glanoid

-module(glanoid).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([make_generator/1]).

-spec do_bit_size(integer(), integer()) -> integer().
do_bit_size(N, Acc) ->
    case N of
        0 ->
            Acc;

        _ ->
            do_bit_size(erlang:'bsr'(N, 1), Acc + 1)
    end.

-spec bit_size(integer()) -> integer().
bit_size(N) ->
    do_bit_size(N, 0).

-spec make_generator(binary()) -> fun((integer()) -> binary()).
make_generator(Alphabet) ->
    Bit_mask = begin
        _pipe = Alphabet,
        _pipe@1 = gleam@string:length(_pipe),
        _pipe@2 = bit_size(_pipe@1),
        _pipe@3 = gleam@int:subtract(_pipe@2, 1),
        _pipe@4 = erlang:'bsl'(1, _pipe@3),
        gleam@int:subtract(_pipe@4, 1)
    end,
    To_alphabet@1 = funtil:fix3(
        fun(To_alphabet, Bits, Alphabet@1, Acc) -> case Bits of
                <<X:8, Rest/bitstring>> ->
                    Index = erlang:'band'(X, Bit_mask),
                    Letter = gleam@string:slice(Alphabet@1, Index, 1),
                    case Letter of
                        <<""/utf8>> ->
                            To_alphabet(Bits, Alphabet@1, Acc);

                        _ ->
                            To_alphabet(
                                Rest,
                                Alphabet@1,
                                <<Acc/binary, Letter/binary>>
                            )
                    end;

                <<>> ->
                    Acc;

                _ ->
                    erlang:error(#{gleam_error => panic,
                            message => <<"panic expression evaluated"/utf8>>,
                            module => <<"glanoid"/utf8>>,
                            function => <<"make_generator"/utf8>>,
                            line => 42})
            end end
    ),
    fun(Size) -> _pipe@5 = crypto:strong_rand_bytes(Size),
        To_alphabet@1(_pipe@5, Alphabet, <<""/utf8>>) end.