#!/bin/bash

name="mktar"
version="1.0"
read -r -d '' help_message <<-EOF
	Wrapper around 'tar' for easier compression
	Usage: mktar FILES [..] [OPTIONS]
	Options:
	 -c, --compress        compress archive with gzip
	 --compress=ALGO       compress archive with [none|gzip|xz|zstd|bzip2]
	 -C, --checksum        create checksum with SHA1
	 -e, --encrypt         encrypt files with GPG
	 -h, --help            print this message
	 -n FILE, --name FILE  name of backup file (Default: archive.tar)
	 -q, --quiet           suppress error messages and prompts
	 -v, --verbose         show additional messages
	 -V, --version         print version number and exit
EOF

source /usr/local/lib/mylib.bash

positional=()
quiet=0
verbose=0
compress=-1
encrypt=-1
checksum=-1
archive_fn=""
while [[ $# -gt 0 ]]; do
  case $1 in

  --compress=xz|--compress=2)
    debug_msg "Setting compress option to 2 (=xz) (was ${compress})"
    compress=2
    shift
    ;;

  --compress=zst|--compress=zstd|--compress=3)
    debug_msg "Setting compress option to 3 (=zstd) (was ${compress})"
    compress=3
    shift
    ;;

  --compress=bz2|--compress=bzip2|--compress=4)
    debug_msg "Setting compress option to 4 (=bzip2) (was ${compress})"
    compress=4
    shift
    ;;

  --compress=gz|--compress=gzip|--compress=1)
    debug_msg "Setting compress option to 1 (=gzip) (was ${compress})"
    compress=1
    shift
    ;;

  --compress=no|--compress=none|--compress=0)
    debug_msg "Setting compress option to 0 (=none) (was ${compress})"
    compress=0
    shift
    ;;

  --compress=*)
    attempted_compression="$(printf "%s\n" "$1" | sed -e 's/^.*=//' )"
    error_msg "Unknown compression '${attempted_compression}'"
    ;;

  -c|--compress)
    debug_msg "Setting compress option to 1 (=gzip) (was ${compress})"
    compress=1
    shift
    ;;

  -C|--checksum)
    debug_msg "Setting checksum option to 1 (=SHA1) (was ${checksum})"
    checksum=1
    shift
    ;;

  -e|--encrypt)
    debug_msg "Setting encrypt option to 1 (=GPG) (was ${encrypt})"
    encrypt=1
    shift
    ;;

  -h|--help)
    help_msg
    shift
    ;;

  -n|--name)
    debug_msg "Setting output filename to ${2} (was ${archive_fn})"
    archive_fn="$2"
    shift; shift
    ;;

  -q|--quiet)
    debug_msg "Setting quiet option to 1 (was ${quiet})"
    quiet=1
    shift
    ;;

  -v|--verbose)
    debug_msg "Setting verbose option to 1 (was ${verbose})"
    verbose=1;
    shift
    ;;

  -V|--version)
    version_msg
    ;;

  *)
    debug_msg "Argument '${1}' added to positional array"
    positional+=("$1")
    shift
    ;;
  esac
done

# error if no filenames given
if [[ "${#positional[@]}" -lt 1 ]]; then
  debug_msg "No input filenames were given"
  usage_msg
fi

# determine tar action
if [[ "$compress" -eq 1 ]]; then
  archive_action="tar.gz"
elif [[ "$compress" -eq 2 ]]; then
  archive_action="tar.xz"
elif [[ "$compress" -eq 3 ]]; then
  archive_action="tar.zst"
elif [[ "$compress" -eq 4 ]]; then
  archive_action="tar.bz2"
elif [[ -n "$archive_fn" && "$compress" -eq -1 ]]; then
  case "$archive_fn" in
  *.tar)
    archive_action="tar"
    ;;

  *.tar.gz)
    archive_action="tar.gz"
    ;;

  *.tar.xz)
    archive_action="tar.xz"
    ;;

  *.tar.zst)
    archive_action="tar.zst"
    ;;

  *.tar.bz2)
    archive_action="tar.bz2"
    ;;
  esac
else
  archive_action="tar"
fi
if [[ "$encrypt" -eq 1 ]]; then
  archive_action="${archive_action}.gpg"
elif [[ -n "$archive_fn" && "$encrypt" -eq -1 ]]; then
  case "$archive_fn" in
  *.gpg)
    archive_action="${archive_action}.gpg"
    ;;
  esac
fi

# output filename
if [[ -z "$archive_fn" ]]; then
  archive_fn="archive.${archive_action}"
  checksum_fn="archive.sha1"
  debug_msg "No output filename was given, defaulting to '${archive_fn}'"
else
  checksum_fn="$(fn_basename "$archive_fn").sha1"
fi

# check files
if contains "$archive_fn" "${positional[@]}"; then
  error_msg "Output file cannot also be input file"
elif [[ "$checksum" -eq 1 ]] && contains "$checksum_fn" "${positional[@]}"; then
  error_msg "Output file cannot also be input file"
fi
if ! prompt_overwrite "$archive_fn"; then
  exit 1
elif [[ "$checksum" -eq 1 ]] && ! prompt_overwrite "$checksum_fn"; then
  exit 1
fi
for target in "${positional[@]}";do
  if [[ ! -f "$target" ]]; then
    error_msg "No such file '${target}'"
  fi
done

# main routine
code=0
case "$archive_action" in
tar)
  if ! /usr/bin/tar -cf "$archive_fn" "${positional[@]}"; then
    code=1
  fi
  ;;

tar.gpg)
  if ! /usr/bin/tar -c "${positional[@]}" | /usr/bin/gpg -c -o "$archive_fn"; then
    code=1
  fi
  ;;

tar.gz)
  if ! /usr/bin/tar -czf "$archive_fn" "${positional[@]}"; then
    code=1
  fi
  ;;

tar.gz.gpg)
  if ! /usr/bin/tar -cz "${positional[@]}" | /usr/bin/gpg -c -o "$archive_fn"; then
    code=1
  fi
  ;;

tar.xz)
  if ! /usr/bin/tar -cJf "$archive_fn" "${positional[@]}"; then
    code=1
  fi
  ;;

tar.xz.gpg)
  if ! /usr/bin/tar -cJ "${positional[@]}" | /usr/bin/gpg -c -o "$archive_fn"; then
    code=1
  fi
  ;;

tar.zst)
  if ! /usr/bin/tar --zstd -cf "$archive_fn" "${positional[@]}"; then
    code=1
  fi
  ;;

tar.zst.gpg)
  if ! /usr/bin/tar --zstd -c "${positional[@]}" | /usr/bin/gpg -c -o "$archive_fn"; then
    code=1
  fi
  ;;

tar.bz2)
  if ! /usr/bin/tar -cjf "$archive_fn" "${positional[@]}"; then
    code=1
  fi
  ;;

tar.bz2.gpg)
  if ! /usr/bin/tar -cj "${positional[@]}" | /usr/bin/gpg -c -o "$archive_fn"; then
    code=1
  fi
  ;;
esac

# checksum routine
if [[ "$checksum" -eq 1 ]]; then
  if ! /usr/bin/sha1sum "$archive_fn" | /usr/bin/awk '{print $1}' > "$checksum_fn"; then
    code=1
  fi
fi

# return stored code
exit "$code"