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

//#define Green_LED 18
//#define Yellow_LED 19
//#define Red_LED 23

int ledPin = 18; //the number of the LED pin
int ledState = LOW; //ledState used to set the LED
long previousMillis = 0; //will store last time LED
int interval = 1000;

const char* ssid = "Wokwi-GUEST";	// Given by Wokwi
const char* password = "";	// no password

const char* hostname = "broker.hivemq.com"; // MQTT broker address that we are connecting

//Initializes the espClient
WiFiClient espClient;
PubSubClient client(espClient);
const char* espClientName = "esp32Client_yourInitial";
int PORTNUM = 1883;

void setup_wifi()
{
  WiFi.begin(ssid, password);
  while(WiFi.status() != WL_CONNECTED )
  {
    delay(1000);
    Serial.print(".");
  }
  Serial.println();
  Serial.print("Connected to ");
  Serial.println(ssid);
  Serial.print("Given IP by the router to ESP32 is ");
  Serial.println(WiFi.localIP());
}


void connectMQTT()
{
  while(!client.connected() )
  {
    Serial.println("Connecting to MQTT ...");
    if (client.connect(espClientName) ) //, mqttUser, mqttPassword) )
    {
      Serial.println("Connected");
      MQTTSubscribe();
    }
    else
    {
      Serial.print("Failed with state ");
      Serial.print(client.state() );
      delay(2000);
    }
  }
}

void setup_MQTT()
{
  client.setServer(hostname, PORTNUM);
  client.setCallback(callback); 
}

void MQTTSubscribe()
{
  // There is no topics to subscribe at this moment
}

void callback(String topic, byte* payload, unsigned int length)
{
  String messageTemp;
  Serial.print("Message received in topic: ");
  Serial.print(topic);
  Serial.print(" length is: ");
  Serial.println(length);

  Serial.print("Data received from broker: ");
  for (int i = 0; i<length; i++)
  {
    Serial.print( (char)payload[i] );
    messageTemp += (char)payload[i];
  }

  if (topic == "      ")
 {
    // There is no topic and messages to process at this moment
}
}

void setup() 
{
  // put your setup code here, to run once:
  Serial.begin(115200);
  pinMode(ledPin, OUTPUT);
  setup_wifi();
  setup_MQTT();
}

void loop() 
{
  // put your main code here, to run repeatedly:
  if ( !client.connected() )
  {
    connectMQTT();
  }
  client.loop();

}