#include <WiFi.h>
#include <PubSubClient.h>
#include <LiquidCrystal_I2C.h>
LiquidCrystal_I2C LCD = LiquidCrystal_I2C(0x27, 16, 2);


// Update these with values suitable for your network.

const char* ssid = "Wokwi-GUEST";
const char* password = "";
const char* mqtt_server = "broker.hivemq.com";

WiFiClient espClient;
PubSubClient client(espClient);
unsigned long lastMsg = 0;
float temp = 0;
float hum = 0;

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

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

  LCD.setCursor(0, 0);
  LCD.println("Connecting to ");
  LCD.setCursor(0, 1);
  LCD.println("Wifi......");

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

  randomSeed(micros());

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

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

  if (strcmp(topic, "/AnhPD_Test/p/temp") == 0) {
    temp = receivedData.toFloat();
  } else if (strcmp(topic, "/AnhPD_Test/p/hum") == 0) {
    hum = receivedData.toFloat();
  }
}

void reconnect() { 
  // Loop until we're reconnected
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    String clientId = "ESP32Client-";
    clientId += String(random(0xffff), HEX);
    // Attempt to connect
    if (client.connect(clientId.c_str())) {
      Serial.println("Connected to " + clientId);
      // Once connected, publish an announcement...
      client.publish("/AnhPD_Test/p/mqtt", "AnhPD_Test"); 
      // ... and resubscribe
      client.subscribe("/AnhPD_Test/p/mqtt"); 
      client.subscribe("/AnhPD_Test/p/temp");
      client.subscribe("/AnhPD_Test/p/hum");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      // Wait 5 seconds before retrying
      delay(5000);
    }
  }
}

void setup() {
  pinMode(2, OUTPUT);
  Serial.begin(115200);

  LCD.init();
  LCD.backlight();

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

}

void loop() {
  if (!client.connected()) {
    reconnect();
  }
  client.loop();
  LCD.setCursor(0, 0);
  LCD.println("Temp: " + String(temp, 2) + "°C");
  LCD.setCursor(0, 1);
  LCD.println("Humidity: " + String(hum, 1) + "%");
}