change-bright

#!/usr/bin/zsh

# adjust brightness levels
# support for a laptop and one external monitor through xrandr brightness
# occasionally it takes a while to run xbacklight after xrandr, is prob kernel issue

# change this to match your external monitor's name.
# if you don't know it, run `xrandr | grep 'connected | grep -v 'dis'`
extConnected=false
extMonitor=HDMI-0
extStatus="$(xrandr | awk "/$extMonitor/"'{print $2}')"
backlight="$(xbacklight)"

if [[ "${extStatus}" == connected ]]; then
	extBright=$(xrandr --verbose |
		grep -A5 "${extMonitor}" |
		awk -F' ' '/Brightness/{print $2}')
	extConnected=true
fi

lower() {
	# lower brightness of laptop brightness and ext monitor
	if [[ -n "${extConnected}" ]]; then
		if ((extBright > 0.2)); then
			xrandr --output "${extMonitor}" --brightness "$((extBright - 0.05))"
		fi
	fi
	if ((backlight > 20)); then
		xbacklight -dec 5
	fi
	return
}

raise() {
	# raise brightness of laptop and ext monitor
	if [[ -n "${extConnected}" ]]; then
		if ((extBright <= 1.0)); then
			xrandr --output "${extMonitor}" --brightness "$((extBright + 0.05))"
		fi
	fi
	if ((backlight <= 100)); then
		xbacklight -inc 5
	fi
	return
}

min() {
	# set monitors to lowest brightness
	if [[ -n "${extConnected}" ]]; then
		xrandr --output "${extMonitor}" --brightness 0.2
	fi
	xbacklight -set 20
}

max() {
	# set monitors to highest brightness
	if [[ -n "${extConnected}" ]]; then
		xrandr --output "${extMonitor}" --brightness 1.0
	fi
	xbacklight -set 100
}

main() {
	case "$1" in
	lower)
		lower
		;;
	raise)
		raise
		;;
	min)
		min
		;;
	max)
		max
		;;
	*)
		echo "Takes options for: lower, raise, min, max"
		;;
	esac
}

main "$@"
exit 0