const int buttonPin = 53;  // Active-low button input
const int analogPins[] = {A0, A1, A2, A3, A4, A5, A6, A7, A8, A9, A10, A11, A12, A13, A14, A15};
const int digitalPins[] = {2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19,
                            20, 21, 22, 23, 24, 25, 26, 27, 28, 29,
                            30, 31, 32, 33, 34, 35, 36, 37, 38, 39,
                            40, 41, 42, 43, 44, 45, 46, 47, 48, 49,
                            50, 51, 52, };

int currentOutputIndex = 0;
bool isOscillating = false;
unsigned long lastToggleTime = 0;
bool pinState = LOW;

void setup() {
  pinMode(buttonPin, INPUT_PULLUP); // Active-low button
  for (int i = 0; i < sizeof(analogPins) / sizeof(int); i++) {
    pinMode(analogPins[i], OUTPUT);
  }
  for (int i = 0; i < sizeof(digitalPins) / sizeof(int); i++) {
    pinMode(digitalPins[i], OUTPUT);
  }
}

void loop() {
  static bool lastButtonState = HIGH;
  bool buttonState = digitalRead(buttonPin);

  // Check for falling edge
  if (lastButtonState == HIGH && buttonState == LOW) {
    // Turn off previous pin
    setCurrentPin(LOW);

    // Move to next pin
    currentOutputIndex++;
    int totalPins = sizeof(analogPins) / sizeof(int) + sizeof(digitalPins) / sizeof(int);
    if (currentOutputIndex >= totalPins) {
      currentOutputIndex = 0;
    }

    // Start oscillation
    isOscillating = true;
    pinState = LOW;
    lastToggleTime = millis();
  }
  lastButtonState = buttonState;

  // Oscillate selected pin
  if (isOscillating && millis() - lastToggleTime >= 500) { // 1Hz = toggle every 500ms
    pinState = !pinState;
    setCurrentPin(pinState);
    lastToggleTime = millis();
  }
}

void setCurrentPin(bool state) {
  int totalAnalog = sizeof(analogPins) / sizeof(int);
  if (currentOutputIndex < totalAnalog) {
    digitalWrite(analogPins[currentOutputIndex], state);
  } else {
    digitalWrite(digitalPins[currentOutputIndex - totalAnalog], state);
  }
}