-module(n4u_xhr).
-behaviour(cowboy_handler).

-include_lib("n4u/include/n4u.hrl").


% stream bridge to XHR

% cowboy websocket backend
-export([init/2, handle/2, info/3, terminate/3]).


% XHR
init(R, O)                 -> xhr(n4u_proto:init([], R, [{formatter, json}|O], xhr)).

handle(R, S)               -> body(cowboy_req:body(R), S).
info(M, R, S)              -> xhr(n4u_proto:info(M, R, S)).
terminate(_, R, S)         -> n4u_proto:terminate(R, S).

body({ok, D, R2}, S)       -> xhr(n4u_proto:stream({type(D), D}, R2, S));
body(R, S)                 -> {ok, R, S}.

type(<<"N4U,", _/binary>>) -> text;
type(<<"PING">>)           -> text;
type(_)                    -> binary.

xhr({ok, R, S})            -> {ok, R, S};
xhr({shutdown, R, S})      -> {shutdown, R, S};
xhr({reply, D, R, S})      -> {ok, reply(D, R, 200), S}.

reply(D, R, Code)          -> cowboy_req:reply(Code, [], D, R). % R2.