#! /bin/sh -e

case $#,$2 in
  0,* | 1,*) ok=nil ;;
  *,*:*) ok=t ;;
  *) ok=nil ;;
esac
case $ok in
  nil) echo >&2 "usage: $0 DIR,... HOST:DISP [CMD ARGS ...]"; exit 2; ;;
esac
dirs=$1 host=${2%:*} dpy=${2##*:}; shift 2
case $#,$1 in
  0, | 1,:slideshow)
    set -- /usr/lib/xscreensaver/glslideshow -duration 10 -pan 10 \
	-xrm "'*desktopGrabber: ./getimg %s'"
     ;;
  1,:photopile)
    set -- /usr/lib/xscreensaver/photopile -no-titles -no-polaroid -shadows \
	-xrm "'*desktopGrabber: ./getimg %s'"
     ;;
esac

t=$(mktemp -d "${TMPDIR-/tmp}/remote-slidesshow.XXXXXXXX")
mkfifo "$t/pipe"
exec 3<>"$t/pipe"
rm -rf "$t"

ssh -ax "$host" "
	set -e
	tmp=\$(mktemp -d \"\${TMPDIR-/tmp}/remote-slideshow.XXXXXXXX\")
	trap 'cd / && rm -rf \$tmp' EXIT INT TERM HUP
	cd \$tmp
	IMAGEFILE=\$tmp/img; export IMAGEFILE
	DISPLAY=:$dpy; export DISPLAY
	exec 3<&0 4>&1
	cat >getimg <<'EOF'
#! /bin/sh -e
rm -f img
echo \"\$IMAGEFILE\" >&4
xscreensaver-command -deactivate >/dev/null 2>&1 || :
IFS= read -r f <&3
exec xscreensaver-getimage -directory \"\${IMAGEFILE%/*}\" -file img \"\$@\"
EOF
	chmod +x getimg
	$*" <&3 |
while IFS= read -r rdir; do
  set -- \( -false
  for e in jpg jpeg pjpeg pjpg png gif tif tiff xbm xpm; do
    set --  "$@" -o -name "*.$e"
  done
  set -- "$@" \) -type f -print -o -type d \( -false
  dd=$dirs
  while :; do
    case $dd in
      "") break ;;
      *,*) d=${dd##*,} dd=${dd%,*} ;;
      *) d=$dd dd= ;;
    esac
    for i in $(find "$d" -name .slideshow-ignore -type f -print); do
      while IFS= read -r line; do
	case $line in \#*) continue ;; esac
	set -- "$@" -o -path "${i%/*}/$line"
      done <"$i"
    done
    set -- "$d" "$@"
  done
  set -- "$@" \) -prune
  f=$(find "$@" | shuf -n1)
  echo "$f"
  scp "$f" "$host:$rdir" >/dev/null 2>&1
  echo done >&3
done