#include <Arduino.h>
//=========================
//  RFID-RC522 wire pin
//  SDA = 5   SCK =18
//  MOSI=23   MISO=19
//  RST = 4  
//  GND , VCC
//=========================

void setup() {
  Serial.begin(115200); // Initialize serial communications
  // Initial state: turn off buzzer, LEDs, and relay
  Serial.println("Enter MFRC522 UID (format: XX XX XX XX):");
}

void loop() {
  if (Serial.available()) {
    String input = Serial.readStringUntil('\n');
    input.trim(); // Remove any leading or trailing whitespace
    if (isValidFormat(input)) {
      Serial.println("Valid format.");
    } else {
      Serial.println("Invalid format. Enter Enter MFRC522 UID (format: XX XX XX XX):");
    }
  }
}

bool isValidFormat(String input) {
  // Check if the input matches the format "XX XX XX XX"
  if (input.length() == 11 && input.charAt(2) == ' ' && input.charAt(5) == ' ' && input.charAt(8) == ' ') {
    for (int i = 0; i < input.length(); i++) {
      if (i != 2 && i != 5 && i != 8) {
        if (!isDigit(input.charAt(i))) {
          return false;
        }
      }
    }
    return true;
  }
  return false;
}