Add virtual Birthdays calendar computed from contacts

The combined month view now always includes a read-only "Birthdays" calendar (ref "@birthdays"), generated on the fly from every contact's BDAY field across the user's address books — no calendar objects are stored for it. Each birthday appears as an all-day event titled "🎂 Name (Age)" (age omitted if BDAY has no year, e.g. "--MM-DD"), colored pink, and links to the contact's edit page instead of an event editor. Handles both "YYYY-MM-DD"/"YYYYMMDD" and year-less vCard BDAY formats, and skips Feb 29 birthdays in non-leap years. Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
2026-08-20 19:27:55 +02:00
parent adabfd22ca
commit cd96b365d0
3 changed files with 315 additions and 111 deletions
@@ -16,6 +16,7 @@ import (
 	"time"

 	ical "github.com/emersion/go-ical"
+	vcard "github.com/emersion/go-vcard"
 	"github.com/yourusername/caldav-server/internal/db"
 	"github.com/yourusername/caldav-server/internal/web/templates"
 )
@@ -82,6 +83,11 @@ func (s *Server) ownsCalendar(username, cal string) (bool, error) {
 // store.Store/db.DB. If requireWrite is true, a read-only share is
 // rejected with errCalendarReadOnly.
 func (s *Server) resolveCalRef(username, ref string, requireWrite bool) (owner, name string, err error) {
+	if ref == birthdaysCalRef {
+		// The birthdays calendar is virtual/computed, not backed by any
+		// stored calendar object — there's nothing to resolve to.
+		return "", "", errCalendarNotFound
+	}
 	if owner, name, ok := strings.Cut(ref, calRefSep); ok {
 		if !resourceNameRe.MatchString(owner) || !resourceNameRe.MatchString(name) {
 			return "", "", errCalendarNotFound
@@ -117,13 +123,28 @@ type calendarEntry struct {
 	Name     string // calendar's own name (unqualified)
 	Color    string
 	Writable bool
+	Virtual  bool // true for computed calendars (e.g. birthdays) with no backing store objects
 }

-// listCalendarEntries returns every calendar visible to username: their
-// own calendars (always writable) plus any calendars shared with them
-// (writable only if the share grants write permission).
+// birthdaysCalRef is the fixed reference for the synthetic "Birthdays"
+// calendar. It deliberately can't collide with a real calendar's ref: "@"
+// is not in resourceNameRe's character class (so it can't be a bare own
+// calendar name) and it contains no calRefSep ("~") (so it can't be
+// mistaken for an "owner~name" shared-calendar ref either).
+const birthdaysCalRef = "@birthdays"
+
+// birthdayColor is the fixed display color for the virtual birthdays
+// calendar (a pink, distinct from typical user-picked calendar colors).
+const birthdayColor = "#ec4899"
+
+// listCalendarEntries returns every calendar visible to username: the
+// synthetic birthdays calendar, their own calendars (always writable),
+// and any calendars shared with them (writable only if the share grants
+// write permission).
 func (s *Server) listCalendarEntries(username string) ([]calendarEntry, error) {
-	var entries []calendarEntry
+	entries := []calendarEntry{
+		{Ref: birthdaysCalRef, Owner: username, Name: "Birthdays", Color: birthdayColor, Writable: false, Virtual: true},
+	}

 	own, err := s.dbase.ListCalendars(username)
 	if err != nil {
@@ -241,9 +262,16 @@ func (s *Server) buildMonthView(username string, year int, month time.Month) (te
 		}
 		calSummaries = append(calSummaries, templates.CalendarSummary{
 			Ref: entry.Ref, Name: entry.Name, Owner: entry.Owner, Color: entry.Color,
-			Shared: entry.Owner != username, Writable: entry.Writable,
+			Shared: entry.Owner != username, Writable: entry.Writable, Virtual: entry.Virtual,
 		})

+		if entry.Ref == birthdaysCalRef {
+			if err := s.addBirthdayEvents(username, entry, gridStart, gridEnd, dayIndex, days); err != nil {
+				s.logger.Warn("computing birthday events", "error", err)
+			}
+			continue
+		}
+
 		ids, err := s.store.ListObjects(entry.Owner, "cal-"+entry.Name)
 		if err != nil {
 			continue
@@ -944,3 +972,145 @@ func (s *Server) handleCalendarImport(w http.ResponseWriter, r *http.Request) {

 	http.Redirect(w, r, "/web/calendar?imported="+strconv.Itoa(imported), http.StatusSeeOther)
 }
+
+// birthdayContact holds one contact's parsed birthday, ready to be placed
+// on the month grid.
+type birthdayContact struct {
+	Name  string
+	Book  string
+	ID    string
+	Month time.Month
+	Day   int
+	Year  int // 0 if the vCard's BDAY has no year (e.g. "--08-20")
+}
+
+// birthdayFullRe matches a BDAY value that includes a year, in either
+// "YYYY-MM-DD" or the older vCard 3.0 "YYYYMMDD" form.
+var birthdayFullRe = regexp.MustCompile(`^(\d{4})-?(\d{2})-?(\d{2})`)
+
+// birthdayNoYearRe matches a year-less BDAY value per RFC 6350 §4.3.1,
+// "--MM-DD" or "--MMDD".
+var birthdayNoYearRe = regexp.MustCompile(`^--(\d{2})-?(\d{2})`)
+
+// parseBirthday extracts month/day (and year, if present) from a vCard
+// BDAY field value. Returns ok=false if v isn't a recognized date format
+// or names an impossible month/day.
+func parseBirthday(v string) (month time.Month, day int, year int, ok bool) {
+	v = strings.TrimSpace(v)
+	if m := birthdayNoYearRe.FindStringSubmatch(v); m != nil {
+		mo, _ := strconv.Atoi(m[1])
+		d, _ := strconv.Atoi(m[2])
+		if mo < 1 || mo > 12 || d < 1 || d > 31 {
+			return 0, 0, 0, false
+		}
+		return time.Month(mo), d, 0, true
+	}
+	if m := birthdayFullRe.FindStringSubmatch(v); m != nil {
+		y, _ := strconv.Atoi(m[1])
+		mo, _ := strconv.Atoi(m[2])
+		d, _ := strconv.Atoi(m[3])
+		if mo < 1 || mo > 12 || d < 1 || d > 31 {
+			return 0, 0, 0, false
+		}
+		return time.Month(mo), d, y, true
+	}
+	return 0, 0, 0, false
+}
+
+// collectBirthdays scans every one of username's own address books for
+// contacts with a parseable BDAY field.
+func (s *Server) collectBirthdays(username string) ([]birthdayContact, error) {
+	books, err := s.dbase.ListAddressBooks(username)
+	if err != nil {
+		return nil, err
+	}
+
+	var contacts []birthdayContact
+	for _, book := range books {
+		ids, err := s.store.ListObjects(username, "card-"+book)
+		if err != nil {
+			continue
+		}
+		for _, id := range ids {
+			data, err := s.store.GetObject(username, "card-"+book, id)
+			if err != nil {
+				continue
+			}
+			card, err := vcard.NewDecoder(bytes.NewReader(data)).Decode()
+			if err != nil {
+				continue
+			}
+			bday := card.PreferredValue(vcard.FieldBirthday)
+			if bday == "" {
+				continue
+			}
+			month, day, year, ok := parseBirthday(bday)
+			if !ok {
+				continue
+			}
+			name := card.PreferredValue(vcard.FieldFormattedName)
+			if name == "" {
+				name = id
+			}
+			contacts = append(contacts, birthdayContact{
+				Name: name, Book: book, ID: id, Month: month, Day: day, Year: year,
+			})
+		}
+	}
+	return contacts, nil
+}
+
+// addBirthdayEvents places one virtual all-day event per contact
+// birthday falling within [gridStart, gridEnd] into days, titled
+// "🎂 Name" (or "🎂 Name (Age)" when the birth year is known). Each event
+// links to the contact's edit page instead of an event edit page, since
+// there is no underlying calendar object to edit.
+func (s *Server) addBirthdayEvents(username string, entry calendarEntry, gridStart, gridEnd time.Time, dayIndex map[string]int, days []templates.MonthDay) error {
+	contacts, err := s.collectBirthdays(username)
+	if err != nil {
+		return err
+	}
+	if len(contacts) == 0 {
+		return nil
+	}
+
+	// The 42-day grid can span at most two calendar years (e.g. a
+	// December/January boundary), so only those years' occurrences need
+	// checking.
+	years := []int{gridStart.Year()}
+	if gridEnd.Year() != gridStart.Year() {
+		years = append(years, gridEnd.Year())
+	}
+
+	for _, c := range contacts {
+		for _, year := range years {
+			occurrence := time.Date(year, c.Month, c.Day, 0, 0, 0, 0, gridStart.Location())
+			// Guard against date normalization (e.g. Feb 29 in a
+			// non-leap year rolling over into March) placing the event
+			// on the wrong day.
+			if occurrence.Month() != c.Month || occurrence.Day() != c.Day {
+				continue
+			}
+			if occurrence.Before(gridStart) || occurrence.After(gridEnd) {
+				continue
+			}
+			idx, ok := dayIndex[occurrence.Format(dateLayout)]
+			if !ok {
+				continue
+			}
+			summary := "🎂 " + c.Name
+			if c.Year > 0 {
+				summary += fmt.Sprintf(" (%d)", year-c.Year)
+			}
+			days[idx].Events = append(days[idx].Events, templates.EventSummary{
+				ID:      c.Book + "/" + c.ID,
+				CalRef:  entry.Ref,
+				Color:   entry.Color,
+				Summary: summary,
+				AllDay:  true,
+				LinkURL: "/web/contacts/" + c.Book + "/" + c.ID + "/edit",
+			})
+		}
+	}
+	return nil
+}