#!/bin/bash

if [[ "$(upower -i /org/freedesktop/UPower/devices/battery_BAT0 | grep native-path | awk '{print $2}')" == '(null)' ]]; then
	exit
fi

battery_notify () {
	# if battery percentage is equal to given one, if battery percentage inside /tmp/battery.tmp is not equal to given one and if power indicator is the given on
	if [ ${__bat_per} -eq $1 ] && ! grep -q $1 "/tmp/battery.tmp" && [[ ${__bat_power} = $2 ]]; then
		# Send notification and rewrite battery.tmp file with current percentage
		notify-send -u critical -i battery-low -t 99999999 "$3"
		echo $1 > /tmp/battery.tmp
	fi
}

# If upower command is available
if command -v upower > /dev/null 2>&1 ; then

	# Get battery power indicator (charging/discharging/fully charged) and stop script if there is no value for it (if there is no battery in device)
	__bat_power=$(upower -i /org/freedesktop/UPower/devices/battery_BAT0 | grep state | awk '{print $2}')
	if [[ -n ${__bat_per} ]]; then
		exit
	fi

	# Set the battery power indicator icon
	__bat_power_ind=""
	if [[ ${__bat_power} = "charging" ]]; then __bat_power_ind=""
		elif [[ ${__bat_power} = "discharging" ]]; then __bat_power_ind=""
		elif [[ ${__bat_power} = "fully-charged" ]]; then __bat_power_ind=""
	fi

	# Get the battery percentage, time until the battery is empty and time until the battery is full
	__bat_per=$(upower -i /org/freedesktop/UPower/devices/battery_BAT0 | grep percentage | awk '{print $2}' | sed "s|%||g")
	__time_empt=$(upower -i /org/freedesktop/UPower/devices/battery_BAT0 | grep "time to empty" | awk '{print $4 $5}' | grep -o '^[0-9.]*[a-z]')
	__time_full=$(upower -i /org/freedesktop/UPower/devices/battery_BAT0 | grep "time to full" | awk '{print $4 $5}' | grep -o '^[0-9.]*[a-z]')

	# Print the battery power indicator icon, percentage and time until empty or time until full
	echo -n " ${__bat_power_ind} ${__bat_per}%"
	if [[ ${__bat_power} = "discharging"  ]]; then
		echo " ${__time_empt}"
	else
		echo " ${__time_full}"
	fi

	# Create the temporary battery file, if it doesn't exist
	if [ ! -f "/tmp/battery.tmp" ]; then
		touch /tmp/battery.tmp
	fi

	# Setup for battery notifications
	battery_notify 100 'fully-charged' 'Battery 100%'
	battery_notify  80 'charging'      'Battery 80%'
	battery_notify  20 'discharging'   'Battery 20%'
	battery_notify  15 'discharging'   'Battery 15%'
	battery_notify  10 'discharging'   'Battery 10%'
	battery_notify   5 'discharging'   'Battery 5%'
fi