#!/bin/sh

help() { echo "brightness - change screen brightness
USAGE: brightness <up|down>"; }

[ "$#" -lt 1 ] && help >&2 && exit 1

brightness="$(brightnessctl --machine-readable | cut -d, -f4 | tr -d %)"
step="$(( brightness / 10 + 1))"

case "$1" in
	up) brightnessctl --quiet set +${step}% ;;
	down) brightnessctl --quiet set ${step}%- ;;
	*) help >&2; exit 1 ;;
esac

brightness="$(brightnessctl --machine-readable | cut -d, -f4)"

if [ -n "$TMUX" ]; then
	tmux display "Brightness: $brightness"
	exit
fi

notify() { [ -n "$DISPLAY" ] && notify-send -r 45234 "$1" "$2"; }
case "${brightness%\%}" in
	[0-9]) notify "💡 Brightness: $brightness" ;;
	[1-7][0-9]) notify "🔅 Brightness: $brightness" ;;
	[89][0-9]) notify "🔆 Brightness: $brightness" ;;
	100) notify "🔆 MAX Brightness: $brightness" ;;
	*) notify "brightness" "can't determine brightness"
esac
exit 0