thirtytwo

-module(thirtytwo).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/thirtytwo.gleam").
-export([crockford_decode/2, z_base_32_decode/1, geohash_decode/1, encode/2, hex_encode/2, crockford_encode/2, z_base_32_encode/1, geohash_encode/1, decode/1, hex_decode/1]).

-if(?OTP_RELEASE >= 27).
-define(MODULEDOC(Str), -moduledoc(Str)).
-define(DOC(Str), -doc(Str)).
-else.
-define(MODULEDOC(Str), -compile([])).
-define(DOC(Str), -compile([])).
-endif.

?MODULEDOC(
    " Base32 encoding and decoding for Gleam, targeting both Erlang and JavaScript.\n"
    "\n"
    " Supports five base32 variants:\n"
    "\n"
    " - **RFC 4648** (`encode` / `decode`) — the standard alphabet with optional\n"
    "   padding and case-insensitive decoding.\n"
    " - **Extended Hex** (`hex_encode` / `hex_decode`) — preserves sort order of\n"
    "   the underlying binary data (RFC 4648 §7).\n"
    " - **Crockford** (`crockford_encode` / `crockford_decode`) — omits I, L, O, U\n"
    "   to reduce ambiguity; supports hyphens, character aliases, and an optional\n"
    "   mod-37 check digit.\n"
    " - **z-base-32** (`z_base_32_encode` / `z_base_32_decode`) — human-oriented\n"
    "   lowercase alphabet optimized for readability.\n"
    " - **Geohash** (`geohash_encode` / `geohash_decode`) — the alphabet used by\n"
    "   the Geohash geocoding system.\n"
    "\n"
    " ## Examples\n"
    "\n"
    " ```gleam\n"
    " thirtytwo.encode(<<\"wibble\":utf8>>, padding: True)\n"
    " // -> \"O5UWEYTMMU======\"\n"
    "\n"
    " thirtytwo.decode(\"O5UWEYTMMU======\")\n"
    " // -> Ok(<<\"wibble\":utf8>>)\n"
    "\n"
    " thirtytwo.crockford_encode(<<\"wibble\":utf8>>, check: False)\n"
    " // -> \"EXMP4RKCCM\"\n"
    " ```\n"
).

-file("src/thirtytwo.gleam", 52).
-spec 'bor'(integer(), integer()) -> integer().
'bor'(A, B) ->
    erlang:'bor'(A, B).

-file("src/thirtytwo.gleam", 56).
-spec 'band'(integer(), integer()) -> integer().
'band'(A, B) ->
    erlang:'band'(A, B).

-file("src/thirtytwo.gleam", 60).
-spec shl(integer(), integer()) -> integer().
shl(A, N) ->
    erlang:'bsl'(A, N).

-file("src/thirtytwo.gleam", 64).
-spec shr(integer(), integer()) -> integer().
shr(A, N) ->
    erlang:'bsr'(A, N).

-file("src/thirtytwo.gleam", 182).
-spec compute_check_value(bitstring(), integer()) -> integer().
compute_check_value(Input, Acc) ->
    case Input of
        <<Byte, Rest/binary>> ->
            compute_check_value(Rest, ((Acc * 256) + Byte) rem 37);

        _ ->
            Acc
    end.

-file("src/thirtytwo.gleam", 220).
-spec encode_group(integer(), integer(), integer(), integer(), integer()) -> list(integer()).
encode_group(B0, B1, B2, B3, B4) ->
    C0 = shr(B0, 3),
    C1 = 'bor'(shl('band'(B0, 16#07), 2), shr(B1, 6)),
    C2 = 'band'(shr(B1, 1), 16#1F),
    C3 = 'bor'(shl('band'(B1, 16#01), 4), shr(B2, 4)),
    C4 = 'bor'(shl('band'(B2, 16#0F), 1), shr(B3, 7)),
    C5 = 'band'(shr(B3, 2), 16#1F),
    C6 = 'bor'(shl('band'(B3, 16#03), 3), shr(B4, 5)),
    C7 = 'band'(B4, 16#1F),
    [C0, C1, C2, C3, C4, C5, C6, C7].

-file("src/thirtytwo.gleam", 247).
-spec lookup_char(gleam@dict:dict(integer(), binary()), integer()) -> binary().
lookup_char(Alphabet, Index) ->
    _pipe = gleam_stdlib:map_get(Alphabet, Index),
    gleam@result:unwrap(_pipe, <<""/utf8>>).

-file("src/thirtytwo.gleam", 232).
-spec encode_remainder(
    integer(),
    integer(),
    integer(),
    integer(),
    integer(),
    gleam@dict:dict(integer(), binary()),
    list(binary())
) -> list(binary()).
encode_remainder(B0, B1, B2, B3, Count, Alphabet, Acc) ->
    _pipe = encode_group(B0, B1, B2, B3, 0),
    _pipe@1 = gleam@list:take(_pipe, Count),
    _pipe@2 = gleam@list:map(
        _pipe@1,
        fun(_capture) -> lookup_char(Alphabet, _capture) end
    ),
    gleam@list:fold(_pipe@2, Acc, fun gleam@list:prepend/2).

-file("src/thirtytwo.gleam", 200).
-spec do_encode_bytes(
    bitstring(),
    gleam@dict:dict(integer(), binary()),
    list(binary())
) -> list(binary()).
do_encode_bytes(Input, Alphabet, Acc) ->
    case Input of
        <<B0, B1, B2, B3, B4, Rest/binary>> ->
            _pipe = encode_group(B0, B1, B2, B3, B4),
            _pipe@1 = gleam@list:map(
                _pipe,
                fun(_capture) -> lookup_char(Alphabet, _capture) end
            ),
            _pipe@2 = gleam@list:fold(_pipe@1, Acc, fun gleam@list:prepend/2),
            do_encode_bytes(Rest, Alphabet, _pipe@2);

        <<B0@1, B1@1, B2@1, B3@1>> ->
            encode_remainder(B0@1, B1@1, B2@1, B3@1, 7, Alphabet, Acc);

        <<B0@2, B1@2, B2@2>> ->
            encode_remainder(B0@2, B1@2, B2@2, 0, 5, Alphabet, Acc);

        <<B0@3, B1@3>> ->
            encode_remainder(B0@3, B1@3, 0, 0, 4, Alphabet, Acc);

        <<B0@4>> ->
            encode_remainder(B0@4, 0, 0, 0, 2, Alphabet, Acc);

        _ ->
            Acc
    end.

-file("src/thirtytwo.gleam", 258).
-spec build_decode_map(binary(), boolean()) -> gleam@dict:dict(binary(), integer()).
build_decode_map(Alphabet, Case_insensitive) ->
    Chars = gleam@string:to_graphemes(Alphabet),
    Pairs = gleam@list:index_map(Chars, fun(Char, Index) -> {Char, Index} end),
    Lower_pairs = case Case_insensitive of
        true ->
            gleam@list:index_map(
                Chars,
                fun(Char@1, Index@1) -> {string:lowercase(Char@1), Index@1} end
            );

        false ->
            []
    end,
    _pipe = lists:append(Pairs, Lower_pairs),
    maps:from_list(_pipe).

-file("src/thirtytwo.gleam", 325).
-spec decode_group(
    integer(),
    integer(),
    integer(),
    integer(),
    integer(),
    integer(),
    integer(),
    integer()
) -> {integer(), integer(), integer(), integer(), integer()}.
decode_group(V0, V1, V2, V3, V4, V5, V6, V7) ->
    Byte0 = 'bor'(shl(V0, 3), shr(V1, 2)),
    Byte1 = 'bor'(shl('band'(V1, 16#03), 6), 'bor'(shl(V2, 1), shr(V3, 4))),
    Byte2 = 'bor'(shl('band'(V3, 16#0F), 4), shr(V4, 1)),
    Byte3 = 'bor'(shl('band'(V4, 16#01), 7), 'bor'(shl(V5, 2), shr(V6, 3))),
    Byte4 = 'bor'(shl('band'(V6, 16#07), 5), V7),
    {Byte0, Byte1, Byte2, Byte3, Byte4}.

-file("src/thirtytwo.gleam", 343).
-spec decode_remainder(list(integer()), list(bitstring())) -> {ok, bitstring()} |
    {error, nil}.
decode_remainder(Values, Acc) ->
    {Last_value, Mask, Byte_count} = case Values of
        [_, V1] ->
            {V1, 16#03, 1};

        [_, _, _, V3] ->
            {V3, 16#0F, 2};

        [_, _, _, _, V4] ->
            {V4, 16#01, 3};

        [_, _, _, _, _, _, V6] ->
            {V6, 16#07, 4};

        _ ->
            {0, 0, 0}
    end,
    gleam@bool:guard(
        Byte_count =:= 0,
        {error, nil},
        fun() ->
            gleam@bool:guard(
                'band'(Last_value, Mask) /= 0,
                {error, nil},
                fun() ->
                    Padded = lists:append(
                        Values,
                        gleam@list:repeat(0, 8 - erlang:length(Values))
                    ),
                    case Padded of
                        [V0, V1@1, V2, V3@1, V4@1, V5, V6@1, V7] ->
                            {B0, B1, B2, B3, _} = decode_group(
                                V0,
                                V1@1,
                                V2,
                                V3@1,
                                V4@1,
                                V5,
                                V6@1,
                                V7
                            ),
                            Bytes = <<B0, B1, B2, B3>>,
                            {ok,
                                begin
                                    _pipe@1 = [begin
                                            _pipe = gleam_stdlib:bit_array_slice(
                                                Bytes,
                                                0,
                                                Byte_count
                                            ),
                                            gleam@result:unwrap(_pipe, <<>>)
                                        end |
                                        Acc],
                                    _pipe@2 = lists:reverse(_pipe@1),
                                    gleam_stdlib:bit_array_concat(_pipe@2)
                                end};

                        _ ->
                            {error, nil}
                    end
                end
            )
        end
    ).

-file("src/thirtytwo.gleam", 310).
-spec decode_values(list(integer()), list(bitstring())) -> {ok, bitstring()} |
    {error, nil}.
decode_values(Values, Acc) ->
    case Values of
        [V0, V1, V2, V3, V4, V5, V6, V7 | Rest] ->
            {Byte0, Byte1, Byte2, Byte3, Byte4} = decode_group(
                V0,
                V1,
                V2,
                V3,
                V4,
                V5,
                V6,
                V7
            ),
            decode_values(Rest, [<<Byte0, Byte1, Byte2, Byte3, Byte4>> | Acc]);

        [] ->
            {ok,
                begin
                    _pipe = Acc,
                    _pipe@1 = lists:reverse(_pipe),
                    gleam_stdlib:bit_array_concat(_pipe@1)
                end};

        Remaining ->
            decode_remainder(Remaining, Acc)
    end.

-file("src/thirtytwo.gleam", 273).
-spec do_decode(binary(), gleam@dict:dict(binary(), integer())) -> {ok,
        bitstring()} |
    {error, nil}.
do_decode(Input, Decode_map) ->
    Chars = gleam@string:to_graphemes(Input),
    gleam@result:'try'(
        gleam@list:try_map(
            Chars,
            fun(C) -> gleam_stdlib:map_get(Decode_map, C) end
        ),
        fun(Values) ->
            Remainder = erlang:length(Values) rem 8,
            gleam@bool:guard(
                gleam@list:contains([1, 3, 6], Remainder),
                {error, nil},
                fun() -> decode_values(Values, []) end
            )
        end
    ).

-file("src/thirtytwo.gleam", 172).
-spec build_crockford_decode_map() -> gleam@dict:dict(binary(), integer()).
build_crockford_decode_map() ->
    _pipe = build_decode_map(<<"0123456789ABCDEFGHJKMNPQRSTVWXYZ"/utf8>>, true),
    _pipe@1 = gleam@dict:insert(_pipe, <<"O"/utf8>>, 0),
    _pipe@2 = gleam@dict:insert(_pipe@1, <<"o"/utf8>>, 0),
    _pipe@3 = gleam@dict:insert(_pipe@2, <<"I"/utf8>>, 1),
    _pipe@4 = gleam@dict:insert(_pipe@3, <<"i"/utf8>>, 1),
    _pipe@5 = gleam@dict:insert(_pipe@4, <<"L"/utf8>>, 1),
    gleam@dict:insert(_pipe@5, <<"l"/utf8>>, 1).

-file("src/thirtytwo.gleam", 116).
?DOC(
    " Decode a Crockford base32 string. Hyphens are stripped, decoding is\n"
    " case-insensitive, and the aliases O→0, I/L→1 are normalized. When\n"
    " `check` is `True`, the trailing check digit is validated.\n"
    " Returns `Error(Nil)` on invalid input or a failed check.\n"
).
-spec crockford_decode(binary(), boolean()) -> {ok, bitstring()} | {error, nil}.
crockford_decode(Input, Check) ->
    Cleaned = gleam@string:replace(Input, <<"-"/utf8>>, <<""/utf8>>),
    Decode_map = build_crockford_decode_map(),
    case Check andalso (Cleaned /= <<""/utf8>>) of
        true ->
            gleam@bool:guard(
                string:length(Cleaned) < 2,
                {error, nil},
                fun() ->
                    Body = gleam@string:drop_end(Cleaned, 1),
                    gleam@result:'try'(
                        gleam@string:last(Cleaned),
                        fun(Check_char) ->
                            Check_decode_map = build_decode_map(
                                <<"0123456789ABCDEFGHJKMNPQRSTVWXYZ*~$=U"/utf8>>,
                                true
                            ),
                            gleam@result:'try'(
                                gleam_stdlib:map_get(
                                    Check_decode_map,
                                    Check_char
                                ),
                                fun(Check_index) ->
                                    gleam@result:'try'(
                                        do_decode(Body, Decode_map),
                                        fun(Decoded) ->
                                            Expected = compute_check_value(
                                                Decoded,
                                                0
                                            ),
                                            gleam@bool:guard(
                                                Check_index /= Expected,
                                                {error, nil},
                                                fun() -> {ok, Decoded} end
                                            )
                                        end
                                    )
                                end
                            )
                        end
                    )
                end
            );

        false ->
            do_decode(Cleaned, Decode_map)
    end.

-file("src/thirtytwo.gleam", 147).
?DOC(
    " Decode a z-base-32 string. Decoding is case-sensitive.\n"
    " Returns `Error(Nil)` on invalid input.\n"
).
-spec z_base_32_decode(binary()) -> {ok, bitstring()} | {error, nil}.
z_base_32_decode(Input) ->
    Decode_map = build_decode_map(
        <<"ybndrfg8ejkmcpqxot1uwisza345h769"/utf8>>,
        false
    ),
    do_decode(Input, Decode_map).

-file("src/thirtytwo.gleam", 161).
?DOC(
    " Decode a Geohash base32 string. Decoding is case-sensitive.\n"
    " Returns `Error(Nil)` on invalid input.\n"
).
-spec geohash_decode(binary()) -> {ok, bitstring()} | {error, nil}.
geohash_decode(Input) ->
    Decode_map = build_decode_map(
        <<"0123456789bcdefghjkmnpqrstuvwxyz"/utf8>>,
        false
    ),
    do_decode(Input, Decode_map).

-file("src/thirtytwo.gleam", 251).
-spec apply_padding(binary(), boolean()) -> binary().
apply_padding(Encoded, Padding) ->
    gleam@bool:guard(
        not Padding,
        Encoded,
        fun() ->
            Remainder = string:length(Encoded) rem 8,
            gleam@bool:guard(
                Remainder =:= 0,
                Encoded,
                fun() ->
                    <<Encoded/binary,
                        (gleam@string:repeat(<<"="/utf8>>, 8 - Remainder))/binary>>
                end
            )
        end
    ).

-file("src/thirtytwo.gleam", 189).
-spec do_encode(bitstring(), binary(), boolean()) -> binary().
do_encode(Input, Alphabet, Padding) ->
    Alphabet_map = begin
        _pipe = gleam@string:to_graphemes(Alphabet),
        _pipe@1 = gleam@list:index_map(
            _pipe,
            fun(Char, Index) -> {Index, Char} end
        ),
        maps:from_list(_pipe@1)
    end,
    _pipe@2 = do_encode_bytes(Input, Alphabet_map, []),
    _pipe@3 = lists:reverse(_pipe@2),
    _pipe@4 = erlang:list_to_binary(_pipe@3),
    apply_padding(_pipe@4, Padding).

-file("src/thirtytwo.gleam", 72).
?DOC(
    " Encode a bit array using the standard RFC 4648 base32 alphabet.\n"
    " The input must be byte-aligned; non-byte-aligned bit arrays produce\n"
    " undefined results.\n"
    " When `padding` is `True`, the output is padded with `=` to a multiple of 8.\n"
).
-spec encode(bitstring(), boolean()) -> binary().
encode(Input, Padding) ->
    do_encode(Input, <<"ABCDEFGHIJKLMNOPQRSTUVWXYZ234567"/utf8>>, Padding).

-file("src/thirtytwo.gleam", 86).
?DOC(
    " Encode a bit array using the base32hex alphabet (RFC 4648 section 7).\n"
    " Preserves sort order of the underlying data. The input must be\n"
    " byte-aligned; non-byte-aligned bit arrays produce undefined results.\n"
    " When `padding` is `True`, the output is padded with `=` to a multiple of 8.\n"
).
-spec hex_encode(bitstring(), boolean()) -> binary().
hex_encode(Input, Padding) ->
    do_encode(Input, <<"0123456789ABCDEFGHIJKLMNOPQRSTUV"/utf8>>, Padding).

-file("src/thirtytwo.gleam", 100).
?DOC(
    " Encode a bit array using Crockford's base32 alphabet. The output is\n"
    " always unpadded and uppercase. The input must be byte-aligned;\n"
    " non-byte-aligned bit arrays produce undefined results. When `check`\n"
    " is `True`, a mod-37 check digit is appended.\n"
).
-spec crockford_encode(bitstring(), boolean()) -> binary().
crockford_encode(Input, Check) ->
    Encoded = do_encode(
        Input,
        <<"0123456789ABCDEFGHJKMNPQRSTVWXYZ"/utf8>>,
        false
    ),
    case Check andalso (Encoded /= <<""/utf8>>) of
        true ->
            Check_value = compute_check_value(Input, 0),
            Check_char = gleam@string:slice(
                <<"0123456789ABCDEFGHJKMNPQRSTVWXYZ*~$=U"/utf8>>,
                Check_value,
                1
            ),
            <<Encoded/binary, Check_char/binary>>;

        false ->
            Encoded
    end.

-file("src/thirtytwo.gleam", 141).
?DOC(
    " Encode a bit array using the z-base-32 alphabet. The output is always\n"
    " lowercase and unpadded. The input must be byte-aligned; non-byte-aligned\n"
    " bit arrays produce undefined results.\n"
).
-spec z_base_32_encode(bitstring()) -> binary().
z_base_32_encode(Input) ->
    do_encode(Input, <<"ybndrfg8ejkmcpqxot1uwisza345h769"/utf8>>, false).

-file("src/thirtytwo.gleam", 155).
?DOC(
    " Encode a bit array using the Geohash base32 alphabet. The output is\n"
    " always lowercase and unpadded. The input must be byte-aligned;\n"
    " non-byte-aligned bit arrays produce undefined results.\n"
).
-spec geohash_encode(bitstring()) -> binary().
geohash_encode(Input) ->
    do_encode(Input, <<"0123456789bcdefghjkmnpqrstuvwxyz"/utf8>>, false).

-file("src/thirtytwo.gleam", 303).
-spec count_trailing_pad(binary(), integer()) -> integer().
count_trailing_pad(Input, Remaining) ->
    case (Remaining > 0) andalso gleam_stdlib:string_ends_with(
        Input,
        <<"="/utf8>>
    ) of
        true ->
            count_trailing_pad(gleam@string:drop_end(Input, 1), Remaining - 1) + 1;

        false ->
            0
    end.

-file("src/thirtytwo.gleam", 289).
-spec validate_padding(binary()) -> {ok, binary()} | {error, nil}.
validate_padding(Input) ->
    Len = string:length(Input),
    Pad_count = count_trailing_pad(Input, Len),
    gleam@bool:guard(
        Pad_count =:= 0,
        {ok, Input},
        fun() ->
            Has_interior_pad = gleam_stdlib:contains_string(
                gleam@string:drop_end(Input, Pad_count),
                <<"="/utf8>>
            ),
            gleam@bool:guard(
                Has_interior_pad,
                {error, nil},
                fun() ->
                    gleam@bool:guard(
                        (Len rem 8) /= 0,
                        {error, nil},
                        fun() -> case Pad_count of
                                1 ->
                                    {ok,
                                        gleam@string:drop_end(Input, Pad_count)};

                                3 ->
                                    {ok,
                                        gleam@string:drop_end(Input, Pad_count)};

                                4 ->
                                    {ok,
                                        gleam@string:drop_end(Input, Pad_count)};

                                6 ->
                                    {ok,
                                        gleam@string:drop_end(Input, Pad_count)};

                                _ ->
                                    {error, nil}
                            end end
                    )
                end
            )
        end
    ).

-file("src/thirtytwo.gleam", 166).
-spec decode_with_padding(binary(), binary()) -> {ok, bitstring()} |
    {error, nil}.
decode_with_padding(Input, Alphabet) ->
    Decode_map = build_decode_map(Alphabet, true),
    gleam@result:'try'(
        validate_padding(Input),
        fun(Stripped) -> do_decode(Stripped, Decode_map) end
    ).

-file("src/thirtytwo.gleam", 78).
?DOC(
    " Decode a standard RFC 4648 base32 string. Padding is optional and\n"
    " decoding is case-insensitive. Returns `Error(Nil)` on invalid input.\n"
).
-spec decode(binary()) -> {ok, bitstring()} | {error, nil}.
decode(Input) ->
    decode_with_padding(Input, <<"ABCDEFGHIJKLMNOPQRSTUVWXYZ234567"/utf8>>).

-file("src/thirtytwo.gleam", 92).
?DOC(
    " Decode a base32hex string. Padding is optional and decoding is\n"
    " case-insensitive. Returns `Error(Nil)` on invalid input.\n"
).
-spec hex_decode(binary()) -> {ok, bitstring()} | {error, nil}.
hex_decode(Input) ->
    decode_with_padding(Input, <<"0123456789ABCDEFGHIJKLMNOPQRSTUV"/utf8>>).