Stage 3.3

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].