#!/usr/bin/bash

SAVE_FILE="${HOME}/.cache/brightness-control-cache"

notify-brightness() {
    brightness="$(brightnessctl -m | sed 's/,/ /g' | awk '{print $4}' | tr -d '\n' | tr -d '%')"
    notify-send -h string:x-canonical-private-synchronous:brightness-control-sh -t 4000 -u normal -a "Brightness" -h int:value:"$brightness" "$brightness%"
}

save-brightness() {
    brightness="$(brightnessctl -m | sed 's/,/ /g' | awk '{print $4}' | tr -d '\n' | tr -d '%')"
    printf '%d' "${brightness}" >"${SAVE_FILE}"
}

restore-brightness() {
    if [ ! -e "${SAVE_FILE}" ]; then
        echo "brightness-control.sh: error: save file at \"${SAVE_FILE}\" not found" >&2
        exit 1
    fi
    brightness="$(cat "${SAVE_FILE}")"
    brightnessctl s "${brightness}%"
}

print-usage() {
    echo 'usage: brightness-control.sh [up|down|set|restore|display] <ammount>' 1>&2
    exit 1
}

if [ "$#" -lt 1 ]; then
    print-usage
fi

ammount='5%'
value='50%'
if [ "${#}" -gt 1 ]; then
    ammount="${2}"
    value="${2}"
fi

case "${1}" in
    'up')
        brightnessctl s "+${ammount}" > /dev/null
        notify-brightness
        save-brightness
        ;;
    'down')
        brightnessctl s "${ammount}-" > /dev/null
        notify-brightness
        save-brightness
        ;;
    'set')
        brightnessctl s "${value}" > /dev/null
        notify-brightness
        save-brightness
        ;;
    'display')
        notify-brightness
        ;;
    'restore')
        restore-brightness
        ;;
    *)
        print-usage
        ;;
esac