%%%-------------------------------------------------------------------
%%% @doc Обработчик регистрации пользователя (клиентский API).
%%% POST – создаёт нового пользователя (статус pending), возвращает
%%%        информацию о пользователе без JWT токена.
%%% @end
%%%-------------------------------------------------------------------
-module(handler_register).
-behaviour(cowboy_handler).

-export([init/2]).
-export([trails/0]).

-include("records.hrl").

%%% cowboy_handler callback
-spec init(cowboy_req:req(), any()) -> {ok, cowboy_req:req(), any()}.
init(Req, Opts) ->
  handle(Req, Opts).

%%% Swagger metadata
-spec trails() -> [map()].
trails() ->
  [
    #{
      path        => <<"/v1/register">>,
      method      => <<"POST">>,
      description => <<"Register a new user (account will be pending until email verified)">>,
      tags        => [<<"Auth">>],
      requestBody => #{
        required => true,
        content  => #{<<"application/json">> => #{schema => #{
          type       => object,
          required   => [<<"email">>, <<"password">>],
          properties => #{
            email    => #{type => string, format => <<"email">>},
            password => #{type => string, format => <<"password">>}
          }
        }}}
      },
      responses => #{
        201 => #{description => <<"User registered successfully (pending verification)">>},
        400 => #{description => <<"Missing email or password, or invalid JSON">>},
        409 => #{description => <<"Email already exists">>}
      }
    }
  ].

%%%===================================================================
%%% HTTP-методы
%%%===================================================================

%% @private
-spec handle(cowboy_req:req(), any()) -> {ok, cowboy_req:req(), any()}.
handle(Req, _Opts) ->
  case cowboy_req:method(Req) of
    <<"POST">> -> register(Req);
    _          -> handler_utils:send_error(Req, 405, <<"Method not allowed">>)
  end.

%% @doc POST /v1/register — регистрация нового пользователя.
-spec register(cowboy_req:req()) -> {ok, binary(), cowboy_req:req()}.
register(Req) ->
  case cowboy_req:has_body(Req) of
    true ->
      {ok, Body, Req1} = cowboy_req:read_body(Req),
      case Body of
        <<>> ->
          handler_utils:send_error(Req1, 400, <<"Empty request body">>);
        _ ->
          try jsx:decode(Body, [return_maps]) of
            #{<<"email">> := Email, <<"password">> := Password} ->
              case core_user:email_exists(Email) of
                true ->
                  handler_utils:send_error(Req1, 409, <<"Email already exists">>);
                false ->
                  case core_user:create(Email, Password) of
                    {ok, User} ->
                      % Создаём верификационный токен и отправляем письмо
                      {ok, VerificationToken, _Expires} = core_verification:create_token(User#user.id),
                      logic_email:send_verification_email(Email, VerificationToken),
                      Response = #{
                        user  => #{
                          id     => User#user.id,
                          email  => User#user.email,
                          role   => atom_to_binary(User#user.role, utf8),
                          status => atom_to_binary(User#user.status, utf8)  % <<"pending">>
                        }
                      },
                      handler_utils:send_json(Req1, 201, Response);
                    {error, email_exists} ->
                      handler_utils:send_error(Req1, 409, <<"Email already exists">>);
                    {error, _} ->
                      handler_utils:send_error(Req1, 500, <<"Internal server error">>)
                  end
              end;
            _ ->
              handler_utils:send_error(Req1, 400, <<"Missing email or password">>)
          catch
            _:_ -> handler_utils:send_error(Req1, 400, <<"Invalid JSON">>)
          end
      end;
    false ->
      handler_utils:send_error(Req, 400, <<"Missing request body">>)
  end.