const int buzzerPin = 2;
const int redLedPins[4] = {8, 9, 10, 11};
const int greenLedPins[4] = {4, 5, 6, 7};
const int buttonPin = 12;

#define RED_ON    for( auto pin:redLedPins)   digitalWrite(pin, HIGH)
#define RED_OFF   for( auto pin:redLedPins)   digitalWrite(pin, LOW)
#define GREEN_ON  for( auto pin:greenLedPins) digitalWrite(pin, HIGH)
#define GREEN_OFF for( auto pin:greenLedPins) digitalWrite(pin, LOW)

bool triggered = false;
unsigned long previousMillisDuration;
const unsigned long duration = 2000;       // duration of blinking leds and buzzer
unsigned long previousMillisBlink;
const unsigned long blinkTime = 500;       // blinktime for blinking leds
int count;

int lastButtonState;

void setup() 
{
  Serial.begin(9600);
  Serial.println( "Led flasher");
  Serial.println( "-----------");


  pinMode( buzzerPin, OUTPUT);

  for( auto pin:redLedPins)
    pinMode( pin, OUTPUT);
  for( auto pin:greenLedPins)
    pinMode( pin, OUTPUT);

  pinMode( buttonPin, INPUT);


  // --------------------------------------------------
  // STARTUP ROUTINE - All LED's FLASH TWICE
  // --------------------------------------------------
  for( int i=0; i<2; i++)
  {
    RED_ON; 
    GREEN_ON;
    delay(500);
    RED_OFF;
    GREEN_OFF;
    delay(500);
  }
}


void loop() 
{
  unsigned long currentMillis = millis();

  // --------------------------------------------------
  // State Change Detection for trigger input
  // --------------------------------------------------
  int buttonState = digitalRead( buttonPin);
  if( buttonState != lastButtonState)
  {
    if( buttonState == HIGH)        // triggered ?
    {
      Serial.println( "Trigger");
      previousMillisDuration = currentMillis;
      triggered = true;

      tone( 2, 500);
    }
    lastButtonState = buttonState;
  }

  // --------------------------------------------------
  // millis-timer
  // --------------------------------------------------
  if( triggered)
  {
    if( currentMillis - previousMillisBlink >= blinkTime)
    {
      previousMillisBlink = currentMillis;

      switch( count)
      {
        case 0:
          GREEN_ON;
          break;
        case 1:
          GREEN_OFF;
          break;
        case 2:
          RED_ON;
          break;
        case 3:
          RED_OFF;
          break;
      }

      count++;
      if( count >= 4)
        count = 0;
    }

    if( currentMillis - previousMillisDuration >= duration)
    {
      noTone( 2);
      GREEN_OFF;
      RED_OFF;
      triggered = false;
      Serial.println( "Waiting ...");
    }
  }
}