#include <WiFi.h>
#include<WiFiClient.h>
#include<PubSubClient.h>

float duration, distance;
String status;
String data3;
void callback(char* subscribetopic, byte* payload, unsigned int payLoadLength);

#define ORG "7qml3n"
#define DEVICE_TYPE "IOT"
#define DEVICE_ID "Waste_management"
#define TOKEN "l4FVB93I&hZMANLp?D"

// pin declaration
#define LED 18
#define BUZZER 23
#define TRIG_PIN 13 // ESP32 pin GIOP23 connected to Ultrasonic Sensor's TRIG pin
#define ECHO_PIN 12 // ESP32 pin GIOP22 connected to Ultrasonic Sensor's ECHO pin


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;
PubSubClient client(server, 1883, callback, wifiClient);

void setup() {

  Serial.begin(115200);
  Serial.println();
  pinMode(LED, OUTPUT);
  // configure the trigger pin to output mode
  pinMode(TRIG_PIN, OUTPUT);
  // configure the echo pin to input mode
  pinMode(ECHO_PIN, INPUT);
  delay(10);
  wifiConnect(); // to connect to wifi
  mqttConnect(); // to connect to mqtt client
}

void loop() {
 // generate 10-microsecond pulse to TRIG pin
  digitalWrite(TRIG_PIN, HIGH);
  delayMicroseconds(10);
  digitalWrite(TRIG_PIN, LOW);

  // measure duration of pulse from ECHO pin
  duration = pulseIn(ECHO_PIN, HIGH);

  // calculate the distance
  distance = 0.017 * duration;

  // print the value to Serial Monitor
  Serial.print("distance: ");
  Serial.print(distance);
  Serial.println(" cm");
  if(distance>300)
  {
    status = "\"alert\"";
  }
  else 
  {
    status = "\"normal\"";
  }
  publishData(status, distance);
  delay(2000);
  if (!client.loop()) 
  {
    mqttConnect();
  }
}
void 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 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("Connected\n");
  }
}
void initManagedDevice() {
  if (client.subscribe(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=="alert")
  {
    Serial.println(data3);
    digitalWrite(LED,HIGH);
    tone(BUZZER, 600);
 
  }

  else 
  {
    Serial.println(data3);
    digitalWrite(LED,LOW);
    noTone(BUZZER);

  }
  data3="";
}

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