feat: backend service

backend/internal/notification/cascade.go

@@ -0,0 +1,35 @@
+package notification
+
+import (
+	"context"
+
+	"github.com/google/uuid"
+	"go.uber.org/zap"
+)
+
+// OnUserDeleted is the user-side soft-delete cascade hook. It marks
+// every pending or retrying route owned by userID as `skipped` so the
+// worker stops trying to deliver to a vanished account; published
+// rows stay intact as audit trail.
+//
+// The catalog (`backend/README.md` §10) does not include a
+// `user.*` kind, so this is the only place where the notification
+// module reacts to user lifecycle events directly. The cascade is
+// idempotent — repeated invocations on the same user simply find no
+// pending rows.
+func (s *Service) OnUserDeleted(ctx context.Context, userID uuid.UUID) error {
+	if userID == uuid.Nil {
+		return nil
+	}
+	skipped, err := s.deps.Store.SkipPendingRoutesForUser(ctx, userID, s.nowUTC())
+	if err != nil {
+		return err
+	}
+	if skipped > 0 {
+		s.deps.Logger.Info("notification routes skipped on user delete",
+			zap.String("user_id", userID.String()),
+			zap.Int64("count", skipped),
+		)
+	}
+	return nil
+}