tcpea

-module(tcpea@client).
-compile([no_auto_import, nowarn_unused_vars, nowarn_unused_function, nowarn_nomatch]).

-export([new/2, timeout/2, ip_version/2, send/2, 'receive'/2, shutdown/1, connect/1]).

-spec new(binary(), integer()) -> tcpea@client@types:tcpea_options().
new(Host, Port) ->
    {tcpea_options, Host, Port, 1000, transparent}.

-spec timeout(tcpea@client@types:tcpea_options(), integer()) -> tcpea@client@types:tcpea_options().
timeout(Options, Timeout) ->
    erlang:setelement(4, Options, Timeout).

-spec ip_version(
    tcpea@client@types:tcpea_options(),
    tcpea@client@types:ip_version()
) -> tcpea@client@types:tcpea_options().
ip_version(Options, Ip_version) ->
    erlang:setelement(5, Options, Ip_version).

-spec send(tcpea@client@types:socket(), bitstring()) -> {ok, nil} |
    {error, tcpea@client@types:error()}.
send(Socket, Packet) ->
    tcpea_ffi:send(Socket, Packet).

-spec 'receive'(tcpea@client@types:socket(), integer()) -> {ok, bitstring()} |
    {error, tcpea@client@types:error()}.
'receive'(Socket, Timeout) ->
    gen_tcp:recv(Socket, 0, Timeout).

-spec shutdown(tcpea@client@types:socket()) -> {ok, nil} |
    {error, tcpea@client@types:error()}.
shutdown(Socket) ->
    tcpea_ffi:shutdown(Socket, read_write).

-spec happy_eyeballs_select(
    gleam@erlang@process:selector({ok, tcpea@client@types:socket()} |
        {error, tcpea@client@types:error()}),
    integer()
) -> {ok, tcpea@client@types:socket()} | {error, tcpea@client@types:error()}.
happy_eyeballs_select(Selector, Attempts) ->
    case gleam_erlang_ffi:select(Selector) of
        {error, Err} ->
            case Attempts of
                1 ->
                    {error, Err};

                _ ->
                    happy_eyeballs_select(Selector, Attempts - 1)
            end;

        A ->
            A
    end.

-spec connect_single_stack(tcpea@client@types:tcpea_options()) -> {ok,
        tcpea@client@types:socket()} |
    {error, tcpea@client@types:error()}.
connect_single_stack(Options) ->
    tcpea_ffi:connect(
        erlang:element(2, Options),
        erlang:element(3, Options),
        [{active, false}, {mode, binary}, case erlang:element(5, Options) of
                ipv4 ->
                    inet;

                ipv6 ->
                    inet6;

                _ ->
                    erlang:error(#{gleam_error => panic,
                            message => <<"unreachable"/utf8>>,
                            module => <<"tcpea/client"/utf8>>,
                            function => <<"connect_single_stack"/utf8>>,
                            line => 118})
            end],
        erlang:element(4, Options)
    ).

-spec happy_eyeballs_attempt(
    gleam@erlang@process:subject({ok, tcpea@client@types:socket()} |
        {error, tcpea@client@types:error()}),
    gleam@erlang@process:pid_(),
    tcpea@client@types:tcpea_options()
) -> nil.
happy_eyeballs_attempt(Subject, Pid, Options) ->
    gleam@erlang@process:send(Subject, case connect_single_stack(Options) of
            {ok, Socket} ->
                _assert_subject = tcpea_ffi:controlling_process(Socket, Pid),
                {ok, nil} = case _assert_subject of
                    {ok, nil} -> _assert_subject;
                    _assert_fail ->
                        erlang:error(#{gleam_error => let_assert,
                                    message => <<"Assertion pattern match failed"/utf8>>,
                                    value => _assert_fail,
                                    module => <<"tcpea/client"/utf8>>,
                                    function => <<"happy_eyeballs_attempt"/utf8>>,
                                    line => 90})
                end,
                {ok, Socket};

            A ->
                A
        end).

-spec connect_happy_eyeballs(tcpea@client@types:tcpea_options()) -> {ok,
        tcpea@client@types:socket()} |
    {error, tcpea@client@types:error()}.
connect_happy_eyeballs(Options) ->
    Subject = gleam@erlang@process:new_subject(),
    Pid = erlang:self(),
    gleam@erlang@process:start(
        fun() ->
            happy_eyeballs_attempt(
                Subject,
                Pid,
                erlang:setelement(5, Options, ipv6)
            )
        end,
        true
    ),
    gleam@erlang@process:start(
        fun() ->
            gleam_erlang_ffi:sleep(250),
            happy_eyeballs_attempt(
                Subject,
                Pid,
                erlang:setelement(5, Options, ipv4)
            )
        end,
        true
    ),
    _pipe = gleam_erlang_ffi:new_selector(),
    _pipe@1 = gleam@erlang@process:selecting(
        _pipe,
        Subject,
        fun(Res) -> Res end
    ),
    happy_eyeballs_select(_pipe@1, 2).

-spec connect(tcpea@client@types:tcpea_options()) -> {ok,
        tcpea@client@types:socket()} |
    {error, tcpea@client@types:error()}.
connect(Options) ->
    case erlang:element(5, Options) of
        transparent ->
            connect_happy_eyeballs(Options);

        _ ->
            connect_single_stack(Options)
    end.