#! /bin/sh

# Invoke geomview possibly remotely.
# For use within Maple, install this remotegv script somewhere in users'
# search paths (e.g. in /usr/local/bin).
# This script attempts to guess which machine to invoke geomview on by
# examining the DISPLAY environment variable.  If DISPLAY isn't set or
# if geomview should run on a different machine, use the -h host option.
#
# The script also assumes that geomview should display on the machine where
# it is invoked, so for that copy of geomview, it sets DISPLAY to ":0".
# If the display should appear elsewhere (on an X terminal, say),
# use the -display option.
#
# We use "rsh" (remote shell) to pass data to the other computer, so 
# the remote computer must allow this -- either with an entry in
# /etc/hosts.equiv, or in a .rhosts file in the user's home directory
# on the machine where geomview will run.  The account name on the other
# machine is assumed to be the same as on this machine; if different,
# use the -l username or -h username@othermachine options.
#
# In case permissions are not set up correctly, the symptom
# is liable to be a "Permission denied." message followed by the
# immediate termination of the Maple process -- so if you're using it for
# the first time, check it out before doing much else in your Maple session!
# Sorry, but MapleV3 is just not very good at connecting to other programs.
#
# Note that togeomview and geomview MUST BE IN THE USER'S DEFAULT SEARCH PATH
# on the remote machine.
#
# To use this script within Maple, you'd say:
#    readlib(gvplot);
# then
#    gvcommand := `remotegv`;
# or e.g.
#    gvcommand := `remotegv -h othermachine -display myxterm:0`;
# or, if the account on the other machine is different from yours,
#    gvcommand := `remotegv -l otheraccount`;
# or
#    gvcommand := `remotegv -h otheraccount@othermachine`;
# Following any remotegv options, you can add the command to be invoked as
# geomview, possibly including options, as in:
#    gvcommand := `remotegv -l person /u/person/bin/gv -wpos 300x200`;
#
# Then use gvplot() as usual.
#
# Normally, error messages reporting problems on the other machine (for
# example, being unable to run geomview) are suppressed; this is unfortunately
# necessary, or you'd never get another Maple prompt until quitting from
# geomview.  There's a test mode to aid in tracing problems; use it as in
#    gvcommand := `remotegv -test -h othermachine`;
# i.e. add "-test" to whatever other options you'd give to remotegv.
# 
# Option summary:
# -l user  or  -l user@host
# -h host  or  -h user@host
# -display host:number		(set display on remote end)
# -test
# also accepts togeomview's options (-g, -M[c][g][p][s]).

# Invokes rsh to specified machine, invokes togeomview there by default.
#
# By default, we assume DISPLAY points to the machine where we'd like to be;
#   -h {host-portion-of-DISPLAY} -display :0
# Incorporates settings from "$RGVOPTS" environment variable.

set -- $RGVOPTS "$@"

while
  case "$1" in
  -l)
	case "$2" in
	*@*) user="`expr match "$2" '\([^@]*\)'`"
	     host="`expr match "$2" '.*@\(.*\)'`" ;;
	*) user="$2" ;;
	esac
	shift 2 ;;

  -h)   case "$2" in
	*@*) user="`expr match "$2" '\([^@]*\)'`"
	     host="`expr match "$2" '.*@\(.*\)'`" ;;
	*) host="$2" ;;
	esac
	shift 2 ;;

  -test) testopt=-test; shift ;;
  -display) rdisplay="$2"; shift 2 ;;
  -M*) togvopts="$togvopts $1";
	 inpipe="$2"
	 shift 2 ;;
  -g)  gopt=-g; shift ;;
  "") test ;;
  *) togvargs="$togvargs $1"; shift ;;
  esac
do :
done

# Apply defaults

if [ -z "$host" ]; then
  host="`expr match "$DISPLAY" '\([^:]*\)'`"
fi

if [ -z "$rdisplay" ]; then
  rdisplay=":0.0"
fi

case "$inpipe" in
  /*) ;;
  ?*) inpipe=/tmp/geomview/$inpipe ;;
esac

user=${user+"-l $user"}
cmd="${host+rsh $host $user}"

if [ -n "$host" ]; then
  redirect=">/dev/null 2>&1"
  if [ -n "$testopt" ]; then
    echo "Testing setup to $host.  If geomview or togeomview can't be started
there, you should see messages explaining why.  Unfortunately this command
may not finish on its own -- you may need to interrupt (perhaps with control-C)
after seeing the results, before you get another Maple prompt." >&2
    redirect=""
  fi
  if [ -n "$inpipe" ]; then
    rsh $host $user sh -c "\"DISPLAY=$rdisplay togeomview $gopt ${togvopts} $inpipe $togvargs $redirect\"" <$inpipe
  else
    rsh $host $user sh -c "\"DISPLAY=$rdisplay togeomview $gopt ${togvopts} $togvargs $redirect\""
  fi
else
  case "$1" in
    ""|-*) DISPLAY=$rdisplay geomview ${togvopts} $togvargs ;;
    *) DISPLAY=$rdisplay ${togvopts} $togvargs;;
  esac
fi