mist

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

-export([from_header/1, parse_headers/2, parse_request/1, encode_headers/1, status_to_bit_string/1, to_bit_builder/1, handler/1]).
-export_type([packet_type/0, http_uri/0, http_packet/0, decoded_packet/0, decode_error/0, handler_error/0]).

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

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

-type http_packet() :: {http_request,
                        gleam@erlang@atom:atom_(),
                        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() :: invalid_method | invalid_path | unknown_header.

-type handler_error() :: {invalid_request, decode_error()} | not_found.

-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 => 53})
    end,
    gleam@string:lowercase(Value@2).

-spec parse_headers(bitstring(), list({binary(), binary()})) -> {ok,
                                                                 {list({binary(),
                                                                        binary()}),
                                                                  bitstring()}} |
    {error, decode_error()}.
parse_headers(Bs, 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 => 65})
            end,
            parse_headers(Rest, [{Field@1, Value@2} | Headers]);

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

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

-spec parse_request(bitstring()) -> {ok,
                                     gleam@http@request:request(bitstring())} |
    {error, decode_error()}.
parse_request(Bs) ->
    case http_ffi:decode_packet(http_bin, Bs, []) of
        {error, _try} -> {error, _try};
        {ok, {binary_data, Req, Rest}} ->
            {http_request, Method@1, {abs_path, Path@1}, _@2} = case Req of
                {http_request, Method, {abs_path, Path}, _@1} -> {http_request,
                                                                  Method,
                                                                  {abs_path,
                                                                   Path},
                                                                  _@1};
                _try@1 ->
                    erlang:error(#{gleam_error => assert,
                                   message => <<"Assertion pattern match failed"/utf8>>,
                                   value => _try@1,
                                   module => <<"mist/http"/utf8>>,
                                   function => <<"parse_request"/utf8>>,
                                   line => 78})
            end,
            case begin
                _pipe = Method@1,
                _pipe@1 = gleam@erlang@atom:to_string(_pipe),
                _pipe@2 = gleam@http:parse_method(_pipe@1),
                gleam@result:replace_error(_pipe@2, invalid_method)
            end of
                {error, _try@2} -> {error, _try@2};
                {ok, Method@2} ->
                    case parse_headers(Rest, []) of
                        {error, _try@3} -> {error, _try@3};
                        {ok, {Headers, Rest@1}} ->
                            case begin
                                _pipe@3 = Path@1,
                                _pipe@4 = gleam@bit_string:to_string(_pipe@3),
                                gleam@result:replace_error(
                                    _pipe@4,
                                    invalid_path
                                )
                            end of
                                {error, _try@4} -> {error, _try@4};
                                {ok, Path@2} ->
                                    Req@1 = begin
                                        _pipe@5 = gleam@http@request:new(),
                                        _pipe@6 = gleam@http@request:set_body(
                                            _pipe@5,
                                            Rest@1
                                        ),
                                        _pipe@7 = gleam@http@request:set_method(
                                            _pipe@6,
                                            Method@2
                                        ),
                                        gleam@http@request:set_path(
                                            _pipe@7,
                                            Path@2
                                        )
                                    end,
                                    {ok, erlang:setelement(3, Req@1, Headers)}
                            end
                    end
            end
    end.

-spec encode_headers(gleam@map:map_(binary(), binary())) -> gleam@bit_builder:bit_builder().
encode_headers(Headers) ->
    gleam@map:fold(
        Headers,
        gleam@bit_builder:new(),
        fun(Builder, Header, Value) ->
            _pipe = Builder,
            _pipe@1 = gleam@bit_builder:append_string(_pipe, Header),
            _pipe@2 = gleam@bit_builder:append(_pipe@1, <<": "/utf8>>),
            _pipe@3 = gleam@bit_builder:append_string(_pipe@2, Value),
            gleam@bit_builder:append(_pipe@3, <<"\r\n"/utf8>>)
        end
    ).

-spec status_to_bit_string(integer()) -> bitstring().
status_to_bit_string(Status) ->
    case Status of
        101 ->
            <<"Switching Protocols"/utf8>>;

        200 ->
            <<"Ok"/utf8>>;

        201 ->
            <<"Created"/utf8>>;

        202 ->
            <<"Accepted"/utf8>>;

        204 ->
            <<"No Content"/utf8>>;

        301 ->
            <<"Moved Permanently"/utf8>>;

        400 ->
            <<"Bad Request"/utf8>>;

        401 ->
            <<"Unauthorized"/utf8>>;

        403 ->
            <<"Forbidden"/utf8>>;

        404 ->
            <<"Not Found"/utf8>>;

        405 ->
            <<"Method Not Allowed"/utf8>>;

        500 ->
            <<"Internal Server Error"/utf8>>;

        502 ->
            <<"Bad Gateway"/utf8>>;

        503 ->
            <<"Service Unavailable"/utf8>>;

        504 ->
            <<"Gateway Timeout"/utf8>>
    end.

-spec to_bit_builder(gleam@http@response:response(bitstring())) -> gleam@bit_builder:bit_builder().
to_bit_builder(Resp) ->
    Body_size = gleam@bit_string:byte_size(erlang:element(4, Resp)),
    Headers = begin
        _pipe = gleam@map:from_list(
            [{<<"content-type"/utf8>>, <<"text/plain; charset=utf-8"/utf8>>},
             {<<"content-length"/utf8>>, gleam@int:to_string(Body_size)},
             {<<"connection"/utf8>>, <<"close"/utf8>>}]
        ),
        gleam@list:fold(
            erlang:element(3, Resp),
            _pipe,
            fun(Defaults, Tup) ->
                {Key, Value} = Tup,
                gleam@map:insert(Defaults, Key, Value)
            end
        )
    end,
    Body_builder = case Body_size of
        0 ->
            gleam@bit_builder:new();

        _@1 ->
            _pipe@1 = gleam@bit_builder:new(),
            _pipe@2 = gleam@bit_builder:append(_pipe@1, erlang:element(4, Resp)),
            gleam@bit_builder:append(_pipe@2, <<"\r\n"/utf8>>)
    end,
    Status_string = begin
        _pipe@3 = erlang:element(2, Resp),
        _pipe@4 = gleam@int:to_string(_pipe@3),
        _pipe@5 = gleam@bit_builder:from_string(_pipe@4),
        _pipe@6 = gleam@bit_builder:append(_pipe@5, <<" "/utf8>>),
        gleam@bit_builder:append(
            _pipe@6,
            status_to_bit_string(erlang:element(2, Resp))
        )
    end,
    _pipe@7 = gleam@bit_builder:new(),
    _pipe@8 = gleam@bit_builder:append(_pipe@7, <<"HTTP/1.1 "/utf8>>),
    _pipe@9 = gleam@bit_builder:append_builder(_pipe@8, Status_string),
    _pipe@10 = gleam@bit_builder:append(_pipe@9, <<"\r\n"/utf8>>),
    _pipe@11 = gleam@bit_builder:append_builder(
        _pipe@10,
        encode_headers(Headers)
    ),
    _pipe@12 = gleam@bit_builder:append(_pipe@11, <<"\r\n"/utf8>>),
    gleam@bit_builder:append_builder(_pipe@12, Body_builder).

-spec handler(
    fun((gleam@http@request:request(bitstring())) -> gleam@http@response:response(bitstring()))
) -> fun((glisten@tcp:handler_message(), {glisten@tcp:socket(), nil}) -> gleam@otp@actor:next({glisten@tcp:socket(),
                                                                                               nil})).
handler(Func) ->
    glisten@tcp:handler(
        fun(Msg, State) ->
            {Socket, _@1} = State,
            _pipe = Msg,
            _pipe@1 = parse_request(_pipe),
            _pipe@6 = gleam@result:map(
                _pipe@1,
                fun(Req) ->
                    _pipe@2 = Req,
                    _pipe@3 = Func(_pipe@2),
                    _pipe@4 = to_bit_builder(_pipe@3),
                    _pipe@5 = glisten@tcp:send(Socket, _pipe@4),
                    gleam@result:replace_error(_pipe@5, nil)
                end
            ),
            _pipe@7 = gleam@result:replace(_pipe@6, {stop, normal}),
            gleam@result:unwrap(_pipe@7, {stop, normal})
        end
    ).