-module(mist@http).
-compile(no_auto_import).

-export([from_header/1, parse_headers/4, read_data/4, parse_request/3, read_body/2, upgrade_socket/1, upgrade/3]).
-export_type([packet_type/0, http_uri/0, http_packet/0, decoded_packet/0, decode_error/0, buffer/0, body/0, http_response_body/0]).

-type packet_type() :: http | httph_bin | http_bin.

-type http_uri() :: {abs_path, bitstring()}.

-type http_packet() :: {http_request,
                        gleam@dynamic:dynamic(),
                        http_uri(),
                        {integer(), integer()}} |
    {http_header,
     integer(),
     gleam@erlang@atom:atom_(),
     bitstring(),
     bitstring()}.

-type decoded_packet() :: {binary_data, http_packet(), bitstring()} |
    {end_of_headers, bitstring()} |
    {more_data, gleam@option:option(integer())}.

-type decode_error() :: malformed_request |
    invalid_method |
    invalid_path |
    unknown_header |
    unknown_method |
    invalid_body |
    discard_packet.

-type buffer() :: {buffer, integer(), bitstring()}.

-opaque body() :: {unread, bitstring(), glisten@socket:socket()} |
    {read, bitstring()}.

-type http_response_body() :: {bit_builder_body,
                               gleam@bit_builder:bit_builder()} |
    {file_body, mist@file:file_descriptor(), binary(), integer(), integer()}.

-spec from_header(bitstring()) -> binary().
from_header(Value) ->
    {ok, Value@2} = case gleam@bit_string:to_string(Value) of
        {ok, Value@1} -> {ok, Value@1};
        _try ->
            erlang:error(#{gleam_error => assert,
                           message => <<"Assertion pattern match failed"/utf8>>,
                           value => _try,
                           module => <<"mist/http"/utf8>>,
                           function => <<"from_header"/utf8>>,
                           line => 63})
    end,
    gleam@string:lowercase(Value@2).

-spec parse_headers(
    bitstring(),
    glisten@socket:socket(),
    glisten@socket@transport:transport(),
    gleam@map:map_(binary(), binary())
) -> {ok, {gleam@map:map_(binary(), binary()), bitstring()}} |
    {error, decode_error()}.
parse_headers(Bs, Socket, Transport, Headers) ->
    case http_ffi:decode_packet(httph_bin, Bs, []) of
        {ok, {binary_data, {http_header, _@1, _@2, Field, Value}, Rest}} ->
            Field@1 = from_header(Field),
            {ok, Value@2} = case gleam@bit_string:to_string(Value) of
                {ok, Value@1} -> {ok, Value@1};
                _try ->
                    erlang:error(#{gleam_error => assert,
                                   message => <<"Assertion pattern match failed"/utf8>>,
                                   value => _try,
                                   module => <<"mist/http"/utf8>>,
                                   function => <<"parse_headers"/utf8>>,
                                   line => 81})
            end,
            _pipe = Headers,
            _pipe@1 = gleam@map:insert(_pipe, Field@1, Value@2),
            parse_headers(Rest, Socket, Transport, _pipe@1);

        {ok, {end_of_headers, Rest@1}} ->
            {ok, {Headers, Rest@1}};

        {ok, {more_data, Size}} ->
            Amount_to_read = gleam@option:unwrap(Size, 0),
            case read_data(
                Socket,
                Transport,
                {buffer, Amount_to_read, Bs},
                unknown_header
            ) of
                {error, _try@1} -> {error, _try@1};
                {ok, Next} ->
                    parse_headers(Next, Socket, Transport, Headers)
            end;

        _@3 ->
            {error, unknown_header}
    end.

-spec read_data(
    glisten@socket:socket(),
    glisten@socket@transport:transport(),
    buffer(),
    decode_error()
) -> {ok, bitstring()} | {error, decode_error()}.
read_data(Socket, Transport, Buffer, Error) ->
    To_read = gleam@int:min(erlang:element(2, Buffer), 1000000),
    Timeout = 15000,
    case begin
        _pipe = Socket,
        _pipe@1 = (erlang:element(9, Transport))(_pipe, To_read, Timeout),
        gleam@result:replace_error(_pipe@1, Error)
    end of
        {error, _try} -> {error, _try};
        {ok, Data} ->
            Next_buffer = {buffer,
                           erlang:element(2, Buffer)
                           - To_read,
                           <<(erlang:element(3, Buffer))/bitstring,
                             Data/bitstring>>},
            case erlang:element(2, Next_buffer) > 0 of
                true ->
                    read_data(Socket, Transport, Next_buffer, Error);

                false ->
                    {ok, erlang:element(3, Next_buffer)}
            end
    end.

-spec read_chunk(
    glisten@socket:socket(),
    glisten@socket@transport:transport(),
    buffer(),
    gleam@bit_builder:bit_builder()
) -> {ok, gleam@bit_builder:bit_builder()} | {error, decode_error()}.
read_chunk(Socket, Transport, Buffer, Body) ->
    case {erlang:element(3, Buffer),
          http_ffi:binary_match(
              erlang:element(3, Buffer),
              <<13/integer, 10/integer>>
          )} of
        {_@1, {ok, {Offset, _@2}}} ->
            <<Chunk@1:Offset/binary, _@5/integer, _@6/integer, Rest@1/binary>> = case erlang:element(
                3,
                Buffer
            ) of
                <<Chunk:Offset/binary, _@3/integer, _@4/integer, Rest/binary>> -> <<Chunk:Offset/binary,
                                                                                    _@3/integer,
                                                                                    _@4/integer,
                                                                                    Rest/binary>>;
                _try ->
                    erlang:error(#{gleam_error => assert,
                                   message => <<"Assertion pattern match failed"/utf8>>,
                                   value => _try,
                                   module => <<"mist/http"/utf8>>,
                                   function => <<"read_chunk"/utf8>>,
                                   line => 141})
            end,
            case begin
                _pipe = Chunk@1,
                _pipe@1 = gleam@bit_string:to_string(_pipe),
                _pipe@2 = gleam@result:map(
                    _pipe@1,
                    fun gleam@erlang@charlist:from_string/1
                ),
                gleam@result:replace_error(_pipe@2, invalid_body)
            end of
                {error, _try@1} -> {error, _try@1};
                {ok, Chunk_size} ->
                    case begin
                        _pipe@3 = http_ffi:string_to_int(Chunk_size, 16),
                        gleam@result:replace_error(_pipe@3, invalid_body)
                    end of
                        {error, _try@2} -> {error, _try@2};
                        {ok, Size} ->
                            case Size of
                                0 ->
                                    {ok, Body};

                                Size@1 ->
                                    case Rest@1 of
                                        <<Next_chunk:Size@1/binary,
                                          13/integer,
                                          10/integer,
                                          Rest@2/binary>> ->
                                            read_chunk(
                                                Socket,
                                                Transport,
                                                {buffer, 0, Rest@2},
                                                gleam@bit_builder:append(
                                                    Body,
                                                    Next_chunk
                                                )
                                            );

                                        _@7 ->
                                            case read_data(
                                                Socket,
                                                Transport,
                                                {buffer,
                                                 0,
                                                 erlang:element(3, Buffer)},
                                                invalid_body
                                            ) of
                                                {error, _try@3} -> {error, _try@3};
                                                {ok, Next} ->
                                                    read_chunk(
                                                        Socket,
                                                        Transport,
                                                        {buffer, 0, Next},
                                                        Body
                                                    )
                                            end
                                    end
                            end
                    end
            end;

        {<<>>, _@8} ->
            case read_data(
                Socket,
                Transport,
                {buffer, 0, erlang:element(3, Buffer)},
                invalid_body
            ) of
                {error, _try@4} -> {error, _try@4};
                {ok, Next@1} ->
                    read_chunk(Socket, Transport, {buffer, 0, Next@1}, Body)
            end;

        {_@9, {error, nil}} ->
            {error, invalid_body}
    end.

-spec parse_request(
    bitstring(),
    glisten@socket:socket(),
    glisten@socket@transport:transport()
) -> {ok, gleam@http@request:request(body())} | {error, decode_error()}.
parse_request(Bs, Socket, Transport) ->
    case http_ffi:decode_packet(http_bin, Bs, []) of
        {ok,
         {binary_data, {http_request, Http_method, {abs_path, Path}, _@1}, Rest}} ->
            case begin
                _pipe = Http_method,
                _pipe@1 = gleam@erlang@atom:from_dynamic(_pipe),
                _pipe@2 = gleam@result:map(
                    _pipe@1,
                    fun gleam@erlang@atom:to_string/1
                ),
                _pipe@3 = gleam@result:'or'(
                    _pipe@2,
                    gleam@dynamic:string(Http_method)
                ),
                _pipe@4 = gleam@result:nil_error(_pipe@3),
                _pipe@5 = gleam@result:then(
                    _pipe@4,
                    fun gleam@http:parse_method/1
                ),
                gleam@result:replace_error(_pipe@5, unknown_method)
            end of
                {error, _try} -> {error, _try};
                {ok, Method} ->
                    case parse_headers(Rest, Socket, Transport, gleam@map:new()) of
                        {error, _try@1} -> {error, _try@1};
                        {ok, {Headers, Rest@1}} ->
                            case begin
                                _pipe@6 = Path,
                                _pipe@7 = gleam@bit_string:to_string(_pipe@6),
                                gleam@result:replace_error(
                                    _pipe@7,
                                    invalid_path
                                )
                            end of
                                {error, _try@2} -> {error, _try@2};
                                {ok, Path@1} ->
                                    {Path@4, Query@1} = case gleam@string:split(
                                        Path@1,
                                        <<"?"/utf8>>
                                    ) of
                                        [Path@2] ->
                                            {Path@2, []};

                                        [Path@3, Query_string] ->
                                            Query = begin
                                                _pipe@8 = Query_string,
                                                _pipe@9 = gleam@uri:parse_query(
                                                    _pipe@8
                                                ),
                                                gleam@result:unwrap(_pipe@9, [])
                                            end,
                                            {Path@3, Query}
                                    end,
                                    Req = begin
                                        _pipe@10 = gleam@http@request:new(),
                                        _pipe@11 = gleam@http@request:set_body(
                                            _pipe@10,
                                            {unread, Rest@1, Socket}
                                        ),
                                        _pipe@12 = gleam@http@request:set_method(
                                            _pipe@11,
                                            Method
                                        ),
                                        _pipe@13 = gleam@http@request:set_path(
                                            _pipe@12,
                                            Path@4
                                        ),
                                        gleam@http@request:set_query(
                                            _pipe@13,
                                            Query@1
                                        )
                                    end,
                                    {ok,
                                     erlang:setelement(
                                         3,
                                         Req,
                                         gleam@map:to_list(Headers)
                                     )}
                            end
                    end
            end;

        _@2 ->
            {error, discard_packet}
    end.

-spec read_body(
    gleam@http@request:request(body()),
    glisten@socket@transport:transport()
) -> {ok, gleam@http@request:request(bitstring())} | {error, decode_error()}.
read_body(Req, Transport) ->
    case {gleam@http@request:get_header(Req, <<"transfer-encoding"/utf8>>),
          erlang:element(4, Req)} of
        {{ok, <<"chunked"/utf8>>}, {unread, Rest, Socket}} ->
            case read_chunk(
                Socket,
                Transport,
                {buffer, 0, Rest},
                gleam@bit_builder:new()
            ) of
                {error, _try} -> {error, _try};
                {ok, Chunk} ->
                    {ok,
                     gleam@http@request:set_body(
                         Req,
                         gleam@bit_builder:to_bit_string(Chunk)
                     )}
            end;

        {_@1, {unread, Rest@1, Socket@1}} ->
            Body_size = begin
                _pipe = erlang:element(3, Req),
                _pipe@1 = gleam@list:find(
                    _pipe,
                    fun(Tup) ->
                        gleam@pair:first(Tup)
                        =:= <<"content-length"/utf8>>
                    end
                ),
                _pipe@2 = gleam@result:map(_pipe@1, fun gleam@pair:second/1),
                _pipe@3 = gleam@result:then(_pipe@2, fun gleam@int:parse/1),
                gleam@result:unwrap(_pipe@3, 0)
            end,
            Remaining = Body_size - gleam@bit_string:byte_size(Rest@1),
            _pipe@4 = case {Body_size, Remaining} of
                {0, 0} ->
                    {ok, <<>>};

                {0, _@2} ->
                    {ok, Rest@1};

                {_@3, 0} ->
                    {ok, Rest@1};

                {_@4, _@5} ->
                    read_data(
                        Socket@1,
                        Transport,
                        {buffer, Remaining, Rest@1},
                        invalid_body
                    )
            end,
            _pipe@5 = gleam@result:map(
                _pipe@4,
                fun(_capture) -> gleam@http@request:set_body(Req, _capture) end
            ),
            gleam@result:replace_error(_pipe@5, invalid_body);

        {_@6, {read, _@7}} ->
            {error, invalid_body}
    end.

-spec upgrade_socket(gleam@http@request:request(body())) -> {ok,
                                                             gleam@http@response:response(gleam@bit_builder:bit_builder())} |
    {error, gleam@http@request:request(body())}.
upgrade_socket(Req) ->
    case begin
        _pipe = gleam@http@request:get_header(Req, <<"upgrade"/utf8>>),
        gleam@result:replace_error(_pipe, Req)
    end of
        {error, _try} -> {error, _try};
        {ok, _@1} ->
            case begin
                _pipe@1 = gleam@http@request:get_header(
                    Req,
                    <<"sec-websocket-key"/utf8>>
                ),
                gleam@result:replace_error(_pipe@1, Req)
            end of
                {error, _try@1} -> {error, _try@1};
                {ok, Key} ->
                    case begin
                        _pipe@2 = gleam@http@request:get_header(
                            Req,
                            <<"sec-websocket-version"/utf8>>
                        ),
                        gleam@result:replace_error(_pipe@2, Req)
                    end of
                        {error, _try@2} -> {error, _try@2};
                        {ok, _@2} ->
                            Accept_key = mist@websocket:parse_key(Key),
                            _pipe@3 = gleam@http@response:new(101),
                            _pipe@4 = gleam@http@response:set_body(
                                _pipe@3,
                                gleam@bit_builder:new()
                            ),
                            _pipe@5 = gleam@http@response:prepend_header(
                                _pipe@4,
                                <<"Upgrade"/utf8>>,
                                <<"websocket"/utf8>>
                            ),
                            _pipe@6 = gleam@http@response:prepend_header(
                                _pipe@5,
                                <<"Connection"/utf8>>,
                                <<"Upgrade"/utf8>>
                            ),
                            _pipe@7 = gleam@http@response:prepend_header(
                                _pipe@6,
                                <<"Sec-WebSocket-Accept"/utf8>>,
                                Accept_key
                            ),
                            {ok, _pipe@7}
                    end
            end
    end.

-spec upgrade(
    glisten@socket:socket(),
    glisten@socket@transport:transport(),
    gleam@http@request:request(body())
) -> {ok, nil} | {error, nil}.
upgrade(Socket, Transport, Req) ->
    case begin
        _pipe = upgrade_socket(Req),
        gleam@result:nil_error(_pipe)
    end of
        {error, _try} -> {error, _try};
        {ok, Resp} ->
            case begin
                _pipe@1 = Resp,
                _pipe@2 = mist@encoder:to_bit_builder(_pipe@1),
                _pipe@3 = (erlang:element(10, Transport))(Socket, _pipe@2),
                gleam@result:nil_error(_pipe@3)
            end of
                {error, _try@1} -> {error, _try@1};
                {ok, _@1} ->
                    {ok, nil}
            end
    end.