#include <WiFi.h>            // Include the WiFi library
#include <PubSubClient.h>    // Include the MQTT library

const char* ssid = "iPhone Ernesto (2)";     // WiFi network name (SSID)
const char* password = "****";           // WiFi password
const char* mqtt_server = "broker.hivemq.com"; // MQTT broker server address

WiFiClient espClient;       // Create a WiFi client instance
PubSubClient client(espClient);  // Create a MQTT client instance

void setup() {
  pinMode(10, OUTPUT);      // Set pin 10 as an output for LED
  Serial.begin(115200);     // Start the serial communication
  setup_wifi();             // Setup WiFi connection
  client.setServer(mqtt_server, 1883);   // Set the MQTT broker server and port
  client.setCallback(callback);   // Set callback function to handle incoming messages
}

void setup_wifi() {
  delay(10);
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  
  WiFi.begin(ssid, password);   // Connect to WiFi network
  
  while (WiFi.status() != WL_CONNECTED) {  // Wait for WiFi connection
    delay(500);
    Serial.print(".");
  }

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());   // Print local IP address
}

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message received [");
  Serial.print(topic);
  Serial.print("] ");
  
  String msg;
  for (int i = 0; i < length; i++) {
    msg += (char)payload[i];   // Convert payload to string
  }
  Serial.println(msg);   // Print received message

  if (msg == "H") {
    digitalWrite(10, HIGH);   // Turn on LED if message is "H"
    Serial.println("LED turned on");
  } else if (msg == "L") {
    digitalWrite(10, LOW);    // Turn off LED if message is "L"
    Serial.println("LED turned off");
  }
}

void reconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    if (client.connect("ArduinoUnoR4ESP32S3")) {  // Attempt to connect to MQTT broker
      Serial.println("connected");
      client.subscribe("led/control");   // Subscribe to "led/control" topic
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" trying again in 5 seconds");
      delay(5000);   // Wait 5 seconds before retrying
    }
  }
}

void loop() {
  if (!client.connected()) {
    reconnect();   // If MQTT connection is lost, attempt to reconnect
  }
  client.loop();    // Maintain MQTT connection and handle incoming messages
}