#!/bin/bash

#Config
WARNING_LEVEL=10
SHUTDOWN_LEVEL=2
#End config


STATE=0

while true; do
    level=$(acpi -b | awk -F, 'BEGIN{s=0}{s+=$2}END{print int(s/NR)}')
    charger_connected=$(acpi -b | grep Charging)
    case "$STATE" in
        0) # battery ok
            if [ "$level" -le "$WARNING_LEVEL" -a -z "$charger_connected" ]; then
                zenity --warning --text="Your battery is getting low\!" --no-wrap &
                STATE=1
            fi
            ;;
        1) # battery low
            if [ -n "$charger_connected" ]; then
                STATE=0
            elif [ "$level" -le "$SHUTDOWN_LEVEL" ]; then
                systemctl hibernate;
            else
                notify-send -u critical -a "BatterySystem" "Battery is low!" "Please connect a charger"
            fi
            ;;
    esac
    sleep 20
done