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

//connect wifi
const char* ssid = "Wokwi-GUEST";
const char* password = "";

// Define the pin connected to the DHT22 sensor
const int dhtPin = 26;
DHT dht(dhtPin, DHT22); // Setup a DHT instance

// MQTT Broker Settings 
const char* mqtt_server = "broker.hivemq.com"; // Example public  
const char* mqtt_topic = "Money";   // Topic to subscribe to 
WiFiClient espClient; 
PubSubClient client(espClient); 


// Function to connect to Wi-Fi
void connectWiFi() {
  WiFi.begin(ssid, password);

  Serial.print("Connecting");
  while (WiFi.status() != WL_CONNECTED) {
    delay(1000);
    Serial.print("Connecting to WiFi...");
  }
  Serial.println("\nWiFi Connected!");
  Serial.print("IP Address: ");
  Serial.println(WiFi.localIP());
}

// Function to connect to the MQTT broker 
void connectMQTT() { 
while (!client.connected()) { 
Serial.print("Attempting MQTT connection..."); 

// Create a unique client ID 
String clientId = "ESP32Client-" + String(random(0xffff), HEX); 
if (client.connect(clientId.c_str())) { 
Serial.println("Connected to MQTT broker"); 
} else { 
Serial.print("Failed to connect, state "); 
Serial.println(client.state()); 
delay(5000); 
} 
} 
} 

void setup() { 
    Serial.begin(115200); 
    connectWiFi(); // Initialize WIFI
    dht.begin();  // Initialize the DHT22 sensor
 

client.setServer(mqtt_server, 1883);  // Set MQTT broker address and port
connectMQTT(); 
}

void loop() {

    // Reconnect MQTT if the connection is lost
    if (!client.connected()) { 
    connectMQTT();   
    } 

    client.loop();  // Keep the connection alive
    float temperature = dht.readTemperature();  // Get temperature in Celsius
    float humidity     = dht.readHumidity();     // Get humidity in %

    // Publish a test message every 5 seconds 
    char payload[100];
    sprintf(payload, "{\"temperature\":%.2f,\"humidity\":%.2f}", temperature, humidity);

    client.publish(mqtt_topic, payload);
    Serial.println("Published: ");
    Serial.println(payload);


    //serial monitor
    Serial.print("Temperature: ");
    Serial.print(temperature);
    Serial.println(" °C");

    Serial.print("Humidity: ");
    Serial.print(humidity);
    Serial.println(" %");
    
    delay(5000);  // Delay for 5 seconds before sending the next message
                // DHT22 needs at least 2 seconds between reads
}