#include <WiFi.h>
#include <PubSubClient.h>
#include <LiquidCrystal_I2C.h>

const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqtt_server = "mqtt.telkomiot.id";
const char* topic_sub = "v2.0/pubs/APP668502845056a37361/DEV66a74ef42890e25989";

String accessKey = "190760c7c967ea94";
String accessToken = "190760c7c966edcd";
String clientID = "DEV66a74ef42890e25989";

WiFiClient espClient;
PubSubClient client(espClient);
LiquidCrystal_I2C lcd(0x27, 16, 2);

void setup_wifi() {
  delay(10);
  Serial.println();
  Serial.print("Connecting to ");
  Serial.println(ssid);

  WiFi.mode(WIFI_STA);
  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());
}

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

  if (messageTemp.startsWith("LCD:")) {
    String lcdText = messageTemp.substring(4);
    lcd.clear();
    lcd.print(lcdText);
  }
}

void setup() {
  Serial.begin(115200);
  setup_wifi();
  client.setServer(mqtt_server, 1883);
  client.setCallback(callback);
  
  lcd.init();
  lcd.backlight();
}

void reconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    String clientId = "mqtt.telkomiot.id";
    clientId += String(random(0xffff), HEX);
    if (client.connect(clientID.c_str(), accessKey.c_str(), accessToken.c_str())) {
      Serial.println("Connected");
      client.subscribe(topic_sub);
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

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