////////////////////////////////////// PLAY TUNE
//////////////////////////////////////

#include "play.h"

#include <avr/io.h>
#include <avr/pgmspace.h>

int repcnt;
int dur;
int chan;
const unsigned char *tune;
const unsigned char *tuneStartPos;
int ramTune = 0;
struct tune_rec {
  const unsigned char *ptr;
  const unsigned char *startp;
  int rep;
  int ram;
}tunestk[4];
int tunesp = 0;

void repeatTune(int n)
{
  repcnt = n;
}

void startTune( const unsigned char *data, int ram)
{
  tunestk[tunesp].ptr = tune;
  tunestk[tunesp].ram = ramTune;
  tunestk[tunesp].rep = repcnt;
  tunestk[tunesp].startp = tuneStartPos;
  tune = data;
  tuneStartPos = data;
  ramTune = ram;
  if( tunesp < 3){
    tunesp++;
  }
}

int playing()
{
  if( tune == NULL){
    return 0;
  }
  return 1;
}

void playTune()
{  byte d;
  byte t;

  while( tune){
    if( ramTune){
      d = tune[0];
      t = tune[1];
    }else {
      d = pgm_read_byte_near(tune);
      t = pgm_read_byte_near(tune+1);
    }

    if( d ==0 && t == 0){
      if( repcnt > 0){
        --repcnt;
        if( repcnt == 0){
          tune = NULL;
        }else {
          tune = tuneStartPos; // repeat tune
        }
      }else {
        // pop the tune stack.
        if( tunesp > 0){
          tunesp--;
          tune = tunestk[tunesp].ptr;
          ramTune = tunestk[tunesp].ram;
          repcnt = tunestk[tunesp].rep;
          tuneStartPos = tunestk[tunesp].startp;
        }else {
          tune = NULL;
        }
      }
      monophonic = 0;
      
#ifdef DEBUGNOTE
Serial.print("End of Tune\n");
#endif
	break;
    }else {
      if( t == 1){
       if( noteOn(d, 0x7f, chan) == 0 ){
         tune = &tune[2];
       }
       continue;
      }else if( t == 2){
       noteOff(d, chan);
       tune = &tune[2];
       continue;
      }else if( t == 6){
        if( dur ==0){
          dur = d;
        }else {
          --dur;
          if( dur == 0){
            // end of duration
            tune = &tune[2];
          }
        }
        break;
      }else if( t == 7){
        if( d == 1){
          monophonic = 1;
        }else if( d == 0){
          monophonic = 0;
        }
        tune = &tune[2];
 	   continue;
      }else if( t == 8){
  	   // channel select
        chan = d;
        tune = &tune[2];
        continue;
      }else { 
       tune = &tune[2];
      }
    }
  }
    
}