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

#define BUF_LEN 128

#define SS_PIN  34  // ESP32 pin GIOP5 
#define RST_PIN 40 // ESP32 pin GIOP27 

MFRC522 rfid(SS_PIN, RST_PIN);

const char* wifi_ssid = "WiFi-2.4-F8D8";
const char* wifi_password = "Y11PuvsFc72U";
const char* mqtt_server = "192.168.1.20";

WiFiClient espClient;
PubSubClient client(espClient);

int count_sleep = 0;

char mqtt_buffer[BUF_LEN];


void setup() {
  Serial.begin(115200);
  SPI.begin(); // init SPI bus
  rfid.PCD_Init(); // init MFRC522
  WiFi.mode(WIFI_STA);
  WiFi.begin(wifi_ssid, wifi_password);
  Serial.print("Connecting to WiFi..");
  while (WiFi.status() != WL_CONNECTED) {
    Serial.print('.');
    delay(1000);
  }
  Serial.println("");
  Serial.println(WiFi.localIP());
  client.setServer(mqtt_server, 1883);
  client.connect("esp32");
  Serial.println("Tap an RFID/NFC tag on the RFID-RC522 reader");
}


void loop() {
  char* ptr_buffer;
  if (rfid.PICC_IsNewCardPresent()) { // new tag is available
    if (rfid.PICC_ReadCardSerial()) { // NUID has been readed
      ptr_buffer = mqtt_buffer;
      for (int i = 0; i < rfid.uid.size; i++) {
        sprintf(ptr_buffer, "%02X", rfid.uid.uidByte[i]);
        ptr_buffer += 2;
      }
      *ptr_buffer = '\0'; // null terminator
      
      Serial.print("RFID: ");
      Serial.println(mqtt_buffer);
      client.publish("RFID", mqtt_buffer);

      rfid.PICC_HaltA(); // halt PICC
      rfid.PCD_StopCrypto1(); // stop encryption on PCD
    }
  }
  
  delay(1);
  count_sleep++;
  if (count_sleep == 50) {
    client.publish("esp32", "still connected");                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                             
    count_sleep = 0;
  }
}