const int buttonPin = 2;
const int ledPin = 11;  // Use PWM-capable pin

int buttonState;
int lastButtonState = LOW;
unsigned long lastDebounceTime = 0;
unsigned long debounceDelay = 50;

int state = 0;

void setup() {
  pinMode(buttonPin, INPUT);
  pinMode(ledPin, OUTPUT);
}

void loop() {
  int reading = digitalRead(buttonPin);

  if (reading != lastButtonState) {
    lastDebounceTime = millis();
  }

  if ((millis() - lastDebounceTime) > debounceDelay) {
    if (reading == HIGH && lastButtonState == LOW) {
      state = (state + 1) % 3;
    }
  }

  lastButtonState = reading;

  switch (state) {
    case 0:
      analogWrite(ledPin, 0);  // LED off
      break;

    case 1:
      for (int i = 0; i <= 255; i++) {
        analogWrite(ledPin, i);
        delay(4);  // Roughly 1 second up
      }
      for (int i = 255; i >= 0; i--) {
        analogWrite(ledPin, i);
        delay(4);  // Roughly 1 second down
      }
      break;

    case 2:
      analogWrite(ledPin, 255);  // LED on full
      break;
  }
}