#include <WiFi.h>
#include <PubSubClient.h>
#include <SPI.h>
#include <MFRC522.h>
#include <Wire.h>
#include <LiquidCrystal_I2C.h>

// Pin definitions for RC522
#define SS_PIN   5
#define RST_PIN  2

MFRC522 rfid(SS_PIN, RST_PIN);

// Create an LCD object with I2C address 0x27 (adjust if needed)
LiquidCrystal_I2C lcd(0x27, 16, 2);

// Replace with your network credentials
const char* WIFI_SSID = "Wokwi-GUEST";
const char* WIFI_PASSWORD = "";

// Replace with your MQTT Broker IP or domain
const char* MQTT_SERVER = "test.mosquitto.org";  
// For local Node-RED, use the local machine's IP address, for example "192.168.1.100"

WiFiClient espClient;
PubSubClient client(espClient);

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

  // Initialize LCD (if using)
  lcd.init();
  lcd.backlight();
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Starting...");

  // Initialize SPI and RFID
  SPI.begin();
  rfid.PCD_Init();

  // Connect to Wi-Fi
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
  Serial.print("Connecting to WiFi");
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWiFi connected, IP: ");
  Serial.println(WiFi.localIP());

  // Set up MQTT
  client.setServer(MQTT_SERVER, 1883);

  // Display status
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("WiFi Ready");
  lcd.setCursor(0, 1);
  lcd.print("MQTT Setup...");
}

void loop() {
  // Reconnect to MQTT if needed
  if (!client.connected()) {
    reconnectMQTT();
  }
  client.loop();

  // Check for new cards
  if (rfid.PICC_IsNewCardPresent() && rfid.PICC_ReadCardSerial()) {
    String tagID = "";
    for (byte i = 0; i < rfid.uid.size; i++) {
      if (rfid.uid.uidByte[i] < 0x10) {
        tagID += "0";
      }
      tagID += String(rfid.uid.uidByte[i], HEX);
      if (i < rfid.uid.size - 1) {
        tagID += ":";
      }
    }
    tagID.toUpperCase();

    Serial.print("RFID Detected: ");
    Serial.println(tagID);

    // Publish tag ID to MQTT topic
    client.publish("rfid/data", tagID.c_str());

    // Display on LCD (optional)
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("RFID Tag:");
    lcd.setCursor(0, 1);
    lcd.print(tagID);

    // Halt reading this card so it doesn't repeat instantly
    rfid.PICC_HaltA();
    delay(2000);

    // Optional: show readiness again
    lcd.clear();
    lcd.print("Ready for next");
  }
}

void reconnectMQTT() {
  // Attempt to connect until successful
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    if (client.connect("ESP32Client")) {
      Serial.println("connected");
      // You can subscribe to a topic here if needed
      // client.subscribe("rfid/commands");
    } else {
      Serial.print("failed, rc=");
      Serial.println(client.state());
      delay(2000);
    }
  }
}