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

const char* mqttHost = "broker.hivemq.com";
const int mqttPort = 1883;
const char* topic = "esp32/testme";
String clientId = "ESP32Client-" + String(random(0xffff), HEX);

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message arrived [");
  Serial.print(topic);
  Serial.print("] ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }
  Serial.println();
}

WiFiClient wifiClient;
PubSubClient mqttClient(mqttHost, mqttPort, callback, wifiClient);

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

void setup_wifi() {
  delay(10);
  WiFi.begin("Wokwi-GUEST", "");

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  randomSeed(micros());

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

void reconnect() {
  // Loop until we're reconnected
  while (!mqttClient.connected()) {
    Serial.println("Client is not connected to MQTT broker. Calling client.connect()...");
    // Attempt to connect
    Serial.print("ClientId:");
    Serial.println(clientId);
    if (mqttClient.connect(clientId.c_str())) {
      Serial.println("Client is connected to MQTT broker.");
      
      // subscribe to something...
      if (mqttClient.subscribe(topic)) {
        Serial.println("SUBSCRIBE successful.");
      } else {
        Serial.println("SUBSCRIBE unsuccessful.");
      }


      // publish something...
      if (mqttClient.publish(topic, "Hello, I am ready!")) {
        Serial.println("PUBLISH successful.");
      } else {
        Serial.println("PUBLISH unsuccessful.");
      }


    } else {
      Serial.print("Client.connect() has failed, Reason Code =");
      Serial.print(mqttClient.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}



void loop() {

  if (!mqttClient.connected()) {
    Serial.println("Client is not connected to MQTT broker. Calling reconnect()...");
    reconnect();
  } 
  mqttClient.loop();
}