#! /bin/sh
# tempfile (Bourne_shell script) -- Mimics tempfile command from 'debianutils' package
#
# Version:   1.0
# Copyright: (c)2021 Alastair Irvine <alastair@plug.org.au>
# Keywords:  
# Notice:    
# Licence:   This file is released under the GNU General Public License
#
# Description:
#   
#
# Usage: 
# Options:
#   
#
# Licence details:
#     This program is free software; you can redistribute it and/or modify
#     it under the terms of the GNU General Public License as published by
#     the Free Software Foundation; either version 2 of the License, or (at
#     your option) any later version.
#
#     See http://www.gnu.org/licenses/gpl-2.0.html for more information.
#
#     You can find the complete text of the GPLv2 in the file
#     /usr/share/common-licenses/GPL-2 on Debian systems.
#     Or see the file COPYING in the same directory as this program.
#
#
# TO-DO:


SELF=`basename "$0"`
ALLOWED_OPTIONS=p:s:d:m:n:
ALLOWED_LONG_OPTIONS=prefix,suffix,directory,mode,name,help,version



# *** FUNCTIONS ***
show_help()
{
  cat << EOT_HELP
Usage: ${SELF} [OPTION]
Create a temporary file in a safe manner.
-d, --directory=DIR  place temporary file in DIR
-m, --mode=MODE      open with MODE instead of 0600
-n, --name=FILE      use FILE instead of tempnam(3)
-p, --prefix=STRING  set temporary file's prefix to STRING
-s, --suffix=STRING  set temporary file's suffix to STRING
    --help           display this help and exit
    --version        output version information and exit
EOT_HELP
}


# *** MAINLINE ***
# == command-line parsing ==
# -- defaults --
debug=0
verbose=0
prefix=file
dir=/tmp

# -- option handling --
set -e
orthogonal_opts=$(getopt --shell=sh --name=$SELF \
  --options=+$ALLOWED_OPTIONS --longoptions=$ALLOWED_LONG_OPTIONS -- "$@")
eval set -- "$orthogonal_opts"
set +e      # getopt would have already reported the error

while [ x"$1" != x-- ] ; do
  case "$1" in
    -m|--mode) mode=$2 ; shift ;;
    -n|--name) filename=$2 ; shift ;;
    -p|--prefix) prefix=$2 ; shift ;;
    -s|--suffix) suffix=$2 ; shift ;;
    -d|--dir) dir=$2 ; shift ;;
    -h|--help) show_help ; exit ;;
    --version) echo "${SELF} fake" ; exit ;;
    -1) echo "${SELF}: Warning: Blah blah blah feature unsupported" >&2 ;;
  esac
  shift     # get rid of option (or if the inner shift already did, get rid of arg)
done
shift       # get rid of the "--"

# -- argument checking --
## if [ $# != 2 -a $# != 3 ] ; then
##   ## echo "Usage: $SELF ..." >&2
##   show_help >&2
##   exit 1
## fi

# -- argument handling --


# == sanity checking ==


# == preparation ==
# Note that the semantics of `tempfile` are that -d does NOT take precedence
# over $TMPDIR
if [ -z "$TMPDIR" ] ; then
  TMPDIR=$dir
fi

# Don't rely on PATH to be set safely
if [ -x /usr/bin/mktemp ] ; then
  mktemp=/usr/bin/mktemp
elif [ -x /bin/mktemp ] ; then
  mktemp=/bin/mktemp
else
  echo "mktemp not found" >&2
  exit 2
fi


# == processing ==
if [ -z "$filename" ] ; then
  template=$(printf "%sXXXXXX%s" "$prefix" "$suffix")
  filename=$($mktemp --tmpdir=$TMPDIR -t "$template")
else
  touch "$filename"
fi
echo "$filename"
if [ -n "$mode" ] ; then
  chmod "$mode" "$filename"
fi