battery_check.spell

#!/bin/sh
# Checks battery life and suspends if it's too low.

if acpi 2>&1 | grep 'power_supply'; then
    exit
fi
case "$(hostname)" in tolaria) exit ;; esac
CACHE="/tmp/$LOGNAME"
mkdir -p "$CACHE"

setup() {
    batteries_levels=$(acpi -b | cut -d ' ' -f 4 | grep -o '[0-9]*')
    batteries_state=$(acpi | grep 'Battery' | sed 's/Battery\s[0-9]*: //' | sed 's/, [0-9][0-9]*\%.*//')
    battery_remaining=$(acpi | grep -oh '[0-9:]* remaining' | sed 's/:\w\w remaining$/ Minutes/' | sed 's/00://' | sed 's/:/h /')

    num_batteries=$(echo "$batteries_levels" | wc -l)
    battery_level=$(echo "$batteries_levels" | awk -v n="$num_batteries" '{s+=$1} END {printf "%.0f\n", s/n}')
    # Battery state selection (priority for 'Charging')
    battery_state=$(echo "$batteries_state" | awk '{ if($0=="Charging") {r=$0} else {s=$0} } END{if(r=="") {print s} else {print r}}')

    if [ ! -f "$CACHE/.battery" ]; then
        echo "$battery_level" >$CACHE/.battery
        echo "$battery_state" >>$CACHE/.battery
        exit
    fi

    previous_battery_level=$(head -n 1 $CACHE/.battery)
    previous_battery_state=$(tail -n 1 $CACHE/.battery)
    echo "$battery_level" >$CACHE/.battery
    echo "$battery_state" >>$CACHE/.battery
}

checkBatteryLevel() {
    [ "$battery_level" = "$previous_battery_level" ] && exit

    if [ "$battery_state" != "Discharging" ] && [ "$battery_level" -ge 90 ]; then
        notify-send "Battery almost full: ${battery_level}%, unplug" -u low -a "$(basename "$0")"
    elif [ "$battery_state" = "Discharging" ]; then
        if [ -e $CACHE/use_the_juice ] && [ "$battery_level" -le 5 ]; then
            notify-send 'Shutting down' -u critical -a "$(basename "$0")"
            shutdown
        elif ! [ -e $CACHE/use_the_juice ] && [ "$battery_level" -le 10 ]; then
            systemctl suspend
        elif [ "$battery_level" -le 20 ]; then
            notify-send "Low Battery" "Your computer will suspend soon unless plugged into a power outlet." -u critical -a "$(basename "$0")"
        elif [ "$battery_level" -le 30 ]; then
            notify-send "Low Battery" "$battery_level% ($battery_remaining) of battery remaining." -u normal -a "$(basename "$0")"
        fi
    fi
}

checkBatteryStateChange() {
    if [ "$battery_state" != "Discharging" ] && [ "$previous_battery_state" = "Discharging" ]; then
        notify-send "Charging" "Battery is now plugged in." -u low -a "$(basename "$0")"
    fi

    if [ "$battery_state" = "Discharging" ] && [ "$previous_battery_state" != "Discharging" ]; then
        notify-send "Power Unplugged" "Your computer has been disconnected from power." -u low -a "$(basename "$0")"
    fi
}

while :; do
    setup
    checkBatteryStateChange
    checkBatteryLevel
    sleep 1m
done