/*
  midi-walker.cc -- implement Midi_walker

  source file of the GNU LilyPond music typesetter

  (c) 1997--2006 Han-Wen Nienhuys <hanwen@xs4all.nl>
  Jan Nieuwenhuizen <janneke@gnu.org>
*/

#include "midi-walker.hh"

#include "audio-column.hh"
#include "audio-staff.hh"
#include "midi-item.hh"
#include "midi-stream.hh"
#include "warn.hh"

Midi_note_event::Midi_note_event ()
{
  ignore_b_ = false;
}

int
compare (Midi_note_event const &left, Midi_note_event const &right)
{
  Moment m = (left.key - right.key);

  if (m < 0)
    return -1;
  else if (m > 0)
    return 1;
  else
    return 0;
}

Midi_walker::Midi_walker (Audio_staff *audio_staff, Midi_track *track)
{
  track_ = track;
  index_ = 0;
  items_ = &audio_staff->audio_items_;

  last_mom_ = 0;
}

Midi_walker::~Midi_walker ()
{
  // ugh
  do_stop_notes (last_mom_ + Moment (Rational (10, 1)));
}

/**
   Find out if start_note event is needed, and do it if needed.
*/
void
Midi_walker::do_start_note (Midi_note *note)
{
  Audio_item *ptr = (*items_)[index_];
  Moment stop_mom = note->get_length () + ptr->audio_column_->at_mom ();

  bool play_start = true;
  for (vsize i = 0; i < stop_note_queue.size (); i++)
    {
      /* if this pith already in queue */
      if (stop_note_queue[i].val->get_pitch () == note->get_pitch ())
	{
	  if (stop_note_queue[i].key < stop_mom)
	    {
	      /* let stopnote in queue be ignored,
		 new stop note wins */
	      stop_note_queue[i].ignore_b_ = true;
	      /* don't replay start note, */
	      play_start = false;
	      break;
	    }
	  else
	    {
	      /* skip this stopnote,
		 don't play the start note */
	      delete note;
	      note = 0;
	      break;
	    }
	}
    }

  if (note)
    {
      Midi_note_event e;
      e.val = new Midi_note_off (note);
      e.key = stop_mom;
      stop_note_queue.insert (e);

      if (play_start)
	output_event (ptr->audio_column_->at_mom (), note);
    }
}

/**
   Output note events for all notes which end before #max_mom#
*/
void
Midi_walker::do_stop_notes (Moment max_mom)
{
  while (stop_note_queue.size () && stop_note_queue.front ().key <= max_mom)
    {
      Midi_note_event e = stop_note_queue.get ();
      if (e.ignore_b_)
	{
	  delete e.val;
	  continue;
	}

      Moment stop_mom = e.key;
      Midi_note *note = e.val;

      output_event (stop_mom, note);
    }
}

/**
   Advance the track to #now#, output the item, and adjust current "moment".
*/
void
Midi_walker::output_event (Moment now_mom, Midi_item *l)
{
  Moment delta_t = now_mom - last_mom_;
  last_mom_ = now_mom;

  /*
    this is not correct, but at least it doesn't crash when you
    start with graces
  */
  if (delta_t < Moment (0))
    delta_t = Moment (0);

  track_->add (delta_t, l);
}

void
Midi_walker::process ()
{
  Audio_item *audio = (*items_)[index_];
  do_stop_notes (audio->audio_column_->at_mom ());

  if (Midi_item *midi = Midi_item::get_midi (audio))
    {
      midi->channel_ = track_->channel_;
      //midi->channel_ = track_->number_;
      if (Midi_note *note = dynamic_cast<Midi_note *> (midi))
	{
	  if (note->get_length ().to_bool ())
	    do_start_note (note);
	}
      else
	output_event (audio->audio_column_->at_mom (), midi);
    }
}

bool
Midi_walker::ok () const
{
  return index_ < items_->size ();
}

void
Midi_walker::operator ++ (int)
{
  assert (ok ());
  index_++;
}
