feat: add birthday calendar feature with settings and localization

lib/birthday-calendar.ts

@@ -0,0 +1,199 @@
+import type { ContactCard, CalendarEvent, Calendar, PartialDate, Timestamp } from '@/lib/jmap/types';
+import { getContactDisplayName } from '@/stores/contact-store';
+import { format, eachYearOfInterval, parseISO } from 'date-fns';
+
+export const BIRTHDAY_CALENDAR_ID = '__birthday-calendar__';
+export const BIRTHDAY_CALENDAR_COLOR = '#eab308'; // Yellow
+
+/**
+ * Virtual calendar object for the contact birthday calendar.
+ */
+export function createBirthdayCalendar(name?: string, color?: string): Calendar {
+  return {
+    id: BIRTHDAY_CALENDAR_ID,
+    name: name || 'Birthdays',
+    description: null,
+    color: color || BIRTHDAY_CALENDAR_COLOR,
+    sortOrder: 999,
+    isSubscribed: true,
+    isVisible: true,
+    isDefault: false,
+    includeInAvailability: 'none',
+    defaultAlertsWithTime: null,
+    defaultAlertsWithoutTime: null,
+    timeZone: null,
+    shareWith: null,
+    myRights: {
+      mayReadFreeBusy: true,
+      mayReadItems: true,
+      mayWriteAll: false,
+      mayWriteOwn: false,
+      mayUpdatePrivate: false,
+      mayRSVP: false,
+      mayAdmin: false,
+      mayDelete: false,
+    },
+  };
+}
+
+/**
+ * Extract month and day from an AnniversaryDate.
+ * Returns null if the date cannot be parsed into month/day.
+ */
+function parseBirthdayDate(date: string | PartialDate | Timestamp): { month: number; day: number; year?: number } | null {
+  if (typeof date === 'string') {
+    // Could be ISO date string like "1990-05-15" or partial "--05-15"
+    if (date.startsWith('--')) {
+      // Partial date: --MM-DD
+      const match = date.match(/^--(\d{2})-(\d{2})$/);
+      if (match) {
+        return { month: parseInt(match[1], 10), day: parseInt(match[2], 10) };
+      }
+      return null;
+    }
+    try {
+      const parsed = parseISO(date);
+      if (!isNaN(parsed.getTime())) {
+        return {
+          month: parsed.getMonth() + 1,
+          day: parsed.getDate(),
+          year: parsed.getFullYear(),
+        };
+      }
+    } catch {
+      return null;
+    }
+    return null;
+  }
+
+  if ('utc' in date && date['@type'] === 'Timestamp') {
+    // Timestamp type
+    try {
+      const parsed = parseISO(date.utc);
+      if (!isNaN(parsed.getTime())) {
+        return {
+          month: parsed.getMonth() + 1,
+          day: parsed.getDate(),
+          year: parsed.getFullYear(),
+        };
+      }
+    } catch {
+      return null;
+    }
+    return null;
+  }
+
+  // PartialDate type
+  const partial = date as PartialDate;
+  if (partial.month && partial.day) {
+    return {
+      month: partial.month,
+      day: partial.day,
+      year: partial.year || undefined,
+    };
+  }
+
+  return null;
+}
+
+/**
+ * Generate virtual CalendarEvent objects from contacts that have birthday anniversaries.
+ * Events are generated for each year in the given date range.
+ */
+export function generateBirthdayEvents(
+  contacts: ContactCard[],
+  rangeStart: string,
+  rangeEnd: string,
+): CalendarEvent[] {
+  const events: CalendarEvent[] = [];
+  const start = parseISO(rangeStart);
+  const end = parseISO(rangeEnd);
+
+  if (isNaN(start.getTime()) || isNaN(end.getTime())) {
+    return events;
+  }
+
+  const years = eachYearOfInterval({ start, end });
+  // Also include the end date's year if not already covered
+  const endYear = end.getFullYear();
+  if (!years.some(y => y.getFullYear() === endYear)) {
+    years.push(new Date(endYear, 0, 1));
+  }
+
+  for (const contact of contacts) {
+    if (!contact.anniversaries) continue;
+
+    for (const [key, anniversary] of Object.entries(contact.anniversaries)) {
+      if (anniversary.kind !== 'birth') continue;
+
+      const parsed = parseBirthdayDate(anniversary.date);
+      if (!parsed) continue;
+
+      const displayName = getContactDisplayName(contact);
+      if (!displayName) continue;
+
+      for (const yearDate of years) {
+        const year = yearDate.getFullYear();
+        const monthStr = String(parsed.month).padStart(2, '0');
+        const dayStr = String(parsed.day).padStart(2, '0');
+        const eventStart = `${year}-${monthStr}-${dayStr}T00:00:00`;
+
+        // Check if this birthday occurrence falls within the date range
+        const occurrenceDate = new Date(year, parsed.month - 1, parsed.day);
+        if (occurrenceDate < start || occurrenceDate > end) continue;
+
+        const age = parsed.year ? year - parsed.year : undefined;
+        const ageText = age && age > 0 ? ` (${age})` : '';
+
+        const event: CalendarEvent = {
+          id: `birthday-${contact.id}-${key}-${year}`,
+          calendarIds: { [BIRTHDAY_CALENDAR_ID]: true },
+          isDraft: false,
+          isOrigin: false,
+          utcStart: null,
+          utcEnd: null,
+          '@type': 'Event',
+          uid: `birthday-${contact.id}-${key}`,
+          title: `🎂 ${displayName}${ageText}`,
+          description: '',
+          descriptionContentType: 'text/plain',
+          created: null,
+          updated: '',
+          sequence: 0,
+          start: eventStart,
+          duration: 'P1D',
+          timeZone: null,
+          showWithoutTime: true,
+          status: 'confirmed',
+          freeBusyStatus: 'free',
+          privacy: 'public',
+          color: null,
+          keywords: null,
+          categories: null,
+          locale: null,
+          replyTo: null,
+          organizerCalendarAddress: null,
+          participants: null,
+          mayInviteSelf: false,
+          mayInviteOthers: false,
+          hideAttendees: false,
+          recurrenceId: null,
+          recurrenceIdTimeZone: null,
+          recurrenceRules: null,
+          recurrenceOverrides: null,
+          excludedRecurrenceRules: null,
+          useDefaultAlerts: false,
+          alerts: null,
+          locations: null,
+          virtualLocations: null,
+          links: null,
+          relatedTo: null,
+        };
+
+        events.push(event);
+      }
+    }
+  }
+
+  return events;
+}