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

const char* ssid = "Wokwi-GUEST";
const char* password = "";

const char* mqttServer = "broker.hivemq.com";
const int mqttPort = 1883;

WiFiClient espClient;
PubSubClient client(espClient);

void callback(char* topic, byte* message, unsigned int length) {
  Serial.print("Message from topic: ");
  Serial.println(topic);

  Serial.print("Message: ");
  for (int i = 0; i < length; i++) {
    Serial.print((char)message[i]);
  }
  Serial.println();
}

void connectToMqtt() {
  while (!client.connected()) {
    Serial.println("Connecting to MQTT...");

    if (client.connect("esp32s3-wokwi-client")) {
      Serial.println("MQTT connected!");
      client.subscribe("esp32/wokwi/test");
    } else {
      Serial.print("Failed. Retry in 2 sec...");
      delay(2000);
    }
  }
}

void setup() {
  Serial.begin(115200);
  delay(300);

  Serial.println("Connecting to WiFi...");
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(300);
    Serial.print(".");
  }
  Serial.println("\nWiFi connected!");

  client.setServer(mqttServer, mqttPort);
  client.setCallback(callback);

  connectToMqtt();
}

void loop() {
  if (!client.connected()) {
    connectToMqtt();
  }

  client.loop();

  static unsigned long lastMsg = 0;

  if (millis() - lastMsg > 3000) {
    lastMsg = millis();
    client.publish("esp32/wokwi/test", "Hello from Wokwi ESP32-S3");
    Serial.println("Message published");
  }
}