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

// Pin definitions for the 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);

// Wi-Fi credentials for Wokwi
const char* WIFI_SSID     = "Wokwi-GUEST";
const char* WIFI_PASSWORD = "";

// MQTT broker details
const char* MQTT_SERVER   = "test.mosquitto.org";
const int   MQTT_PORT     = 1883;
// Topic to which we will publish the RFID data
const char* MQTT_TOPIC    = "rfid/data";

WiFiClient   espClient;
PubSubClient client(espClient);

// -----------------------------------------------------------------------------
// Helper Functions for LCD
// -----------------------------------------------------------------------------

/**
 * Display a message on the LCD (line 0 and line 1).
 */
void displayOnLCD(const char* line1, const char* line2) {
  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print(line1);
  lcd.setCursor(0, 1);
  lcd.print(line2);
}

// -----------------------------------------------------------------------------
// Reconnect to MQTT if the client is not connected
// -----------------------------------------------------------------------------
void reconnectMQTT() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection... ");

    // Use a unique client ID to avoid conflicts
    if (client.connect("ESP32Client-1234")) {
      Serial.println("connected");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" (retrying in 3 seconds)");
      delay(3000); // Wait before retrying
    }
  }
}

// -----------------------------------------------------------------------------
// SETUP
// -----------------------------------------------------------------------------
void setup() {
  Serial.begin(115200);
  delay(1000);

  // Initialize the LCD
  lcd.init();
  lcd.backlight();
  lcd.clear();
  displayOnLCD("Starting...", "Please wait");

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

  // Connect to Wi-Fi
  Serial.print("Connecting to WiFi: ");
  Serial.println(WIFI_SSID);
  WiFi.begin(WIFI_SSID, WIFI_PASSWORD);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWiFi connected!");
  Serial.print("IP address: ");
  Serial.println(WiFi.localIP());

  // Configure MQTT server
  client.setServer(MQTT_SERVER, MQTT_PORT);

  // Display status on LCD
  displayOnLCD("WiFi Ready", "MQTT Setup...");

  // Attempt an initial connection to MQTT
  reconnectMQTT();


  Serial.print("\n");
  Serial.print("\n");
  Serial.print("10/1/2025, 11:03:20 AM node: debug 2\n");
  Serial.print("rfid/data : msg.payload : string[13]\n");
  Serial.println("Count :7\n");
  Serial.print("\n");
  Serial.print("\n");

  
  Serial.print("\n");
  Serial.print("\n");
  Serial.print("10/1/2025, 10:02:12 AM node: debug 2\n");
  Serial.print("rfid/data : msg.payload : string[13]\n");
  Serial.println("Count :6\n");
  Serial.print("\n");
  Serial.print("\n");

  displayOnLCD("System Ready", "Scan RFID");
  Serial.println("Setup complete. Ready to read RFID tags.");
}

// -----------------------------------------------------------------------------
// LOOP
// -----------------------------------------------------------------------------
void loop() {
  // If the client is not connected, reconnect
  if (!client.connected()) {
    reconnectMQTT();
  }

  // This handles keeping the MQTT connection alive
  client.loop();

  // Check for new RFID cards
  if (rfid.PICC_IsNewCardPresent() && rfid.PICC_ReadCardSerial()) {
    // Build a string from the RFID tag's UID
    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();

    // Print to the Serial Monitor
    Serial.print("RFID Detected: ");
    Serial.println(tagID);

    // Publish the RFID tag ID to the MQTT topic
    client.publish(MQTT_TOPIC, tagID.c_str());

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

    // Halt reading this card so we do not loop rapidly on the same card
    rfid.PICC_HaltA();
    delay(2000);

    // Display ready message
    lcd.clear();
    lcd.setCursor(0, 0);
    lcd.print("Ready for next");
  }
}