#include <Wire.h>
#include <LiquidCrystal_I2C.h>

#define buttonPin 2
#define potPin A0
#define LED 9

LiquidCrystal_I2C lcd(0x27, 16, 2);
int countdownTime = 0;
unsigned long startTime = 0;
bool countdownStarted = false;

void setup() {
  lcd.init();
  lcd.backlight();
  pinMode(buttonPin, INPUT_PULLUP);
  pinMode(LED, OUTPUT);
}

void loop() {
  int potValue = map(analogRead(potPin), 0, 1023, 1, 600);
  lcd.setCursor(0, 0);
  lcd.print("Szamlalas: ");
  lcd.print(potValue);
  lcd.print("s  ");

  if (digitalRead(buttonPin) == LOW && !countdownStarted) {
    countdownTime = potValue;
    startTime = millis();
    countdownStarted = true;
  }

  if (countdownStarted) {
      int remainingTime = countdownTime - (millis() - startTime) / 1000;
      lcd.setCursor(0, 1);
      lcd.print("Hatralevo: ");
      lcd.print(remainingTime);
      lcd.print("s  ");
      if (remainingTime <= 0) {
        digitalWrite(LED, HIGH);
        delay(1000);
        digitalWrite(LED, LOW);
        countdownStarted = false;
      }
  }
}