-module(ids@uuid).
-compile([no_auto_import, nowarn_unused_vars]).

-export([generate_v4/0]).

-spec e(integer()) -> integer().
e(N) ->
    case N of
        0 ->
            48;

        1 ->
            49;

        2 ->
            50;

        3 ->
            51;

        4 ->
            52;

        5 ->
            53;

        6 ->
            54;

        7 ->
            55;

        8 ->
            56;

        9 ->
            57;

        10 ->
            97;

        11 ->
            98;

        12 ->
            99;

        13 ->
            100;

        14 ->
            101;

        15 ->
            102
    end.

-spec generate_v4() -> {ok, binary()} | {error, binary()}.
generate_v4() ->
    <<U0:48, _:4, U1:12, _:2, U2:62>> = crypto:strong_rand_bytes(16),
    <<A1:4,
        A2:4,
        A3:4,
        A4:4,
        A5:4,
        A6:4,
        A7:4,
        A8:4,
        B1:4,
        B2:4,
        B3:4,
        B4:4,
        C1:4,
        C2:4,
        C3:4,
        C4:4,
        D1:4,
        D2:4,
        D3:4,
        D4:4,
        E1:4,
        E2:4,
        E3:4,
        E4:4,
        E5:4,
        E6:4,
        E7:4,
        E8:4,
        E9:4,
        E10:4,
        E11:4,
        E12:4>> = <<U0:48, 4:4, U1:12, 2:2, U2:62>>,
    Bitstr_id = <<(e(A1)),
        (e(A2)),
        (e(A3)),
        (e(A4)),
        (e(A5)),
        (e(A6)),
        (e(A7)),
        (e(A8)),
        45,
        (e(B1)),
        (e(B2)),
        (e(B3)),
        (e(B4)),
        45,
        (e(C1)),
        (e(C2)),
        (e(C3)),
        (e(C4)),
        45,
        (e(D1)),
        (e(D2)),
        (e(D3)),
        (e(D4)),
        45,
        (e(E1)),
        (e(E2)),
        (e(E3)),
        (e(E4)),
        (e(E5)),
        (e(E6)),
        (e(E7)),
        (e(E8)),
        (e(E9)),
        (e(E10)),
        (e(E11)),
        (e(E12))>>,
    case gleam@bit_string:to_string(Bitstr_id) of
        {ok, Str_id} ->
            _pipe = Str_id,
            {ok, _pipe};

        {error, _} ->
            Error = <<"Error: BitString could not be converted to String."/utf8>>,
            _pipe@1 = Error,
            {error, _pipe@1}
    end.