// From https://randomnerdtutorials.com/esp32-mqtt-publish-subscribe-arduino-ide

#include <WiFi.h>
#include "PubSubClient.h"
#include "DHTesp.h"
#include <LiquidCrystal_I2C_Hangul.h>

const char* ssid = "Wokwi-GUEST";
const char* password = "";
String stMac;
char mac[50];
char clientId[50];

WiFiClient espClient;
PubSubClient client(espClient);

const int led1 = 4;
const int led2 = 2;
const int led3 = 15;

const int dht22 = 27;


LiquidCrystal_I2C_Hangul lcd(0x27, 16, 2);
DHTesp dhtSensor;

void setup() {
  Serial.begin(115200);
  randomSeed(analogRead(0));

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

  wifiConnect();

  Serial.println("");
  Serial.println("WiFi connected");
  Serial.println("IP address: ");
  Serial.println(WiFi.localIP());
  Serial.println(WiFi.macAddress());
  stMac = WiFi.macAddress();
  stMac.replace(":", "_");
  Serial.println(stMac);
  
  client.setServer("public.mqtthq.com", 1883);
  client.setCallback(callback);
  pinMode(led1, OUTPUT);
  pinMode(led2, OUTPUT);
  pinMode(led3, OUTPUT);

  pinMode(dht22, INPUT);
  
  lcd.init();
  lcd.backlight();

  dhtSensor.setup(dht22, DHTesp::DHT22);

  lcd.clear();

  lcd.setCursor(0, 0);
  lcd.print("Code:");
  
  lcd.setCursor(0, 1);
  lcd.print("TestMSG");
}

void wifiConnect() {
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid, password);
  while (WiFi.status() != WL_CONNECTED) {
    delay(500);
    Serial.print(".");
  }
}

void mqttReconnect() {
  while (!client.connected()) {
    Serial.print("Attempting MQTT connection...");
    long r = random(1000);
    sprintf(clientId, "clientId-%ld", r);
    if (client.connect(clientId)) {
      Serial.print(clientId);
      Serial.println(" connected");
      client.subscribe("topicName/led");
    } else {
      Serial.print("failed, rc=");
      Serial.print(client.state());
      Serial.println(" try again in 5 seconds");
      delay(5000);
    }
  }
}

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

  if (String(topic) == "topicName/led") {
    char charMsg[5];

    for (int i = 0; i < 4; i++)
      charMsg[i] = (char)stMessage[i];
    
    charMsg[4] = '\0';
    Serial.println((stMessage));
    
    lcd.clear();

    lcd.setCursor(0, 0);
    lcd.print("Code:");

    lcd.setCursor(0, 1);
    lcd.print(stMessage);
    
    digitalWrite(led1, charMsg[0] == '0' ? LOW : HIGH);
    digitalWrite(led2, charMsg[1] == '0' ? LOW : HIGH);
    digitalWrite(led3, charMsg[2] == '0' ? LOW : HIGH);
  }
}

void loop() {
  delay(10);

  if (!client.connected()) {
    mqttReconnect();
  } else {
    TempAndHumidity dhtData = dhtSensor.getTempAndHumidity();
    int t = (int)dhtData.temperature;
    int h = (int)dhtData.humidity;

    String dataForPublishing = String(t) + "°C\n";
    dataForPublishing += String(h) + "%";
    unsigned char* buf = new unsigned char[100];
    dataForPublishing.getBytes(buf, 100, 0);
    const char *sendMessageData = (const char*)buf;
    
    client.publish("esp32/wokwiClient", sendMessageData);

    delay(1000);
  }
  
  client.loop();
}