void setup() {
  pinMode(2, INPUT);
  pinMode(11, OUTPUT);
  pinMode(10, INPUT);
  pinMode(9, OUTPUT);
  pinMode(A0, INPUT);
}

bool autoMode = true;
int manualColor = 0;

unsigned long btnTime = 0;
bool btnActive = false;

void loop() {
  detectButtonPress();
  if (autoMode) {
    setAutoLight();
  } else {
    setManualColor();
  }
  delay(50);
}

void detectButtonPress() {
  if (digitalRead(2) == LOW && !btnActive) {
    delay(10);                         
    if (digitalRead(2) == LOW) {       
      btnActive = true;
      btnTime = millis()
    }
  }
  if (digitalRead(2) == HIGH && btnActive) {
    delay(10);                         
    if (digitalRead(2) == HIGH) {      
      btnActive = false;
      unsigned long pressTime = millis() - btnTime;
      if (pressTime < 500) {
        if (!autoMode) {
          manualColor = (manualColor + 1) % 3;
        }
      } else {
        changeOperationMode();
      }
    }
  }
}

void changeOperationMode() {
  autoMode = !autoMode;
  setColor(0, 0, 0);
}

void setAutoLight() {
  int light = analogRead(A0);
  if (light > 800) {
    setColor(255, 100, 50);
  } else if (light > 500) {
    setColor(150, 150, 100);
  } else {
    setColor(0, 0, 0);
  }
}

void setManualColor() {
  if (manualColor == 0) {
    setColor(255, 255, 255);
  } else if (manualColor == 1) {
    setColor(255, 150, 50);
  } else if (manualColor == 2) {
    setColor(50, 50, 255);
  }
}

void setColor(int red, int green, int blue) {
  analogWrite(11, red);
  analogWrite(10, green);
  analogWrite(9, blue);
}