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

#define RST_PIN         9          // Configurable, see typical pin layout above
#define SS_PIN          10         // Configurable, see typical pin layout above

MFRC522 mfrc522(SS_PIN, RST_PIN);  // Create MFRC522 instance

Servo myservo;  // create servo object to control a servo

// Define the angles for the servo motor rotation
#define ANGLE_OPEN    90
#define ANGLE_CLOSE   0

void setup() {
  Serial.begin(9600);  // Initialize serial communications with the PC
  SPI.begin();          // Init SPI bus
  mfrc522.PCD_Init();   // Init MFRC522 card

  myservo.attach(3);  // attaches the servo on pin 3 to the servo object
  myservo.write(ANGLE_CLOSE); // Close the servo initially
  delay(500); // Give some time for servo to reach the initial position
}

void loop() {
  // Look for new cards
  if (mfrc522.PICC_IsNewCardPresent() && mfrc522.PICC_ReadCardSerial()) {
    // Show some details of the PICC (Card)
    Serial.print("Card UID: ");
    dump_byte_array(mfrc522.uid.uidByte, mfrc522.uid.size);
    Serial.println();
    
    // Check if the detected card UID matches with the expected UID
    if (checkUID(mfrc522.uid.uidByte, mfrc522.uid.size)) {
      Serial.println("Access Granted!");
      // Open the servo
      myservo.write(ANGLE_OPEN);
      delay(2000); // Keep the servo open for 2 seconds
      // Close the servo
      myservo.write(ANGLE_CLOSE);
    } else {
      Serial.println("Access Denied!");
    }
  }
  mfrc522.PICC_HaltA(); // Halt PICC
  delay(1000); // Pause for 1 second before next scan
}

// Helper function to print a byte array as a hex string
void dump_byte_array(byte *buffer, byte bufferSize) {
  for (byte i = 0; i < bufferSize; i++) {
    Serial.print(buffer[i] < 0x10 ? " 0" : " ");
    Serial.print(buffer[i], HEX);
  }
}

// Function to compare the detected UID with the expected UID
bool checkUID(byte uid[], byte uidSize) {
  // Replace this with your expected UID
  byte expectedUID[] = {0xAB, 0xCD, 0xEF, 0x12};

  // Check if the sizes match
  if (uidSize != sizeof(expectedUID)) {
    return false;
  }

  // Check each byte of the UID
  for (int i = 0; i < uidSize; i++) {
    if (uid[i] != expectedUID[i]) {
      return false;
    }
  }

  return true;
}