// MQTT settings
const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqtt_server = "broker.emqx.io";

// Pin Definitions
const int trigPin = 27;     // Pin IN
const int echoPin = 26;     // Pin OUT
const int ledPin = 19;      // LED Biru
const int buzzerPin = 21;   // Buzzer
const int servoPin = 14;    // Servo

// Create Servo object
Servo myServo;

// Variables for ultrasonic sensor
long duration;
int distance;

// WiFi and MQTT clients
WiFiClient espClient;
PubSubClient client(espClient);

// Function to connect to WiFi
void setup_wifi() {
  delay(10);
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

// Function to connect to MQTT broker
void reconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    if (client.connect("ESP32Client", mqtt_user, mqtt_password)) {
      Serial.println("connected");
      client.subscribe(mqtt_topic);
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

void setup() {
  Serial.begin(115200);

  // Setup WiFi and MQTT
  setup_wifi();
  client.setServer(mqtt_server, mqtt_port);

  // Initialize servo, buzzer, and LED
  myServo.attach(servoPin);
  pinMode(buzzerPin, OUTPUT);
  pinMode(ledPin, OUTPUT);

  // Initialize ultrasonic sensor pins
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);

  // Set initial positions/states
  myServo.write(0); // Servo closed
  digitalWrite(buzzerPin, LOW); // Buzzer off
  digitalWrite(ledPin, LOW); // LED off
}

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

  // Read ultrasonic sensor
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2);
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10);
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = duration * 0.034 / 2;

  // Publish distance to MQTT
  String distanceStr = String(distance);
  client.publish(mqtt_topic, distanceStr.c_str());

  // If distance is less than 100 cm (person detected)
  if (distance < 100) {
    myServo.write(90); // Open servo
    digitalWrite(buzzerPin, HIGH); // Turn on buzzer
    digitalWrite(ledPin, HIGH); // Turn on LED
  } else {
    myServo.write(0); // Close servo
    digitalWrite(buzzerPin, LOW); // Turn off buzzer
    digitalWrite(ledPin, LOW); // Turn off LED
  }

  delay(500); // Delay for stability
}