#include"WiFi.h"
#include<PubSubClient.h>
const char* ssid="Wokwi-GUEST";
const char* password="";
const char*mqttServer="broker.hivemq.com";
int port=1883;
char clientld[50];
WiFiClient espClient;
PubSubClient client(espClient);
void setup(){
  Serial.begin(115200);
  Serial.println("hello,ESP32");
  Serial.print("connecting to:");
  Serial.println(ssid);
  wifiConnect();
  client.setServer(mqttServer,port);
}
void loop(){
  if(!client.connected())
  {
    mqttReconnected();
  }
  else
  {
    client.publish("esp32-pub","data received");

  }
  client.loop();

}
void wifiConnect(){
  WiFi.mode(WIFI_STA);
  WiFi.begin(ssid,password);
  while(WiFi.status()!=WL_CONNECTED){
    delay(500);
    Serial.print(".");
  }
}
void mqttReconnected(){
  while(!client.connected()){
    Serial.print("attempting MQTT connection...");
    long r=random(1000);
    sprintf(clientld,"fcs-clientld-%ld.r");
    if(client.connect(clientld)){
      Serial.print(clientld);
      Serial.println("connected");
    }else{
      Serial.print("failed,rc=");
      Serial.print((client.state()));
      Serial.println("try again in 5 seconds");
      delay(5000);
    }
  }
}