const int dataPin = 11;
const int clockPin = 9;
const int latchPin = 12;

const int buttonUp = 2;    
const int buttonDown = 3;  
const int buzzer = 4;      

int counter = 0;
unsigned long lastDebounceTime = 0;
unsigned long debounceDelay = 50;
int lastButtonUpState = HIGH;
int lastButtonDownState = HIGH;

byte digits[10] = {
  B00111111, 
  B00000110, 
  B01011011, 
  B01001111, 
  B01100110, 
  B01101101, 
  B01111101, 
  B00000111, 
  B01111111, 
  B01101111  
};

void beep() {
  tone(buzzer, 1000, 100);
}

void displayNumber(int number) {
  if (number < 0) number = 0;
  if (number > 9) number = 9;
  
  digitalWrite(latchPin, LOW);
  shiftOut(dataPin, clockPin, MSBFIRST, digits[number]);
  digitalWrite(latchPin, HIGH);
}

void checkButtons() {
  int currentButtonUpState = digitalRead(buttonUp);
  int currentButtonDownState = digitalRead(buttonDown);
  
  if (currentButtonUpState == LOW && lastButtonUpState == HIGH) {
    if (millis() - lastDebounceTime > debounceDelay) {
      if (counter < 9) {
        counter++;
      } else {
        beep();
      }
      lastDebounceTime = millis();
    }
  }
  
  if (currentButtonDownState == LOW && lastButtonDownState == HIGH) {
    if (millis() - lastDebounceTime > debounceDelay) {
      if (counter > 0) {
        counter--;
      } else {
        beep();
      }
      lastDebounceTime = millis();
    }
  }
  
  lastButtonUpState = currentButtonUpState;
  lastButtonDownState = currentButtonDownState;
}

void setup() {
  pinMode(dataPin, OUTPUT);
  pinMode(clockPin, OUTPUT);
  pinMode(latchPin, OUTPUT);
  
  pinMode(buttonUp, INPUT_PULLUP);
  pinMode(buttonDown, INPUT_PULLUP);
  pinMode(buzzer, OUTPUT);
  
  displayNumber(0);
}

void loop() {
  checkButtons();
  displayNumber(counter);
  delay(10); 
}