/*
-----------------------------------------------------------------------------
PROJECT TITLE : ULTRASONIC SENSOR 

THIS PROJECT DEVELOPED BY OUR GROUP 

1.KUMARAN K 
2.KEERTHIKA B
3.TAMILSELVI R
4.VINITHKUMAR R
------------------------------------------------------------------------------
*/

#include <WiFi.h>
#include <PubSubClient.h>
void callback(char* subscribetopic, byte* payload, unsigned intpayloadLength);
//-------credentials of IBM Accounts- - - -
#define ORG "yxaimf"//IBM ORGANITION ID
#define DEVICE_TYPE "ESP32"//Device type mentioned in ibm watson IOTPlatform
#define DEVICE_ID "12345"//Device ID mentioned in ibm watson IOTPlatform
#define TOKEN "Uq3EGjoa0I1AJYeaMg" //Token
String data3;
char server[] = ORG ".messaging.internetofthings.ibmcloud.com";
char publishTopic[] = "iot-2/evt/Data/fmt/json";
char subscribetopic[] = "iot-2/cmd/test/fmt/String";
char authMethod[] = "use-token-auth";
char token[] = TOKEN;
char clientId[] = "d:" ORG ":" DEVICE_TYPE ":" DEVICE_ID;
WiFiClient wifiClient;
PubSubClient client(server, 1883, callback ,wifiClient);
const int trigPin = 5;
const int echoPin = 18;
#define SOUND_SPEED 0.034
long duration;
float distance;
void setup() 
{
  Serial.begin(115200);
  pinMode(trigPin, OUTPUT);
  pinMode(echoPin, INPUT);
  wificonnect();
  mqttconnect();
}
void loop()
{
  digitalWrite(trigPin, LOW);
  delayMicroseconds(2); 
  digitalWrite(trigPin, HIGH);
  delayMicroseconds(10); 
  digitalWrite(trigPin, LOW);
  duration = pulseIn(echoPin, HIGH);
  distance = duration * SOUND_SPEED/2;
  Serial.print("Distance (cm): ");
  Serial.println(distance); 
  if(distance<100){Serial.println("ALERT!!"); 
  delay(1000);
  PublishData(distance);
  delay(1000);
  if (!client.loop()) {mqttconnect();
  } }
  delay(1000);
}
void PublishData(float dist)
{
 mqttconnect();
 String payload = "{\"Distance\":";
 payload += dist;
 payload += ",\"ALERT!!\":""\"Distance less than 100cms\"";
 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()
{
  Serial.println();
  Serial.print("Connecting to "); 
  WiFi.begin("Wokwi-GUEST", "", 6);
  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 intpayloadLength)
  {
    Serial.print("callback invoked for topic: ");
    Serial.println(subscribetopic); 
    for(int i = 0; i < intpayloadLength; i++)
    {
      Serial.print((char)payload[i]);
      data3 += (char)payload[i];
      }
      Serial.println("data: "+ data3);
      data3="";
  }