%%%-------------------------------------------------------------------
%%% @doc Обработчик обновления токена (клиентский API).
%%% POST – принимает refresh_token, возвращает новую пару access + refresh токенов.
%%% @end
%%%-------------------------------------------------------------------
-module(handler_refresh).
-behaviour(cowboy_handler).
-export([init/2]).
-export([trails/0]).

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

%%% Swagger metadata
-spec trails() -> [map()].
trails() ->
  [
    #{
      path => <<"/v1/refresh">>,
      method => <<"POST">>,
      description => <<"Refresh user access token using refresh token">>,
      tags => [<<"Auth">>],
      requestBody => #{
        required => true,
        content => #{
          <<"application/json">> => #{
            schema => #{
              type => object,
              required => [<<"refresh_token">>],
              properties => #{refresh_token => #{type => string}}
            }
          }
        }
      },
      responses => #{
        200 => #{
          description => <<"New user token pair (access + refresh)">>,
          content => #{
            <<"application/json">> => #{
              schema => token_pair_schema()
            }
          }
        },
        400 => #{description => <<"Missing refresh_token field or invalid JSON">>},
        401 => #{description => <<"Refresh token expired or not found">>}
      }
    }
  ].

token_pair_schema() ->
  #{
    type => object,
    properties => #{
      token => #{type => string, description => <<"JWT access token">>},
      refresh_token => #{type => string, description => <<"Refresh token">>}
    }
  }.

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

%% @doc POST /v1/refresh — обновление пользовательского токена.
-spec refresh(cowboy_req:req()) -> {ok, binary(), cowboy_req:req()}.
refresh(Req) ->
  {ok, Body, Req1} = cowboy_req:read_body(Req),
  try jsx:decode(Body, [return_maps]) of
    #{<<"refresh_token">> := RefreshToken} ->
      case logic_auth_session:refresh_user(RefreshToken) of
        {ok, NewToken, NewRefreshToken} ->
          handler_utils:send_json(Req1, 200, #{
            token => NewToken,
            refresh_token => NewRefreshToken
          });
        {error, reuse_detected} ->
          handler_utils:send_error(Req1, 401, <<"Refresh token reuse detected">>);
        {error, not_found} ->
          handler_utils:send_error(Req1, 401, <<"Refresh token not found">>);
        {error, expired} ->
          handler_utils:send_error(Req1, 401, <<"Refresh token expired">>);
        {error, revoked} ->
          handler_utils:send_error(Req1, 401, <<"Refresh token revoked">>);
        {error, _} ->
          handler_utils:send_error(Req1, 401, <<"Invalid refresh token">>)
      end;
    _ ->
      handler_utils:send_error(Req1, 400, <<"Missing refresh_token field">>)
  catch
    _:_ -> handler_utils:send_error(Req1, 400, <<"Invalid JSON">>)
  end.