#ifndef __JDIRECTION2D__
#define __JDIRECTION2D__

#include <istream>
#include <ostream>

#include "JIO/JSerialisable.hh"
#include "JLang/JManip.hh"
#include "JGeometry2D/JVersor2D.hh"
#include "JGeometry2D/JAngle2D.hh"
#include "JGeometry2D/JVector2D.hh"
#include "JGeometry2D/JRotation2D.hh"


/**
 * \author mdejong
 */

namespace JGEOMETRY2D {}
namespace JPP { using namespace JGEOMETRY2D; }

namespace JGEOMETRY2D {

  using JIO::JReader;
  using JIO::JWriter;


  /**
   * Data structure for direction in two dimensions.
   */
  class JDirection2D :
    public JVersor2D 
  {
  public:

    using JVersor2D::getDot;
    using JVersor2D::getPerpDot;
    

    /**
     * Default constructor.
     */
    JDirection2D() :
      JVersor2D()
    {}


    /**
     * Constructor.
     *
     * \param  dir           direction
     */
    JDirection2D(const JVersor2D& dir) :
      JVersor2D(dir.getDY(), dir.getDX())
    {}


    /**
     * Constructor.
     *
     * \param  angle         angle
     */
    JDirection2D(const JAngle2D& angle) :
      JVersor2D(angle.getDX(), angle.getDY())
    {}


    /**
     * Constructor.
     *
     * \param  pos           position
     */
    JDirection2D(const JVector2D& pos) :
      JVersor2D(pos.getY(),pos.getX())
    {}


    /**
     * Constructor.
     *
     * \param  dx            dx value
     * \param  dy            dy value
     */
    JDirection2D(const double dx,
		 const double dy) :
      JVersor2D(dx, dy)
    {}

    
    /**
     * Get direction.
     *
     * \return               direction
     */
     const JDirection2D& getDirection() const
    {
      return static_cast<const JDirection2D&>(*this);
    }


    /**
     * Get direction.
     *
     * \return               direction
     */
    JDirection2D& getDirection()
    {
      return static_cast<JDirection2D&>(*this);
    }


    /**
     * Set direction.
     *
     * \param  dir           direction
     */
    void setDirection(const JDirection2D& dir)
    {
      static_cast<JDirection2D&>(*this) = dir;
    }


    /**
     * Type conversion operator.
     *
     * \return               angle
     */
    operator JAngle2D() const
    {
      return JAngle2D(getDX(), getDY());
    }


    /**
     * Type conversion operator.
     *
     * \return               position
     */
    operator JVector2D() const
    {
      return JVector2D(getDX(), getDY());
    }
    
    
    /**
     * Transform.
     *
     * \param  T             matrix
     * \return               this direction
     */
    JDirection2D& transform(const JMatrix2D& T)
    {
      T.transform(__dx, __dy);

      normalise();

      return *this;
    }


    /**
     * Rotate.
     *
     * \param  R             rotation matrix
     * \return               this direction
     */
    JDirection2D& rotate(const JRotation2D& R)
    {
      R.rotate(__dx, __dy);

      normalise();

      return *this;
    }


    /**
     * Rotate back.
     *
     * \param  R             rotation matrix
     * \return               this direction
     */
    JDirection2D& rotate_back(const JRotation2D& R)
    {
      R.rotate_back(__dx, __dy);

      normalise();

      return *this;
    }


    /**
     * Get dot product.
     *
     * \param  angle         angle
     * \return               dot product
     */
    double getDot(const JAngle2D& angle) const
    {
      return
	getDX() * angle.getDX() +
	getDY() * angle.getDY();
    }

    
    /**
     * Get dot product.
     *
     * \param  pos           position
     * \return               dot product
     */
    double getDot(const JVector2D& pos) const
    {
      return
	getDX() * pos.getX() +
	getDY() * pos.getY();
    }


    /**
     * Get perpendicular dot product.
     *
     * \param  angle         angle
     * \return               perpendicular dot product
     */
    double getPerpDot(const JAngle2D& angle) const
    {
      return
	getDX() * angle.getDY() -
	getDY() * angle.getDX();
    }


    /**
     * Get perpendicular dot product.
     *
     * \param  pos           position
     * \return               perpendicular dot product
     */
    double getPerpDot(const JVector2D& pos) const
    {
      return
	getDX() * pos.getY() -
	getDY() * pos.getX();
    }
    

    /**
     * Read direction from input.
     *
     * \param  in            input stream
     * \param  direction     direction
     * \return               input stream
     */
    friend inline std::istream& operator>>(std::istream& in, JDirection2D& direction)
    {
      in >> direction.__dx >> direction.__dy;

      direction.normalise();

      return in;
    }


    /**
     * Write direction to output.
     *
     * \param  out           output stream
     * \param  direction     direction
     * \return               output stream
     */
    friend inline std::ostream& operator<<(std::ostream& out, const JDirection2D& direction)
    {
      const JFormat format(out, getFormat<JDirection2D>(JFormat_t(9, 6, std::ios::fixed | std::ios::showpos)));

      out << format << direction.getDX() << ' ' 
	  << format << direction.getDY();

      return out;
    }


    /**
     * Read direction from input.
     *
     * \param  in            reader
     * \param  direction     direction
     * \return               reader
     */
    friend inline JReader& operator>>(JReader& in, JDirection2D& direction)
    {
      in >> direction.__dx;
      in >> direction.__dy;

      return in;
    }


    /**
     * Write direction to output.
     *
     * \param  out           writer
     * \param  direction     direction
     * \return               writer
     */
    friend inline JWriter& operator<<(JWriter& out, const JDirection2D& direction)
    {
      out << direction.__dx;
      out << direction.__dy;

      return out;
    }
  };
}

#endif