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

#define SS_PIN 5
#define RST_PIN 22

#define GREEN_LED 2
#define RED_LED 4
#define BUZZER 15

MFRC522 rfid(SS_PIN, RST_PIN);

byte testUID[4] = {0xA3, 0xF4, 0x12, 0xBC};

void setup() {
  Serial.begin(115200);

  SPI.begin(18, 19, 23, 5);
  rfid.PCD_Init();

  pinMode(GREEN_LED, OUTPUT);
  pinMode(RED_LED, OUTPUT);
  pinMode(BUZZER, OUTPUT);

  Serial.println("Ready");
}

void loop() {

  // SIMULATION MODE (Wokwi trick)
  simulateScan();
  delay(3000);
}

void simulateScan() {

  Serial.println("Card detected");

  String uid = "A3F412BC";

  if (uid == "A3F412BC") {
    Serial.println("PRESENT");

    digitalWrite(GREEN_LED, HIGH);
    tone(BUZZER, 1000);
    delay(200);

    digitalWrite(GREEN_LED, LOW);
    noTone(BUZZER);
  }
  else {
    Serial.println("UNKNOWN");

    digitalWrite(RED_LED, HIGH);
    tone(BUZZER, 300);
    delay(500);

    digitalWrite(RED_LED, LOW);
    noTone(BUZZER);
  }
}