##
# systr_repo_resolve_reference <symref> [<path>]
#
# Resolve a revision to a commit ID.  This function is polymorphic
# for both local and remote repositories.  The result is printed to
# stdout.
##
function systr_repo_resolve_reference
{
    if [ $# -lt 1 ]; then
        echo "Fatal: too few arguments to systr_repo_resolve_reference"
        exit 1
    fi

    symref="$1"

    if [ $# -gt 1 ]; then
        path="$2"
    fi

    if [[ "$symref" == "BASE" ]]; then
        cat ".systr/BASE"
    elif [[ "$symref" == "TRAC" ]]; then
        read trac <.systr/TRAC
        systr_repo_resolve_reference "$trac"
    elif [[ "$symref" == "NULL" ]]; then
        echo "NULL"
    fi

    if [[ "$remote" == "" ]]; then
        (
            cd "$path"

            if [[ "$symref" == "HEAD" ]]; then
                cat "refs/HEAD"
            elif [ -f "refs/$symref" ]; then
                cat "refs/$symref"
            elif [ -f "revs/$symref/.commit.systr" ]; then
                echo "$symref"
            else
                echo "$symref not a revision"
                exit 1
            fi
        )
    else
        ssh "$remote" "systrunk resv-ref \"$symref\" \"$path\""
    fi
}