fix: sync sadhna calendar with local timezone

internal/service/sadhna_service.go

@@ -79,10 +79,33 @@ func NewSadhnaService(
 
 const dayFmt = "2006-01-02"
 
-// utcToday returns today's UTC calendar date truncated to midnight, the
-// anchor every day-bucket comparison uses.
-func utcToday() time.Time {
-	now := time.Now().UTC()
+// fallbackTZ is used when the user has no stored timezone — the sādhana day
+// boundary (and thus the nightly chant reset) defaults to India time.
+const fallbackTZ = "Asia/Kolkata"
+
+// resolveTZ returns the user's IANA timezone name + loaded location, falling
+// back to Asia/Kolkata (then UTC) so the day boundary is always defined.
+func (s *SadhnaService) resolveTZ(ctx context.Context, userID string) (string, *time.Location) {
+	tz, _ := s.logs.UserTimezone(ctx, userID)
+	if tz == "" {
+		tz = fallbackTZ
+	}
+	loc, err := time.LoadLocation(tz)
+	if err != nil {
+		tz = fallbackTZ
+		if loc, err = time.LoadLocation(fallbackTZ); err != nil {
+			return "UTC", time.UTC
+		}
+	}
+	return tz, loc
+}
+
+// todayIn returns the current calendar date in loc, anchored at UTC midnight
+// so it round-trips cleanly through Postgres DATE columns and dayFmt. This is
+// the anchor every day-bucket comparison uses — the day rolls over at the
+// user's local midnight.
+func todayIn(loc *time.Location) time.Time {
+	now := time.Now().In(loc)
 	return time.Date(now.Year(), now.Month(), now.Day(), 0, 0, 0, 0, time.UTC)
 }
 
@@ -99,7 +122,10 @@ func (s *SadhnaService) SaveChant(ctx context.Context, userID string, rounds int
 	target := s.targetFor(ctx, userID)
 	chantDone := rounds >= target
 
-	if _, err := s.logs.UpsertToday(ctx, userID, utcToday(), rounds, chantDone); err != nil {
+	// Bucket against the user's local "today" so progress resets at their
+	// local midnight (fallback Asia/Kolkata), not UTC midnight.
+	_, loc := s.resolveTZ(ctx, userID)
+	if _, err := s.logs.UpsertToday(ctx, userID, todayIn(loc), rounds, chantDone); err != nil {
 		return nil, err
 	}
 	return s.Dashboard(ctx, userID)
@@ -109,14 +135,15 @@ func (s *SadhnaService) SaveChant(ctx context.Context, userID string, rounds int
 // logs and quote posts over the trailing window.
 func (s *SadhnaService) Dashboard(ctx context.Context, userID string) (*model.SadhnaDashboard, error) {
 	target := s.targetFor(ctx, userID)
-	today := utcToday()
+	tz, loc := s.resolveTZ(ctx, userID)
+	today := todayIn(loc)
 	since := today.AddDate(0, 0, -(streakWindowDays - 1))
 
 	logs, err := s.logs.ListSince(ctx, userID, since)
 	if err != nil {
 		return nil, err
 	}
-	postsByDay, err := s.posts.PostCountsByDate(ctx, userID, since)
+	postsByDay, err := s.posts.PostCountsByDate(ctx, userID, since, tz)
 	if err != nil {
 		return nil, err
 	}
@@ -361,11 +388,12 @@ func (s *SadhnaService) AckRewards(ctx context.Context, userID string) error {
 // arbitrary week or month. Days with no activity (including future days)
 // come back as all-false. The caller is expected to bound the range.
 func (s *SadhnaService) History(ctx context.Context, userID string, from, to time.Time) ([]model.SadhnaDay, error) {
+	tz, _ := s.resolveTZ(ctx, userID)
 	logs, err := s.logs.ListSince(ctx, userID, from)
 	if err != nil {
 		return nil, err
 	}
-	postsByDay, err := s.posts.PostCountsByDate(ctx, userID, from)
+	postsByDay, err := s.posts.PostCountsByDate(ctx, userID, from, tz)
 	if err != nil {
 		return nil, err
 	}