#!/bin/bash
# gzip-like CLI wrapper for p7zip
set -e

compress=true
file=

usage ()
  {
    echo "Usage: $0 [-d] [-h|--help] [file]"
    echo ""
    echo "    -h print this help"
    echo "    -d decompress file"
    echo ""
    exit 1
  }

while [ "$#" != "0" ] ; do
  case "$1" in
    -d) compress=false ;; # decompressing
    -c) echo "$0: ignoring $1 option (not yet implemented)" ;;
    -h|--help|-*) usage ;;
    *)
      if [ "${file}" = "" ] ; then
        file="$1"
      else
        usage
      fi
    ;;
  esac
  shift
done

# make sure they're present, before we screw up
for i in mktemp 7zr rm cat tty ; do
  if ! which $i > /dev/null ; then
    echo "$0: $i: command not found"
    exit 1
  fi
done

if [ "${file}" != "" ] ; then
  if ${compress} ; then
    7zr a "${file}.7z" "${file}"
    exec rm "${file}"
  else
    case "${file}" in
      *.7z)
        7zr x "${file}"
        exec rm "${file}"
      ;;
      *)
        echo "$0: ${file}: unknown suffix -- ignored"
        exit 0
      ;;
    esac
  fi
fi

tmp=`mktemp`
trap "rm -f ${tmp}" 0

if ${compress} ; then
  if tty -s <&1 >/dev/null ; then
    echo "$0: compressed data not written to a terminal."
    echo "For help, type: $0 -h"
    exit 1
  fi
  rm -f ${tmp}
  7zr a ${tmp} -si >/dev/null
  cat ${tmp}
else
  cat > ${tmp}
  7zr x ${tmp} -so 2>/dev/null | cat
fi

exec rm -f ${tmp}