-module(dove@response).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function]).

-export([decode/1]).
-export_type([decode_result/0]).

-type decode_result() :: more |
    {eoh, binary()} |
    {header, {binary(), binary()}, binary()} |
    {status_line, {{integer(), integer()}, integer(), binary()}, binary()}.

-spec consume_till_crlf(bitstring(), bitstring()) -> {ok,
        {bitstring(), bitstring()}} |
    {error, dove@error:error()}.
consume_till_crlf(Data, Storage) ->
    case erlang:byte_size(Data) of
        0 ->
            {error, more_needed};

        _ ->
            case Data of
                <<"\r\n"/utf8, Rest/bitstring>> ->
                    {ok,
                        {gleam@bit_array:append(Storage, <<"\r\n"/utf8>>), Rest}};

                <<Ch:8, Rest@1/bitstring>> ->
                    consume_till_crlf(
                        Rest@1,
                        gleam@bit_array:append(Storage, <<Ch>>)
                    )
            end
    end.

-spec consume_till_double_crlf(bitstring(), bitstring()) -> {ok,
        {bitstring(), bitstring()}} |
    {error, dove@error:error()}.
consume_till_double_crlf(Data, Storage) ->
    case erlang:byte_size(Data) of
        0 ->
            {error, more_needed};

        _ ->
            case Data of
                <<"\r\n\r\n"/utf8, Rest/bitstring>> ->
                    {ok,
                        {gleam@bit_array:append(Storage, <<"\r\n\r\n"/utf8>>),
                            Rest}};

                <<Ch:8, Rest@1/bitstring>> ->
                    consume_till_double_crlf(
                        Rest@1,
                        gleam@bit_array:append(Storage, <<Ch>>)
                    )
            end
    end.

-spec consume_by_length(bitstring(), integer(), bitstring()) -> {ok,
        {bitstring(), bitstring()}} |
    {error, nil}.
consume_by_length(Data, Length, Storage) ->
    case erlang:byte_size(Data) of
        0 ->
            {error, nil};

        _ ->
            <<Ch:8, Rest/bitstring>> = Data,
            case erlang:byte_size(Storage) =:= Length of
                true ->
                    {ok, {gleam@bit_array:append(Storage, <<Ch>>), Rest}};

                false ->
                    consume_by_length(
                        Rest,
                        Length,
                        gleam@bit_array:append(Storage, <<Ch>>)
                    )
            end
    end.

-spec decode_headers(binary(), list({binary(), binary()})) -> {ok,
        {list({binary(), binary()}), binary()}} |
    {error, dove@error:error()}.
decode_headers(Binary, Storage) ->
    gleam@result:then(
        begin
            _pipe = dove_ffi:decode_header(Binary),
            gleam@result:replace_error(_pipe, invalid_header)
        end,
        fun(Result) -> case Result of
                {eoh, Rest} ->
                    {ok, {Storage, Rest}};

                {header, Header, Rest@1} ->
                    decode_headers(Rest@1, gleam@list:append(Storage, [Header]));

                more ->
                    {error, more_needed};

                {status_line, _, _} ->
                    {error, wrong_packet_type}
            end end
    ).

-spec decode(bitstring()) -> {ok,
        {{integer(),
                list({binary(), binary()}),
                gleam@option:option(bitstring())},
            bitstring()}} |
    {error, dove@error:error()}.
decode(Response) ->
    gleam@result:then(
        consume_till_crlf(Response, <<>>),
        fun(_use0) ->
            {Status_line, Rest} = _use0,
            gleam@result:then(
                begin
                    _pipe = gleam@bit_array:to_string(Status_line),
                    gleam@result:replace_error(_pipe, invalid_status_line)
                end,
                fun(Status_line@1) ->
                    gleam@result:then(
                        consume_till_double_crlf(Rest, <<>>),
                        fun(_use0@1) ->
                            {Headers, Rest@1} = _use0@1,
                            gleam@result:then(
                                begin
                                    _pipe@1 = gleam@bit_array:to_string(Headers),
                                    gleam@result:replace_error(
                                        _pipe@1,
                                        invalid_header
                                    )
                                end,
                                fun(Headers@1) ->
                                    case dove_ffi:decode_status_line(
                                        Status_line@1
                                    ) of
                                        {ok, {status_line, {_, Status, _}, _}} ->
                                            gleam@result:then(
                                                decode_headers(Headers@1, []),
                                                fun(_use0@2) ->
                                                    {Headers@2, _} = _use0@2,
                                                    case begin
                                                        _pipe@2 = gleam@list:key_find(
                                                            Headers@2,
                                                            <<"content-length"/utf8>>
                                                        ),
                                                        _pipe@3 = gleam@result:map(
                                                            _pipe@2,
                                                            fun gleam@int:parse/1
                                                        ),
                                                        gleam@result:flatten(
                                                            _pipe@3
                                                        )
                                                    end of
                                                        {ok, 0} ->
                                                            {ok,
                                                                {{Status,
                                                                        Headers@2,
                                                                        none},
                                                                    Rest@1}};

                                                        {error, nil} ->
                                                            {ok,
                                                                {{Status,
                                                                        Headers@2,
                                                                        none},
                                                                    Rest@1}};

                                                        {ok, Length} ->
                                                            gleam@result:then(
                                                                begin
                                                                    _pipe@4 = consume_by_length(
                                                                        Rest@1,
                                                                        Length - 1,
                                                                        <<>>
                                                                    ),
                                                                    gleam@result:replace_error(
                                                                        _pipe@4,
                                                                        more_needed
                                                                    )
                                                                end,
                                                                fun(_use0@3) ->
                                                                    {Body,
                                                                        Rest@2} = _use0@3,
                                                                    {ok,
                                                                        {{Status,
                                                                                Headers@2,
                                                                                {some,
                                                                                    Body}},
                                                                            Rest@2}}
                                                                end
                                                            )
                                                    end
                                                end
                                            );

                                        {ok, more} ->
                                            {error, more_needed};

                                        {error, nil} ->
                                            {error, invalid_status_line};

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