Scheduler: convert recurrence class to pure functions (#31054)

Co-authored-by: Vladimir Bushmanov <[email protected]>

Author: Ambrozy

packages/devextreme/js/__internal/scheduler/appointments/appointment/m_appointment.ts

@@ -23,8 +23,8 @@ import {
   REDUCED_APPOINTMENT_ICON,
   REDUCED_APPOINTMENT_PARTS_CLASSES,
 } from '../../m_classes';
-import { getRecurrenceProcessor } from '../../m_recurrence';
 import type { SubscribeKey, SubscribeMethods } from '../../m_subscribes';
+import { validateRRule } from '../../recurrence/validate_rule';
 import type { AppointmentDataAccessor } from '../../utils/data_accessor/appointment_data_accessor';
 import type { AppointmentProperties } from './m_types';
 import {
@@ -270,7 +270,7 @@ export class Appointment extends DOMComponent<AppointmentProperties> {
   _renderRecurrenceClass() {
     const rule = this.dataAccessors.get('recurrenceRule', this.rawAppointment);
 
-    if (getRecurrenceProcessor().isValidRecurrenceRule(rule)) {
+    if (validateRRule(rule)) {
       (this.$element() as any).addClass(RECURRENCE_APPOINTMENT_CLASS);
     }
   }

packages/devextreme/js/__internal/scheduler/appointments/m_appointment_collection.ts

@@ -26,8 +26,8 @@ import { dateUtilsTs } from '@ts/core/utils/date';
 
 import { APPOINTMENT_SETTINGS_KEY } from '../constants';
 import { APPOINTMENT_CONTENT_CLASSES, APPOINTMENT_DRAG_SOURCE_CLASS, APPOINTMENT_ITEM_CLASS } from '../m_classes';
-import { getRecurrenceProcessor } from '../m_recurrence';
 import timeZoneUtils from '../m_utils_time_zone';
+import { generateDates } from '../recurrence/generate_dates';
 import type { CompactAppointmentOptions } from '../types';
 import { AppointmentAdapter } from '../utils/appointment_adapter/appointment_adapter';
 import type { AppointmentDataAccessor } from '../utils/data_accessor/appointment_data_accessor';
@@ -1070,7 +1070,7 @@ class SchedulerAppointments extends CollectionWidget {
 
       const timezoneCalculator = this.option('timeZoneCalculator');
 
-      const recurrentDates = getRecurrenceProcessor().generateDates({
+      const recurrentDates = generateDates({
         rule: recurrenceRule,
         exception: recurrenceException,
         start: startDate,