metadir="$DISTFILES"/meta/$1
[ -d "$metadir" ] || {
    echo no "$metadir" found >&2
    exit 1
}

dst=$1
if [ -r cache/$dst ] ; then
    echo using cache/$dst... >&2
    if [ -s "$metadir"/hashes ] ; then
        "$BASS_ROOT"/build/bin/hashes-check "$metadir"/hashes \
        <cache/$dst 2>&1 >/dev/null || {
            echo hash check failed >&2
            exit 1
        }
    else
        echo warning: no $metadir/hashes >&2
        if [ -s "$metadir"/size ] ; then
            read size <"$metadir"/size
            sizeGot=$("$BASS_ROOT"/bin/filessize cache/$dst)
            [ "$sizeGot" -eq "$size" ] || {
                echo size differs: $sizeGot '!=' $size >&2
                exit 1
            }
        else
            echo warning: no $metadir/size >&2
        fi
    fi
    ln cache/$dst $3
    exit 0
fi

(
    # do not depend on generated URLs
    for v in $(env | sed "s/=.*$//" | grep "^REDO") ; do unset $v ; done
    redo-ifchange "$metadir"/urls
)

fn=$(basename $dst)

getMeta4() {
    (
        cd "$DISTFILES"/meta
        ../bin/metadir-to-meta4 $dst
    )
}

tmp=$(mktemp -d ${TMPDIR:-/tmp}/$fn.XXXXXX)
trap "rm -fr $tmp" HUP PIPE INT QUIT TERM EXIT
cd $tmp
case "$DISTFILE_FETCHER" in
justdl)
    FETCHER_URLS_SORT <"$metadir"/urls |
    while read url ; do
        echo trying ${url}... >&2
        url="${url##*|}"
        if [ -s "$metadir"/hashes ] ; then
            $JUSTDL "$url" |
            "$BASS_ROOT"/build/bin/hashes-check "$metadir"/hashes >$fn || {
                echo hash check failed >&2
                rm $fn
                continue
            }
        else
            echo warning: no $metadir/hashes >&2
            $JUSTDL "$url" >$fn || continue
            if [ -s "$metadir"/size ] ; then
                read size <"$metadir"/size
                sizeGot=$("$BASS_ROOT"/bin/filessize $fn)
                [ "$sizeGot" -eq "$size" ] || {
                    echo size differs: $sizeGot '!=' $size >&2
                    continue
                }
            fi
        fi
        break
    done
    [ -s $fn ]
    cat $fn
    ;;
wget-meta4)
    getMeta4 >meta4
    wget --input-metalink=meta4 >&2
    cat "$fn.meta4.#1"
    ;;
aria2c)
    getMeta4 >meta4
    aria2c meta4 >&2
    cat $fn
    ;;
*)
    echo Unknown \$DISTFILE_FETCHER >&2
    exit 1
esac