// Copyright (c) 2000
// Utrecht University (The Netherlands),
// ETH Zurich (Switzerland),
// INRIA Sophia-Antipolis (France),
// Max-Planck-Institute Saarbruecken (Germany),
// and Tel-Aviv University (Israel).  All rights reserved.
//
// This file is part of CGAL (www.cgal.org)
//
// $URL: https://github.com/CGAL/cgal/blob/v6.1.1/Cartesian_kernel/include/CGAL/Cartesian/Direction_2.h $
// $Id: include/CGAL/Cartesian/Direction_2.h 08b27d3db14 $
// SPDX-License-Identifier: LGPL-3.0-or-later OR LicenseRef-Commercial
//
//
// Author(s)     : Andreas Fabri, Herve Bronnimann

#ifndef CGAL_CARTESIAN_DIRECTION_2_H
#define CGAL_CARTESIAN_DIRECTION_2_H

#include <CGAL/array.h>
#include <CGAL/Handle_for.h>

namespace CGAL {

template < class R_ >
class DirectionC2
{
  typedef DirectionC2<R_>                   Self;

  typedef typename R_::Boolean              Boolean;
  typedef typename R_::FT                   FT;
  typedef FT                                RT;
  typedef typename R_::Point_2              Point_2;
  typedef typename R_::Vector_2             Vector_2;
  typedef typename R_::Line_2               Line_2;
  typedef typename R_::Ray_2                Ray_2;
  typedef typename R_::Segment_2            Segment_2;
  typedef typename R_::Direction_2          Direction_2;

  typedef std::array<FT, 2>               Rep;
  typedef typename R_::template Handle<Rep>::type  Base;

  Base base;

public:

  typedef R_                                     R;

  DirectionC2() {}

  DirectionC2(const FT &x, const FT &y)
    : base{x, y} {}

  Boolean operator==(const DirectionC2 &d) const;
  Boolean operator!=(const DirectionC2 &d) const;

  Vector_2 to_vector() const;

  const RT & dx() const
  {
      return get_pointee_or_identity(base)[0];
  }
  const RT & dy() const
  {
      return get_pointee_or_identity(base)[1];
  }
};

template < class R >
inline
typename R::Boolean
DirectionC2<R>::operator==(const DirectionC2<R> &d) const
{
  if (CGAL::identical(base, d.base))
      return true;
  return equal_direction(*this, d);
}

template < class R >
inline
typename R::Boolean
DirectionC2<R>::operator!=(const DirectionC2<R> &d) const
{
  return !( *this == d );
}


template < class R >
inline
typename DirectionC2<R>::Vector_2
DirectionC2<R>::to_vector() const
{
  return Vector_2(dx(), dy());
}

} //namespace CGAL

#endif // CGAL_CARTESIAN_DIRECTION_2_H
