#ifndef __JACOUSTICS__JABSTRACTSOUNDVELOCITY__
#define __JACOUSTICS__JABSTRACTSOUNDVELOCITY__

/**
 * \file
 *
 * Abstract sound velocity.
 * \author mdejong
 */
namespace JACOUSTICS {}
namespace JPP { using namespace JACOUSTICS; }

namespace JACOUSTICS {

  /**
   * Interface for depth dependend velocity of sound.
   *
   * Note that the z-axis is pointing upwards.
   */
  struct JAbstractSoundVelocity {
    /**
     * Virtual destructor.
     */
    virtual ~JAbstractSoundVelocity()
    {}


    /**
     * Get velocity of sound.
     *
     * \return                velocity [m/s]
     */
    virtual double operator()() const = 0;


    /**
     * Get velocity of sound at given depth relative to seabed.
     *
     * \param  z              depdth [m]
     * \return                velocity [m/s]
     */
    virtual double operator()(const double z) const
    {
      return (*this)();
    }


    /**
     * Get distance travelled by sound.
     *
     * \param  t_s            time  [s]
     * \param  z1             depth [m]
     * \param  z2             depth [m]
     * \return                distance [m]
     */
    virtual double getDistance(const double t_s,
			       const double z1,
			       const double z2) const = 0;


    /**
     * Get propagation time of sound.
     * 
     * \param  D_m            distance [m]
     * \param  z1             depth [m]
     * \param  z2             depth [m]
     * \return                time  [s]
     */
    virtual double getTime(const double D_m,
			   const double z1,
			   const double z2) const = 0;


    /**
     * Get inverse velocity of sound.
     *
     * \param  D_m            distance [m]
     * \param  z1             depth [m]
     * \param  z2             depth [m]
     * \return                inverse velocity [s/m]
     */
    virtual double getInverseVelocity(const double D_m,
				      const double z1,
				      const double z2) const = 0;
  };
}

#endif