Add .ics calendar feed support

doot reads Google Calendar through a service account, by calendar ID. That
cannot consume an .ics URL, and it cannot see a calendar subscribed to inside a
personal Google account either, because Google does not allow re-sharing a
subscribed calendar. Published schedules — sports fixtures, school terms, bin
collections — are distributed almost exclusively as .ics, so none of them could
be added at all.

Feeds are now fetched on the normal calendar refresh and merged into
calendar_events alongside Google events, so the timeline, widget and everything
downstream keep seeing one list and needed no changes.

Failure handling is deliberately asymmetric. A Google error is still returned as
an error, unchanged, so an outage there surfaces. A single failing feed is
recorded against that feed and skipped, because one dead URL should not take the
whole calendar down — and last_error is shown in settings, since a feed that has
quietly stopped resolving otherwise looks identical to a team with no games
left.

The parser handles what real feeds actually contain: line unfolding, CRLF and
LF, UTC / TZID / VALUE=DATE times, and escaped text. Two details worth naming:
a TZID time is wall-clock in that zone, and reading it as UTC would put a 1:15pm
Pacific kickoff on the timeline at 1:15pm local — wrong by the offset but
entirely plausible-looking. And non-calendar content is a hard error rather than
zero events, because an HTML error page from a moved feed URL is the common
failure and "no events" reads as success.

RRULE is deliberately unsupported: every schedule feed this targets expands
recurrence itself, one VEVENT per fixture, and a correct expansion is a large
amount of subtle code. A recurring event appears once rather than wrongly.

Settings gains an add/enable/disable/remove UI. webcal:// links are accepted and
rewritten, since that is how feeds are usually advertised.

16 parser tests, 5 store tests. Verified against the real Seattle Seahawks feed:
21 events, all with valid times.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_018AwnALZL6bD4VBtATDVv3B

1 files changed, 95 insertions, 0 deletions

diff --git a/internal/store/ics_feeds.go b/internal/store/ics_feeds.go
new file mode 100644
index 0000000..6495e13
--- /dev/null
+++ b/internal/store/ics_feeds.go
@@ -0,0 +1,95 @@
+package store
+
+import (
+	"database/sql"
+	"time"
+)
+
+// ICSFeed is a subscribed iCalendar feed.
+type ICSFeed struct {
+	ID            int64
+	Name          string
+	URL           string
+	Enabled       bool
+	LastFetchedAt *time.Time
+	LastError     string
+	EventCount    int
+	CreatedAt     time.Time
+}
+
+// AddICSFeed stores a feed. Re-adding an existing URL updates its name and
+// re-enables it rather than failing on the unique constraint — "add it again"
+// is the obvious way to try to fix a feed that was turned off.
+func (s *Store) AddICSFeed(name, url string) error {
+	_, err := s.db.Exec(`
+		INSERT INTO ics_feeds (name, url, enabled)
+		VALUES (?, ?, 1)
+		ON CONFLICT(url) DO UPDATE SET name = excluded.name, enabled = 1
+	`, name, url)
+	return err
+}
+
+// GetICSFeeds returns every feed, enabled or not, newest name-order first.
+func (s *Store) GetICSFeeds() ([]ICSFeed, error) {
+	return s.queryICSFeeds(`
+		SELECT id, name, url, enabled, last_fetched_at, COALESCE(last_error, ''), event_count, created_at
+		FROM ics_feeds ORDER BY name`)
+}
+
+// GetEnabledICSFeeds returns only the feeds that should be fetched.
+func (s *Store) GetEnabledICSFeeds() ([]ICSFeed, error) {
+	return s.queryICSFeeds(`
+		SELECT id, name, url, enabled, last_fetched_at, COALESCE(last_error, ''), event_count, created_at
+		FROM ics_feeds WHERE enabled = 1 ORDER BY name`)
+}
+
+func (s *Store) queryICSFeeds(query string) ([]ICSFeed, error) {
+	rows, err := s.db.Query(query)
+	if err != nil {
+		return nil, err
+	}
+	defer func() { _ = rows.Close() }()
+
+	var feeds []ICSFeed
+	for rows.Next() {
+		var f ICSFeed
+		var lastFetched sql.NullTime
+		if err := rows.Scan(&f.ID, &f.Name, &f.URL, &f.Enabled, &lastFetched,
+			&f.LastError, &f.EventCount, &f.CreatedAt); err != nil {
+			return nil, err
+		}
+		if lastFetched.Valid {
+			t := lastFetched.Time
+			f.LastFetchedAt = &t
+		}
+		feeds = append(feeds, f)
+	}
+	return feeds, rows.Err()
+}
+
+// SetICSFeedEnabled turns a feed on or off without losing it.
+func (s *Store) SetICSFeedEnabled(id int64, enabled bool) error {
+	_, err := s.db.Exec(`UPDATE ics_feeds SET enabled = ? WHERE id = ?`, enabled, id)
+	return err
+}
+
+// DeleteICSFeed removes a feed entirely.
+func (s *Store) DeleteICSFeed(id int64) error {
+	_, err := s.db.Exec(`DELETE FROM ics_feeds WHERE id = ?`, id)
+	return err
+}
+
+// RecordICSFeedResult stores the outcome of a fetch. A successful fetch clears
+// any previous error, so a feed that recovers stops being reported as broken.
+func (s *Store) RecordICSFeedResult(id int64, eventCount int, fetchErr error) error {
+	errText := ""
+	if fetchErr != nil {
+		errText = fetchErr.Error()
+	}
+	_, err := s.db.Exec(`
+		UPDATE ics_feeds
+		SET last_fetched_at = CURRENT_TIMESTAMP, last_error = ?, event_count = ?
+		WHERE id = ?
+	`, errText, eventCount, id)
+	return err
+}