// Copyright (c) 2000  Utrecht University (The Netherlands),
// ETH Zurich (Switzerland), Freie Universitaet Berlin (Germany),
// INRIA Sophia-Antipolis (France), Martin-Luther-University Halle-Wittenberg
// (Germany), Max-Planck-Institute Saarbruecken (Germany), RISC Linz (Austria),
// and Tel-Aviv University (Israel).  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 Lesser General Public License as
// published by the Free Software Foundation; version 2.1 of the License.
// See the file LICENSE.LGPL 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.
//
// $Source$
// $Revision$ $Date$
// $Name$
//
// Author(s)     : Andreas Fabri

#ifndef CGAL_CARTESIAN_DIRECTION_3_H
#define CGAL_CARTESIAN_DIRECTION_3_H

#include <CGAL/Threetuple.h>

CGAL_BEGIN_NAMESPACE

template < class R_ >
class DirectionC3
{
  typedef typename R_::FT                   FT;
  typedef typename R_::Vector_3             Vector_3;
  typedef typename R_::Line_3               Line_3;
  typedef typename R_::Ray_3                Ray_3;
  typedef typename R_::Segment_3            Segment_3;
  typedef typename R_::Direction_3          Direction_3;
  typedef typename R_::Aff_transformation_3 Aff_transformation_3;

  typedef Threetuple<FT>                           Rep;
  typedef typename R_::template Handle<Rep>::type  Base;

  Base base;

public:
  typedef R_                                R;

  DirectionC3() {}

  DirectionC3(const Vector_3 &v)
    : base(v.x(), v.y(), v.z()) {}
  // { *this = v.direction(); }

  DirectionC3(const Line_3 &l)
  { *this = l.direction(); }

  DirectionC3(const Ray_3 &r)
  { *this = r.direction(); }

  DirectionC3(const Segment_3 &s)
  { *this = s.direction(); }

  DirectionC3(const FT &x, const FT &y, const FT &z)
    : base(x, y, z) {}

  bool           operator==(const DirectionC3 &d) const;
  bool           operator!=(const DirectionC3 &d) const;

  Vector_3       to_vector() const;
  Vector_3       vector() const { return to_vector(); }

  Direction_3    transform(const Aff_transformation_3 &t) const
  {
    return t.transform(*this);
  }

  Direction_3    operator-() const;

  const FT & delta(int i) const;
  const FT & dx() const
  {
      return get(base).e0;
  }
  const FT & dy() const
  {
      return get(base).e1;
  }
  const FT & dz() const
  {
      return get(base).e2;
  }

  const FT & hdx() const
  {
      return dx();
  }
  const FT & hdy() const
  {
      return dy();
  }
  const FT & hdz() const
  {
      return dz();
  }
  FT hw() const
  {
      return FT(1);
  }
};

template < class R >
inline
bool
DirectionC3<R>::operator==(const DirectionC3<R> &d) const
{
  if (CGAL::identical(base, d.base))
      return true;
  return equal_directionC3(dx(), dy(), dz(), d.dx(), d.dy(), d.dz());
}

template < class R >
inline
bool
DirectionC3<R>::operator!=(const DirectionC3<R> &d) const
{
  return !(*this == d);
}

template < class R >
inline
typename DirectionC3<R>::Vector_3
DirectionC3<R>::to_vector() const
{
  return Vector_3(dx(), dy(), dz());
}

template < class R >
inline
typename DirectionC3<R>::Direction_3
DirectionC3<R>::operator-() const
{
  return DirectionC3<R>(-dx(), -dy(), -dz());
}

template < class R >
const typename DirectionC3<R>::FT &
DirectionC3<R>::delta(int i) const
{
  CGAL_kernel_precondition( i >= 0 && i <= 2 );
  if (i==0) return dx();
  if (i==1) return dy();
  return dz();
}

#ifndef CGAL_NO_OSTREAM_INSERT_DIRECTIONC3
template < class R >
std::ostream &
operator<<(std::ostream &os, const DirectionC3<R> &d)
{
  typename R::Vector_3 v = d.to_vector();
  switch(os.iword(IO::mode)) {
    case IO::ASCII :
      return os << v.x() << ' ' << v.y()  << ' ' << v.z();
    case IO::BINARY :
      write(os, v.x());
      write(os, v.y());
      write(os, v.z());
      return os;
    default:
      os << "DirectionC3(" << v.x() << ", " << v.y() << ", " << v.z() << ")";
      return os;
  }
}
#endif // CGAL_NO_OSTREAM_INSERT_DIRECTIONC3

#ifndef CGAL_NO_ISTREAM_EXTRACT_DIRECTIONC3
template < class R >
std::istream &
operator>>(std::istream &is, DirectionC3<R> &d)
{
  typename R::FT x, y, z;
  switch(is.iword(IO::mode)) {
    case IO::ASCII :
      is >> x >> y >> z;
      break;
    case IO::BINARY :
      read(is, x);
      read(is, y);
      read(is, z);
      break;
    default:
      std::cerr << "" << std::endl;
      std::cerr << "Stream must be in ascii or binary mode" << std::endl;
      break;
  }
  if (is)
      d = DirectionC3<R>(x, y, z);
  return is;
}
#endif // CGAL_NO_ISTREAM_EXTRACT_DIRECTIONC3

CGAL_END_NAMESPACE

#endif // CGAL_CARTESIAN_DIRECTION_3_H