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

LiquidCrystal_I2C lcd(0x27, 16, 2); // SDA na 21 a SCL na 22

const byte ROWS = 4; 
const byte COLS = 4; 
char keys[ROWS][COLS] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};
byte rowPins[ROWS] = {33, 18, 19, 23}; 
byte colPins[COLS] = {26, 25, 4, 32}; 
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

String enteredCode = "";
String correctCode = "1234"; // Defaultný kód
bool enteringNewCode = false;

void setup() {
  Serial.begin(115200);
  lcd.init();
  lcd.backlight();
  lcd.print("Enter code:");
}

void loop() {
  char key = keypad.getKey();

  if (key) {
    handleKeypadInput(key);
  }
}

void handleKeypadInput(char key) {
  if (key == '#') { // Confirm code
    lcd.clear();
    if (!enteringNewCode) {
      if (enteredCode == correctCode) {
        lcd.print("Code OK");
      } else {
        lcd.print("Wrong code");
      }
    } else {
      correctCode = enteredCode;
      lcd.print("Code updated");
      enteringNewCode = false;
    }
    enteredCode = "";
    delay(1500);
    lcd.clear();
    lcd.print("Enter code:");
  } else if (key == '*') { // Clear input
    enteredCode = "";
    lcd.clear();
    lcd.print("Enter code:");
  } else if (key == 'A') { // Start changing code
    enteringNewCode = true;
    enteredCode = "";
    lcd.clear();
    lcd.print("New code:");
  } else { // Add to entered code
    enteredCode += key;
    lcd.clear();
    lcd.print(enteredCode);
  }
}