#!/usr/bin/env bash
# Script to lower/ raise screen brightness using xbacklight (xorg-xbacklight)

set -e -u

export DISPLAY=:0
x11user=$(w |grep -w :0 | cut -d " " -f1)
export XAUTHORITY=/home/$x11user/.Xauthority
step=5

if [ -x /usr/bin/xbacklight ]; then
  if [ "$1" = "video/brightnessup" ] && [ $2 = "BRTUP" ]; then
    xbacklight -inc "$step"
  elif [ "$1" = "video/brightnessdown" ] && [ $2 = "BRTDN" ]; then
    xbacklight -dec "$step"
  else
    exit 1
  fi
else
  exit 1
fi

exit 0