%%%-------------------------------------------------------------------
%%% @author anlicheng
%%% @copyright (C) 2024, <COMPANY>
%%% @doc
%%%
%%% @end
%%% Created : 07. 5月 2024 11:17
%%%-------------------------------------------------------------------
-module(endpoint_http).
-author("anlicheng").
-include("endpoint.hrl").

-behaviour(gen_server).

%% API
-export([start_link/2]).
-export([get_name/1, get_pid/1, forward/4, get_stat/1, cleanup/1]).

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

-define(SERVER, ?MODULE).

-record(state, {
    endpoint :: #endpoint{},
    buffer :: endpoint_buffer:buffer()
}).

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

-spec get_name(Name :: binary() | #endpoint{}) -> atom().
get_name(Id) when is_integer(Id) ->
    list_to_atom("endpoint:" ++ integer_to_list(Id)).

-spec get_pid(Id :: integer()) -> undefined | pid().
get_pid(Id) when is_integer(Id) ->
    whereis(get_name(Id)).

-spec forward(Pid :: undefined | pid(), LocationCode :: binary(), Fields :: list(), Timestamp :: integer()) -> no_return().
forward(undefined, _, _, _) ->
    ok;
forward(Pid, LocationCode, Fields, Timestamp) when is_pid(Pid), is_binary(LocationCode), is_list(Fields); is_binary(Fields), is_integer(Timestamp) ->
    gen_server:cast(Pid, {forward, LocationCode, Fields, Timestamp}).

-spec get_stat(Pid :: pid()) -> {ok, Stat :: #{}}.
get_stat(Pid) when is_pid(Pid) ->
    gen_server:call(Pid, get_stat, 5000).

-spec cleanup(Pid :: pid()) -> ok.
cleanup(Pid) when is_pid(Pid) ->
    gen_server:cast(Pid, cleanup).

%% @doc Spawns the server and registers the local name (unique)
-spec(start_link(Name, Endpoint :: #http_endpoint{}) ->
    {ok, Pid :: pid()} | ignore | {error, Reason :: term()}).
start_link(Name, Endpoint = #endpoint{config = #http_endpoint{}}) when is_atom(Name) ->
    gen_server:start_link({local, Name}, ?MODULE, [Endpoint], []).

%%%===================================================================
%%% 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([Endpoint]) ->
    Buffer = endpoint_buffer:new(Endpoint, 10),
    {ok, #state{endpoint = Endpoint, buffer = Buffer}}.

%% @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(get_stat, _From, State = #state{buffer = Buffer}) ->
    Stat = endpoint_buffer:stat(Buffer),
    {reply, {ok, Stat}, 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({forward, LocationCode, Fields, Timestamp}, State = #state{buffer = Buffer}) ->
    NBuffer = endpoint_buffer:append({LocationCode, Fields, Timestamp}, Buffer),
    {noreply, State#state{buffer = NBuffer}};

handle_cast(cleanup, State = #state{buffer = Buffer}) ->
    endpoint_buffer:cleanup(Buffer),
    {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({next_data, Id, _LocationCode, Body}, State = #state{buffer = Buffer, http_endpoint = #http_endpoint{url = Url}}) ->
    Headers = [
        {<<"content-type">>, <<"application/json">>}
    ],
    case hackney:request(post, Url, Headers, Body) of
        {ok, 200, _, ClientRef} ->
            {ok, RespBody} = hackney:body(ClientRef),
            hackney:close(ClientRef),
            lager:debug("[http_postman] url: ~p, response is: ~p", [Url, RespBody]),
            NBuffer = endpoint_buffer:ack(Buffer, Id),

            {noreply, State#state{buffer = NBuffer}};
        {ok, HttpCode, _, ClientRef} ->
            {ok, RespBody} = hackney:body(ClientRef),
            hackney:close(ClientRef),
            lager:debug("[http_postman] url: ~p, http_code: ~p, response is: ~p", [Url, HttpCode, RespBody]),
            {noreply, State};
        {error, Reason} ->
            lager:warning("[http_postman] url: ~p, get error: ~p", [Url, Reason]),
            {noreply, State}
    end.

%% @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
%%%===================================================================