-module(bot_controller).
-include("records.hrl").

-export([register/0, stop/0, delete/0, count_bots/0]).

-define(REG_NAME, {bot_registration, node()}).

%% ------------------------------------------------------------------
%% @doc Асинхронно регистрирует ботов (одновременно только один процесс).
%% Возвращает pid процесса или ошибку.
%% ------------------------------------------------------------------
register() ->
  Count = list_to_integer(os:getenv("BOT_COUNT", "0")),
  Domain = list_to_binary(os:getenv("BOT_DOMAIN", "eventhub.com")),
  Password = list_to_binary(os:getenv("BOT_DEFAULT_PASSWORD", "botpass123")),
  if Count =< 0 ->
    {error, <<"BOT_COUNT must be greater than 0">>};
    true ->
      io:format("Starting async registration of ~p bots with domain ~s...~n", [Count, Domain]),
      Pid = spawn(fun() ->
        register_bots(Count, Domain, Password)
                  end),
      case global:register_name(?REG_NAME, Pid) of
        yes ->
          {ok, Pid};
        no ->
          % Уже есть активный процесс регистрации
          exit(Pid, kill),
          {error, registration_already_running}
      end
  end.

%% ------------------------------------------------------------------
%% @doc Останавливает текущий процесс регистрации.
%% ------------------------------------------------------------------
stop() ->
  case global:whereis_name(?REG_NAME) of
    undefined ->
      io:format("No active bot registration found.~n");
    Pid ->
      exit(Pid, kill),
      io:format("Bot registration process ~p stopped.~n", [Pid])
  end.

%% ------------------------------------------------------------------
%% @doc Удаляет всех пользователей с ролью bot.
%% ------------------------------------------------------------------
delete() ->
  Bots = mnesia:dirty_match_object(#user{role = bot, _ = '_'}),
  lists:foreach(fun(#user{id = Id}) ->
    mnesia:dirty_delete({user, Id})
                end, Bots),
  io:format("Deleted ~p bots.~n", [length(Bots)]),
  ok.

%% ------------------------------------------------------------------
%% @doc Возвращает количество ботов в базе.
%% ------------------------------------------------------------------
count_bots() ->
  length(mnesia:dirty_match_object(#user{role = bot, _ = '_'})).

%% ------------------------------------------------------------------
%% Внутренние функции
%% ------------------------------------------------------------------
register_bots(Count, Domain, Password) ->
  register_bots(Count, Domain, Password, []).

register_bots(0, _, _, Acc) ->
  io:format("Async registration completed. Created ~p bots.~n", [length(Acc)]),
  global:unregister_name(?REG_NAME);
register_bots(N, Domain, Password, Acc) ->
  Email = generate_email(Domain),
  case core_user:create_bot(Email, Password) of
    {ok, _User} ->
      register_bots(N-1, Domain, Password, [Email | Acc]);
    {error, duplicate_email} ->
      register_bots(N, Domain, Password, Acc);
    {error, _} ->
      register_bots(N-1, Domain, Password, Acc)
  end.

generate_email(Domain) ->
  Name = random_string(8),
  <<"bot_", Name/binary, "@", Domain/binary>>.

random_string(Length) ->
  Chars = <<"abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789">>,
  list_to_binary([lists:nth(rand:uniform(byte_size(Chars)), binary_to_list(Chars)) || _ <- lists:seq(1, Length)]).