%% @author Maas-Maarten Zeeman <mmzeeman@xs4all.nl>
%% @copyright 2012-2013, Maas-Maarten Zeeman; 2018, elli-lib team
%%
%% @doc Elli Websocket Handler
%% @end
%%
%% Copyright 2012-2013, Maas-Maarten Zeeman
%% Copyright 2018,      elli-lib team
%%
%% Licensed under the Apache License, Version 2.0 (the "License");
%% you may not use this file except in compliance with the License.
%% You may obtain a copy of the License at
%%
%%     http://www.apache.org/licenses/LICENSE-2.0
%%
%% Unless required by applicable law or agreed to in writing, software
%% distributed under the License is distributed on an "AS IS" BASIS,
%% WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
%% See the License for the specific language governing permissions and
%% limitations under the License.

-module(elli_websocket).
-author("Maas-Maarten Zeeman <mmzeeman@xs4all.nl>").

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

%%
%% Api
%%

-export([upgrade/2]).

%%
%% Public types
%%

-export_type([payload/0, message/0, event/0]).

-type payload() :: binary() | iolist().

-type message() :: {text, payload()} |
                   {binary, payload()} |
                   {ping, payload()} |
                   {pong, payload()}.

-type event() ::
        websocket_open | websocket_close |
        websocket_throw | websocket_error | websocket_exit.


%%    Args: proplist with settings.
%%            handler: Websocket callback module
%%            handler_opts: Options to pass to the websocket_init
%%                callback.
%%            resp_compress: bool(), when set to true the traffic
%%                will be compressed if the client supports it.
%%

%% @doc Upgrade the request to a websocket, will respond with
%% bad request when something is wrong.
-spec upgrade(Req :: elli:req(), list()) -> ok.
upgrade(Req, Args) ->
    RespCompress = proplists:get_value(resp_compress, Args, false),
    ReqAdapter = elli_ws_request_adapter:init(Req, RespCompress),
    {handler, Handler} = proplists:lookup(handler, Args),
    HandlerOpts = proplists:get_value(handler_opts, Args, []),

    %% Adapter is ready, hand over to ws_protocol
    _UpgradeResponse = elli_ws_protocol:upgrade(ReqAdapter, Args, Handler, HandlerOpts),
    ok.