mist

-module(mist@internal@websocket).
-compile([no_auto_import, nowarn_unused_vars]).

-export([frame_from_message/3, frame_to_bit_builder/1, to_text_frame/1, to_binary_frame/1, initialize_connection/5]).
-export_type([data_frame/0, control_frame/0, frame/0, valid_message/1, websocket_message/1, websocket_connection/0]).

-type data_frame() :: {text_frame, integer(), bitstring()} |
    {binary_frame, integer(), bitstring()}.

-type control_frame() :: {close_frame, integer(), bitstring()} |
    {ping_frame, integer(), bitstring()} |
    {pong_frame, integer(), bitstring()}.

-type frame() :: {data, data_frame()} | {control, control_frame()}.

-type valid_message(ITX) :: {internal, frame()} | socket_closed | {user, ITX}.

-type websocket_message(ITY) :: {valid, valid_message(ITY)} | invalid.

-type websocket_connection() :: {websocket_connection,
        glisten@socket:socket(),
        glisten@socket@transport:transport()}.

-spec unmask_data(bitstring(), list(bitstring()), integer(), bitstring()) -> bitstring().
unmask_data(Data, Masks, Index, Resp) ->
    case Data of
        <<>> ->
            Resp;

        <<Masked:8/bitstring, Rest/bitstring>> ->
            _assert_subject = gleam@list:at(Masks, Index rem 4),
            {ok, Mask_value} = case _assert_subject of
                {ok, _} -> _assert_subject;
                _assert_fail ->
                    erlang:error(#{gleam_error => let_assert,
                                message => <<"Assertion pattern match failed"/utf8>>,
                                value => _assert_fail,
                                module => <<"mist/internal/websocket"/utf8>>,
                                function => <<"unmask_data"/utf8>>,
                                line => 48})
            end,
            Unmasked = crypto:exor(Mask_value, Masked),
            unmask_data(
                Rest,
                Masks,
                Index + 1,
                <<Resp/bitstring, Unmasked/bitstring>>
            )
    end.

-spec frame_from_message(
    glisten@socket:socket(),
    glisten@socket@transport:transport(),
    bitstring()
) -> {ok, frame()} | {error, nil}.
frame_from_message(Socket, Transport, Message) ->
    <<_:1, Rest/bitstring>> = case Message of
        <<_:1, _/bitstring>> -> Message;
        _assert_fail ->
            erlang:error(#{gleam_error => let_assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _assert_fail,
                        module => <<"mist/internal/websocket"/utf8>>,
                        function => <<"frame_from_message"/utf8>>,
                        line => 65})
    end,
    <<_:3, Rest@1/bitstring>> = case Rest of
        <<_:3, _/bitstring>> -> Rest;
        _assert_fail@1 ->
            erlang:error(#{gleam_error => let_assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _assert_fail@1,
                        module => <<"mist/internal/websocket"/utf8>>,
                        function => <<"frame_from_message"/utf8>>,
                        line => 66})
    end,
    <<Opcode:4/integer, Rest@2/bitstring>> = case Rest@1 of
        <<_:4/integer, _/bitstring>> -> Rest@1;
        _assert_fail@2 ->
            erlang:error(#{gleam_error => let_assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _assert_fail@2,
                        module => <<"mist/internal/websocket"/utf8>>,
                        function => <<"frame_from_message"/utf8>>,
                        line => 67})
    end,
    <<1:1, Rest@3/bitstring>> = case Rest@2 of
        <<1:1, _/bitstring>> -> Rest@2;
        _assert_fail@3 ->
            erlang:error(#{gleam_error => let_assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _assert_fail@3,
                        module => <<"mist/internal/websocket"/utf8>>,
                        function => <<"frame_from_message"/utf8>>,
                        line => 69})
    end,
    <<Payload_length:7/integer, Rest@4/bitstring>> = case Rest@3 of
        <<_:7/integer, _/bitstring>> -> Rest@3;
        _assert_fail@4 ->
            erlang:error(#{gleam_error => let_assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _assert_fail@4,
                        module => <<"mist/internal/websocket"/utf8>>,
                        function => <<"frame_from_message"/utf8>>,
                        line => 70})
    end,
    {Payload_length@1, Rest@7} = case Payload_length of
        126 ->
            <<Length:16/integer, Rest@5/bitstring>> = case Rest@4 of
                <<_:16/integer, _/bitstring>> -> Rest@4;
                _assert_fail@5 ->
                    erlang:error(#{gleam_error => let_assert,
                                message => <<"Assertion pattern match failed"/utf8>>,
                                value => _assert_fail@5,
                                module => <<"mist/internal/websocket"/utf8>>,
                                function => <<"frame_from_message"/utf8>>,
                                line => 73})
            end,
            {Length, Rest@5};

        127 ->
            <<Length@1:64/integer, Rest@6/bitstring>> = case Rest@4 of
                <<_:64/integer, _/bitstring>> -> Rest@4;
                _assert_fail@6 ->
                    erlang:error(#{gleam_error => let_assert,
                                message => <<"Assertion pattern match failed"/utf8>>,
                                value => _assert_fail@6,
                                module => <<"mist/internal/websocket"/utf8>>,
                                function => <<"frame_from_message"/utf8>>,
                                line => 77})
            end,
            {Length@1, Rest@6};

        _ ->
            {Payload_length, Rest@4}
    end,
    <<Mask1:8/bitstring,
        Mask2:8/bitstring,
        Mask3:8/bitstring,
        Mask4:8/bitstring,
        Rest@8/bitstring>> = case Rest@7 of
        <<_:8/bitstring,
            _:8/bitstring,
            _:8/bitstring,
            _:8/bitstring,
            _/bitstring>> -> Rest@7;
        _assert_fail@7 ->
            erlang:error(#{gleam_error => let_assert,
                        message => <<"Assertion pattern match failed"/utf8>>,
                        value => _assert_fail@7,
                        module => <<"mist/internal/websocket"/utf8>>,
                        function => <<"frame_from_message"/utf8>>,
                        line => 82})
    end,
    _pipe@5 = case Payload_length@1 - gleam@bit_string:byte_size(Rest@8) of
        0 ->
            {ok, unmask_data(Rest@8, [Mask1, Mask2, Mask3, Mask4], 0, <<>>)};

        Need ->
            _pipe = Need,
            _pipe@1 = (erlang:element(9, Transport))(Socket, _pipe),
            _pipe@2 = gleam@result:replace_error(_pipe@1, nil),
            gleam@result:map(_pipe@2, fun(Needed) -> _pipe@3 = Rest@8,
                    _pipe@4 = gleam@bit_string:append(_pipe@3, Needed),
                    unmask_data(_pipe@4, [Mask1, Mask2, Mask3, Mask4], 0, <<>>) end)
    end,
    gleam@result:map(_pipe@5, fun(Data) -> case Opcode of
                1 ->
                    {data, {text_frame, Payload_length@1, Data}};

                2 ->
                    {data, {binary_frame, Payload_length@1, Data}};

                8 ->
                    {control, {close_frame, Payload_length@1, Data}};

                9 ->
                    {control, {ping_frame, Payload_length@1, Data}};

                10 ->
                    {control, {pong_frame, Payload_length@1, Data}}
            end end).

-spec make_frame(integer(), integer(), bitstring()) -> gleam@bit_builder:bit_builder().
make_frame(Opcode, Length, Payload) ->
    Length_section = case Length of
        Length@1 when Length@1 > 65535 ->
            <<127:7, Length@1:64/integer>>;

        Length@2 when Length@2 >= 126 ->
            <<126:7, Length@2:16/integer>>;

        _ ->
            <<Length:7>>
    end,
    _pipe = <<1:1,
        0:3,
        Opcode:4,
        0:1,
        Length_section/bitstring,
        Payload/bitstring>>,
    gleam@bit_builder:from_bit_string(_pipe).

-spec frame_to_bit_builder(frame()) -> gleam@bit_builder:bit_builder().
frame_to_bit_builder(Frame) ->
    case Frame of
        {data, {text_frame, Payload_length, Payload}} ->
            make_frame(1, Payload_length, Payload);

        {control, {close_frame, Payload_length@1, Payload@1}} ->
            make_frame(8, Payload_length@1, Payload@1);

        {data, {binary_frame, Payload_length@2, Payload@2}} ->
            make_frame(2, Payload_length@2, Payload@2);

        {control, {pong_frame, Payload_length@3, Payload@3}} ->
            make_frame(10, Payload_length@3, Payload@3);

        {control, {ping_frame, Payload_length@4, Payload@4}} ->
            make_frame(9, Payload_length@4, Payload@4)
    end.

-spec to_text_frame(bitstring()) -> gleam@bit_builder:bit_builder().
to_text_frame(Data) ->
    Size = gleam@bit_string:byte_size(Data),
    frame_to_bit_builder({data, {text_frame, Size, Data}}).

-spec to_binary_frame(bitstring()) -> gleam@bit_builder:bit_builder().
to_binary_frame(Data) ->
    Size = gleam@bit_string:byte_size(Data),
    frame_to_bit_builder({data, {binary_frame, Size, Data}}).

-spec initialize_connection(
    IUG,
    gleam@option:option(gleam@erlang@process:selector(IUH)),
    fun((IUG, websocket_connection(), valid_message(IUH)) -> gleam@otp@actor:next(IUG)),
    glisten@socket:socket(),
    glisten@socket@transport:transport()
) -> {ok, gleam@erlang@process:subject(websocket_message(IUH))} | {error, nil}.
initialize_connection(Initial_state, User_selector, Handler, Socket, Transport) ->
    Connection = {websocket_connection, Socket, Transport},
    _pipe@23 = gleam@otp@actor:start_spec(
        {spec,
            fun() ->
                Selector@1 = begin
                    _pipe = gleam_erlang_ffi:new_selector(),
                    _pipe@7 = gleam@erlang@process:selecting_record3(
                        _pipe,
                        erlang:binary_to_atom(<<"tcp"/utf8>>),
                        fun(_, Data) -> _pipe@1 = Data,
                            _pipe@2 = gleam@dynamic:bit_string(_pipe@1),
                            _pipe@3 = gleam@result:replace_error(_pipe@2, nil),
                            _pipe@4 = gleam@result:then(
                                _pipe@3,
                                fun(_capture) ->
                                    frame_from_message(
                                        Socket,
                                        Transport,
                                        _capture
                                    )
                                end
                            ),
                            _pipe@5 = gleam@result:map(
                                _pipe@4,
                                fun(Field@0) -> {internal, Field@0} end
                            ),
                            _pipe@6 = gleam@result:map(
                                _pipe@5,
                                fun(Field@0) -> {valid, Field@0} end
                            ),
                            gleam@result:unwrap(_pipe@6, invalid) end
                    ),
                    _pipe@14 = gleam@erlang@process:selecting_record3(
                        _pipe@7,
                        erlang:binary_to_atom(<<"ssl"/utf8>>),
                        fun(_, Data@1) -> _pipe@8 = Data@1,
                            _pipe@9 = gleam@dynamic:bit_string(_pipe@8),
                            _pipe@10 = gleam@result:replace_error(_pipe@9, nil),
                            _pipe@11 = gleam@result:then(
                                _pipe@10,
                                fun(_capture@1) ->
                                    frame_from_message(
                                        Socket,
                                        Transport,
                                        _capture@1
                                    )
                                end
                            ),
                            _pipe@12 = gleam@result:map(
                                _pipe@11,
                                fun(Field@0) -> {internal, Field@0} end
                            ),
                            _pipe@13 = gleam@result:map(
                                _pipe@12,
                                fun(Field@0) -> {valid, Field@0} end
                            ),
                            gleam@result:unwrap(_pipe@13, invalid) end
                    ),
                    _pipe@15 = gleam@erlang@process:selecting_record2(
                        _pipe@14,
                        erlang:binary_to_atom(<<"ssl_closed"/utf8>>),
                        fun(_) -> {valid, socket_closed} end
                    ),
                    _pipe@16 = gleam@erlang@process:selecting_record2(
                        _pipe@15,
                        erlang:binary_to_atom(<<"tcp_closed"/utf8>>),
                        fun(_) -> {valid, socket_closed} end
                    ),
                    (fun(Selector) -> case User_selector of
                            {some, User_selector@1} ->
                                _pipe@17 = User_selector@1,
                                _pipe@18 = gleam_erlang_ffi:map_selector(
                                    _pipe@17,
                                    fun(Field@0) -> {user, Field@0} end
                                ),
                                _pipe@19 = gleam_erlang_ffi:map_selector(
                                    _pipe@18,
                                    fun(Field@0) -> {valid, Field@0} end
                                ),
                                gleam_erlang_ffi:merge_selector(
                                    _pipe@19,
                                    Selector
                                );

                            _ ->
                                Selector
                        end end)(_pipe@16)
                end,
                {ready, Initial_state, Selector@1}
            end,
            500,
            fun(Msg, State) -> case Msg of
                    {valid, {internal, {control, {close_frame, _, _}} = Frame}} ->
                        _assert_subject = (erlang:element(
                            11,
                            erlang:element(3, Connection)
                        ))(
                            erlang:element(2, Connection),
                            frame_to_bit_builder(Frame)
                        ),
                        {ok, _} = case _assert_subject of
                            {ok, _} -> _assert_subject;
                            _assert_fail ->
                                erlang:error(#{gleam_error => let_assert,
                                            message => <<"Assertion pattern match failed"/utf8>>,
                                            value => _assert_fail,
                                            module => <<"mist/internal/websocket"/utf8>>,
                                            function => <<"initialize_connection"/utf8>>,
                                            line => 231})
                        end,
                        {stop, normal};

                    {valid,
                        {internal, {control, {ping_frame, Length, Payload}}}} ->
                        _pipe@20 = (erlang:element(
                            11,
                            erlang:element(3, Connection)
                        ))(
                            erlang:element(2, Connection),
                            frame_to_bit_builder(
                                {control, {pong_frame, Length, Payload}}
                            )
                        ),
                        _pipe@21 = gleam@result:map(
                            _pipe@20,
                            fun(_) -> {continue, State} end
                        ),
                        gleam@result:unwrap(
                            _pipe@21,
                            {stop,
                                {abnormal, <<"Failed to send pong frame"/utf8>>}}
                        );

                    invalid ->
                        mist@internal@logger:error(
                            {<<"Received a malformed Websocket frame"/utf8>>}
                        ),
                        {continue, State};

                    {valid, Msg@1} ->
                        _pipe@22 = gleam_erlang_ffi:rescue(
                            fun() -> Handler(State, Connection, Msg@1) end
                        ),
                        gleam@result:lazy_unwrap(
                            _pipe@22,
                            fun() ->
                                mist@internal@logger:error(
                                    <<"Caught error in websocket handler"/utf8>>
                                ),
                                {stop,
                                    {abnormal, <<"Websocket terminated"/utf8>>}}
                            end
                        )
                end end}
    ),
    _pipe@24 = gleam@result:replace_error(_pipe@23, nil),
    _pipe@25 = gleam@result:map(
        _pipe@24,
        fun(Subj) ->
            Websocket_pid = gleam@erlang@process:subject_owner(Subj),
            _assert_subject@1 = (erlang:element(
                5,
                erlang:element(3, Connection)
            ))(erlang:element(2, Connection), Websocket_pid),
            {ok, _} = case _assert_subject@1 of
                {ok, _} -> _assert_subject@1;
                _assert_fail@1 ->
                    erlang:error(#{gleam_error => let_assert,
                                message => <<"Assertion pattern match failed"/utf8>>,
                                value => _assert_fail@1,
                                module => <<"mist/internal/websocket"/utf8>>,
                                function => <<"initialize_connection"/utf8>>,
                                line => 265})
            end,
            _assert_subject@2 = (erlang:element(
                12,
                erlang:element(3, Connection)
            ))(erlang:element(2, Connection), [{active_mode, active}]),
            {ok, _} = case _assert_subject@2 of
                {ok, _} -> _assert_subject@2;
                _assert_fail@2 ->
                    erlang:error(#{gleam_error => let_assert,
                                message => <<"Assertion pattern match failed"/utf8>>,
                                value => _assert_fail@2,
                                module => <<"mist/internal/websocket"/utf8>>,
                                function => <<"initialize_connection"/utf8>>,
                                line => 267})
            end,
            Subj
        end
    ),
    gleam@result:replace_error(_pipe@25, nil).