// Program to play the Star Wars theme song when a button is pressed, 
// and stops playing the song as soon as the button is released.
const int pushButton = 2;
const int buzzer = 8;

// this function will delay for the given number of milliseconds
// it will constantly check for the button release
// it will return true immediately if the button is released
// it will return false if the button has not been released after the wait 
bool nonblockingDelay(int millisecond) {
  for (int i=0; i<millisecond; i++) {	// loop to count how many milliseconds
    if (digitalRead(pushButton) == LOW) {
      return true; // return immediately if button is released
    }
    // although the following command is still a blocking delay call
    // 1 millisecond is so fast that it'll be alright for what we want to do
    delay(1);
  }
  return false;
}

// instead of using the long blocking delay commands
// use the non-blocking delay function above
void StarWars() {
  int NOTE_C4 = 262;
  int NOTE_D4 = 294;
  int NOTE_E4 = 330;
  int NOTE_F4 = 349;
  int NOTE_G4 = 392;
  int NOTE_A4 = 440;
  int NOTE_B4 = 494;
  int NOTE_C5 = 523;

  // code to play the first 16 notes of the Star Wars Theme song
  tone(buzzer, NOTE_C4);
  if (nonblockingDelay(1000)) return; // exit song if button was released
  tone(buzzer, NOTE_G4);
  if (nonblockingDelay(1000)) return; // exit song if button was released 
  tone(buzzer, NOTE_F4);
  if (nonblockingDelay(167)) return; // exit song if button was released 
  tone(buzzer, NOTE_E4);
  if (nonblockingDelay(167)) return; // exit song if button was released 
  tone(buzzer, NOTE_D4);
  if (nonblockingDelay(167)) return; // exit song if button was released 
  tone(buzzer, NOTE_C5);
  if (nonblockingDelay(1000)) return; // exit song if button was released 
  tone(buzzer, NOTE_G4);
  if (nonblockingDelay(500)) return; // exit song if button was released 

  tone(buzzer, NOTE_F4);
  if (nonblockingDelay(167)) return; // exit song if button was released 
  tone(buzzer, NOTE_E4);
  if (nonblockingDelay(167)) return; // exit song if button was released 
  tone(buzzer, NOTE_D4);
  if (nonblockingDelay(167)) return; // exit song if button was released 
  tone(buzzer, NOTE_C5);
  if (nonblockingDelay(1000)) return; // exit song if button was released 
  tone(buzzer, NOTE_G4);
  if (nonblockingDelay(500)) return; // exit song if button was released 
  
  tone(buzzer, NOTE_F4);
  if (nonblockingDelay(167)) return; // exit song if button was released 
  tone(buzzer, NOTE_E4);
  if (nonblockingDelay(167)) return; // exit song if button was released 
  tone(buzzer, NOTE_F4);
  if (nonblockingDelay(167)) return; // exit song if button was released 
  tone(buzzer, NOTE_D4);
  if (nonblockingDelay(2000)) return; // exit song if button was released 
  noTone(8);
}

void setup() {
  pinMode(pushButton, OUTPUT);	// use internal pull-down resistor
  pinMode(buzzer, OUTPUT);
}

void loop() {
  if (digitalRead(pushButton) == HIGH) {
    StarWars();
  } else {
    noTone(buzzer);
  }
}