/*
  tempo-performer.cc -- implement Tempo_performer

  source file of the GNU LilyPond music typesetter

  (c) 1997--2004 Jan Nieuwenhuizen <janneke@gnu.org>
*/


#include "audio-item.hh"
#include "performer.hh"

class Tempo_performer : public Performer
{
public:
  TRANSLATOR_DECLARATIONS (Tempo_performer);
  ~Tempo_performer ();

protected:

  virtual bool try_music (Music* req);
  virtual void stop_translation_timestep ();
  virtual void create_audio_elements ();

private:
Music* tempo_req_;
  Audio_tempo* audio_;
};

Tempo_performer::Tempo_performer ()
{
  tempo_req_ = 0;
  audio_ = 0;
}

Tempo_performer::~Tempo_performer ()
{
}


void
Tempo_performer::create_audio_elements ()
{
  if (tempo_req_)
    {

      SCM met = tempo_req_->get_property ("metronome-count");
      Duration *d = unsmob_duration (tempo_req_->get_property ("tempo-unit"));
      
      Rational r =  (d->get_length () / Moment (Rational (1, 4)) * Moment (scm_to_int (met))).main_part_;
      
      audio_ = new Audio_tempo (int (r));

      Audio_element_info info (audio_, tempo_req_);
      announce_element (info);
      tempo_req_ = 0;
    }
}

void
Tempo_performer::stop_translation_timestep ()
{
  if (audio_)
    {
      play_element (audio_);
      audio_ = 0;
    }
}

bool
Tempo_performer::try_music (Music* req)
{
  if (tempo_req_)
    return false;

      tempo_req_ = req;
      return true;
}




ENTER_DESCRIPTION (Tempo_performer, "","",
		   "metronome-change-event",
		   "","","" );
