#!/usr/bin/env bash
function get_props_key() {
	local v="$(grep "$1" <<<"$props")"
	echo "${v/*=}"
}

function do_check() {
	while read line; do
		key="${line/=*}"
		value="${line/*=}"
		[[ $key = "POWER_SUPPLY_STATUS" ]] && status="$value"
		[[ $key = "POWER_SUPPLY_CHARGE_NOW" ]] && charge="$value"
		[[ $key = "POWER_SUPPLY_CHARGE_FULL_DESIGN" ]] && full="$value"
	done </sys/class/power_supply/BAT1/uevent

	percent="$(( charge * 100 / full ))"

	if [[ $status = "Discharging" && $percent -le 30 ]]; then
		i3-nagbar -m "Battery is at $percent%!"
	fi
}

while true; do
	do_check
	sleep 30
done