#!/bin/ksh
#
# e
# 
# AUTHOR:
#   Dan Harkless                                                    <opensource@
#   http://harkless.org/dan/software/                              harkless.org>
# 
# COPYRIGHT:
#   This file is Copyright (C) 1999 by Dan Harkless, and is released under the
#   GNU General Public License <http://www.gnu.org/copyleft/gpl.html>.
#
# USAGE:
#   % e [-wait] <file1> [<file2>...]
#
# DESCRIPTION:
#   gnuclient is a wonderful tool if you're like me and leave an emacs / xemacs
#   invocation running at all times.  However, a raw call to gnuclient won't
#   work in certain situations, hence this wrapper script.
#
#   gnuclient works great if you run it on the same machine emacs is running on,
#   but when the machines are different, things get tougher.  gnuclient has a -h
#   parameter (equivalent to the $GNU_HOST environment variable) which is
#   supposed to attach to a gnuserv process running on a different machine, but
#   I have always had problems getting this mechanism to work.  In any case, I
#   sometimes log onto machines that don't even have gnuclient installed.
#
#   The solution this script takes is to remsh to the machine emacs is running
#   on and execute gnuclient there.  How do we determine which machine that is?
#   Well, if $GNUSERV_HOST (not $GNU_HOST!) is set, we use that.  If not, we use
#   the machine specified by $DISPLAY (people with real X workstations generally
#   run emacs on their local machines).
#
#   One thing a naked gnuclient doesn't take into account is the situation where
#   you are logged onto a remote machine and want to edit a file in a directory
#   that isn't available on your emacs machine.  For instance, you might want to
#   edit a file in /tmp, a directory that's local to each machine.  If your file
#   is in a partition that is typically not NFS-mounted, this script will copy
#   the file to your ~/tmp directory (please create one if you don't have one
#   already), have emacs edit it there, and then move it onto the original if
#   you actually modified it.
#
#   One last feature of this script is that if $DISPLAY isn't set, we assume
#   you're not logging in from an X terminal, and instead of calling gnuclient,
#   we run 'emacs -nw'.
#
# DATE        MODIFICATION
# ==========  ==================================================================
# 1999-04-22  Changed name of required ~/temp directory to more standard ~/tmp.
# 1999-04-13  HP-UX's ksh doesn't support -e for file existence check -- use -a.
# 1999-04-05  If you're on an X terminal or are running emacs remotely, $HOST is
#             not the emacs host.  If $GNUSERV_HOST is set, use that instead.
# 1998-07-28  Added -wait: don't exit until gnuclient does.
# 1996-09-19  Original.

wait_for_gnuclient_exit=0
if [[ $1 = -wait ]]; then
    wait_for_gnuclient_exit=1
    shift
fi

if [[ -z $DISPLAY ]]; then
    exec emacs -nw "$@"
elif [[ -z $GNUSERV_HOST ]]; then
    if [[ $DISPLAY = *:* ]]; then
	# $DISPLAY is of the form "[<machine>]:0.0".
	GNUSERV_HOST=${DISPLAY%%:*}
	if [[ -z $GNUSERV_HOST ]]; then
	    # $DISPLAY is of the form ":0.0".
	    GNUSERV_HOST=$HOST
	fi
    else
	# $DISPLAY is of the form "<machine>".
	GNUSERV_HOST=$DISPLAY
    fi
fi

if [[ $HOST = $GNUSERV_HOST ]]; then
    if [[ $wait_for_gnuclient_exit = 1 ]]; then
	gnuclient "$@"
    else
	(gnuclient "$@" &)
    fi
else
    e=${0##*/}  # get the root name in case we need to display errors
    orig_wd=$PWD
    for f_path in "$@"; do
	f=${f_path##*/}
	if [[ $f != $f_path ]]; then
	    f_dir=`dirname "$f_path"`  # can't do this with a single substr. op.
	    if [[ -d $f_dir ]]; then
		cd $f_dir
	    else
		echo "$e: Directory '$f_dir' does not exist!"
		continue  # do the next iteration of the for
	    fi
	else
	    cd $orig_wd
	fi
	
	partition=/`pwd | cut -d/ -f2` # can't do this with a single substr. op.
	case $partition in
	    / | /etc | /opt | /tmp | /usr | /var)
		if [[ -a ~/tmp/$f ]]; then
		    echo "$e: Can't edit $f_path because ~/tmp/$f exists!"
		    echo "$e: Aborting."
		    exit 1
		else
		    cp -p $f_path ~/tmp
		fi
		# In this situation we always have to behave like -wait was used
		# so we can check whether the file was changed or not.
		remsh $GNUSERV_HOST "gnuclient ~/tmp/'$f'"
		if cmp -s ~/tmp/"$f" "$f_path"; then
		    # File is unchanged.
		    rm -f ~/tmp/"$f"
		else
		    # File was modified: move the ~/tmp copy onto the original.
		    mv ~/tmp/"$f" "$f_path"
		    if [[ $? != 0 ]]; then
			print -n "$e: Delete ~/tmp/$f [Ny]? "
			read answer
			[[ $answer = y* ]] && rm -f ~/tmp/"$f"
		    fi
		fi
		;;

	    *)
		if [[ $wait_for_gnuclient_exit = 1 ]]; then
		    remsh $GNUSERV_HOST "gnuclient '$PWD/$f'"
		else
		    (remsh $GNUSERV_HOST -n "(gnuclient '$PWD/$f' &)" &)
		fi
	esac
    done
fi