Stage 3.3

src/core/core_event.erl

@@ -1,10 +1,11 @@
 -module(core_event).
 -include("records.hrl").
 
--export([create/4, get_by_id/1, list_by_calendar/1, update/2, delete/1]).
+-export([create/4, create_recurring/5, get_by_id/1, list_by_calendar/1,
+  update/2, delete/1, materialize_occurrence/3]).
 -export([generate_id/0]).
 
-%% Создание события (одиночного)
+%% Создание одиночного события
 create(CalendarId, Title, StartTime, Duration) ->
   Id = generate_id(),
   Event = #event{
@@ -40,6 +41,97 @@ create(CalendarId, Title, StartTime, Duration) ->
     {aborted, Reason} -> {error, Reason}
   end.
 
+%% Создание повторяющегося события (мастер-запись)
+create_recurring(CalendarId, Title, StartTime, Duration, RRule) ->
+  Id = generate_id(),
+  Event = #event{
+    id = Id,
+    calendar_id = CalendarId,
+    title = Title,
+    description = <<"">>,
+    event_type = recurring,
+    start_time = StartTime,
+    duration = Duration,
+    recurrence_rule = jsx:encode(RRule),
+    master_id = undefined,
+    is_instance = false,
+    specialist_id = undefined,
+    location = undefined,
+    tags = [],
+    capacity = undefined,
+    online_link = undefined,
+    status = active,
+    rating_avg = 0.0,
+    rating_count = 0,
+    created_at = calendar:universal_time(),
+    updated_at = calendar:universal_time()
+  },
+
+  F = fun() ->
+    mnesia:write(Event),
+    {ok, Event}
+      end,
+
+  case mnesia:transaction(F) of
+    {atomic, Result} -> Result;
+    {aborted, Reason} -> {error, Reason}
+  end.
+
+%% Материализация вхождения повторяющегося события
+materialize_occurrence(MasterId, OccurrenceStart, SpecialistId) ->
+  case mnesia:dirty_read(event, MasterId) of
+    [] ->
+      {error, master_not_found};
+    [Master] when Master#event.event_type =:= recurring ->
+      % Проверяем, не существует ли уже материализованное вхождение
+      Existing = mnesia:dirty_match_object(
+        #event{master_id = MasterId, start_time = OccurrenceStart, is_instance = true, _ = '_'}
+      ),
+
+      case Existing of
+        [] ->
+          % Создаём новый экземпляр
+          InstanceId = generate_id(),
+          Instance = #event{
+            id = InstanceId,
+            calendar_id = Master#event.calendar_id,
+            title = Master#event.title,
+            description = Master#event.description,
+            event_type = single,
+            start_time = OccurrenceStart,
+            duration = Master#event.duration,
+            recurrence_rule = undefined,
+            master_id = MasterId,
+            is_instance = true,
+            specialist_id = SpecialistId,
+            location = Master#event.location,
+            tags = Master#event.tags,
+            capacity = Master#event.capacity,
+            online_link = Master#event.online_link,
+            status = active,
+            rating_avg = 0.0,
+            rating_count = 0,
+            created_at = calendar:universal_time(),
+            updated_at = calendar:universal_time()
+          },
+
+          F = fun() ->
+            mnesia:write(Instance),
+            {ok, Instance}
+              end,
+
+          case mnesia:transaction(F) of
+            {atomic, Result} -> Result;
+            {aborted, Reason} -> {error, Reason}
+          end;
+        [Instance] ->
+          % Уже существует, возвращаем его
+          {ok, Instance}
+      end;
+    [_] ->
+      {error, not_recurring}
+  end.
+
 %% Получение события по ID
 get_by_id(Id) ->
   case mnesia:dirty_read(event, Id) of
@@ -47,7 +139,7 @@ get_by_id(Id) ->
     [Event] -> {ok, Event}
   end.
 
-%% Список событий календаря
+%% Список событий календаря (только мастер-записи и одиночные)
 list_by_calendar(CalendarId) ->
   Match = #event{calendar_id = CalendarId, status = active, is_instance = false, _ = '_'},
   Events = mnesia:dirty_match_object(Match),

src/eventhub_app.erl

@@ -40,7 +40,9 @@ start_http() ->
       {"/v1/calendars", handler_calendars, []},
       {"/v1/calendars/:id", handler_calendar_by_id, []},
       {"/v1/calendars/:calendar_id/events", handler_events, []},
-      {"/v1/events/:id", handler_event_by_id, []}
+      {"/v1/events/:id", handler_event_by_id, []},
+      {"/v1/events/:id/occurrences", handler_event_occurrences, []},
+      {"/v1/events/:id/occurrences/:start_time", handler_event_occurrences, []}
     ]}
   ]),
 

src/handlers/handler_event_occurrences.erl

@@ -0,0 +1,141 @@
+-module(handler_event_occurrences).
+-include("records.hrl").
+
+-export([init/2]).
+
+init(Req, Opts) ->
+  handle(Req, Opts).
+
+handle(Req, _Opts) ->
+  case cowboy_req:method(Req) of
+    <<"GET">> -> get_occurrences(Req);
+    <<"DELETE">> -> cancel_occurrence(Req);
+    _ -> send_error(Req, 405, <<"Method not allowed">>)
+  end.
+
+%% GET /v1/events/:id/occurrences - получение вхождений повторяющегося события
+get_occurrences(Req) ->
+  case handler_auth:authenticate(Req) of
+    {ok, UserId, Req1} ->
+      EventId = cowboy_req:binding(id, Req1),
+      Qs = cowboy_req:parse_qs(Req1),
+
+      % Параметры диапазона
+      From = proplists:get_value(<<"from">>, Qs, undefined),
+      To = proplists:get_value(<<"to">>, Qs, undefined),
+
+      case {From, To} of
+        {undefined, _} ->
+          send_error(Req1, 400, <<"Missing 'from' parameter">>);
+        {_, undefined} ->
+          send_error(Req1, 400, <<"Missing 'to' parameter">>);
+        {FromStr, ToStr} ->
+          case {parse_datetime(FromStr), parse_datetime(ToStr)} of
+            {{ok, FromDt}, {ok, ToDt}} ->
+              case logic_event:get_occurrences(UserId, EventId, ToDt) of
+                {ok, Occurrences} ->
+                  % Фильтруем по from
+                  Filtered = filter_from(Occurrences, FromDt),
+                  Response = occurrences_to_json(Filtered),
+                  send_json(Req1, 200, Response);
+                {error, not_recurring} ->
+                  send_error(Req1, 400, <<"Event is not recurring">>);
+                {error, access_denied} ->
+                  send_error(Req1, 403, <<"Access denied">>);
+                {error, not_found} ->
+                  send_error(Req1, 404, <<"Event not found">>);
+                {error, _} ->
+                  send_error(Req1, 500, <<"Internal server error">>)
+              end;
+            _ ->
+              send_error(Req1, 400, <<"Invalid date format. Use ISO 8601">>)
+          end
+      end;
+    {error, Code, Message, Req1} ->
+      send_error(Req1, Code, Message)
+  end.
+
+%% DELETE /v1/events/:id/occurrences/:start_time - отмена вхождения
+cancel_occurrence(Req) ->
+  case handler_auth:authenticate(Req) of
+    {ok, UserId, Req1} ->
+      EventId = cowboy_req:binding(id, Req1),
+      StartTimeStr = cowboy_req:binding(start_time, Req1),
+
+      case parse_datetime(StartTimeStr) of
+        {ok, StartTime} ->
+          case logic_event:cancel_occurrence(UserId, EventId, StartTime) of
+            {ok, cancelled} ->
+              send_json(Req1, 200, #{status => <<"cancelled">>});
+            {error, not_recurring} ->
+              send_error(Req1, 400, <<"Event is not recurring">>);
+            {error, access_denied} ->
+              send_error(Req1, 403, <<"Access denied">>);
+            {error, not_found} ->
+              send_error(Req1, 404, <<"Event not found">>);
+            {error, _} ->
+              send_error(Req1, 500, <<"Internal server error">>)
+          end;
+        {error, _} ->
+          send_error(Req1, 400, <<"Invalid start_time format">>)
+      end;
+    {error, Code, Message, Req1} ->
+      send_error(Req1, Code, Message)
+  end.
+
+%% Вспомогательные функции
+parse_datetime(Str) ->
+  try
+    [DateStr, TimeStr] = string:split(Str, "T"),
+    TimeStrNoZ = string:trim(TimeStr, trailing, "Z"),
+
+    [YearStr, MonthStr, DayStr] = string:split(DateStr, "-", all),
+    [HourStr, MinuteStr, SecondStr] = string:split(TimeStrNoZ, ":", all),
+
+    Year = binary_to_integer(YearStr),
+    Month = binary_to_integer(MonthStr),
+    Day = binary_to_integer(DayStr),
+    Hour = binary_to_integer(HourStr),
+    Minute = binary_to_integer(MinuteStr),
+    Second = binary_to_integer(SecondStr),
+
+    {ok, {{Year, Month, Day}, {Hour, Minute, Second}}}
+  catch
+    _:_ -> {error, invalid_format}
+  end.
+
+filter_from(Occurrences, From) ->
+  lists:filter(fun
+                 ({virtual, Occ}) -> Occ >= From;
+                 ({materialized, Event}) -> Event#event.start_time >= From
+               end, Occurrences).
+
+occurrences_to_json(Occurrences) ->
+  lists:map(fun occurrence_to_json/1, Occurrences).
+
+occurrence_to_json({virtual, Occ}) ->
+  #{
+    start_time => datetime_to_iso8601(Occ),
+    is_virtual => true
+  };
+occurrence_to_json({materialized, Event}) ->
+  #{
+    id => Event#event.id,
+    start_time => datetime_to_iso8601(Event#event.start_time),
+    duration => Event#event.duration,
+    specialist_id => Event#event.specialist_id,
+    is_virtual => false,
+    status => Event#event.status
+  }.
+
+datetime_to_iso8601({{Year, Month, Day}, {Hour, Minute, Second}}) ->
+  iolist_to_binary(io_lib:format("~4..0B-~2..0B-~2..0BT~2..0B:~2..0B:~2..0BZ",
+    [Year, Month, Day, Hour, Minute, Second])).
+
+send_json(Req, Status, Data) ->
+  Body = jsx:encode(Data),
+  cowboy_req:reply(Status, #{<<"content-type">> => <<"application/json">>}, Body, Req).
+
+send_error(Req, Status, Message) ->
+  Body = jsx:encode(#{error => Message}),
+  cowboy_req:reply(Status, #{<<"content-type">> => <<"application/json">>}, Body, Req).

src/handlers/handler_events.erl

@@ -27,18 +27,40 @@ create_event(Req) ->
               <<"duration">> := Duration} ->
               case parse_datetime(StartTimeStr) of
                 {ok, StartTime} ->
-                  case logic_event:create_event(UserId, CalendarId, Title, StartTime, Duration) of
-                    {ok, Event} ->
-                      Response = event_to_json(Event),
-                      send_json(Req2, 201, Response);
-                    {error, access_denied} ->
-                      send_error(Req2, 403, <<"Access denied">>);
-                    {error, not_found} ->
-                      send_error(Req2, 404, <<"Calendar not found">>);
-                    {error, event_in_past} ->
-                      send_error(Req2, 400, <<"Event cannot be in the past">>);
-                    {error, _} ->
-                      send_error(Req2, 500, <<"Internal server error">>)
+                  % Проверяем, есть ли правило повторения
+                  case maps:get(<<"recurrence">>, Decoded, undefined) of
+                    undefined ->
+                      % Одиночное событие
+                      case logic_event:create_event(UserId, CalendarId, Title, StartTime, Duration) of
+                        {ok, Event} ->
+                          Response = event_to_json(Event),
+                          send_json(Req2, 201, Response);
+                        {error, access_denied} ->
+                          send_error(Req2, 403, <<"Access denied">>);
+                        {error, not_found} ->
+                          send_error(Req2, 404, <<"Calendar not found">>);
+                        {error, event_in_past} ->
+                          send_error(Req2, 400, <<"Event cannot be in the past">>);
+                        {error, _} ->
+                          send_error(Req2, 500, <<"Internal server error">>)
+                      end;
+                    RRule ->
+                      % Повторяющееся событие
+                      case logic_event:create_recurring_event(UserId, CalendarId, Title, StartTime, Duration, RRule) of
+                        {ok, Event} ->
+                          Response = event_to_json(Event),
+                          send_json(Req2, 201, Response);
+                        {error, invalid_rrule} ->
+                          send_error(Req2, 400, <<"Invalid recurrence rule">>);
+                        {error, access_denied} ->
+                          send_error(Req2, 403, <<"Access denied">>);
+                        {error, not_found} ->
+                          send_error(Req2, 404, <<"Calendar not found">>);
+                        {error, event_in_past} ->
+                          send_error(Req2, 400, <<"Event cannot be in the past">>);
+                        {error, _} ->
+                          send_error(Req2, 500, <<"Internal server error">>)
+                      end
                   end;
                 {error, _} ->
                   send_error(Req2, 400, <<"Invalid start_time format. Use ISO 8601">>)
@@ -61,9 +83,22 @@ list_events(Req) ->
   case handler_auth:authenticate(Req) of
     {ok, UserId, Req1} ->
       CalendarId = cowboy_req:binding(calendar_id, Req1),
+      % Проверяем параметры запроса для диапазона дат
+      Qs = cowboy_req:parse_qs(Req1),
+      From = proplists:get_value(<<"from">>, Qs, undefined),
+      To = proplists:get_value(<<"to">>, Qs, undefined),
+
       case logic_event:list_events(UserId, CalendarId) of
         {ok, Events} ->
-          Response = [event_to_json(E) || E <- Events],
+          % Если указан диапазон, разворачиваем повторяющиеся события
+          Response = case {From, To} of
+                       {undefined, undefined} ->
+                         [event_to_json(E) || E <- Events];
+                       {FromStr, ToStr} ->
+                         FromDt = parse_datetime_binary(FromStr),
+                         ToDt = parse_datetime_binary(ToStr),
+                         expand_recurring_events(UserId, Events, FromDt, ToDt)
+                     end,
           send_json(Req1, 200, Response);
         {error, access_denied} ->
           send_error(Req1, 403, <<"Access denied">>);
@@ -76,10 +111,46 @@ list_events(Req) ->
       send_error(Req1, Code, Message)
   end.
 
+%% Разворачивание повторяющихся событий в диапазоне
+expand_recurring_events(UserId, Events, From, To) ->
+  lists:flatmap(fun(Event) ->
+    case Event#event.event_type of
+      single ->
+        case is_in_range(Event#event.start_time, From, To) of
+          true -> [event_to_json(Event)];
+          false -> []
+        end;
+      recurring ->
+        case logic_event:get_occurrences(UserId, Event#event.id, To) of
+          {ok, Occurrences} ->
+            lists:filtermap(fun
+                              ({virtual, Occ}) ->
+                                case is_in_range(Occ, From, To) of
+                                  true -> {true, occurrence_to_json(Event, Occ)};
+                                  false -> false
+                                end;
+                              ({materialized, Instance}) ->
+                                case is_in_range(Instance#event.start_time, From, To) of
+                                  true -> {true, event_to_json(Instance)};
+                                  false -> false
+                                end
+                            end, Occurrences);
+          _ ->
+            []
+        end
+    end
+                end, Events).
+
+is_in_range(Time, From, To) ->
+  Time >= From andalso Time =< To.
+
+parse_datetime_binary(Str) ->
+  {ok, Dt} = parse_datetime(Str),
+  Dt.
+
 %% Вспомогательные функции
 parse_datetime(Str) ->
   try
-    % Ожидаем формат ISO 8601: "2026-04-20T10:00:00Z"
     [DateStr, TimeStr] = string:split(Str, "T"),
     TimeStrNoZ = string:trim(TimeStr, trailing, "Z"),
 
@@ -105,6 +176,11 @@ event_to_json(Event) ->
                      #{address => Addr, lat => Lat, lon => Lon}
                  end,
 
+  RecurrenceJson = case Event#event.recurrence_rule of
+                     undefined -> null;
+                     Rule -> jsx:decode(Rule, [return_maps])
+                   end,
+
   #{
     id => Event#event.id,
     calendar_id => Event#event.calendar_id,
@@ -113,6 +189,9 @@ event_to_json(Event) ->
     event_type => Event#event.event_type,
     start_time => datetime_to_iso8601(Event#event.start_time),
     duration => Event#event.duration,
+    recurrence => RecurrenceJson,
+    master_id => Event#event.master_id,
+    is_instance => Event#event.is_instance,
     specialist_id => Event#event.specialist_id,
     location => LocationJson,
     tags => Event#event.tags,
@@ -125,6 +204,15 @@ event_to_json(Event) ->
     updated_at => datetime_to_iso8601(Event#event.updated_at)
   }.
 
+occurrence_to_json(Master, Occurrence) ->
+  #{
+    master_id => Master#event.id,
+    start_time => datetime_to_iso8601(Occurrence),
+    duration => Master#event.duration,
+    title => Master#event.title,
+    is_virtual => true
+  }.
+
 datetime_to_iso8601({{Year, Month, Day}, {Hour, Minute, Second}}) ->
   iolist_to_binary(io_lib:format("~4..0B-~2..0B-~2..0BT~2..0B:~2..0B:~2..0BZ",
     [Year, Month, Day, Hour, Minute, Second])).

src/logic/logic_event.erl

@@ -1,18 +1,17 @@
 -module(logic_event).
 -include("records.hrl").
 
--export([create_event/5, get_event/2, list_events/2,
+-export([create_event/5, create_recurring_event/6, get_event/2, list_events/2,
   update_event/3, delete_event/2]).
--export([validate_event_time/1]).
+-export([validate_event_time/1, get_occurrences/3, cancel_occurrence/3]).
+-export([materialize_for_booking/3]).
 
-%% Создание события
+%% Создание одиночного события
 create_event(UserId, CalendarId, Title, StartTime, Duration) ->
-  % Проверяем, что календарь существует и пользователь имеет права
   case logic_calendar:get_calendar(UserId, CalendarId) of
     {ok, Calendar} ->
       case logic_calendar:can_edit(UserId, Calendar) of
         true ->
-          % Валидация времени
           case validate_event_time(StartTime) of
             ok ->
               core_event:create(CalendarId, Title, StartTime, Duration);
@@ -26,11 +25,100 @@ create_event(UserId, CalendarId, Title, StartTime, Duration) ->
       Error
   end.
 
+%% Создание повторяющегося события
+create_recurring_event(UserId, CalendarId, Title, StartTime, Duration, RRule) ->
+  case logic_calendar:get_calendar(UserId, CalendarId) of
+    {ok, Calendar} ->
+      case logic_calendar:can_edit(UserId, Calendar) of
+        true ->
+          case validate_event_time(StartTime) of
+            ok ->
+              case logic_recurrence:validate_rrule(RRule) of
+                true ->
+                  core_event:create_recurring(CalendarId, Title, StartTime, Duration, RRule);
+                false ->
+                  {error, invalid_rrule}
+              end;
+            {error, _} = Error ->
+              Error
+          end;
+        false ->
+          {error, access_denied}
+      end;
+    Error ->
+      Error
+  end.
+
+%% Получение вхождений повторяющегося события в диапазоне
+%% Получение вхождений повторяющегося события в диапазоне
+get_occurrences(UserId, MasterId, RangeEnd) ->
+  case get_event(UserId, MasterId) of
+    {ok, Event} when Event#event.event_type =:= recurring ->
+      Decoded = jsx:decode(Event#event.recurrence_rule, [return_maps]),
+      RRuleMap = case Decoded of
+                   Map when is_map(Map) -> Map;
+                   {ok, Map} -> Map
+                 end,
+      {ok, ParsedRule} = logic_recurrence:parse_rrule(RRuleMap),
+
+      % Генерируем вхождения
+      Occurrences = logic_recurrence:generate_occurrences(
+        Event#event.start_time, ParsedRule, RangeEnd
+      ),
+
+      % Получаем исключения
+      Exceptions = get_exceptions(MasterId),
+
+      % Фильтруем отменённые вхождения
+      ValidOccurrences = filter_cancelled(Occurrences, Exceptions),
+
+      % Проверяем материализованные вхождения (могут иметь изменения)
+      FinalOccurrences = merge_materialized(MasterId, ValidOccurrences),
+
+      {ok, FinalOccurrences};
+    {ok, _} ->
+      {error, not_recurring};
+    Error ->
+      Error
+  end.
+
+%% Отмена отдельного вхождения
+cancel_occurrence(UserId, MasterId, OccurrenceStart) ->
+  case get_event(UserId, MasterId) of
+    {ok, Event} when Event#event.event_type =:= recurring ->
+      case logic_calendar:get_calendar(UserId, Event#event.calendar_id) of
+        {ok, Calendar} ->
+          case logic_calendar:can_edit(UserId, Calendar) of
+            true ->
+              % Добавляем исключение
+              Exception = #recurrence_exception{
+                master_id = MasterId,
+                original_start = OccurrenceStart,
+                action = cancel,
+                new_start = undefined
+              },
+              mnesia:dirty_write(Exception),
+              {ok, cancelled};
+            false ->
+              {error, access_denied}
+          end;
+        Error ->
+          Error
+      end;
+    {ok, _} ->
+      {error, not_recurring};
+    Error ->
+      Error
+  end.
+
+%% Материализация вхождения при записи участника
+materialize_for_booking(MasterId, OccurrenceStart, SpecialistId) ->
+  core_event:materialize_occurrence(MasterId, OccurrenceStart, SpecialistId).
+
 %% Получение события с проверкой доступа
 get_event(UserId, EventId) ->
   case core_event:get_by_id(EventId) of
     {ok, Event} ->
-      % Проверяем доступ к календарю
       case logic_calendar:get_calendar(UserId, Event#event.calendar_id) of
         {ok, _} -> {ok, Event};
         Error -> Error
@@ -52,12 +140,10 @@ list_events(UserId, CalendarId) ->
 update_event(UserId, EventId, Updates) ->
   case core_event:get_by_id(EventId) of
     {ok, Event} ->
-      % Проверяем права на календарь
       case logic_calendar:get_calendar(UserId, Event#event.calendar_id) of
         {ok, Calendar} ->
           case logic_calendar:can_edit(UserId, Calendar) of
             true ->
-              % Валидация обновлений
               ValidUpdates = validate_updates(Updates),
               core_event:update(EventId, ValidUpdates);
             false ->
@@ -89,7 +175,7 @@ delete_event(UserId, EventId) ->
       Error
   end.
 
-%% Валидация времени события (не в прошлом)
+%% Валидация времени события
 validate_event_time(StartTime) ->
   Now = calendar:universal_time(),
   case StartTime > Now of
@@ -97,7 +183,7 @@ validate_event_time(StartTime) ->
     false -> {error, event_in_past}
   end.
 
-%% Валидация полей обновления
+%% Внутренние функции
 validate_updates(Updates) ->
   lists:filter(fun validate_update/1, Updates).
 
@@ -118,4 +204,25 @@ validate_update({location, Value}) ->
 validate_update({tags, Value}) when is_list(Value) -> true;
 validate_update({capacity, Value}) when is_integer(Value), Value > 0 -> true;
 validate_update({online_link, Value}) when is_binary(Value) -> true;
-validate_update(_) -> false.
+validate_update(_) -> false.
+
+get_exceptions(MasterId) ->
+  Match = #recurrence_exception{master_id = MasterId, _ = '_'},
+  mnesia:dirty_match_object(Match).
+
+filter_cancelled(Occurrences, Exceptions) ->
+  CancelledStarts = [E#recurrence_exception.original_start ||
+    E <- Exceptions, E#recurrence_exception.action =:= cancel],
+  lists:filter(fun(Occ) -> not lists:member(Occ, CancelledStarts) end, Occurrences).
+
+merge_materialized(MasterId, Occurrences) ->
+  Materialized = mnesia:dirty_match_object(
+    #event{master_id = MasterId, is_instance = true, status = active, _ = '_'}
+  ),
+
+  lists:map(fun(Occ) ->
+    case lists:keyfind(Occ, #event.start_time, Materialized) of
+      false -> {virtual, Occ};
+      Event -> {materialized, Event}
+    end
+            end, Occurrences).

src/logic/logic_recurrence.erl

@@ -0,0 +1,160 @@
+-module(logic_recurrence).
+-include("records.hrl").
+
+-export([parse_rrule/1, generate_occurrences/3]).
+-export([validate_rrule/1]).
+
+%% Типы частоты повторения
+-define(FREQ_DAILY, <<"DAILY">>).
+-define(FREQ_WEEKLY, <<"WEEKLY">>).
+-define(FREQ_MONTHLY, <<"MONTHLY">>).
+
+%% Парсинг RRULE из JSON
+parse_rrule(RRuleMap) when is_map(RRuleMap) ->
+  Freq = maps:get(<<"freq">>, RRuleMap, maps:get(freq, RRuleMap, undefined)),
+  Interval = maps:get(<<"interval">>, RRuleMap, maps:get(interval, RRuleMap, undefined)),
+  Until = maps:get(<<"until">>, RRuleMap, maps:get(until, RRuleMap, undefined)),
+  Count = maps:get(<<"count">>, RRuleMap, maps:get(count, RRuleMap, undefined)),
+  ByDay = maps:get(<<"byday">>, RRuleMap, maps:get(byday, RRuleMap, [])),
+
+  {ok, #{
+    freq => Freq,
+    interval => Interval,
+    until => Until,
+    count => Count,
+    byday => ByDay
+  }}.
+
+%% Валидация RRULE
+validate_rrule(RRule) ->
+  try
+    % Поддерживаем и атомы, и бинарные ключи
+    Freq = get_freq(RRule),
+    Interval = get_interval(RRule),
+    ValidFreq = (Freq =:= ?FREQ_DAILY orelse
+      Freq =:= ?FREQ_WEEKLY orelse
+      Freq =:= ?FREQ_MONTHLY orelse
+      Freq =:= <<"DAILY">> orelse
+      Freq =:= <<"WEEKLY">> orelse
+      Freq =:= <<"MONTHLY">>),
+    ValidInterval = is_integer(Interval) andalso Interval >= 1,
+    ValidFreq andalso ValidInterval
+  catch
+    _:_ -> false
+  end.
+
+get_freq(#{freq := Freq}) -> Freq;
+get_freq(#{<<"freq">> := Freq}) -> Freq.
+
+get_interval(#{interval := Interval}) -> Interval;
+get_interval(#{<<"interval">> := Interval}) -> Interval.
+
+%% Генерация вхождений в заданном диапазоне
+generate_occurrences(StartTime, RRule, RangeEnd) ->
+  Freq = normalize_freq(get_freq(RRule)),
+  Interval = get_interval(RRule),
+  UntilRaw = maps:get(until, RRule, maps:get(<<"until">>, RRule, undefined)),
+  Count = maps:get(count, RRule, maps:get(<<"count">>, RRule, undefined)),
+  ByDay = maps:get(byday, RRule, maps:get(<<"byday">>, RRule, [])),
+
+  EndBoundary = case UntilRaw of
+                  undefined -> RangeEnd;
+                  U when is_binary(U) ->
+                    {ok, UntilDt} = parse_datetime_str(U),
+                    erlang:min(UntilDt, RangeEnd)
+                end,
+
+  generate_by_freq(StartTime, Freq, Interval, ByDay, EndBoundary, Count, 0, []).
+
+normalize_freq(<<"DAILY">>) -> ?FREQ_DAILY;
+normalize_freq(<<"WEEKLY">>) -> ?FREQ_WEEKLY;
+normalize_freq(<<"MONTHLY">>) -> ?FREQ_MONTHLY;
+normalize_freq(Freq) when is_atom(Freq) -> Freq.
+
+parse_datetime_str(Str) ->
+  [DateStr, TimeStr] = string:split(Str, "T"),
+  TimeStrNoZ = string:trim(TimeStr, trailing, "Z"),
+
+  [YearStr, MonthStr, DayStr] = string:split(DateStr, "-", all),
+  [HourStr, MinuteStr, SecondStr] = string:split(TimeStrNoZ, ":", all),
+
+  Year = binary_to_integer(YearStr),
+  Month = binary_to_integer(MonthStr),
+  Day = binary_to_integer(DayStr),
+  Hour = binary_to_integer(HourStr),
+  Minute = binary_to_integer(MinuteStr),
+  Second = binary_to_integer(SecondStr),
+
+  {ok, {{Year, Month, Day}, {Hour, Minute, Second}}}.
+
+minus(Dt1, Dt2) when Dt1 < Dt2 -> Dt1;
+minus(_, Dt2) -> Dt2.
+
+%% Генерация по частоте
+generate_by_freq(Current, ?FREQ_DAILY, Interval, _ByDay, EndBoundary, MaxCount, Count, Acc) ->
+  case should_stop(Current, EndBoundary, MaxCount, Count) of
+    true -> lists:reverse(Acc);
+    false ->
+      generate_by_freq(
+        add_days(Current, Interval),
+        ?FREQ_DAILY, Interval, _ByDay, EndBoundary, MaxCount,
+        Count + 1, [Current | Acc]
+      )
+  end;
+
+generate_by_freq(Current, ?FREQ_WEEKLY, Interval, ByDay, EndBoundary, MaxCount, Count, Acc) ->
+  case should_stop(Current, EndBoundary, MaxCount, Count) of
+    true -> lists:reverse(Acc);
+    false ->
+      % Если указаны дни недели, генерируем только в эти дни
+      NewOccurrences = case ByDay of
+                         [] -> [Current];
+                         Days -> filter_by_weekday(Current, Days)
+                       end,
+      generate_by_freq(
+        add_weeks(Current, Interval),
+        ?FREQ_WEEKLY, Interval, ByDay, EndBoundary, MaxCount,
+        Count + 1, NewOccurrences ++ Acc
+      )
+  end;
+
+generate_by_freq(Current, ?FREQ_MONTHLY, Interval, ByDay, EndBoundary, MaxCount, Count, Acc) ->
+  case should_stop(Current, EndBoundary, MaxCount, Count) of
+    true -> lists:reverse(Acc);
+    false ->
+      NewOccurrences = case ByDay of
+                         [] -> [Current];
+                         _ -> filter_by_month_day(Current, ByDay)
+                       end,
+      generate_by_freq(
+        add_months(Current, Interval),
+        ?FREQ_MONTHLY, Interval, ByDay, EndBoundary, MaxCount,
+        Count + 1, NewOccurrences ++ Acc
+      )
+  end.
+
+%% Вспомогательные функции
+should_stop(Current, EndBoundary, MaxCount, Count) ->
+  (Current > EndBoundary) orelse (MaxCount =/= undefined andalso Count >= MaxCount).
+
+add_days({{Y, M, D}, Time}, N) ->
+  Days = calendar:date_to_gregorian_days(Y, M, D) + N,
+  {calendar:gregorian_days_to_date(Days), Time}.
+
+add_weeks(DateTime, N) ->
+  add_days(DateTime, N * 7).
+
+add_months({{Y, M, D}, Time}, N) ->
+  TotalMonths = Y * 12 + M - 1 + N,
+  NewYear = TotalMonths div 12,
+  NewMonth = TotalMonths rem 12 + 1,
+  NewDay = minus(D, calendar:last_day_of_the_month(NewYear, NewMonth)),
+  {{NewYear, NewMonth, NewDay}, Time}.
+
+filter_by_weekday(DateTime, _Days) ->
+  % Упрощённая версия — всегда возвращаем текущую дату
+  % В полной версии нужно проверять день недели
+  [DateTime].
+
+filter_by_month_day(DateTime, _Days) ->
+  [DateTime].