const int buttonPin = 4;
const int ledPin = 9;

int currentBrightness = 128;
int savedBrightness = 128;
unsigned long pressStartTime = 0;
bool isLongPress = false;


bool isFading = false;
int fadeTarget = 0;
unsigned long fadePreviousMillis = 0;
const int fadeInterval = 10;
void setup() {
  pinMode(buttonPin, INPUT_PULLUP);
  pinMode(ledPin, OUTPUT);
  analogWrite(ledPin, currentBrightness);
}

void loop() {
  unsigned long currentMillis = millis();

 
  if (digitalRead(buttonPin) == LOW) {
    if (pressStartTime == 0) {
      pressStartTime = currentMillis;
    }
    
    if (currentMillis - pressStartTime > 1000 && !isLongPress) {
      isLongPress = true;
      startFade(0); 
    }
  } else {
    
    if (pressStartTime != 0) {
      if (!isLongPress) {
       
        savedBrightness = random(10, 255);
        analogWrite(ledPin, savedBrightness);
        currentBrightness = savedBrightness;
      }
      pressStartTime = 0;
      isLongPress = false;
    }
  }

  
  if (isFading) {
    updateFade(currentMillis);
  }
}


void startFade(int target) {
  fadeTarget = target;
  isFading = true;
  fadePreviousMillis = millis();
}


void updateFade(unsigned long currentMillis) {
  if (currentMillis - fadePreviousMillis >= fadeInterval) {
    fadePreviousMillis = currentMillis;

    if (currentBrightness < fadeTarget) {
      currentBrightness++;
      analogWrite(ledPin, currentBrightness);
    } else if (currentBrightness > fadeTarget) {
      currentBrightness--;
      analogWrite(ledPin, currentBrightness);
    }

    
    if (currentBrightness == fadeTarget) {
      isFading = false;
      
      if (fadeTarget == 0) {
        delay(300);
        startFade(savedBrightness);
      }
    }
  }
}