%%--------------------------------------------------------------------
%% Copyright (c) 2020-2024 EMQ Technologies Co., Ltd. All Rights Reserved.
%%
%% 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(emqx_exhook_sup).

-include("emqx_exhook.hrl").

-behaviour(supervisor).

-export([
    start_link/0,
    init/1
]).

-export([
    start_grpc_client_channel/3,
    stop_grpc_client_channel/1
]).

-define(DEFAULT_TIMEOUT, 5000).

-define(CHILD(Mod, Type, Args, Timeout), #{
    id => Mod,
    start => {Mod, start_link, Args},
    type => Type,
    shutdown => Timeout
}).

%% TODO: export_type:
%% grpc_client_sup:options/0
-type grpc_client_sup_options() :: map().

%%--------------------------------------------------------------------
%%  Supervisor APIs & Callbacks
%%--------------------------------------------------------------------

start_link() ->
    supervisor:start_link({local, ?MODULE}, ?MODULE, []).

init([]) ->
    _ = emqx_exhook_metrics:init(),
    _ = emqx_exhook_mgr:init_ref_counter_table(),
    Mngr = ?CHILD(emqx_exhook_mgr, worker, [], force_shutdown_timeout()),
    {ok, {{one_for_one, 10, 100}, [Mngr]}}.

%%--------------------------------------------------------------------
%% APIs
%%--------------------------------------------------------------------

-spec start_grpc_client_channel(
    binary(),
    uri_string:uri_string(),
    grpc_client_sup_options()
) -> {ok, pid()} | {error, term()}.
start_grpc_client_channel(Name, SvrAddr, Options) ->
    grpc_client_sup:create_channel_pool(Name, SvrAddr, Options).

-spec stop_grpc_client_channel(binary()) -> ok.
stop_grpc_client_channel(Name) ->
    %% Avoid crash due to hot-upgrade had unloaded
    %% grpc application
    try
        grpc_client_sup:stop_channel_pool(Name)
    catch
        _:_:_ ->
            ok
    end.

%% Calculate the maximum timeout, which will help to shutdown the
%% emqx_exhook_mgr process correctly.
force_shutdown_timeout() ->
    Factor = max(3, length(emqx:get_config([exhook, servers])) + 1),
    Factor * ?SERVER_FORCE_SHUTDOWN_TIMEOUT.