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

int servoPin = 11;
const int keypadRows = 4;
const int keypadColumns = 4;

const byte rowPins[keypadRows] = {9, 8, 7, 6};
const byte colPins[keypadColumns] = {5, 4, 3, 2};

char keys[keypadRows][keypadColumns] = {
  {'1', '2', '3', 'A'},
  {'4', '5', '6', 'B'},
  {'7', '8', '9', 'C'},
  {'*', '0', '#', 'D'}
};

Keypad keypad = Keypad(makeKeymap((char*)keys), rowPins, colPins, keypadRows, keypadColumns);
LiquidCrystal_I2C lcd(0x27, 20, 4);
Servo servo;

int servoUnlockPos = 90;
 int servoLockPos = 0;

String password = "1234";

void setup() {
  lcd.begin(20, 4);
  lcd.init();
  lcd.setCursor(0, 0);
  lcd.backlight();

  servo.attach(servoPin);
  servo.write(servoLockPos);
}

void loop() {
  lcd.setCursor(1, 0);
  lcd.print("Enter password:");
  String input = inputPassword();

  if (input == password) {
    lcd.clear();
    lcd.setCursor(3, 0);
    lcd.print("Unlocked!");
    servo.write(servoUnlockPos);
    delay(1000);
  } else {
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("WRONG PASSWORD!");
    delay(1000);
  }
}

String inputPassword() {
  String input = "";
  while (input.length() < 4) {
    char key = keypad.getKey();
    if (key >= '0' && key <= '9') {
      lcd.print('*');
      input += key;
    }
  }
  return input;
}