sface_ = l.incident_sface_;
	facet_ = l.facet_;
	mark_ = l.mark_;
	circle_ = l.circle_;
	return *this;
      }

    Mark& mark() { return mark_;}
    const Mark& mark() const { return mark_; }

    SHalfloop_handle& twin() { return twin_; }
    SHalfloop_const_handle twin() const { return twin_; }

    Sphere_circle& circle() { return circle_; }
    const Sphere_circle& circle() const { return circle_; }

    SFace_handle& incident_sface() { return incident_sface_; }
    SFace_const_handle incident_sface() const { return incident_sface_; }

    Halffacet_handle& facet() { return facet_; }
    Halffacet_const_handle facet() const { return facet_; }

 public:
    std::string debug() const
      { std::stringstream os; 
	set_pretty_mode(os); 
	os<<"sl [ "<<circle_<<" ] ";
	return os.str();
      }

    bool is_twin() const { return (&*twin_ < this); }

    bool is_valid( bool verb = false, int level = 0) const {
      
      Verbose_ostream verr(verb);
      verr << "begin CGAL::SNC_items<...>::SHalfloop_base::is_valid( verb=true, "
	"level = " << level << "):" << std::endl;

      bool valid = (twin_  != SHalfloop_handle() && twin_  != NULL);
      valid = valid && (incident_sface_ != SFace_handle() && 
			incident_sface_ != NULL);
      valid = valid && (facet_ != Halffacet_handle() &&
			facet_ != NULL);
      valid = valid && (circle_.d() == 0);
      valid = valid && (circle_.a() != 0 || circle_.b() != 0 || circle_.c() !=0);
      
      verr << "end of CGAL::SNC_items<...>::SHalfloop_base::is_valid(): structure is "
	   << ( valid ? "valid." : "NOT VALID.") << std::endl;

      return valid;
    }

}; // SHalfloop_base

} //namespace CGAL
#endif //CGAL_NEF_SHALFLOOP_H
