#!/bin/bash

# vshnu-bash - VSHNU<->BASH INTEGRATION
#
# written by Marc Schaefer, marc_schaefer@gmx.de, Sep 01
# to be distributed under the same terms as vshnu
# some vshnu 1.0100 and Solaris compatability tweaks by
#   Steve Kinzler, kinzler@cs.indiana.edu, Mar 02
# tweak for VSHNUCWD file format
#   Steve Kinzler, kinzler@cs.indiana.edu, Jul 03
#
# To use, put vshnu-bash into your path and add the following lines to
# your .bashrc
#
#	alias v=". vshnu-bash; vshnu_invoke v"
#	alias vv=". vshnu-bash; vshnu_invoke vv"
#
# Then v starts vshnu / returns to a suspended vshnu in your current
# directory, while vv starts vshnu or returns to a suspended vshnu in
# the directory you were last in.
#
# This code aliases exit to kill a suspended vshnu without warnings
# when terminating the shell.

function vshnu_set_dir() {

  # Unless $VSHNUTMP is set, creates a directory in $TEMP,
  # $TMPDIR or /tmp which belongs to ME and to ME ALONE!
  # BUHAAHAHAHA!

  local COUNTER
  local TEMP=`echo ${TEMP:-${TMPDIR:-/tmp}} | sed -e "s/\\/$//"`
  if [ ! -e "$VSHNUTMP" ]; then
    COUNTER=0
    # use %m%d%H%M%S instead of original %s for Solaris,etc compat -kinzler
    VSHNUTMP=$TEMP/vshnu.$$.`date +%m%d%H%M%S`
    until mkdir -m 700 $VSHNUTMP &>/dev/null; do
      (( COUNTER = COUNTER + 1 ))
      VSHNUTMP=$TEMP/vshnu.$$.`date +%m%d%H%M%S`.$COUNTER
      if [ $COUNTER -ge 10 ]; then
	echo "vshnu_bash: Unable to create temporary directory in $TEMP."
	return 1
      fi
    done
    trap "rm -rf $VSHNUTMP" EXIT
    VSHNUCWD=curdir; VSHNUENV=env
    export VSHNUTMP VSHNUCWD VSHNUENV
  fi
  return 0
}

function vshnu_job_from_pid () {

  # prints the job no corresponding to the given pid

  jobs -l | sed -n "s/^\\[\\([0-9]\\)\\][+-] *$1.*\$/\\1/p"
}

function vshnu_start() {

  # starts vshnu unless there is a vshnu job running
  # sets VSHNUPID and VSHNUJOB as a side effect

  vshnu_set_dir || return 1;

  if [ -z "$VSHNUPID" -o -z "`vshnu_job_from_pid $VSHNUPID`" ]; then
    { vshnu & }
    VSHNUPID=$!
  fi

  VSHNUJOB=`vshnu_job_from_pid $VSHNUPID`
  return 0
}

function vshnu_set_environ {

  # Propagates the current directory and the current environment
  # to vshnu

  vshnu_set_dir
  echo `pwd` >$VSHNUTMP/curdir
  perl -MData::Dumper -e "print '%ENV=%{' . Dumper(\%ENV) . '}'" >$VSHNUTMP/env
}

function vshnu_restore_cwd {

  # Called by $PROMPT_COMMAND to propagate directory changes from
  # vshnu to bash

  vshnu_set_dir
  if [ -e "$VSHNUTMP/curdir" ]; then
    cd `sed 1q $VSHNUTMP/curdir`
  fi
}

function vshnu_future_restore_cwd {
  PROMPT_COMMAND='vshnu_restore_cwd; unset PROMPT_COMMAND'
}

function vshnu_kill_on_exit {

  # Kills vshnu if there is a stopped one.

  if [ -n "$VSHNUPID" -a -n "`vshnu_job_from_pid $VSHNUPID`" ]; then
    kill %`vshnu_job_from_pid $VSHNUPID`
  fi
}

function vshnu_invoke {
  vshnu_start || return
  if [ "$1" = "v" ]; then
    vshnu_set_environ
  fi
  vshnu_future_restore_cwd
  %$VSHNUJOB
}

unset VSHNUTMP
unset VSHNUPID

alias v="vshnu_invoke v"
alias vv="vshnu_invoke vv"

alias exit="vshnu_kill_on_exit; exit"