%%%-------------------------------------------------------------------
%%% @author anlicheng
%%% @copyright (C) 2025, <COMPANY>
%%% @doc
%%%
%%% @end
%%% Created : 20. 4月 2025 18:47
%%%-------------------------------------------------------------------
-module(efka_agent).
-author("anlicheng").
-include("message_pb.hrl").
-include("efka.hrl").

-behaviour(gen_server).

%% API
-export([start_link/0]).

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

-define(SERVER, ?MODULE).

-define(STATE_DENIED, denied).
-define(STATE_ACTIVATED, activated).

-record(state, {
    transport_pid :: undefined | pid(),
    status = ?STATE_DENIED
}).

%%%===================================================================
%%% API
%%%===================================================================

%% @doc Spawns the server and registers the local name (unique)
-spec(start_link() ->
    {ok, Pid :: pid()} | ignore | {error, Reason :: term()}).
start_link() ->
    gen_server:start_link({local, ?SERVER}, ?MODULE, [], []).

%%%===================================================================
%%% gen_server callbacks
%%%===================================================================

%% @private
%% @doc Initializes the server
-spec(init(Args :: term()) ->
    {ok, State :: #state{}} | {ok, State :: #state{}, timeout() | hibernate} |
    {stop, Reason :: term()} | ignore).
init([]) ->
    erlang:process_flag(trap_exit, true),
    erlang:start_timer(0, self(), create_transport),
    {ok, #state{}}.

%% @private
%% @doc Handling call messages
-spec(handle_call(Request :: term(), From :: {pid(), Tag :: term()}, State :: #state{}) ->
    {reply, Reply :: term(), NewState :: #state{}} |
    {reply, Reply :: term(), NewState :: #state{}, timeout() | hibernate} |
    {noreply, NewState :: #state{}} |
    {noreply, NewState :: #state{}, timeout() | hibernate} |
    {stop, Reason :: term(), Reply :: term(), NewState :: #state{}} |
    {stop, Reason :: term(), NewState :: #state{}}).
handle_call(_Request, _From, State = #state{}) ->
    {reply, ok, State}.

%% @private
%% @doc Handling cast messages
-spec(handle_cast(Request :: term(), State :: #state{}) ->
    {noreply, NewState :: #state{}} |
    {noreply, NewState :: #state{}, timeout() | hibernate} |
    {stop, Reason :: term(), NewState :: #state{}}).
handle_cast(_Request, State = #state{}) ->
    {noreply, State}.

%% @private
%% @doc Handling all non call/cast messages
-spec(handle_info(Info :: timeout() | term(), State :: #state{}) ->
    {noreply, NewState :: #state{}} |
    {noreply, NewState :: #state{}, timeout() | hibernate} |
    {stop, Reason :: term(), NewState :: #state{}}).
handle_info({timeout, _, create_transport}, State = #state{}) ->
    case efka_transport:start_link(self()) of
        {ok, TransportPid} ->
            Ref = efka_transport:auth_request(TransportPid, 5000),
            receive
                 %% 验证通过
                {auth_reply, Ref, {ok, #auth_reply{code = 1, message = Message, repository_url = RepositoryUrl}}} ->
                    lager:debug("[efka_agent] auth result: ~p, repository_url: ~p", [Message, RepositoryUrl]),
                    {noreply, State#state{transport_pid = TransportPid, status = ?STATE_ACTIVATED}};

                %% 主机denied状态
                {auth_reply, Ref, {ok, #auth_reply{code = -1, message = Message, repository_url = RepositoryUrl}}} ->
                    lager:debug("[efka_agent] auth failed, message: ~p, repository_url: ~p", [Message, RepositoryUrl]),
                    {noreply, State};

                %% 验证不通过
                {auth_reply, Ref, {ok, #auth_reply{code = -2, message = Message, repository_url = RepositoryUrl}}} ->
                    lager:debug("[efka_agent] auth failed, message: ~p, repository_url: ~p", [Message, RepositoryUrl]),
                    {noreply, State};

                {auth_reply, Ref, {error, Reason}} ->
                    lager:debug("[efka_agent] auth_request failed, error: ~p", [Reason]),
                    {noreply, State}
            end;
        {error, Reason} ->
            lager:warning("[efka_agent] connect get error: ~p", [Reason]),
            {noreply, State}
    end;

handle_info({'EXIT', Pid, Reason}, State = #state{}) ->
    lager:debug("[efka_agent] transport pid: ~p, exit with reason: ~p", [Pid, Reason]),
    erlang:start_timer(5000, self(), create_transport),
    {noreply, State#state{transport_pid = undefined}};

handle_info(Info, State = #state{}) ->
    lager:debug("[efka_agent] get unknown info: ~p", [Info]),
    {noreply, State}.

%% @private
%% @doc This function is called by a gen_server when it is about to
%% terminate. It should be the opposite of Module:init/1 and do any
%% necessary cleaning up. When it returns, the gen_server terminates
%% with Reason. The return value is ignored.
-spec(terminate(Reason :: (normal | shutdown | {shutdown, term()} | term()),
        State :: #state{}) -> term()).
terminate(_Reason, _State = #state{}) ->
    ok.

%% @private
%% @doc Convert process state when code is changed
-spec(code_change(OldVsn :: term() | {down, term()}, State :: #state{},
        Extra :: term()) ->
    {ok, NewState :: #state{}} | {error, Reason :: term()}).
code_change(_OldVsn, State = #state{}, _Extra) ->
    {ok, State}.

%%%===================================================================
%%% Internal functions
%%%===================================================================