#!/bin/bash
# rdiff: remote diff, copyleft 2013 under GPL jc.unternet.net
# for bug reports replace first dot with @
set +H  # prevent history expansion
sshfs_mount() {
 remote="$1"  # rather, purported remote; we shall find out
 if [ ! -e "$remote" -a "${remote%%:*}" != "$remote" ]; then
  old_remote="$remote"
  remote=$(mktemp -d)
  if ! sshfs "$old_remote" "$remote"; then
   if ! sshfs "${old_remote%[:/]*}" "$remote"; then
    rmdir $remote
    remote="$old_remote"
   else
    remote="$remote/${old_remote##*[:/]}"
   fi
  fi
 fi
 echo "$remote"
}
sshfs_umount() {
 tempdir="$1"
 while [ ${#tempdir} -gt 1 -a ! -d "$tempdir" ]; do
  if [ "$tempdir" = "${tempdir%/*}" ]; then
   break
  else
   tempdir="${tempdir%/*}"
  fi
 done
 while [ ${#tempdir} -gt 1 -a -d "$tempdir" ]; do
  if fusermount -u "$tempdir"; then
   rmdir "$tempdir"
   break
  elif [ "$tempdir" = "${tempdir%/*}" ]; then
   break
  else
   tempdir=${tempdir%/*}
  fi
 done
}
diff_source="$(sshfs_mount "${@:$#-1:1}")"
diff_target="$(sshfs_mount "${@:$#:1}")"
diff "${@:1:$#-2}" "$diff_source" "$diff_target"
exstat=$?
sshfs_umount "$diff_source"
sshfs_umount "$diff_target"
exit $exstat