const int buttonPin = D0;
const int ledPin = D1;

bool ledState = false;
bool lastButtonState = HIGH;

void setup() {
  pinMode(buttonPin, INPUT_PULLUP); // internal pull-up
  pinMode(ledPin, OUTPUT);

  Serial.begin(115200);
}

void loop() {
  bool buttonState = digitalRead(buttonPin);

  // Detect button press (HIGH → LOW)
  if (lastButtonState == HIGH && buttonState == LOW) {
    ledState = !ledState;              // toggle LED
    digitalWrite(ledPin, ledState);

    if (ledState) {
      Serial.println("LED is ON");
    } else {
      Serial.println("LED is OFF");
    }

    delay(200); // simple debounce
  }

  lastButtonState = buttonState;
}