_PACK_SUPPORTED=".tar$|.zip$"

# Pack files into desired format.
# Usage: pack <TARGET.ext> <FILES>
pack()
{
  local output="${1}"
  local targets=("${@:2}")
  local format="${output##*.}"
  local name="${output%.*}"

  # report no output.
  if [[ "${output}" = "" ]]; then
    echo "Usage: pack <TARGET.ext> <FILES>"
    return 1
  fi

  # report no format.
  if [[ "${format}" = "" ]]; then
    echo "Could not determine output format."
    echo "Usage: pack <TARGET.ext> <FILES>"
    return 2
  fi

  # report no targets.
  if [[ "${targets}" = "" ]]; then
    echo "Usage: pack <TARGET.ext> <FILES>"
    return 3
  fi

  # process.
  case "${format}" in
    "tgz")
      _pack_tgz "${@}"
      ;;
    "txz")
      _pack_txz "${@}"
      ;;
    "tar")
      _pack_tar "${@}"
      ;;
    "zip")
      _pack_zip "${@}"
      ;;
  esac
}

# attempt to unpack everything.
# usage: unpack <FILES>
unpack()
{
  local targets=("${@}")
  local count=0
  local failed=0
  local total=${#targets[@]}

  # show error if no target specified.
  if [[ "${targets}" = "" ]]; then
    targets=($(ls | grep -E ${_PACK_SUPPORTED}))
    total=${#targets[@]}
  fi

  # process all files.
  for target in "${targets[@]}"; do
    # increment counter.
    ((count++))

    # prepare status.
    local status="[${count}/${total}] ${target}"

    # show status.
    echo -e "${status}"

    # unpack file type.
    local type="${target##*.}"

    # unpack content.
    case "${type,,}" in
      "zip")
        _unpack_zip "${target}"
        ;;
      "7z")
        _unpack_7z "${target}"
        ;;
      "tgz")
        _unpack_tgz "${target}"
        ;;
      "txz")
        _unpack_txz "${target}"
        ;;
      "tar")
        _unpack_tar "${target}"
        ;;
      *)
        echo "${target}: format not supported."
        return 2
        ;;
    esac

    # actions on error.
    if [[ $? != 0 ]]; then
      _error "${target}"
      ((failed++))
    fi
  done 

  # print report.
  if [[ ${count} -gt 1 ]]; then
    if [[ ${failed} -gt 0 ]]; then
      echo -e "${color_bred}Items failed to unpack: ${failed}.${color_default}"
    else
      echo -e "${color_green}All successful.${color_default}"
    fi
  fi
}

# show error.
_error()
{
  echo -e "${color_bred}${1}: failed.${color_default}"
}

# Pack zip.
_pack_zip()
{
  zip -9 -r "${@}"
}

# pack tgz.
_pack_tgz()
{
  tar -c "${@:2}" | pv -s $(du -csb "${@:2}" | sed -n -e '$p' | awk '{print $1}') | gzip -1 > "${1}"
}

# pack txz.
_pack_txz()
{
  tar -c "${@:2}" | pv -s $(du -csb "${@:2}" | sed -n -e '$p' | awk '{print $1}') | xz -9e > "${1}"
}

# pack tar.
_pack_tar()
{
  tar -c "${@:2}" | pv -s $(du -csb "${@:2}" | sed -n -e '$p' | awk '{print $1}') > "${1}"
}

# unpack zip archive.
_unpack_zip()
{
  unzip "${1}"
}

# unpack 7z archive.
_unpack_7z()
{
  7z x "${1}"
}

# unpack tgz archive.
_unpack_tgz()
{
  pv "${1}" | gzip -d | tar -xf -
}

# unpack txz archive.
_unpack_txz()
{
  pv "${1}" | xz -d | tar -xf -
}

# unpack tar archive.
_unpack_tar()
{
  pv "${1}" | tar -xf -
}