#include <WiFi.h>//library for wifi
#include <WiFiClient.h>
#include <PubSubClient.h>//library for MQtt 
// creating the instance by passing pin and typr of dht connected
 float distance;
#define sound_speed 0.034  
 int trigpin=18; 
 int echopin=19;
 int led=5;
 int LED=9; 
 long duration;
 String message;// creating the instance by passing pin and typr of dht connected

void callback(char* subscribetopic, byte* payload, unsigned int payloadLength); 

//-------credentials of IBM Accounts------

#define ORG "10ilxy"//IBM ORGANITION ID
#define DEVICE_TYPE "ultrasonic_mvvh"//Device type mentioned in ibm watson IOT Platform
#define DEVICE_ID "SenSor_mvvh"//Device ID mentioned in ibm watson IOT Platform
#define TOKEN "eCHFw6NSwFct0yY8yw"     //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/fmt/json";// topic name and type of event perform and format in which data to be send
char subscribetopic[] = "iot-2/cmd/command/fmt/String";// cmd  REPRESENT command type AND COMMAND IS TEST OF FORMAT STRING
char authMethod[] = "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 predefined client id by passing parameter like server id,portand wificredential
void setup()// configureing the ESP32 
{
  Serial.begin(115200);
pinMode(trigpin,OUTPUT); 
pinMode(echopin,INPUT); 
pinMode(led,OUTPUT);
  delay(10);
  Serial.println();
  wificonnect();
  mqttconnect();
}

void loop()// Recursive Function
{

digitalWrite(trigpin,LOW); 
digitalWrite(trigpin,HIGH); 
delay(1000); 
digitalWrite(trigpin,LOW); 
duration=pulseIn(echopin,HIGH); 
distance=duration*sound_speed/2; 
Serial.println("distance"+String(distance)+"cm");
 if(distance<100) 
 {
   message="Alert"; 
   digitalWrite(led,HIGH);
   } else
{
  message="No problem"; 
  digitalWrite(led,LOW);
  } 
  delay(1000); 
  PublishData(distance,message);
  // if (!client.loop()) {
  //   mqttconnect();
  // }
}



/*.....................................retrieving to Cloud...............................*/

void PublishData(float d, String a) {
  mqttconnect();//function call for connecting to ibm
  /*
     creating the String in in form JSon to update the data to ibm cloud
  */
  String payload = "{\"distance\":"; 
  payload += d; payload += "}"; 
  payload += "," "{\"message\":";
  payload += a;
  payload += "}";

  
  Serial.print("Sending payload: ");
  Serial.println(payload);

  
  if (client.publish(publishTopic, (char*) payload.c_str())) {
    Serial.println("Publish ok");// if it sucessfully upload data on the cloud then it will print publish ok in Serial monitor or else it will print publish failed
  } 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("Wokwi-GUEST", "", 6);//passing the wifi credentials to establish the connection
  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[i]);
    data3 += (char)payload[i];
  } 
  Serial.println("data: "+ data3); 
  if(data3=="lighton")
  {
Serial.println(data3);
digitalWrite(LED,HIGH);
  }
  else 
  {
Serial.println(data3);
digitalWrite(LED,LOW);
  }
data3="";  
}