#include <WiFi.h>
#include <PubSubClient.h>
#include <WiFiClient.h>

// =====================
// ** Wi-Fi Credentials **
// =====================
const char* ssid = "Wokwi-GUEST";  // Replace with your Wi-Fi SSID
const char* password = "";         // Replace with your Wi-Fi password

// =====================
// ** MQTT Credentials **
// =====================
const char* mqttServer = "broker.emqx.io"; // Public MQTT broker
const int mqttPort =1883 ;
const char* mqttTopic = "esp32/led";          // Topic for LED control

WiFiClient espClient;
PubSubClient client(espClient);

// =====================
// ** LED Configuration **
// =====================
#define LED_PIN 5 // GPIO5 connected to the LED

// =====================
// ** Callback Function **
// =====================
void callback(char* topic, byte* message, unsigned int length) {
  String msg;
  for (int i = 0; i < length; i++) {
    msg += (char)message[i];
  }

  Serial.print("Message received on topic ");
  Serial.print(topic);
  Serial.print(": ");
  Serial.println(msg);

  if (msg == "ON") {
    digitalWrite(LED_PIN, HIGH);
    Serial.println("LED turned ON");
  } else if (msg == "OFF") {
    digitalWrite(LED_PIN, LOW);
    Serial.println("LED turned OFF");
  }
}

// =====================
// ** Setup Function **
// =====================
void setup() {
  // Initialize Serial Communication
  Serial.begin(115200);
  pinMode(LED_PIN, OUTPUT);
  digitalWrite(LED_PIN, LOW); // Start with LED OFF

  // Connect to Wi-Fi
  Serial.println("Connecting to Wi-Fi...");
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("\nWi-Fi connected");
  Serial.print("IP Address: ");
  Serial.println(WiFi.localIP());

  // Setup MQTT
  client.setServer(mqttServer, mqttPort);
  client.setCallback(callback);

  while (!client.connected()) {
    Serial.println("Connecting to MQTT...");
    if (client.connect("ESP32Client")) {
      Serial.println("Connected to MQTT broker");
    } else {
      Serial.print("Failed to connect. Error: ");
      Serial.print(client.state());
      delay(2000);
    }
  }

  // Subscribe to the LED control topic
  client.subscribe(mqttTopic);
  Serial.println("Subscribed to topic: esp32/led");
}

// =====================
// ** Loop Function **
// =====================
void loop() {
  // Ensure the ESP32 stays connected to the MQTT broker
  if (!client.connected()) {
    reconnect();
  }
  client.loop(); // Process incoming messages
  
  // Debugging MQTT connection status

}
void reconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    if (client.connect("ESP32Client")) {
      Serial.println("connected");
      client.subscribe(mqttTopic); // Subscribe to the topic once connected
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000); // Retry after 5 seconds
    }
  }
}