notif cursor

src/modules/notifications/services/notification.service.ts

@@ -15,7 +15,7 @@ export class NotificationService {
     private readonly preferenceService: NotificationPreferenceService,
     private readonly queueService: NotificationQueueService,
     private readonly notificationGateway: NotificationsGateway,
-  ) {}
+  ) { }
 
   async sendNotification(params: NotifRequest): Promise<Notification[]> {
     const { recipients, message, metadata, restaurantId } = params;
@@ -96,16 +96,42 @@ export class NotificationService {
     return notification;
   }
 
-  async findByRestaurant(restaurantId: string, limit = 50): Promise<Notification[]> {
-    return this.em.find(
-      Notification,
-      { restaurant: { id: restaurantId } },
-      {
-        orderBy: { createdAt: 'DESC' },
-        limit,
-        populate: ['user'],
-      },
-    );
+  async findByRestaurant(
+    restaurantId: string,
+    limit = 50,
+    cursor?: string,
+    status?: 'seen' | 'unseen',
+  ): Promise<{ data: Notification[]; nextCursor: string | null }> {
+    const where: FilterQuery<Notification> = {
+      restaurant: { id: restaurantId },
+    };
+
+    // Filter by status (seen/unseen)
+    if (status === 'seen') {
+      where.seenAt = { $ne: null };
+    } else if (status === 'unseen') {
+      where.seenAt = null;
+    }
+
+    // Cursor-based pagination: if cursor is provided, get items with id < cursor
+    if (cursor) {
+      where.id = { $lt: cursor };
+    }
+
+    const notifications = await this.em.find(Notification, where, {
+      orderBy: { createdAt: 'DESC', id: 'DESC' },
+      limit: limit + 1, // fetch one extra to determine next page
+      populate: ['user'],
+    });
+
+    const hasNextPage = notifications.length > limit;
+    const data = hasNextPage ? notifications.slice(0, limit) : notifications;
+    const nextCursor = hasNextPage && data.length > 0 ? data[data.length - 1].id : null;
+
+    return {
+      data,
+      nextCursor: nextCursor ?? null,
+    };
   }
 
   async findByUserAndRestaurant(
@@ -144,7 +170,7 @@ export class NotificationService {
 
     return {
       data,
-      nextCursor,
+      nextCursor: nextCursor ?? null,
     };
   }