-module(multipartkit@internal@headers).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch, inline]).
-define(FILEPATH, "src/multipartkit/internal/headers.gleam").
-export([parse_block/1, derive_meta/1]).
-export_type([derived_meta/0]).

-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(false).

-type derived_meta() :: {derived_meta,
        gleam@option:option(binary()),
        gleam@option:option(binary()),
        gleam@option:option(binary())}.

-file("src/multipartkit/internal/headers.gleam", 30).
?DOC(false).
-spec drop_trailing_empty(list(binary())) -> list(binary()).
drop_trailing_empty(Lines) ->
    case lists:reverse(Lines) of
        [<<""/utf8>> | Rest] ->
            lists:reverse(Rest);

        _ ->
            Lines
    end.

-file("src/multipartkit/internal/headers.gleam", 73).
?DOC(false).
-spec trim_trailing_ows(binary()) -> binary().
trim_trailing_ows(Value) ->
    case gleam_stdlib:string_ends_with(Value, <<" "/utf8>>) orelse gleam_stdlib:string_ends_with(
        Value,
        <<"\t"/utf8>>
    ) of
        false ->
            Value;

        true ->
            case string:length(Value) of
                0 ->
                    Value;

                N ->
                    trim_trailing_ows(gleam@string:slice(Value, 0, N - 1))
            end
    end.

-file("src/multipartkit/internal/headers.gleam", 68).
?DOC(false).
-spec trim_ows(binary()) -> binary().
trim_ows(Value) ->
    Leading = multipartkit@internal@text:skip_ows(Value),
    trim_trailing_ows(Leading).

-file("src/multipartkit/internal/headers.gleam", 51).
?DOC(false).
-spec parse_line(binary()) -> {ok, {binary(), binary()}} |
    {error, multipartkit@error:multipart_error()}.
parse_line(Line) ->
    case gleam_stdlib:string_starts_with(Line, <<" "/utf8>>) orelse gleam_stdlib:string_starts_with(
        Line,
        <<"\t"/utf8>>
    ) of
        true ->
            {error, {invalid_header, Line}};

        false ->
            case gleam@string:split_once(Line, <<":"/utf8>>) of
                {error, nil} ->
                    {error, {invalid_header, Line}};

                {ok, {Name, Value}} ->
                    case Name of
                        <<""/utf8>> ->
                            {error, {invalid_header, Line}};

                        _ ->
                            {ok, {Name, trim_ows(Value)}}
                    end
            end
    end.

-file("src/multipartkit/internal/headers.gleam", 37).
?DOC(false).
-spec parse_lines(list(binary()), list({binary(), binary()})) -> {ok,
        list({binary(), binary()})} |
    {error, multipartkit@error:multipart_error()}.
parse_lines(Lines, Acc) ->
    case Lines of
        [] ->
            {ok, lists:reverse(Acc)};

        [Line | Rest] ->
            case parse_line(Line) of
                {error, Err} ->
                    {error, Err};

                {ok, Entry} ->
                    parse_lines(Rest, [Entry | Acc])
            end
    end.

-file("src/multipartkit/internal/headers.gleam", 16).
?DOC(false).
-spec parse_block(bitstring()) -> {ok, list({binary(), binary()})} |
    {error, multipartkit@error:multipart_error()}.
parse_block(Block) ->
    case gleam@bit_array:to_string(Block) of
        {error, _} ->
            {error, {invalid_header, <<""/utf8>>}};

        {ok, Text_block} ->
            Normalized = gleam@string:replace(
                Text_block,
                <<"\r\n"/utf8>>,
                <<"\n"/utf8>>
            ),
            Lines = gleam@string:split(Normalized, <<"\n"/utf8>>),
            Lines@1 = drop_trailing_empty(Lines),
            parse_lines(Lines@1, [])
    end.

-file("src/multipartkit/internal/headers.gleam", 125).
?DOC(false).
-spec first_header_ci(list({binary(), binary()}), binary()) -> gleam@option:option(binary()).
first_header_ci(Headers, Name) ->
    case Headers of
        [] ->
            none;

        [{K, V} | Rest] ->
            case multipartkit@internal@text:equals_ci(K, Name) of
                true ->
                    {some, V};

                false ->
                    first_header_ci(Rest, Name)
            end
    end.

-file("src/multipartkit/internal/headers.gleam", 96).
?DOC(false).
-spec derive_meta(list({binary(), binary()})) -> {ok, derived_meta()} |
    {error, multipartkit@error:multipart_error()}.
derive_meta(Headers) ->
    Cd = first_header_ci(Headers, <<"content-disposition"/utf8>>),
    Ct = first_header_ci(Headers, <<"content-type"/utf8>>),
    case Cd of
        none ->
            {ok, {derived_meta, none, none, Ct}};

        {some, Value} ->
            case multipartkit@content_disposition:parse(Value) of
                {error, _} ->
                    {error, {invalid_content_disposition, Value}};

                {ok, Parsed} ->
                    {Name, Filename} = case multipartkit@content_disposition:disposition(
                        Parsed
                    ) of
                        <<"form-data"/utf8>> ->
                            {multipartkit@content_disposition:name(Parsed),
                                multipartkit@content_disposition:filename(
                                    Parsed
                                )};

                        _ ->
                            {none, none}
                    end,
                    {ok, {derived_meta, Name, Filename, Ct}}
            end
    end.