#!/bin/sh
#---------------------------------------------
#   xdg-screensaver
#
#   Utility script to control screensaver.
#
#   Refer to the usage() function below for usage.
#
#   Copyright 2006, Bryce Harrington <bryce@osdl.org>
#
#   LICENSE:
#
#---------------------------------------------

manualpage()
{
cat << _MANUALPAGE
_MANUALPAGE
}

usage()
{
cat << _USAGE
_USAGE
}

#@xdg-utils-common@

# Check if we can use "mv -T"
if mv -T ... ... 2>&1 | grep '\.\.\.' > /dev/null ; then
   # We can securely move files in /tmp with mv -T
   DEBUG 1 "mv -T available"
   MV="mv -T"
   screensaver_file="/tmp/xdg-screensaver-$USER-"`echo $DISPLAY | sed 's/:/-/g'`
else
   # No secure moves available, use home dir
   DEBUG 1 "mv -T not available"
   MV="mv"
   screensaver_file="$HOME/.xdg-screensaver-"`echo $(hostname)-$DISPLAY | sed 's/:/-/g'`
fi
lockfile_command=`which lockfile 2> /dev/null`

lockfile()
{
  if [ -n "$lockfile_command" ] ; then
     $lockfile_command -1 -l 10 -s 3 "$screensaver_file".lock
  else
     # Poor man's attempt at doing a lockfile
     # Be careful not to facilitate a symlink attack
     local try
     try=0
     while ! ln -s "$screensaver_file".lock "$screensaver_file".lock 2> /dev/null;
     do
        sleep 1
        try=$(($try+1))
        if [ $try -eq 3 ] ; then
            rm -f "$screensaver_file".lock || return # Can't remove lockfile
            try=0
        fi
     done
  fi
}

unlockfile()
{
  rm -f "$screensaver_file".lock
}

perform_action()
{
  result=1

  if [ "$1" = "resume" ] ; then
      # Restore DPMS state
      if [ -f "$screensaver_file.dpms" ]; then
          rm "$screensaver_file.dpms"
          # Re-enable DPMS
          xset +dpms
      fi
  fi
  if [ "$1" = "reset" ] ; then
      if xset -q | grep 'DPMS is Enabled' > /dev/null 2> /dev/null; then
          xset dpms force on
      fi
  fi

  case "$DE" in
    kde)
      if [ x"$KDE_SESSION_VERSION" = x"4" ]; then
          screensaver_freedesktop "$1"
      else
          screensaver_kde "$1"
      fi
      ;;

    gnome)
      screensaver_gnome "$1"
      ;;

    xscreensaver)
      screensaver_xscreensaver "$1"
      ;;
  esac

  if [ "$1" = "suspend" ] ; then
      # Save DPMS state
      if xset -q | grep 'DPMS is Enabled' > /dev/null 2> /dev/null; then
          test "${TMPDIR+set}" = set || TMPDIR=/tmp
          tmpfile=`mktemp $TMPDIR/tmp.XXXXXXXXXX`
          $MV "$tmpfile" "$screensaver_file.dpms"
          # Disable DPMS
          xset -dpms
      fi
  fi

}

cleanup_suspend()
{
  lockfile
  test "${TMPDIR+set}" = set || TMPDIR=/tmp
  tmpfile=`mktemp $TMPDIR/tmp.XXXXXXXXXX`
  grep -v "$window_id:$xprop_pid\$" "$screensaver_file" > "$tmpfile" 2> /dev/null
  $MV "$tmpfile" "$screensaver_file"
  if [ ! -s "$screensaver_file" ] ; then
      rm "$screensaver_file"
      unlockfile
      # $screensaver_file is empty, do resume
      perform_action resume
  else
      unlockfile
  fi
}

do_resume()
{
  lockfile # Obtain lockfile
  # Find the PID of the trackingprocess
  xprop_pid=`grep "$window_id:" "$screensaver_file" 2> /dev/null | cut -d ':' -f 2`
  unlockfile # Free lockfile
  if [ -n "$xprop_pid" ] && ps -p "$xprop_pid" 2> /dev/null | grep xprop > /dev/null; then
     # Kill the tracking process
     kill -s TERM $xprop_pid
  fi
  cleanup_suspend
}

XPROP=`which xprop 2> /dev/null`

check_window_id()
{
  if [ -z "$XPROP" ]; then
     DEBUG 3 "xprop not found"
     return
  fi
  DEBUG 2 "Running $XPROP -id $window_id"
  if $XPROP -id $window_id > /dev/null 2> /dev/null; then
     DEBUG 3 Window $window_id exists
  else
     DEBUG 3 Window $window_id does not exist
     exit_failure_operation_failed "Window $window_id does not exist"
  fi
}

track_window()
{
  if [ -z "$XPROP" ]; then
     # Don't track window if we don't have xprop
     return
  fi
  lockfile

  test "${TMPDIR+set}" = set || TMPDIR=/tmp
  tmpfile=`mktemp $TMPDIR/tmp.XXXXXXXXXX`
  # Filter stale entries from the xdg-screensaver status file
  # Return if $window_id is being tracked already
  (
    already_tracked=1
    IFS_save="$IFS"
    IFS=":"
    while read wid pid; do
      if ps -p "$pid" 2> /dev/null | grep xprop > /dev/null; then
        echo "$wid:$pid"
        if [ $wid = $window_id ] ; then
          already_tracked=0
        fi
      fi
    done
    IFS="$IFS_save"
    exit $already_tracked
  ) < $screensaver_file > $tmpfile
  already_tracked=$?

  if [ "$already_tracked" -eq "0" ] ; then
    $MV "$tmpfile" "$screensaver_file"
    # We are already tracking $window_id, don't do anything
    unlockfile
    return
  fi

  # Start tracking $window_id
  $XPROP -id $window_id -spy > /dev/null &
  xprop_pid=$!
  # Add window_id and xprop_pid to the xdg-screensave status file
  echo "$window_id:$xprop_pid" >> $tmpfile
  $MV "$tmpfile" "$screensaver_file"
  unlockfile
  # Wait for xprop to edit, it means that the window disappeared
  wait $xprop_pid
  # Clean up the administration and resume the screensaver
  cleanup_suspend
}

screensaver_freedesktop()
{
    case "$1" in
        suspend)
        dbus-send --session \
                  --dest=org.freedesktop.ScreenSaver \
                  --type=method_call \
                  --print-reply \
                  --reply-timeout=2000 \
                  /ScreenSaver \
                  org.freedesktop.ScreenSaver.Inhibit \
                  string:$window_id \
                  string:xdg-screensaver \
                  | grep uint32 | cut -d ' ' -f 5 >| "$screensaver_file.cookie" \
                  2> /dev/null
        result=$?
        ;;

        resume)
        if [ -f "$screensaver_file.cookie" ] ; then
            value=`cat "$screensaver_file.cookie"`
            dbus-send --session \
                      --dest=org.freedesktop.ScreenSaver \
                      --type=method_call \
                      /ScreenSaver \
                      org.freedesktop.ScreenSaver.UnInhibit \
                      uint32:$value \
                      2> /dev/null
            rm -f "$screensaver_file.cookie"
        fi
        result=$?
        ;;

        activate)
        dbus-send --session \
                  --dest=org.freedesktop.ScreenSaver \
                  --type=method_call \
                  /ScreenSaver \
                  org.freedesktop.ScreenSaver.SetActive \
                  boolean:true \
                  2> /dev/null
        result=$?
        ;;

        lock)
        dbus-send --session \
                  --dest=org.freedesktop.ScreenSaver \
                  --type=method_call \
                  /ScreenSaver \
                  org.freedesktop.ScreenSaver.Lock \
                  2> /dev/null
        ;;

        reset)
        if [ -f "$screensaver_file.cookie" ] ; then
            value=`cat "$screensaver_file.cookie"`
            dbus-send --session \
                      --dest=org.freedesktop.ScreenSaver \
                      --type=method_call \
                      /ScreenSaver \
                      org.freedesktop.ScreenSaver.UnInhibit \
                      uint32:$value \
                      2> /dev/null
            rm -f "$screensaver_file.cookie"
        fi
        result=$?
        ;;

        status)
        status=`dbus-send --session \
                          --dest=org.freedesktop.ScreenSaver \
                          --type=method_call \
                          --print-reply \
                          --reply-timeout=2000 \
                          /ScreenSaver \
                          org.freedesktop.ScreenSaver.GetActive \
                          | grep boolean | cut -d ' ' -f 5`
        result=$?
        if [ x"$status" = "xtrue" ]; then
            echo "enabled"
        elif [ x"$status" = "xfalse" ]; then
            echo "disabled"
        else
            echo "ERROR: dbus org.freedesktop.ScreenSaver.GetActive returned '$status'" >&2
            return 1
        fi
        ;;

        *)
        echo "ERROR:  Unknown command '$1'" >&2
        return 1
        ;;
    esac
}

screensaver_kde()
{
    case "$1" in
        suspend)
        dcop kdesktop KScreensaverIface enable false > /dev/null
        result=$?
        ;;

        resume)
        dcop kdesktop KScreensaverIface configure > /dev/null
        result=$?
        ;;

        activate)
        dcop kdesktop KScreensaverIface save > /dev/null
        result=$?
        ;;

        lock)
        dcop kdesktop KScreensaverIface lock > /dev/null
        result=$?
        ;;

        reset)
        # Turns the screensaver off right now
        dcop kdesktop KScreensaverIface quit > /dev/null
        result=$?
        ;;

        status)
        status=`dcop kdesktop KScreensaverIface isEnabled`
        result=$?
        if [ x"$status" = "xtrue" ]; then
            echo "enabled"
        elif [ x"$status" = "xfalse" ]; then
            echo "disabled"
        else
            echo "ERROR:  kdesktop KScreensaverIface isEnabled returned '$status'" >&2
            return 1
        fi
        ;;

        *)
        echo "ERROR:  Unknown command '$1'" >&2
        return 1
        ;;
    esac
}

screensaver_suspend_loop()
{
  lockfile
  test "${TMPDIR+set}" = set || TMPDIR=/tmp
  tmpfile=`mktemp $TMPDIR/tmp.XXXXXXXXXX`
  # Filter stale entries from the xdg-screensaver status file
  cat "$screensaver_file" 2> /dev/null | (
    IFS_save="$IFS"
    IFS=":"
    while read wid pid; do
      if ps -p "$pid" 2> /dev/null | grep xprop > /dev/null; then
        echo "$wid:$pid"
      fi
    done
    IFS="$IFS_save"
  ) > $tmpfile
  if [ -s "$tmpfile" ] ; then
    # Suspend pending, don't do a thing
    $MV "$tmpfile" "$screensaver_file"
    unlockfile
    return
  fi
  $MV "$tmpfile" "$screensaver_file"
  unlockfile
  (while [ -f "$screensaver_file" ]; do $*; sleep 50; done) > /dev/null 2> /dev/null &
}

screensaver_gnome()
{
# TODO
# There seems to be a DBUS interface for gnome-screensaver
# See http://lists.mplayerhq.hu/pipermail/mplayer-dev-eng/2006-April/042579.html and
# http://cvs.gnome.org/viewcvs/gnome-screensaver/src/gs-listener-dbus.c?rev=1.36&view=log
# A problem seems to be that Inhibit is tied to the lifetime of the DBUS appname and
# this can not be used from a script
    case "$1" in
        suspend)
        screensaver_suspend_loop gnome-screensaver-command --poke
        result=0
        ;;

        resume)
        # Automatic resume when $screensaver_file disappears
        result=0
        ;;

        activate)
        gnome-screensaver-command --activate > /dev/null 2> /dev/null
        result=$?
        ;;

        lock)
        gnome-screensaver-command --lock > /dev/null 2> /dev/null
        result=$?
        ;;

        reset)
        # Turns the screensaver off right now
        gnome-screensaver-command --deactivate > /dev/null 2> /dev/null
        result=$?
        ;;

        status)
        result=0
        if [ -f "$screensaver_file" ] ; then
            echo "disabled"
        elif gnome-screensaver-command --query > /dev/null 2> /dev/null; then
            echo "enabled"
        else
            # Something is wrong
            echo "disabled"
        fi
        ;;

        *)
        echo "ERROR:  Unknown command '$1" >&2
        return 1
        ;;
    esac
}

screensaver_xscreensaver()
{
    case "$1" in
        suspend)
        screensaver_suspend_loop xscreensaver-command -deactivate
        result=0
        ;;

        resume)
        # Automatic resume when $screensaver_file disappears
        result=0
        ;;

        activate)
        xscreensaver-command -activate > /dev/null 2> /dev/null
        result=$?
        ;;

        lock)
        xscreensaver-command -lock > /dev/null 2> /dev/null
        result=$?
        ;;

        reset)
        # Turns the screensaver off right now
        xscreensaver-command -deactivate > /dev/null 2> /dev/null
        result=$?
        ;;

        status)
        result=0
        if [ -f "$screensaver_file" ] ; then
            echo "disabled"
        else
            echo "enabled"
        fi
        ;;

        *)
        echo "ERROR:  Unknown command '$1" >&2
        return 1
        ;;
    esac
}

[ x"$1" != x"" ] || exit_failure_syntax

action=
window_id=

case $1 in
  suspend)
    action="$1"

    shift

    if [ -z "$1" ] ; then
        exit_failure_syntax "WindowID argument missing"
    fi

    window_id="$1"
    check_window_id
    ;;

  resume)
    action="$1"

    shift

    if [ -z "$1" ] ; then
        exit_failure_syntax "WindowID argument missing"
    fi

    window_id="$1"
    check_window_id
    ;;

  activate)
    action="$1"
    ;;

  lock)
    action="$1"
    ;;

  reset)
    action="$1"
    ;;

  status)
    action="$1"
    ;;

  *)
    exit_failure_syntax "unknown command '$1'"
    ;;
esac

detectDE
# Consider "xscreensaver" a separate DE
xscreensaver-command -version 2> /dev/null | grep XScreenSaver > /dev/null && DE="xscreensaver"

if [ "$action" = "resume" ] ; then
    do_resume
    exit_success
fi

perform_action "$action"

if [ "$action" = "suspend" ] ; then
    # Start tracking $window_id and resume the screensaver once it disappears
    ( track_window  ) 2> /dev/null > /dev/null &
fi

if [ $result -eq 0 ]; then
    exit_success
else
    exit_failure_operation_failed
fi
