#include <WiFi.h>
#include <PubSubClient.h>
#include <WiFiClientSecure.h>
// WiFi credentials
const char* ssid = "Wokwi-GUEST";
const char* password = "";

// HiveMQ Cloud credentials
const char* mqtt_server = "a198173aad6e4aab93cfc9eada1636e3.s1.eu.hivemq.cloud";
const int mqtt_port = 8883;
const char* mqtt_user = "ippsm_node";
const char* mqtt_password = "DkE!iZm3jKD2QQS";

WiFiClientSecure espClient;
PubSubClient client(espClient);

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 HiveMQ...");

    String clientId = "ESP32Client-";
    clientId += String(random(0xffff), HEX);

    if (client.connect(
          clientId.c_str(),
          mqtt_user,
          mqtt_password)) {

      Serial.println("Connected");

      client.subscribe("esp32/test");
    } else {
      Serial.print("Failed, rc=");
      Serial.print(client.state());
      Serial.println(" retrying in 5 seconds");

      delay(5000);
    }
  }
}

void callback(char* topic, byte* payload, unsigned int length) {
  Serial.print("Message received [");
  Serial.print(topic);
  Serial.print("]: ");

  for (unsigned int i = 0; i < length; i++) {
    Serial.print((char)payload[i]);
  }

  Serial.println();
}

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

  connectWiFi();

  // For testing only. Production should use HiveMQ CA certificate.
  espClient.setInsecure();

  client.setServer(mqtt_server, mqtt_port);
  client.setCallback(callback);
}

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

  client.loop();

  static unsigned long lastMsg = 0;

  if (millis() - lastMsg > 5000) {
    lastMsg = millis();

    String message = "Hello from ESP32";
    client.publish("nodes", message.c_str());

    Serial.println("Published: " + message);
  }
}