#!/bin/bash

INTERVAL="1"  # update interval in seconds

network_name=$(tmux show-option -gqv "@dracula-network-bandwith")

main() {
  while true
    do
      initial_download=`cat /sys/class/net/$network_name/statistics/rx_bytes`
      initial_upload=`cat /sys/class/net/$network_name/statistics/tx_bytes`
      
      sleep $INTERVAL
      
      final_download=`cat /sys/class/net/$network_name/statistics/rx_bytes`
      final_upload=`cat /sys/class/net/$network_name/statistics/tx_bytes`

      total_download_bps=`expr $final_download - $initial_download`
      total_upload_bps=`expr $final_upload - $initial_upload`

      total_download_kbps=$(echo "scale=2; $total_download_bps / 1024" | bc)
      total_upload_kbps=$(echo "scale=2; $total_upload_bps / 1024" | bc)

      echo "↓ $total_download_kbps kB/s • ↑ $total_upload_kbps kB/s"
    done
}
main