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

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

// ===================== MQTT
const char* mqtt_server = "broker.hivemq.com";

WiFiClient espClient;
PubSubClient client(espClient);

// ===================== PIN
#define TRIG 5
#define ECHO 18
#define LDR 34
#define LED 2

long duration;
int distance;
int ldrValue;

// ===================== STATE LED
bool ledState = false;

// ===================== CALLBACK
void callback(char* topic, byte* payload, unsigned int length) {
  String message = "";

  for (int i = 0; i < length; i++) {
    message += (char)payload[i];
  }

  message.trim();
  message.toUpperCase();

  Serial.print("TOPIC: ");
  Serial.println(topic);

  Serial.print("MESSAGE: ");
  Serial.println(message);

  if (message == "ON") {
    ledState = true;
    digitalWrite(LED, HIGH);
    Serial.println("LED ON");

    client.publish("iot/led/status", "ON");
  }
  else if (message == "OFF") {
    ledState = false;
    digitalWrite(LED, LOW);
    Serial.println("LED OFF");

    client.publish("iot/led/status", "OFF");
  }
  else {
    Serial.println("UNKNOWN COMMAND");
  }
}

// ===================== WIFI
void setup_wifi() {
  delay(10);
  Serial.println("Connecting WiFi...");
  WiFi.begin(ssid, password);

  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }

  Serial.println("\nWiFi Connected!");
  Serial.print("IP: ");
  Serial.println(WiFi.localIP());
}

// ===================== MQTT RECONNECT
void reconnect() {
  while (!client.connected()) {
    Serial.println("Connecting MQTT...");

    // 🔥 FIX PENTING: client ID harus unik
    String clientId = "ESP32Client-";
    clientId += String(random(0xffff), HEX);

    if (client.connect(clientId.c_str())) {
      Serial.println("MQTT Connected!");
      Serial.print("Client ID: ");
      Serial.println(clientId);

      client.subscribe("iot/led");
      Serial.println("Subscribed: iot/led");

      client.publish("iot/led/status", ledState ? "ON" : "OFF");
    }
    else {
      Serial.print("Failed, rc=");
      Serial.println(client.state());
      delay(2000);
    }
  }
}

// ===================== SETUP
void setup() {
  Serial.begin(115200);

  pinMode(TRIG, OUTPUT);
  pinMode(ECHO, INPUT);
  pinMode(LED, OUTPUT);

  digitalWrite(LED, LOW);
  ledState = false;

  setup_wifi();

  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
}

// ===================== LOOP
void loop() {
  if (!client.connected()) reconnect();
  client.loop();

  // ===== ULTRASONIC =====
  digitalWrite(TRIG, LOW);
  delayMicroseconds(2);
  digitalWrite(TRIG, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG, LOW);

  duration = pulseIn(ECHO, HIGH, 30000);
  distance = duration * 0.034 / 2;

  if (distance == 0 || distance > 400) distance = -1;

  // ===== LDR =====
  ldrValue = analogRead(LDR);

  // ===== MQTT PUBLISH SENSOR =====
  client.publish("iot/jarak", String(distance).c_str());
  client.publish("iot/cahaya", String(ldrValue).c_str());

  // ===== DEBUG =====
  Serial.print("Jarak: ");
  Serial.print(distance);
  Serial.print(" cm | Cahaya: ");
  Serial.print(ldrValue);
  Serial.print(" | LED: ");
  Serial.println(ledState ? "ON" : "OFF");

  Serial.println("----------------------");

  delay(2000);
}