// ======================================================================
//
// Copyright (c) 2000 The CGAL Consortium
//
// This software and related documentation is part of an INTERNAL release
// of the Computational Geometry Algorithms Library (CGAL). It is not
// intended for general use.
//
// ----------------------------------------------------------------------
//
// release       :
// release_date  :
//
// file          : include/CGAL/Cartesian/Line_3.h
// revision      : $Revision$
// revision_date : $Date$
// author(s)     : Andreas Fabri
// coordinator   : INRIA Sophia-Antipolis (Mariette.Yvinec@sophia.inria.fr)
//
// ======================================================================

#ifndef CGAL_CARTESIAN_LINE_3_H
#define CGAL_CARTESIAN_LINE_3_H

#include <CGAL/Cartesian/redefine_names_3.h>
#include <CGAL/Twotuple.h>
#include <CGAL/Cartesian/constructions_on_lines_3.h>

CGAL_BEGIN_NAMESPACE

template < class R_ >
class LineC3 CGAL_ADVANCED_KERNEL_PARTIAL_SPEC
  : public Handle_for<Twotuple<typename R_::Point_3> >
{
public:
  typedef R_                               R;
  typedef typename R::FT                   FT;
  typedef typename R::RT                   RT;
#ifndef CGAL_CFG_NO_ADVANCED_KERNEL
  typedef LineC3<R CGAL_CTAG>              Self;
  typedef typename R::Point_3              Point_3;
  typedef typename R::Vector_3             Vector_3;
  typedef typename R::Direction_3          Direction_3;
  typedef typename R::Plane_3              Plane_3;
  typedef typename R::Ray_3                Ray_3;
  typedef typename R::Segment_3            Segment_3;
  typedef typename R::Aff_transformation_3 Aff_transformation_3;
#else
  typedef LineC3<R>                             Self;
  typedef typename R::Point_3_base              Point_3;
  typedef typename R::Vector_3_base             Vector_3;
  typedef typename R::Direction_3_base          Direction_3;
  typedef typename R::Plane_3_base              Plane_3;
  typedef typename R::Ray_3_base                Ray_3;
  typedef typename R::Segment_3_base            Segment_3;
  typedef typename R::Aff_transformation_3_base Aff_transformation_3;
#endif

  LineC3();
  LineC3(const Self  &l);
  LineC3(const Point_3 &p, const Point_3 &q);
  LineC3(const Segment_3 &s);
  LineC3(const Ray_3 &r);
  LineC3(const Point_3 &p, const Direction_3 &d);
  ~LineC3() {}

  bool        operator==(const Self &l) const;
  bool        operator!=(const Self &l) const;

  Plane_3     perpendicular_plane(const Point_3 &p) const;
  Self        opposite() const;

  Point_3     point() const;
  Point_3     point(int i) const;

  Point_3     projection(const Point_3 &p) const;

  Direction_3 direction() const;

  bool        has_on(const Point_3 &p) const;
  bool        is_degenerate() const;

  Self        transform(const Aff_transformation_3 &t) const;

private:
  void            new_rep(const Point_3 &p,
                          const Vector_3 &v);
};

template < class R >
inline
void
LineC3<R CGAL_CTAG>::
new_rep(const typename LineC3<R CGAL_CTAG>::Point_3 &p,
        const typename LineC3<R CGAL_CTAG>::Vector_3 &v)
{
  // CGAL_kernel_precondition(  v != NULL_VECTOR );
  new ( static_cast< void*>(ptr)) Twotuple< Point_3 > (p, ORIGIN+v);
}

template < class R >
CGAL_KERNEL_CTOR_INLINE
LineC3<R CGAL_CTAG>::LineC3()
{
  new ( static_cast< void*>(ptr)) Twotuple<Point_3>();
}

template < class R >
CGAL_KERNEL_CTOR_INLINE
LineC3<R CGAL_CTAG>::LineC3(const LineC3<R CGAL_CTAG>  &l)
  : Handle_for<Twotuple<typename R::Point_3 > >(l)
{}

template < class R >
CGAL_KERNEL_CTOR_INLINE
LineC3<R CGAL_CTAG>::
LineC3(const typename LineC3<R CGAL_CTAG>::Point_3 &p,
       const typename LineC3<R CGAL_CTAG>::Point_3 &q)
{
  new_rep(p, q-p);
}

template < class R >
CGAL_KERNEL_CTOR_INLINE
LineC3<R CGAL_CTAG>::
LineC3(const typename LineC3<R CGAL_CTAG>::Segment_3 &s)
{
  new_rep(s.start(), s.end() - s.start());
}

template < class R >
CGAL_KERNEL_CTOR_INLINE
LineC3<R CGAL_CTAG>::
LineC3(const typename LineC3<R CGAL_CTAG>::Ray_3 &r)
{
  new_rep(r.start(), r.point(1) - r.start());
}

template < class R >
CGAL_KERNEL_CTOR_INLINE
LineC3<R CGAL_CTAG>::
LineC3(const typename LineC3<R CGAL_CTAG>::Point_3 &p,
       const typename LineC3<R CGAL_CTAG>::Direction_3 &d)
{
  new_rep(p, d.to_vector());
}

template < class R >
inline
bool
LineC3<R CGAL_CTAG>::operator==(const LineC3<R CGAL_CTAG> &l) const
{
  if (ptr == l.ptr) return true;
  return has_on(l.point()) && (direction() == l.direction());
}

template < class R >
inline
bool
LineC3<R CGAL_CTAG>::operator!=(const LineC3<R CGAL_CTAG> &l) const
{
  return !(*this == l);
}

template < class R >
inline
typename LineC3<R CGAL_CTAG>::Point_3
LineC3<R CGAL_CTAG>::point() const
{
  return ptr->e0;
}

template < class R >
inline
typename LineC3<R CGAL_CTAG>::Direction_3
LineC3<R CGAL_CTAG>::
direction() const
{
  return ((ptr->e1) - ORIGIN).direction();
}

template < class R >
inline
typename LineC3<R CGAL_CTAG>::Point_3
LineC3<R CGAL_CTAG>::
point(int i) const
{
  return point_on_line(i,*this);
}

template < class R >
inline
typename LineC3<R CGAL_CTAG>::Plane_3
LineC3<R CGAL_CTAG>::
perpendicular_plane(const typename LineC3<R CGAL_CTAG>::Point_3 &p) const
{
  return Plane_3(p, direction().to_vector());
}

template < class R >
inline
LineC3<R CGAL_CTAG>
LineC3<R CGAL_CTAG>::
opposite() const
{
  return LineC3<R CGAL_CTAG>(point(), -direction());
}

template < class R >
inline
typename LineC3<R CGAL_CTAG>::Point_3
LineC3<R CGAL_CTAG>::
projection(const typename LineC3<R CGAL_CTAG>::Point_3 &p) const
{
  return projection_line(p,*this);
}

template < class R >
inline
bool
LineC3<R CGAL_CTAG>::
has_on(const typename LineC3<R CGAL_CTAG>::Point_3 &p) const
{
  return collinear(point(), point()+direction().to_vector(), p);
}

template < class R >
inline
bool
LineC3<R CGAL_CTAG>::is_degenerate() const
{
  return direction() == Direction_3(0,0,0);
}

template < class R >
inline
LineC3<R CGAL_CTAG>
LineC3<R CGAL_CTAG>::
transform(const typename LineC3<R CGAL_CTAG>::Aff_transformation_3 &t) const
{
  return LineC3<R CGAL_CTAG>( t.transform(point()), t.transform(direction()));
}

#ifndef CGAL_CARTESIAN_NO_OSTREAM_INSERT_LINEC3
template < class R >
std::ostream &
operator<<(std::ostream &os, const LineC3<R CGAL_CTAG> &l)
{
    switch(os.iword(IO::mode)) {
    case IO::ASCII :
        return os << l.point(0) << ' ' << l.point(1);
    case IO::BINARY :
        return os << l.point(0) <<  l.point(1);
    default:
        return  os << "LineC3(" << l.point(0) << ", " << l.point(1) << ")";
    }
}
#endif // CGAL_CARTESIAN_NO_OSTREAM_INSERT_LINEC3

#ifndef CGAL_CARTESIAN_NO_ISTREAM_EXTRACT_LINEC3
template < class R >
std::istream &
operator>>(std::istream &is, LineC3<R CGAL_CTAG> &l)
{
    typename LineC3<R CGAL_CTAG>::Point_3 p, q;
    is >> p >> q;
    l = LineC3<R CGAL_CTAG>(p, q);
    return is;
}
#endif // CGAL_CARTESIAN_NO_ISTREAM_EXTRACT_LINEC3

CGAL_END_NAMESPACE

#endif // CGAL_CARTESIAN_LINE_3_H