feat: stabilize social backend contracts

src/modules/posts/posts.service.ts

@@ -1,6 +1,7 @@
 import { BadRequestException, ForbiddenException, Injectable, Logger, NotFoundException } from '@nestjs/common';
 import { extname } from 'path';
-import { Types } from 'mongoose';
+import { Connection, Types } from 'mongoose';
+import { InjectConnection } from '@nestjs/mongoose';
 import { ModerationStatus } from '../../common/enums/moderation-status.enum';
 import { PostType } from '../../common/enums/post-type.enum';
 import { PostVisibility } from '../../common/enums/post-visibility.enum';
@@ -72,6 +73,7 @@ export class PostsService {
   private readonly logger = new Logger(PostsService.name);
 
   constructor(
+    @InjectConnection() private readonly connection: Connection,
     private readonly postsRepository: PostsRepository,
     private readonly usersRepository: UsersRepository,
     private readonly storageService: ManagedStorageService,
@@ -525,7 +527,7 @@ export class PostsService {
     return post;
   }
 
-  async findUserPosts(userId: string, query: PostQueryDto) {
+  async findUserPosts(userId: string, query: PostQueryDto, viewerUserId?: string) {
     if (!Types.ObjectId.isValid(userId)) {
       throw new BadRequestException('Invalid user id');
     }
@@ -538,6 +540,21 @@ export class PostsService {
       authorId: new Types.ObjectId(userId),
       isArchived: { $ne: true },
     };
+    if (viewerUserId && viewerUserId !== userId) {
+      const isBlocked = await this.hasBlockBetween(viewerUserId, userId);
+      if (isBlocked) {
+        return buildPaginatedResponse([], {
+          page,
+          limit,
+          total: 0,
+          offset: skip,
+        });
+      }
+      const isFollowing = await this.isFollowing(viewerUserId, userId);
+      filter.visibility = isFollowing
+        ? { $in: [PostVisibility.PUBLIC, PostVisibility.FOLLOWERS] }
+        : PostVisibility.PUBLIC;
+    }
     if (query.visibility) {
       filter.visibility = query.visibility;
     }
@@ -1602,4 +1619,30 @@ export class PostsService {
 
     return '';
   }
+
+  private async isFollowing(followerId: string, followingId: string): Promise<boolean> {
+    if (!Types.ObjectId.isValid(followerId) || !Types.ObjectId.isValid(followingId)) {
+      return false;
+    }
+    const count = await this.connection.collection('follows').countDocuments({
+      followerId: new Types.ObjectId(followerId),
+      followingId: new Types.ObjectId(followingId),
+    });
+    return count > 0;
+  }
+
+  private async hasBlockBetween(userA: string, userB: string): Promise<boolean> {
+    if (!Types.ObjectId.isValid(userA) || !Types.ObjectId.isValid(userB)) {
+      return false;
+    }
+    const userAId = new Types.ObjectId(userA);
+    const userBId = new Types.ObjectId(userB);
+    const count = await this.connection.collection('blocks').countDocuments({
+      $or: [
+        { blockerId: userAId, blockedId: userBId },
+        { blockerId: userBId, blockedId: userAId },
+      ],
+    });
+    return count > 0;
+  }
 }