Changelog

Two issues fixed:

1. Drag-and-drop event time changes were not setting SyncState to

"pending_push", so the next sync cycle's pull phase would see

content changes and overwrite the local edit with server data.

2. All CalDAV changes (edit, create, delete) waited up to 15 minutes

for the next scheduled sync to push. Now triggers an immediate

background sync for the affected subscription after any local

CalDAV event modification (save, drag-and-drop, delete).

Two bugs caused CalDAV all-day events to display on two days instead

of one (e.g., a birthday on Feb 24 showing on both Feb 24 and Feb 25):

1. IcsParserService: DATE-only values (DTSTART;VALUE=DATE:20260224)

were parsed with UTC offset (TimeSpan.Zero). When converted to

local time, midnight UTC shifts to the previous day in western

timezones. Now uses local timezone offset so the date is preserved.

2. CalendarViewModel: EventSpansDate and GetEventsForDate only adjusted

exclusive end dates for non-all-day events. Per RFC 5545, all-day

DTEND is exclusive (20260225 means "up to but not including Feb 25").

Now applies the -1 day adjustment for all-day events too.

The provider buttons in AddSubscriptionOverlay were hardcoded with no

command bindings — selecting iCloud or Google had no effect. This adds:

• Three toggle buttons (Generic/Nextcloud, iCloud, Google) bound to

SetCalDavProviderCommand with active-state highlighting

• Google Account picker (ComboBox) visible only when Google is selected
• Server URL field visible only for Generic provider
• Username/Password fields hidden when Google is selected
• xmlns:sdk namespace for ConnectionInfo DataTemplate

Wire the Calendar plugin into the existing shell-level Google OAuth

connection to support CalDAV sync with Google Calendar. Previously

the CalDavClient only supported HTTP Basic auth, which Google has

deprecated.

Changes:

• CalDavProviderType: add Google enum value
• CalDavCredentials: add BearerToken property (takes precedence

over Username/Password when set)

• CalDavClient: rename SetBasicAuth → SetAuth, support Bearer

authorization header for OAuth providers

• CalendarSubscription: add GoogleConnectionId field to persist

which Google OAuth account is linked to the subscription

• CalendarPlugin: implement IConnectionConsumer declaring Google

with calendar scope, pass IConnectionService through to sync

service and ViewModel

• AddSubscriptionViewModel: when provider is Google, load connected

Google accounts, skip username/password fields, use bearer token

for calendar discovery. Store GoogleConnectionId on subscription

• CalendarSyncService: add ResolveCalDavCredentialsAsync that

fetches OAuth bearer tokens from IConnectionService for Google

subscriptions, vault credentials for others

Google CalDAV endpoint: apidata.googleusercontent.com/caldav/v2

Setup: enable CalDAV API and Google Calendar API in Google Cloud

Console, then connect Google account in Settings → Connections.

Critical fixes:

• Delete propagation: CalDAV events now marked pending_delete instead of being

immediately removed from the store. The sync service handles the server DELETE

and local cleanup on the next cycle.

• Occurrence changes: Deleting or editing a single occurrence of a recurring

CalDAV event now marks the parent as pending_push so ExcludedDates propagate

to the server.

• Editor metadata: Editing a CalDAV event preserves SourceUid, CalDavEtag,

CalDavHref, and ExcludedDates from the original event, preventing silent

metadata wipe and broken ETag concurrency.

• Sync token initialization: After a full-fetch fallback (no token or expired

token), GetSyncTokenAsync PROPFIND acquires the current sync-token so

subsequent syncs use incremental sync-collection instead of full fetch.

• Multi-VEVENT resources: CalDAV resources containing multiple VEVENTs (parent

+ exception overrides) are now all processed, not just the first.

ICS parser/exporter improvements:

• EXDATE: Parse and export excluded dates for recurring events.
• VALARM: Parse TRIGGER durations from VALARM sub-components into

ReminderMinutes. Export reminders as VALARM blocks with proper duration

formatting (e.g., -P1D, -PT1H, -PT30M).

• Week duration: P#W format now correctly parsed as days (P1W = 7 days).
• UNTIL date-only: 8-char UNTIL values (e.g., UNTIL=20250301) now route

through the VALUE=DATE parser branch instead of floating-time.

• RECURRENCE-ID: Parsed into OriginalStart for CalDAV exception events.

Tests: 15 new test cases covering EXDATE, VALARM, week duration, UNTIL

date-only, RECURRENCE-ID, multi-VEVENT, and GetSyncTokenAsync.