%%%-------------------------------------------------------------------
%%% @author licheng5
%%% @copyright (C) 2021, <COMPANY>
%%% @doc
%%%
%%% @end
%%% Created : 11. 1月 2021 上午12:17
%%%-------------------------------------------------------------------
-module(tcp_channel).
-author("licheng5").
-include("iot.hrl").
-include("message_pb.hrl").

%% API
-export([publish/3, stop/2, send/2]).

-export([start_link/2]).
%% gen_server callbacks
-export([init/1, handle_call/3, handle_cast/2, handle_info/2, terminate/2, code_change/3, terminate/2]).

-record(state, {
    transport,
    socket,

    uuid :: undefined | binary(),
    %% 用户进程id
    host_pid = undefined,
    %% 发送消息对应的id
    packet_id = 1 :: integer(),

    %% 请求响应的对应关系
    inflight = #{}
}).

%% 向通道中写入消息
-spec publish(Pid :: pid(), ReceiverPid :: pid(), Msg :: binary()) -> Ref :: reference().
publish(Pid, ReceiverPid, Msg) when is_pid(Pid), is_binary(Msg) ->
    Ref = make_ref(),
    Pid ! {publish, ReceiverPid, Ref, Msg},
    Ref.

%% 向通道中写入消息
-spec send(Pid :: pid(), Msg :: binary()) -> no_return().
send(Pid, Msg) when is_pid(Pid), is_binary(Msg) ->
    Pid ! {send, Msg}.

%% 关闭方法
-spec stop(Pid :: pid(), Reason :: any()) -> no_return().
stop(undefined, _Reason) ->
    ok;
stop(Pid, Reason) when is_pid(Pid) ->
    Pid ! {stop, Reason}.

%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%
%% 逻辑处理方法
%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%%

start_link(Transport, Sock) ->
    {ok, proc_lib:spawn_link(?MODULE, init, [[Transport, Sock]])}.

init([Transport, Sock]) ->
    lager:debug("[sdlan_channel] get a new connection: ~p", [Sock]),
    case Transport:wait(Sock) of
        {ok, NewSock} ->
            Transport:setopts(Sock, [{active, true}]),
            % erlang:start_timer(?PING_TICKER, self(), ping_ticker),
            gen_server:enter_loop(?MODULE, [], #state{transport = Transport, socket = NewSock});
        {error, Reason} ->
            {stop, Reason}
    end.

handle_call(_Request, _From, State) ->
    {reply, ok, State}.

handle_cast(_Msg, State) ->
    {noreply, State}.

%% auth验证
handle_info({tcp, Socket, <<?PACKET_REQUEST, PacketId:32, ?METHOD_AUTH:8, AuthRequestBin/binary>>}, State = #state{transport = Transport, socket = Socket}) ->
    #auth_request{ uuid = UUID, username = Username, token = Token, salt = Salt, timestamp = Timestamp } = message_pb:decode_msg(AuthRequestBin, auth_request),
    lager:debug("[ws_channel] auth uuid: ~p, request message: ~p", [UUID]),
    case iot_auth:check(Username, Token, UUID, Salt, Timestamp) of
        true ->
            case host_bo:get_host_by_uuid(UUID) of
                undefined ->
                    lager:warning("[ws_channel] uuid: ~p, user: ~p, host not found", [UUID, Username]),
                    {stop, State};
                {ok, _} ->
                    %% 尝试启动主机的服务进程
                    {ok, HostPid} = iot_host_sup:ensured_host_started(UUID),
                    case iot_host:attach_channel(HostPid, self()) of
                        ok ->
                            %% 建立到host的monitor
                            erlang:monitor(process, HostPid),
                            AuthReplyBin = message_pb:encode_msg(#auth_reply{
                                code = 1,
                                message = <<"ok">>,
                                repository_url = <<"https://www.baidu.com">>
                            }),
                            Transport:send(Socket, <<?PACKET_RESPONSE, PacketId:32, 0:8, AuthReplyBin/binary>>),

                            {noreply, State#state{uuid = UUID, host_pid = HostPid}};
                        {error, Reason} ->
                            lager:debug("[ws_channel] uuid: ~p, attach channel get error: ~p", [UUID, Reason]),
                            {stop, State}
                    end
            end;
        false ->
            lager:warning("[ws_channel] uuid: ~p, user: ~p, auth failed", [UUID, Username]),
            {stop, State}
    end;

handle_info({binary, <<?PACKET_REQUEST, PacketId:32, ?METHOD_CREATE_SESSION:8, PubKey/binary>>}, State = #state{host_pid = HostPid}) when is_pid(HostPid) ->
    {ok, Reply} = iot_host:create_session(HostPid, PubKey),
    {reply, {binary, <<?PACKET_RESPONSE, PacketId:32, Reply/binary>>}, State};

handle_info({binary, <<?PACKET_REQUEST, _PacketId:32, ?METHOD_DATA:8, Data/binary>>}, State = #state{host_pid = HostPid}) when is_pid(HostPid) ->
    iot_host:handle(HostPid, {data, Data}),
    {ok, State};

handle_info({binary, <<?PACKET_REQUEST, _PacketId:32, ?METHOD_PING:8, CipherMetric/binary>>}, State = #state{host_pid = HostPid}) when is_pid(HostPid) ->
    iot_host:handle(HostPid, {ping, CipherMetric}),
    {ok, State};

handle_info({binary, <<?PACKET_REQUEST, _PacketId:32, ?METHOD_INFORM:8, CipherInfo/binary>>}, State = #state{host_pid = HostPid}) when is_pid(HostPid) ->
    iot_host:handle(HostPid, {inform, CipherInfo}),
    {ok, State};

handle_info({binary, <<?PACKET_REQUEST, _PacketId:32, ?METHOD_FEEDBACK_STEP:8, CipherInfo/binary>>}, State = #state{host_pid = HostPid}) when is_pid(HostPid) ->
    iot_host:handle(HostPid, {feedback_step, CipherInfo}),
    {ok, State};

handle_info({binary, <<?PACKET_REQUEST, _PacketId:32, ?METHOD_FEEDBACK_RESULT:8, CipherInfo/binary>>}, State = #state{host_pid = HostPid}) when is_pid(HostPid) ->
    iot_host:handle(HostPid, {feedback_result, CipherInfo}),
    {ok, State};

handle_info({binary, <<?PACKET_REQUEST, _PacketId:32, ?METHOD_EVENT:8, CipherEvent/binary>>}, State = #state{host_pid = HostPid}) when is_pid(HostPid) ->
    iot_host:handle(HostPid, {event, CipherEvent}),
    {ok, State};

handle_info({binary, <<?PACKET_REQUEST, _PacketId:32, ?METHOD_AI_EVENT:8, CipherEvent/binary>>}, State = #state{host_pid = HostPid}) when is_pid(HostPid) ->
    iot_host:handle(HostPid, {ai_event, CipherEvent}),
    {ok, State};

%% 主机端的消息响应
handle_info({binary, <<?PACKET_PUBLISH_RESPONSE, 0:32, Body/binary>>}, State = #state{uuid = UUID}) ->
    lager:debug("[ws_channel] uuid: ~p, get send response message: ~p", [UUID, Body]),
    {ok, State};
handle_info({binary, <<?PACKET_PUBLISH_RESPONSE, PacketId:32, Body/binary>>}, State = #state{uuid = UUID, inflight = Inflight}) when PacketId > 0 ->
    lager:debug("[ws_channel] uuid: ~p, get publish response message: ~p, packet_id: ~p", [UUID, Body, PacketId]),
    case maps:take(PacketId, Inflight) of
        error ->
            lager:warning("[ws_channel] get unknown publish response message: ~p, packet_id: ~p", [Body, PacketId]),
            {ok, State};
        {{ReceiverPid, Ref}, NInflight} ->
            case is_pid(ReceiverPid) andalso is_process_alive(ReceiverPid) of
                true when Body == <<>> ->
                    ReceiverPid ! {ws_response, Ref};
                true ->
                    ReceiverPid ! {ws_response, Ref, Body};
                false ->
                    lager:warning("[ws_channel] get publish response message: ~p, packet_id: ~p, but receiver_pid is deaded", [Body, PacketId])
            end,
            {ok, State#state{inflight = NInflight}}
    end;

handle_info({tcp, Socket, Data}, State = #state{transport = Transport, socket = Socket}) ->
    lager:debug("[ws_channel] socket: ~p, get a message: ~p", [Socket, Data]),

    Transport:send(Socket, <<"hello world reply">>),

    {noreply, State};

handle_info(Info, State) ->
    lager:error("[ws_channel] get a unknown message: ~p, channel will closed", [Info]),
    {stop, State};

handle_info({tcp_error, Sock, Reason}, State = #state{socket = Sock}) ->
    lager:notice("[sdlan_channel] tcp_error: ~p", [Reason]),
    {stop, normal, State};

handle_info({tcp_closed, Sock}, State = #state{socket = Sock}) ->
    lager:notice("[sdlan_channel] tcp_closed"),
    {stop, normal, State};

%% 关闭当前通道
handle_info({stop, Reason}, State) ->
    {stop, Reason, State};

handle_info(Info, State) ->
    lager:warning("[sdlan_channel] get a unknown message: ~p, channel will closed", [Info]),
    {noreply, State}.

terminate(Reason, #state{}) ->
    lager:warning("[sdlan_channel] stop with reason: ~p", [Reason]),
    ok.

code_change(_OldVsn, State, _Extra) ->
    {ok, State}.

%% 处理关闭信号
websocket_info({stop, Reason}, State) ->
    lager:debug("[ws_channel] the channel will be closed with reason: ~p", [Reason]),
    {stop, State};

%% 发送消息
websocket_info({publish, ReceiverPid, Ref, Msg}, State = #state{packet_id = PacketId, inflight = Inflight}) when is_binary(Msg) ->
    NInflight = maps:put(PacketId, {ReceiverPid, Ref}, Inflight),
    {reply, {binary, <<?PACKET_PUBLISH, PacketId:32, Msg/binary>>}, State#state{packet_id = PacketId + 1, inflight = NInflight}};

%% 发送消息, 不需要等待回复
websocket_info({send, Msg}, State) when is_binary(Msg) ->
    {reply, {binary, <<?PACKET_PUBLISH, 0:32, Msg/binary>>}, State};

%% 用户进程关闭，则关闭通道
websocket_info({'DOWN', _, process, HostPid, Reason}, State = #state{uuid = UUID, host_pid = HostPid}) ->
    lager:debug("[ws_channel] uuid: ~p, channel will close because host exited with reason: ~p", [UUID, Reason]),
    {stop, State};

%% 处理其他未知消息
websocket_info(Info, State = #state{uuid = UUID}) ->
    lager:debug("[ws_channel] channel get unknown info: ~p, uuid: ~p", [Info, UUID]),
    {ok, State}.