# bash completion for GNU tar

have tar && {
_tar()
{
    local cur ext regex tar untar

    COMPREPLY=()
    _get_comp_words_by_ref cur

    if [ $COMP_CWORD -eq 1 ]; then
        COMPREPLY=( $( compgen -W 'c t x u r d A' -- "$cur" ) )
        return 0
    fi

    case ${COMP_WORDS[1]} in
        ?(-)[cr]*f)
            _filedir
            return 0
            ;;
        +([^IZzJjy])f)
            ext='@(@(tar|gem|spkg)?(.@(Z|[gx]z|bz?(2)|lzma))|t@([glx]z|bz?(2)))'
            regex='\(\(tar\|gem\|spkg\)\(\.\(Z\|[gx]z\|bz?(2)\|lzma\)\)\?\|t\([glx]z\|bz2\?\)\)'
            ;;
        *[Zz]*f)
            ext='@(t?(ar.)|gem.|spkg.)@(gz|Z)'
            regex='\(t\(ar\.\)\?\|gem\.\|spkg\.\)\(gz\|Z\)'
            ;;
        *[Ijy]*f)
            ext='@(@(t?(ar.)|gem.)bz?(2)|spkg)'
            regex='\(\(t\(ar\.\)\?\|gem\.\)bz2\?\|spkg\)'
            ;;
        *[J]*f)
            ext='@(t?(ar.)|gem.|spkg.)@(lz?(ma)|xz)'
            regex='\(t\(ar\.\)\?\|gem\.\|spkg\.\)\(lzma\|xz\)\?'
            ;;
        *)
            _filedir
            return 0
            ;;
    esac

    if [[ "$COMP_LINE" == *$ext' ' ]]; then
        # complete on files in tar file
        #
        # get name of tar file from command line
        tar=$( sed -e 's/^.* \([^ ]*'$regex'\) .*$/\1/' <<<"$COMP_LINE" )
        # devise how to untar and list it
        untar=t${COMP_WORDS[1]//[^Izjyf]/}

        local IFS=$'\n'
        COMPREPLY=( $( compgen -W "$( printf '%s\n' $( tar $untar $tar \
            2>/dev/null ) )" -- "$cur" ) )
        return 0
    fi

    # file completion on relevant files
    _filedir "$ext"

    return 0
}
[ -n "${COMP_TAR_INTERNAL_PATHS:-}" ] && complete -F _tar -o dirnames tar ||
    complete -F _tar tar
}

# Local variables:
# mode: shell-script
# sh-basic-offset: 4
# sh-indent-comment: t
# indent-tabs-mode: nil
# End:
# ex: ts=4 sw=4 et filetype=sh