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

// LCD setup
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Keypad setup
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] = {19, 18, 5, 17};
byte colPins[COLS] = {16, 4, 2, 15};
Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

// Password
String password = "1234";
String inputPassword = "";

// Lock LED
#define LED_PIN 23  

void setup() {
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW); // Locked by default

  lcd.init();
  lcd.backlight();
  lcd.setCursor(0,0);
  lcd.print("Enter Password:");
}

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

  if (key) {
    if (key == '#') { // Enter
      if (inputPassword == password) {
        lcd.clear();
        lcd.print("Access Granted");
        digitalWrite(LED_PIN, HIGH); // Unlock (LED ON)
        delay(2000);
      } else {
        lcd.clear();
        lcd.print("Access Denied");
        digitalWrite(LED_PIN, LOW); // Keep locked
        delay(2000);
      }
      inputPassword = "";
      lcd.clear();
      lcd.print("Enter Password:");
    } 
    else if (key == '*') { // Clear input
      inputPassword = "";
      lcd.clear();
      lcd.print("Enter Password:");
    } 
    else {
      inputPassword += key;
      lcd.setCursor(0,1);
      lcd.print(inputPassword);
    }
  }
}