#!/bin/bash

set -e

verwendung() {
  >&2 echo 'mark-as-expendable-dir creates CACHEDIR.TAG and .rsync-filter files to hide directory from backups by "tar --exclude-caches" and "rsync -F".'
  >&2 echo ''
  >&2 echo 'Usage: mark-as-expendable-dir [OPTIONS] [DIRECTORIES]'
  >&2 echo '  -c,--caller=caller  name of caller to put into comment of CACHEDIR.TAG'
  >&2 echo \
'#HELPTEXT#           #'
  exit 1
}

eval set -- "$(getopt -o c: --long caller:,help,version -n "$(basename "$0")" -- "$@" || echo verwendung)"

caller="$(ps -o comm= $PPID)"

while true
do
  case "$1" in
    -c|--caller)
      shift
      caller="$1"
    ;;
    --help)
      verwendung 0
      ;;
    --version)
      echo '#VERSION#'
      exit 0
      ;;
    --)
      shift
      break
      ;;
    *)
      >&2 echo "FEHLER: Verstehe Option \"$1\" doch nicht! Ich beende."
      verwendung
      ;;
  esac
  shift
done

if [ $# -eq 0 ]
then
  >&2 echo 'No directories given - was this intented?'
  verwendung
fi

for dir in "$@"
do
  if [ ! -d "${dir}" ]
  then
    >&2 echo "Argument '${dir}' is not a directory."
    verwendung
  fi
done

for dir in "$@"
do
  (
    echo -n 'Signature: '
    echo -n '.IsCacheDirectory' | \
      md5sum - | \
      cut -d ' ' -f 1
    echo '# This file is a cache directory tag created by '"$(basename "$0")"' for '"${caller}"'.'
    echo '# For information about cache directory tags, see:'
    echo '#      http://www.brynosaurus.com/cachedir/'
  ) > "${dir}/CACHEDIR.TAG"
  (
    echo '+ .rsync-filter'
    echo '- *'
  ) > "${dir}/.rsync-filter"
  touch "${dir}/.nobackup"
done