//AIM- Display current time in HH:MM (written in python) on seven seg- display on wokwi
//IMP- In Library Manager, add PubSubClient and Sevseg library too

#include "WiFi.h"
#include "PubSubClient.h"    //to connect to MQTT server
#include "SevSeg.h"   //library to display on seven segment display unit

char clientId[50];    // random id with storage of 50
int t;  //time variable

SevSeg sevseg;   
WiFiClient espClient;
PubSubClient client(espClient);  //function to make client
 
void setup() 
{
  Serial.begin(115200);  //starts communication with ESP32 with  transfer rate(speed- 115200),

  byte numDigits = 4;
  byte digitPins[] = {14, 15, 2, 5}; // help us to control the 4 digits seven-segment display
  byte segmentPins[] = {12, 4, 19, 26, 27, 13, 18, 25}; //will help us to control all seven LEDs and the Decimal Point of seven-segment display.

  byte hardwareConfig = COMMON_ANODE; // used to set the pins of display in positive mode of ESP32

  sevseg.begin(hardwareConfig, numDigits, digitPins, segmentPins);

  WiFi.mode(WIFI_STA); //search a WiFi station where ESP32 connects
  WiFi.begin("Wokwi-GUEST", "");
  
  client.setServer("broker.emqx.io", 1883);
  client.setCallback(callback); //function written below
}


void loop() 
{
  if (!client.connected()) 
  {
    mqttReconnect();
  }
  client.loop();

  sevseg.setNumber(t);  //set time received from python file to display om sevSeg Display
  sevseg.refreshDisplay();
  delay(1);
}

void mqttReconnect() 
{
  while (!client.connected()) 
  {
    Serial.print("Attempting MQTT connection...");
    if (client.connect(clientId)) 
    {
      Serial.println("Connected");
      client.subscribe("topicName/time"); //receive message 
    } 
    else 
    {
      Serial.println("Connection failed trying again in 10 seconds");
      delay(5000);
    }
  }
}

void callback(char* topic, byte* message, unsigned int length) 
{
  String stMessage;  //variable
  for (int i = 0; i < length; i++)
  {
    stMessage += (char)message[i];  //holds whole message or time (HH:MM)
  }
  Serial.println(stMessage);
  t = stMessage.toInt();  //converts time
}

//OUTPUT- Run Python Then Run wokwi file to see output