#!/bin/bash

cmd="$1"
iface="$(ip route show default | head -n 1 | awk '{print $5}')"

net_format="%3d"

this_dir="$( cd "$( dirname "${BASH_SOURCE[0]}" )" &> /dev/null && pwd )"
source "$this_dir/common"

get_bits() {
    awk '{print($1*8)}' "$1"
}

get_down(){
    get_bits "/sys/class/net/$iface/statistics/rx_bytes"
}

get_up(){
    get_bits "/sys/class/net/$iface/statistics/tx_bytes"
}

get_time() {
  date +%s.%N
}

if [[ "$cmd" == "down" ]]; then
    bits="$(get_down)"
elif [[ "$cmd" == "up" ]]; then
    bits="$(get_up)"
else
    echo "Invalid command"
    exit 1
fi

cached_eval "network_$cmd" "$bits" "$(get_time)" \
    | awk -v f="$net_format" \
          "$(printf '%s' \
                   '{x=$1} END { '\
                   'if (x>=1073741824) printf(f " Gib/s", x/1073741824); '\
                   'else if (x>=1048576) printf(f " Mib/s", x/1048576); '\
                   'else if (x>=1024) printf(f " Kib/s", x/1024); '\
                   'else printf(f " bit/s", x)'\
                   '}')"