const int numLEDs = 19;
const int ledPins[numLEDs] = {2, 4, 5, 12, 13, 14, 15, 16, 17, 18, 19, 21, 22, 23, 25, 26, 27, 32, 33};
const int buttonOnOffPin = 34;
const int buttonDurationPin = 35;
const int buttonPausePin = 39;
const int statusLedPin = 0;

int currentLED = 0;
// Default duration, need to store to EEPROM
unsigned long duration = 500;
bool isRunning = false;
bool isPaused = false;
unsigned long previousMillis = 0;

void setup() {
  Serial.begin(115200);
  for (int i = 0; i < numLEDs; i++) {
    pinMode(ledPins[i], OUTPUT);
  }
  pinMode(buttonOnOffPin, INPUT_PULLUP);
  pinMode(buttonDurationPin, INPUT_PULLUP);
  pinMode(buttonPausePin, INPUT_PULLUP);
  pinMode(statusLedPin, OUTPUT);
}

void turnOffAllLEDs() {
  Serial.println("STOPPED.");
  for (int i = 0; i < numLEDs; i++) {
    digitalWrite(ledPins[i], LOW);
  }
}

void loop() 
{
  if (digitalRead(buttonOnOffPin) == LOW) {
    delay(200); 
    isRunning = !isRunning;
    if (isRunning) {
      currentLED = 0;
      previousMillis = millis();
      //Release Pause
      if(isPaused){
        isPaused = false;
      }
    } else {
      turnOffAllLEDs();
    }
  }

  if (digitalRead(buttonDurationPin) == LOW) {
      delay(200);
      
      // Toggle between durations
      if (duration == 500) {
        duration = 1000;
        }
        else if (duration == 1000) {
        duration = 2000;
      } else if (duration == 2000) {
        duration = 3000;
      } else if (duration == 3000) {
        duration = 4000;
      } else if (duration == 4000) {
        duration = 5000;
      } else {
        duration = 1000;
      }
      
      Serial.printf("DURATION %d\n", duration);
      
      // Blink status LED based on duration
      int blinkCount = duration / 1000;
      for (int i = 0; i < blinkCount; i++) {
        digitalWrite(statusLedPin, HIGH);
        delay(500);
        digitalWrite(statusLedPin, LOW);
        delay(500);
      }
    }


    if (digitalRead(buttonPausePin) == LOW) {
      Serial.println("PAUSED..");
      delay(200); 
      isPaused = !isPaused;
    }

    // LED sequence logic
    if (isRunning && !isPaused) {
      unsigned long currentMillis = millis();
      if (currentMillis - previousMillis >= duration) {
        previousMillis = currentMillis;
        turnOffAllLEDs(); 
        if (currentLED < numLEDs) {
          Serial.printf("turning on led %d\n",ledPins[currentLED]);
          digitalWrite(ledPins[currentLED], HIGH);
          currentLED++;
        } else {
          isRunning = false;
        }
      }
    }
}