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

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

// MQTT broker shiftr.io
const char* mqtt_server = "pings-112.cloud.shiftr.io";
const int   mqtt_port   = 1883;
const char* mqtt_user   = "pings-112";
const char* mqtt_pass   = "pinsss";
const char* topic_distance = "esp32/ultrasonic";

// Pin Ultrasonic & Buzzer
#define TRIG_PIN 5
#define ECHO_PIN 18
#define BUZZER   19

WiFiClient espClient;
PubSubClient client(espClient);

long duration;
int distance;

void setup_wifi() {
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
  }
}

void reconnect() {
  while (!client.connected()) {
    String clientId = "pingsssscuy" + String(random(0xffff), HEX);
    client.connect(clientId.c_str(), mqtt_user, mqtt_pass);
    delay(2000);
  }
}

int getDistance() {
  digitalWrite(TRIG_PIN, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);
  duration = pulseIn(ECHO_PIN, HIGH);
  return duration * 0.034 / 2;
}

void setup() {
  Serial.begin(115200);
  pinMode(TRIG_PIN, OUTPUT);
  pinMode(ECHO_PIN, INPUT);
  pinMode(BUZZER, OUTPUT);
  setup_wifi();
  client.setServer(mqtt_server, mqtt_port);
}

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

  distance = getDistance();

  if (distance < 10) {
    tone(BUZZER, 2000);
  } else {
    noTone(BUZZER);
  }

  char buffer[10];
  sprintf(buffer, "%d", distance);
  client.publish(topic_distance, buffer);

  Serial.print("Jarak: ");
  Serial.print(distance);
  Serial.println(" cm");

  delay(1000);
}