#! /bin/bash

function help () {
   echo "Usage: $0 [OPTIONS] <file>"
   echo "Cleans up xscreensaver graphic programs left behind after killing xscreensaver itself."
   echo " -u     specify a username for which to kill xscreensaver artifacts"
   echo " -h     display this output"
   exit 1
}

while getopts ':u:' opt ; do
   case "$opt" in
      u)
         username="${OPTARG}"
         userid=`id -u "$username" 2>/dev/null` || { echo "$username is not a user on this system" && exit 1 ;}
         [ "$userid" -lt 1000 ] && echo "User $username seems to be a systemuser (uid: $userid). Please specify a normal user." && exit 1
         ;; 
      h) help ;;
      :)
         echo "$0: Must supply an argument to -$OPTARG." >&2
         exit 1
         ;;
      ?)
         echo "Invalid option: -${OPTARG}."
         exit 2
         ;;
   esac
done

username="${username:-$USER}"
homedir=`eval echo "~$username"`
selected_graphic_nr=`grep selected "$homedir/.xscreensaver" | cut -f 2`
regex='/\\n\\/'
graphic_process_name=`cat "$homedir/.xscreensaver"  | awk "$regex && ++n == "$selected_graphic_nr" {getline; print; exit}" | cut -f 5 | cut -d ' ' -f 1 `
echo "graphic_process_name: $graphic_process_name"
[ -z "$graphic_process_name" ] && { echo Could not find selected graphic application && exit 1; }
graphic_processes=`ps -U "$username" | grep "$graphic_process_name" | awk '{$1=$1};1' | cut -d ' ' -f 1 | tr '\n' ' ' ` || { echo "No screensaver graphic processes were found for $username" && exit 0; }
echo "graphic_processes: $graphic_processes"
[ -z "$graphic_processes" ] && { echo "No xscreensaver graphic processes seem to be running for $username" && exit 0; }
process_count=`echo $graphic_processes | wc -w`
kill $graphic_processes && echo "killed $process_count screensaver graphic processes for $username"