Refactor/update icalendar (#3352)

* Remove ical weekday parsing code

I noticed that the icalendar package has already released a new
version containing the `vWeekday` fixes, so the hacky parsing code
can now be removed 🎉

- Upgrade the icalendar package
- replace the manual weekday parsing function with the icalendar
  functionality

Author: david-venhoff

integreat_cms/cms/utils/external_calendar_utils.py

@@ -7,7 +7,6 @@
 import dataclasses
 import datetime
 import logging
-import re
 from typing import Any, Self
 
 import icalendar.cal
@@ -28,11 +27,6 @@
 from integreat_cms.cms.models import EventTranslation, ExternalCalendar, RecurrenceRule
 from integreat_cms.cms.utils.content_utils import clean_content
 
-# Copied from https://github.com/collective/icalendar/blob/4725c1bd57ca3afe61e7d45805a2b337842fbd29/src/icalendar/prop.py#L68-L69
-WEEKDAY_RULE = re.compile(
-    r"(?P<signal>[+-]?)(?P<relative>[\d]{0,2})(?P<weekday>[\w]{2})$"
-)
-
 
 @dataclasses.dataclass(frozen=True, kw_only=True)
 class ImportResult:
@@ -196,7 +190,6 @@ class RecurrenceRuleData:
     def from_ical_rrule(
         cls, recurrence_rule: vRecur, start: datetime.date, logger: logging.Logger
     ) -> Self:
-        # pylint: disable=too-many-locals
         """
         Constructs this class from an ical recurrence rule.
         :return: An instance of this class
@@ -226,19 +219,17 @@ def pop_single_value(name: str, *, required: bool = False) -> Any:
 
         # by_set_pos can also be specified in `by_day`. We don't support multiple days with `by_set_pos` right now, though.
         if by_day and len(by_day) == 1:
-            set_pos, weekday = _parse_weekday(by_day[0])
-            if by_set_pos is not None and set_pos is not None:
+            if by_set_pos is not None and by_day[0].relative is not None:
                 raise ValueError(
                     f"Conflicting `BYSETPOS` and `BYDAY`: {by_set_pos} and {by_day}"
                 )
-            by_day[0] = weekday
-            by_set_pos = set_pos or by_set_pos
+            by_set_pos = by_day[0].relative or by_set_pos
+            by_day[0] = by_day[0].weekday
         elif by_day:
             updated_days = []
             for day in by_day:
-                set_pos, weekday = _parse_weekday(day)
-                updated_days.append(weekday)
-                if set_pos is not None:
+                updated_days.append(day.weekday)
+                if day.relative is not None:
                     raise ValueError(
                         f"Cannot support multiple days with frequency right now: {by_day}"
                     )
@@ -338,30 +329,6 @@ def decode_by_day(self) -> list[int]:
         return weekdays
 
 
-def _parse_weekday(weekdaynum: str) -> tuple[int | None, str]:
-    """
-    Parses a weekday according to https://www.rfc-editor.org/rfc/rfc5545#section-3.3.10 (see `weekdaynum`)
-    TODO: This should be handled by our icalendar package. Remove this code when a new version of icalendar is released.
-    :param weekdaynum: The weekday + frequency number
-    :return: A tuple of frequency and weekday, where the frequency is None if the weekdaynum only contained a weekday.
-    """
-    match = WEEKDAY_RULE.match(weekdaynum)
-    assert match is not None
-    sign = match["signal"]
-    ordinal_week_number = match["relative"]
-    weekday = match["weekday"]
-    if not ordinal_week_number:
-        return None, weekday
-    ordinal_week_number = int(ordinal_week_number)
-    match sign:
-        case "-":
-            return -ordinal_week_number, weekday
-        case "+" | "":
-            return ordinal_week_number, weekday
-        case _:
-            return None, weekday
-
-
 def import_events(calendar: ExternalCalendar, logger: logging.Logger) -> ImportResult:
     """
     Imports events from this calendar and sets or clears the errors field of the calendar

pyproject.toml

@@ -169,7 +169,7 @@ pinned = [
     "grpcio==1.66.2",
     "grpcio-status==1.66.2",
     "html5lib==1.1",
-    "icalendar==6.0.0",
+    "icalendar==6.1.1",
     "idna==3.10",
     "ipython==8.27.0",
     "jedi==0.19.1",