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

long duration;
float distanceCM;
float distanceINCH;

const int trigPin = 5;
const int echoPin = 18;

#define SOUND_SPEED 0.034


String temperatureString = "";

// WiFi
const char *ssid = "Wokwi-GUEST"; // Enter your Wi-Fi name
const char *password = "";  // Enter Wi-Fi password

// MQTT Broker
const char *mqtt_broker = "broker.emqx.io";//"broker.hivemq.com";
const char *topic = "emqx/esp32";
const char *mqtt_username = "";//"emqx";
const char *mqtt_password = "";//"public";
const int mqtt_port = 1883;

WiFiClient espClient;
PubSubClient client(espClient);


void setup() {
  
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
 
    // Set software serial baud to 115200;
    Serial.begin(115200);
    // Connecting to a WiFi network
    WiFi.begin(ssid, password);
    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.println("Connecting to WiFi..");
    }
    Serial.println("Connected to the Wi-Fi network");
    //connecting to a mqtt broker
    client.setServer(mqtt_broker, mqtt_port);
    client.setCallback(callback);
    while (!client.connected()) {
        String client_id = "esp32-client-";
        client_id += String(WiFi.macAddress());
        Serial.printf("The client %s connects to the public MQTT broker\n", client_id.c_str());
        if (client.connect(client_id.c_str(), mqtt_username, mqtt_password)) {
            Serial.println("Public EMQX MQTT broker connected");
        } else {
            Serial.print("failed with state ");
            Serial.print(client.state());
            delay(2000);
        }
    }
    // Publish and subscribe
    client.publish(topic, "Olá ESP32");
    client.subscribe(topic);
}

void callback(char *topic, byte *payload, unsigned int length) {
    Serial.print("Message arrived in topic: ");
    Serial.println(topic);
    Serial.print("Message:");
    for (int i = 0; i < length; i++) {
        Serial.print((char) payload[i]);
    }
    Serial.println();
    Serial.println("-----------------------");
}

void loop() {

digitalWrite(trigPin, LOW);
delayMicroseconds(2);

digitalWrite(trigPin, HIGH);
delayMicroseconds(10);
digitalWrite(trigPin, LOW);

duration = pulseIn(echoPin, HIGH);

distanceCM = duration * SOUND_SPEED/2;

Serial.print("Distancia (cm): ");
Serial.println(distanceCM);
   
//int temperature = random(100);
    temperatureString = String(distanceCM);
    
    client.publish(topic, temperatureString.c_str());
    client.loop();
    delay(5000);
}