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

// Update these with values suitable for your network.
const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqtt_server = "";
const char* topic = "";

WiFiClient espClient;
PubSubClient client(espClient);

LiquidCrystal_I2C lcd(0x27, 16, 2); 

void setup_wifi() {
  delay(10);
  // We start by connecting to a WiFi network
  Serial.println();
  Serial.print("Conectando a ");
  Serial.println(ssid);

  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);

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

  randomSeed(micros());

  Serial.println("");
  Serial.println("WiFi conectado");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
}

void callback(char* topic, byte* payload, unsigned int length) {
  String receivedData;
  for (int i = 0; i < length; i++) {
    receivedData += (char)payload[i];
  }

  lcd.clear();
  lcd.setCursor(0, 0);
  lcd.print("Distancia:");
  

  if (strcmp(topic, "emqx/aula7") == 0) {
    lcd.setCursor(0, 1); 
    lcd.print(receivedData + " cm    "); 
  } 
}

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

  
  lcd.init();
  lcd.backlight();
  lcd.setCursor(0, 0);
  lcd.print("Distancia:");
  
}

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

void reconnect() {
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    String clientId = "IoTLab24";
    clientId += String(random(0xffff), HEX);
    // Attempt to connect
    if (client.connect(clientId.c_str())) {
      Serial.println("Connected to " + clientId);
      // Once connected, subscribe to the topics
      client.subscribe(topic);
      
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}