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

#define TRIG_PIN 19
#define ECHO_PIN 18

// WiFi credentials (Wokwi uses "Wokwi-GUEST" without a password)
const char* WIFI_SSID = "Wokwi-GUEST";
const char* WIFI_PASSWORD = "";  

// ThingsBoard MQTT settings
const char* THINGSBOARD_HOST = "thingsboard.cloud";  // Change if self-hosted
const char* ACCESS_TOKEN = "e4ipEEOfugRCXfGgS4nC";  // Change this to your device token
const int MQTT_PORT = 1883;

WiFiClient espClient;
PubSubClient client(espClient);

// Function to connect to WiFi
void setupWiFi() {
    Serial.print("Connecting to WiFi...");
    WiFi.begin(WIFI_SSID, WIFI_PASSWORD);
    while (WiFi.status() != WL_CONNECTED) {
        delay(500);
        Serial.print(".");
    }
    Serial.println("\nConnected to WiFi!");
}

// Function to connect to ThingsBoard MQTT
void reconnectMQTT() {
    while (!client.connected()) {
        Serial.print("Connecting to ThingsBoard...");
        if (client.connect("ESP32-Client", ACCESS_TOKEN, "")) {
            Serial.println("Connected!");
        } else {
            Serial.print("Failed, rc=");
            Serial.print(client.state());
            Serial.println(" Trying again in 5 seconds...");
            delay(5000);
        }
    }
}

// Function to measure distance
float getDistance() {
    digitalWrite(TRIG_PIN, LOW);
    delayMicroseconds(2);
    digitalWrite(TRIG_PIN, HIGH);
    delayMicroseconds(10);
    digitalWrite(TRIG_PIN, LOW);

    long duration = pulseIn(ECHO_PIN, HIGH);
    float distance = duration * 0.034 / 2;  // Convert to cm
    return distance;
}

void setup() {
    Serial.begin(115200);
    pinMode(TRIG_PIN, OUTPUT);
    pinMode(ECHO_PIN, INPUT);

    setupWiFi();
    client.setServer(THINGSBOARD_HOST, MQTT_PORT);
}

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

    float distance = getDistance();
    Serial.print("Distance: ");
    Serial.print(distance);
    Serial.println(" cm");

    // Create JSON payload
    String payload = "{\"distance\": " + String(distance) + "}";
    client.publish("v1/devices/me/telemetry", payload.c_str());

    delay(2000);  // Send data every 2 seconds
}