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

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

const char* mqttServer = "broker.hivemq.com";
const int mqttPort = 1883;
const char* mqttTopic = "sija/iot/dht";

const int DHTPin = 4; 
const int DHTType = DHT22; 

WiFiClient wifiClient;
PubSubClient mqttClient(wifiClient);
DHT dht(DHTPin, DHTType); 

void setup() {
  Serial.begin(9600);
  connectToInternet();
  setupMQTT();
  dht.begin();
}

void connectToInternet() {
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
  }
  Serial.println("");
  Serial.println("Connected to Wi-Fi");
  Serial.print("IP Address : ");
  Serial.println(WiFi.localIP());
}

void setupMQTT() {
  mqttClient.setServer(mqttServer, mqttPort);
}

void reconnectMQTT() {
  Serial.println("Connecting to MQTT Broker...");
  while (!mqttClient.connected()) {
      Serial.println("Attempting MQTT connection...");
      String clientId = "ESP32Client-";
      clientId += String(random(0xffff), HEX);
      
      if (mqttClient.connect(clientId.c_str())) {
        Serial.println("Connected to MQTT Broker.");
      } else {
        Serial.print("Failed, rc=");
        Serial.print(mqttClient.state());
        Serial.println(" Retrying in 5 seconds...");
        delay(5000);
      }     
  }
}

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

  float temperature = dht.readTemperature();
  float humidity = dht.readHumidity();

  if (!isnan(temperature) && !isnan(humidity)) {
    StaticJsonDocument<100> doc;
    doc["temperature"] = temperature;
    doc["humidity"] = humidity;

    char buffer[100];
    serializeJson(doc, buffer);

    mqttClient.publish(mqttTopic, buffer);
  }

  delay(5000);
}