#include <WiFi.h>
#include <PubSubClient.h>
// https://testclient-cloud.mqtt.cool/ has to be opened separately
// WiFi credentials (Wokwi default)
const char* ssid = "Wokwi-GUEST";
const char* password = "";

// MQTT Broker details
const char* mqttServer = "broker.hivemq.com";
const int mqttPort = 1883;

// MQTT topic to subscribe
const char* subscribeTopic = "esp32/wokwi/MQTT";

// WiFi & MQTT clients
WiFiClient espClient;
PubSubClient client(espClient);

// Callback when message is received
void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message received on topic: ");
  Serial.println(topic);

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

void connectWiFi() {
  Serial.print("Connecting to WiFi");
  WiFi.begin(ssid, password);

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

  Serial.println("\nWiFi connected");
  Serial.print("IP Address: ");
  Serial.println(WiFi.localIP());
}

void reconnectMQTT() {
  while (!client.connected()) {
    Serial.print("Connecting to MQTT...");
    if (client.connect("ESP32-Wokwi-Subscriber")) {
      Serial.println("connected");
      client.subscribe(subscribeTopic);
      Serial.print("Subscribed to topic: ");
      Serial.println(subscribeTopic);
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" retrying in 5 seconds");
      delay(5000);
    }
  }
}

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

  connectWiFi();

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

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

  client.loop();
}