Handle no avatar, add delete avatar support

backend/internal/user/repository.go

@@ -179,6 +179,28 @@ func (r *Repository) SetAvatar(ctx context.Context, id int64, data []byte) error
 	return nil
 }
 
+func (r *Repository) DeleteAvatar(ctx context.Context, id int64) error {
+	query := "DELETE FROM avatars WHERE id = ?"
+	_, err := r.q.ExecContext(ctx, query, id)
+	if err != nil {
+		slog.Error("delete avatar", slog.String("op", "repo.DeleteAvatar"), slog.Int64("user_id", id), slog.Any("error", err))
+		return ErrInternal
+	}
+	return nil
+}
+
+// HasAvatar reports whether the user currently has an avatar stored.
+func (r *Repository) HasAvatar(ctx context.Context, id int64) (bool, error) {
+	query := "SELECT EXISTS(SELECT 1 FROM avatars WHERE id = ?)"
+	var exists bool
+	err := r.q.QueryRowContext(ctx, query, id).Scan(&exists)
+	if err != nil {
+		slog.Error("has avatar", slog.String("op", "repo.HasAvatar"), slog.Int64("user_id", id), slog.Any("error", err))
+		return false, ErrInternal
+	}
+	return exists, nil
+}
+
 func (r *Repository) CleanupUsers(ctx context.Context) error {
 	query := "DELETE FROM users WHERE activated_at IS NULL and created_at < ?"
 	_, err := r.q.ExecContext(ctx, query, time.Now().UTC().Add(-5*time.Minute))

backend/internal/user/service.go

@@ -163,6 +163,17 @@ func (s *Service) Avatar(ctx context.Context, user *User) ([]byte, error) {
 	return s.r.Avatar(ctx, user.Id)
 }
 
+// DeleteAvatar removes a user's avatar. It is a no-op when no avatar is stored,
+// so the operation is idempotent.
+func (s *Service) DeleteAvatar(ctx context.Context, user *User) error {
+	return s.r.DeleteAvatar(ctx, user.Id)
+}
+
+// HasAvatar reports whether the user currently has an avatar stored.
+func (s *Service) HasAvatar(ctx context.Context, user *User) (bool, error) {
+	return s.r.HasAvatar(ctx, user.Id)
+}
+
 func (s *Service) ActivateUser(ctx context.Context, user *User) (*User, error) {
 	tx, err := s.r.Db.BeginTx(ctx, nil)
 	if err != nil {