#include <SPI.h>
#include <MFRC522.h>
#include <Keypad.h>
#include <LiquidCrystal_I2C.h>
#include <Servo.h>

#define SS_PIN 5
#define RST_PIN 22
#define PIR_PIN 27
#define BUZZER 2
#define SERVO_PIN 4

MFRC522 mfrc522(SS_PIN, RST_PIN);
LiquidCrystal_I2C lcd(0x27, 16, 2);
Servo myServo;

String correctUID = "A1B2C3D4";   // Replace with your card UID
String correctPIN = "1234";

String enteredPIN = "";

// 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] = {13, 12, 14, 26};
byte colPins[COLS] = {25, 33, 32, 15};

Keypad keypad = Keypad(makeKeymap(keys), rowPins, colPins, ROWS, COLS);

void setup() {
  Serial.begin(115200);
  SPI.begin();
  mfrc522.PCD_Init();

  pinMode(PIR_PIN, INPUT);
  pinMode(BUZZER, OUTPUT);

  myServo.attach(SERVO_PIN);
  myServo.write(0); // Lock position

  lcd.init();
  lcd.backlight();
  lcd.print("Security System");
  delay(2000);
  lcd.clear();
}

void loop() {

  if (digitalRead(PIR_PIN) == HIGH) {
    lcd.setCursor(0,0);
    lcd.print("Scan Card/PIN");

    checkRFID();
    checkKeypad();
  }
}

void checkRFID() {
  if (!mfrc522.PICC_IsNewCardPresent()) return;
  if (!mfrc522.PICC_ReadCardSerial()) return;

  String uidStr = "";
  for (byte i = 0; i < mfrc522.uid.size; i++) {
    uidStr += String(mfrc522.uid.uidByte[i], HEX);
  }

  uidStr.toUpperCase();

  if (uidStr == correctUID) {
    grantAccess();
  } else {
    denyAccess();
  }
}

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

  if (key) {
    if (key == '#') {
      if (enteredPIN == correctPIN) {
        grantAccess();
      } else {
        denyAccess();
      }
      enteredPIN = "";
    } else {
      enteredPIN += key;
    }
  }
}

void grantAccess() {
  lcd.clear();
  lcd.print("Access Granted");
  myServo.write(90); // Unlock
  delay(5000);
  myServo.write(0);  // Lock
  lcd.clear();
}

void denyAccess() {
  lcd.clear();
  lcd.print("Access Denied");
  digitalWrite(BUZZER, HIGH);
  delay(2000);
  digitalWrite(BUZZER, LOW);
  lcd.clear();
}