//industrial workers health and safety system based on IoT
#include <WiFi.h>//library for WiFi
#include <PubSubClient.h>//library for MQTT
#include "DHT.h"//Library for DHT11
#include <NewPing.h>//Library for ultrasonic sensor

#define DHTPIN 4     // what pin we're connected to
#define DHTTYPE DHT11   // define type of sensor DHT 11

#define TRIGGER_PIN 12  // Arduino pin tied to trigger pin on the ultrasonic sensor.
#define ECHO_PIN 13  // Arduino pin tied to echo pin on the ultrasonic sensor.
#define MAX_DISTANCE 200 // Maximum distance we want to ping for (in centimeters).

DHT dht (DHTPIN, DHTTYPE);// creating the instance by passing pin and type of DHT connected
NewPing sonar(TRIGGER_PIN, ECHO_PIN, MAX_DISTANCE); // Creating an instance for the ultrasonic sensor

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

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

#define ORG "j1q0lx"//IBM ORGANIZATION ID
#define DEVICE_TYPE "abcd"//Device type mentioned in IBM Watson IoT Platform
#define DEVICE_ID "1234"//Device ID mentioned in IBM Watson IoT Platform
#define TOKEN "12345678"     //Token
String data3;
float t;
int p;
int distance;

//-------- 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 performed and format in which data is sent
char subscribetopic[] = "iot-2/cmd/test/fmt/String";// Command represents the command type, and the 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 an instance for WiFiClient
PubSubClient client(server, 1883, callback, wifiClient); // Calling the predefined client ID by passing parameters like server ID, port, and WiFi credentials

void setup()// Configuring the ESP32 
{
  Serial.begin(115200);
  dht.begin();
  delay(10);
  Serial.println();
  wificonnect();
  mqttconnect();
}

void loop()// Recursive function
{
  t = dht.readTemperature();
  p = random(60, 150);
  distance = sonar.ping_cm();
  
  Serial.print("Temperature: ");
  Serial.println(t);
  Serial.print("Pulse: ");
  Serial.println(p);
  Serial.print("Distance: ");
  Serial.println(distance);

  PublishData(t, p, distance);
  delay(1000);
  
  if (!client.loop()) {
    mqttconnect();
  }
}

/*.....................................retrieving to Cloud...............................*/
void PublishData(float temp, int pulse, int dist) {
  mqttconnect(); // Function call for connecting to IBM
  /*
    Creating the JSON payload to update the data to IBM Cloud
  */
  String payload = "{\"temperature\":";
  payload += temp;
  payload += "," "\"pulse\":";
  payload += pulse;
  payload += "," "\"distance\":";
  payload += dist;
  payload += "}";

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

  if (client.publish(publishTopic, (char*)payload.c_str())) {
    Serial.println("Publish OK"); // If it successfully uploads data to the cloud, it will print "Publish OK" in the Serial monitor; otherwise, 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 definition for WiFi connect
{
  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++) {
    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 = "";
}