#include <WiFi.h>//library for wifi
#include <PubSubClient.h>//library for MQtt
#include "ultrasonic.h"
Ultrasonic ultrasonic (2, 4);
float distance;
void callback(char* subscribetopic, byte* payload, unsigned int payloadLength);
//.credentials of IBM Accounts.............. 
#define ORG "O5st2r"//IBM ORGNITION ID
#define DEVICE_TYPE "abcd"
#define DEVICE_ID "1234" //Device ID mentioned in the watson TOT Platform
#define TOKEN "12345678" //Token
String data3;
//Float h, t
//.......Customise the above values......... 
char server[]= ORG ".messaging, internetofthings.ibmcloud.com";// Server Name
char publishTopic[] = "iot-2/evt/Data/fnt/json"; // topic name and type of event perform
char subscribetopic[] = "Lot-2/cmd/test/fmt/String;
char authetethod[]"use-token-auth";// authentication method
char token[]]=TOKEN;
char clientid[] = "d:" ORG":"DEVICE_TYPE";" DEVICE_ID;//client id

WiFiClient wifiClient; // creating the instance for wificlient
PubSubClient client (server, 1883, callback wificlient); //calling the prodefined client
void setup()// configureing the ESP32
{
Serial.begin(115200);
delay(10);
 Serial.println();
wificonnect();
mqttconnect();
}
void loop()// Recursive Function
{
distance = ultrasonic.read(CM);
Serial.print("Distance in CM: ");
Serial.println(distance);
delay(1000);
PublishData(distance);
delay(1000); 
if (!client.loop()) {
  mqttconnect();
}
}
void PublishData(float distance) {
mqttconnect();//function call for connecting to ibm
string payload="{\"distance\":";
payload+= distance;
payload += "}";
Serial.print("Sending payload: ");
Serial.println(payload);
if (client.publish(publishTopic, (char*) payload.c_str())) {
Serial.println("Publish ok");
}else{
Serial.println("Publish failed");
}
}

void mqttconnect() {
if (!client.connected()) { 
Serial.print("Reconnecting client to ");
Serial.println(server);
while (!!!client.connect(clientId, authmethod, token)) {
Serial.print(".");
delay(500);
}
initManagedDevice(); 
Serial.println();
}
 }
  void wificonnect() //function defination for wificonnect
  {
Serial.println();
Serial.print("connecting to ");
WiFi.begin("Wakwi-GUEST", "", 6);//passing the wifi credentials to establish the conne 
while (WiFi.status() != WL_CONNECTED) {
delay(500);
Serial.print(".");
}
Serial.println("");
Serial.println("WiFi connected");
Serial.println("IP address: ");
Serial.println(WiFi.localIP());
  }
void initManagedDevice() {
if (client.subscribe(subscribetopic)) {
 Serial.println((subscribetopic));
 Serial.println("subscribe to cmd OK");
} else {
serial.println("subscribe to cmd FAILED");
}
}
void callback(char* subscribetopic, byte* payload, unsigned int payloadLength)
{
Serial.print("callback invoked for topic: ");
Serial.println(subscribetopic);
for (int i = 0; i < payloadLength; i++) {
   //Serial.print((char)payload[1]); 
   data3 += (char)payload[i];
}
Serial.println("data: "+ data3);

data3="";
}