feat: stabilize social backend contracts

oudelaa_dashboard/lib/api/endpoints.ts

@@ -13,6 +13,28 @@ export const apiEndpoints = {
     revokeSuperAdminSession: (sessionId: string) => `/auth/superadmin/sessions/${sessionId}/revoke`,
   },
   users: {
+    meProfileSetup: "/users/me/profile-setup",
+    meMusicSetup: "/users/me/music-setup",
+    me: "/users/me",
+    publicList: "/users",
+    publicById: (userId: string) => `/users/${userId}`,
+    publicDiscover: (params: Record<string, string | number | boolean | null | undefined> = {}) =>
+      `/users/discover?${toQueryString(params)}`,
+    publicProfileOverview: (userId: string) => `/users/${userId}/profile-overview`,
+    publicPresence: (userId: string) => `/users/${userId}/presence`,
+    publicPosts: (userId: string, params: Record<string, string | number | boolean | null | undefined> = {}) =>
+      `/users/${userId}/posts?${toQueryString(params)}`,
+    follow: (userId: string) => `/users/${userId}/follow`,
+    unfollow: (userId: string) => `/users/${userId}/follow`,
+    followStatus: (userId: string) => `/users/${userId}/follow-status`,
+    followers: (userId: string, params: Record<string, string | number | boolean | null | undefined> = {}) =>
+      `/users/${userId}/followers?${toQueryString(params)}`,
+    following: (userId: string, params: Record<string, string | number | boolean | null | undefined> = {}) =>
+      `/users/${userId}/following?${toQueryString(params)}`,
+    myFollowers: (params: Record<string, string | number | boolean | null | undefined> = {}) =>
+      `/users/me/followers?${toQueryString(params)}`,
+    myFollowing: (params: Record<string, string | number | boolean | null | undefined> = {}) =>
+      `/users/me/following?${toQueryString(params)}`,
     all: (params: Record<string, string | number | boolean | null | undefined> = {}) =>
       `/users/admin?${toQueryString(params)}`,
     byId: (userId: string) => `/users/admin/${userId}`,
@@ -31,6 +53,24 @@ export const apiEndpoints = {
     profileOverview: (userId: string) => `/users/admin/${userId}/profile-overview`,
   },
   posts: {
+    create: "/posts",
+    reelsCreate: "/posts/reels",
+    reels: (params: Record<string, string | number | boolean | null | undefined> = {}) =>
+      `/posts/reels?${toQueryString(params)}`,
+    byId: (postId: string) => `/posts/${postId}`,
+    byUser: (userId: string, params: Record<string, string | number | boolean | null | undefined> = {}) =>
+      `/posts/user/${userId}?${toQueryString(params)}`,
+    update: (postId: string) => `/posts/${postId}`,
+    repost: (postId: string) => `/posts/${postId}/repost`,
+    commentSettings: (postId: string) => `/posts/${postId}/comment-settings`,
+    pinProfile: (postId: string) => `/posts/${postId}/pin-profile`,
+    unpinProfile: (postId: string) => `/posts/${postId}/unpin-profile`,
+    archive: (postId: string) => `/posts/${postId}/archive`,
+    restoreArchive: (postId: string) => `/posts/${postId}/restore-archive`,
+    remove: (postId: string) => `/posts/${postId}`,
+    view: (postId: string) => `/posts/${postId}/view`,
+    play: (postId: string) => `/posts/${postId}/play`,
+    share: (postId: string) => `/posts/${postId}/share`,
     moderation: (params: Record<string, string | number | boolean | null | undefined> = {}) =>
       `/posts/admin/moderation?${toQueryString(params)}`,
     adminDelete: (postId: string) => `/posts/admin/${postId}`,
@@ -41,9 +81,39 @@ export const apiEndpoints = {
     adminDelete: (commentId: string) => `/comments/admin/${commentId}`,
   },
   notifications: {
+    mine: (params: Record<string, string | number | boolean | null | undefined> = {}) =>
+      `/notifications?${toQueryString(params)}`,
+    unreadCount: "/notifications/unread-count",
+    markRead: (notificationId: string) => `/notifications/${notificationId}/read`,
+    markAllRead: "/notifications/read-all",
     superAdmin: (params: Record<string, string | number | boolean | null | undefined> = {}) =>
       `/notifications/superadmin?${toQueryString(params)}`,
   },
+  follows: {
+    toggle: "/follows/toggle",
+    followers: (userId: string, params: Record<string, string | number | boolean | null | undefined> = {}) =>
+      `/follows/followers/${userId}?${toQueryString(params)}`,
+    following: (userId: string, params: Record<string, string | number | boolean | null | undefined> = {}) =>
+      `/follows/following/${userId}?${toQueryString(params)}`,
+    status: (targetUserId: string) => `/follows/status/${targetUserId}`,
+    suggestions: (params: Record<string, string | number | boolean | null | undefined> = {}) =>
+      `/follows/suggestions?${toQueryString(params)}`,
+    requests: (params: Record<string, string | number | boolean | null | undefined> = {}) =>
+      `/follows/requests?${toQueryString(params)}`,
+    approveRequest: (requestId: string) => `/follows/requests/${requestId}/approve`,
+    rejectRequest: (requestId: string) => `/follows/requests/${requestId}/reject`,
+  },
+  devices: {
+    register: "/devices/register",
+    unregister: "/devices/unregister",
+  },
+  collaborationRequests: {
+    create: (postId: string) => `/posts/${postId}/collaboration-requests`,
+    list: (params: Record<string, string | number | boolean | null | undefined> = {}) =>
+      `/collaboration-requests?${toQueryString(params)}`,
+    approve: (requestId: string) => `/collaboration-requests/${requestId}/approve`,
+    reject: (requestId: string) => `/collaboration-requests/${requestId}/reject`,
+  },
   reports: {
     superAdmin: (params: Record<string, string | number | boolean | null | undefined> = {}) =>
       `/reports/superadmin?${toQueryString(params)}`,

oudelaa_dashboard/lib/api/mobile-social.ts

@@ -0,0 +1,173 @@
+import { apiEndpoints } from "@/lib/api/endpoints";
+import { fetchWithAuth } from "@/lib/auth/client";
+import type {
+  CollaborationRequestItem,
+  CollaborationRequestsResponse,
+  DeviceItem,
+  FollowListResponse,
+  FollowStatusResponse,
+  NotificationsResponse,
+  PostsResponse,
+  PresenceResponse,
+  RegisterDevicePayload,
+  SuccessMessage,
+  UnregisterDevicePayload,
+} from "@/types/api";
+
+export async function getUserPresence(userId: string) {
+  return fetchWithAuth<PresenceResponse>(apiEndpoints.users.publicPresence(userId));
+}
+
+export async function listUserPosts(
+  userId: string,
+  params: Record<string, string | number | boolean | null | undefined> = {},
+) {
+  return fetchWithAuth<PostsResponse>(apiEndpoints.users.publicPosts(userId, params));
+}
+
+export async function followUser(userId: string) {
+  return fetchWithAuth<FollowStatusResponse>(apiEndpoints.users.follow(userId), {
+    method: "POST",
+    body: JSON.stringify({}),
+  });
+}
+
+export async function unfollowUser(userId: string) {
+  return fetchWithAuth<FollowStatusResponse>(apiEndpoints.users.unfollow(userId), {
+    method: "DELETE",
+  });
+}
+
+export async function getFollowStatus(userId: string) {
+  return fetchWithAuth<FollowStatusResponse>(apiEndpoints.users.followStatus(userId));
+}
+
+export async function listUserFollowers(
+  userId: string,
+  params: Record<string, string | number | boolean | null | undefined> = {},
+) {
+  return fetchWithAuth<FollowListResponse>(apiEndpoints.users.followers(userId, params));
+}
+
+export async function listUserFollowing(
+  userId: string,
+  params: Record<string, string | number | boolean | null | undefined> = {},
+) {
+  return fetchWithAuth<FollowListResponse>(apiEndpoints.users.following(userId, params));
+}
+
+export async function registerDevice(payload: RegisterDevicePayload) {
+  return fetchWithAuth<DeviceItem>(apiEndpoints.devices.register, {
+    method: "POST",
+    body: JSON.stringify(payload),
+  });
+}
+
+export async function unregisterDevice(payload: UnregisterDevicePayload) {
+  return fetchWithAuth<SuccessMessage>(apiEndpoints.devices.unregister, {
+    method: "POST",
+    body: JSON.stringify(payload),
+  });
+}
+
+export async function createCollaborationRequest(postId: string, targetUserId: string) {
+  return fetchWithAuth<CollaborationRequestItem>(apiEndpoints.collaborationRequests.create(postId), {
+    method: "POST",
+    body: JSON.stringify({ targetUserId }),
+  });
+}
+
+export async function listCollaborationRequests(
+  params: Record<string, string | number | boolean | null | undefined> = {},
+) {
+  return fetchWithAuth<CollaborationRequestsResponse>(apiEndpoints.collaborationRequests.list(params));
+}
+
+export async function approveCollaborationRequest(requestId: string) {
+  return fetchWithAuth<CollaborationRequestItem>(apiEndpoints.collaborationRequests.approve(requestId), {
+    method: "PATCH",
+    body: JSON.stringify({}),
+  });
+}
+
+export async function rejectCollaborationRequest(requestId: string) {
+  return fetchWithAuth<CollaborationRequestItem>(apiEndpoints.collaborationRequests.reject(requestId), {
+    method: "PATCH",
+    body: JSON.stringify({}),
+  });
+}
+
+export async function listMyNotifications(
+  params: Record<string, string | number | boolean | null | undefined> = {},
+) {
+  return fetchWithAuth<NotificationsResponse>(apiEndpoints.notifications.mine(params));
+}
+
+export async function getMyUnreadNotificationCount() {
+  return fetchWithAuth<{ unreadCount: number }>(apiEndpoints.notifications.unreadCount);
+}
+
+export async function markMyNotificationRead(notificationId: string) {
+  return fetchWithAuth<SuccessMessage>(apiEndpoints.notifications.markRead(notificationId), {
+    method: "PATCH",
+    body: JSON.stringify({}),
+  });
+}
+
+export async function markAllMyNotificationsRead() {
+  return fetchWithAuth<SuccessMessage>(apiEndpoints.notifications.markAllRead, {
+    method: "PATCH",
+    body: JSON.stringify({}),
+  });
+}
+
+export type MobileSocialRouteGroup = {
+  title: string;
+  routes: string[];
+};
+
+export const mobileSocialRouteGroups: MobileSocialRouteGroup[] = [
+  {
+    title: "users",
+    routes: [
+      "GET /users/:userId",
+      "GET /users/:userId/presence",
+      "GET /users/:userId/posts",
+      "GET /users/:userId/profile-overview",
+    ],
+  },
+  {
+    title: "follows",
+    routes: [
+      "POST /users/:userId/follow",
+      "DELETE /users/:userId/follow",
+      "GET /users/:userId/follow-status",
+      "GET /users/:userId/followers",
+      "GET /users/:userId/following",
+      "GET /users/me/followers",
+      "GET /users/me/following",
+    ],
+  },
+  {
+    title: "devices",
+    routes: ["POST /devices/register", "POST /devices/unregister"],
+  },
+  {
+    title: "collaborationRequests",
+    routes: [
+      "POST /posts/:postId/collaboration-requests",
+      "GET /collaboration-requests",
+      "PATCH /collaboration-requests/:requestId/approve",
+      "PATCH /collaboration-requests/:requestId/reject",
+    ],
+  },
+  {
+    title: "notifications",
+    routes: [
+      "GET /notifications",
+      "GET /notifications/unread-count",
+      "PATCH /notifications/:notificationId/read",
+      "PATCH /notifications/read-all",
+    ],
+  },
+];

oudelaa_dashboard/postman/oudelaa-route-map.json

@@ -4,7 +4,8 @@
   "notes": [
     "This dashboard must authenticate with /auth/superadmin/* routes only.",
     "User-only routes are not a valid contract for this dashboard unless they have a dedicated /admin or /superadmin variant.",
-    "The dashboard proxy should target the Nest backend API base URL defined in .env.local."
+    "The dashboard proxy should target the Nest backend API base URL defined in .env.local.",
+    "Mobile-facing routes are mirrored here for frontend contract visibility, but normal user routes require a normal user access token when called from Flutter."
   ],
   "modules": {
     "auth": [
@@ -15,6 +16,22 @@
       "POST /auth/superadmin/sessions/:sessionId/revoke"
     ],
     "users": [
+      "PATCH /users/me/profile-setup",
+      "PATCH /users/me/music-setup",
+      "PATCH /users/me",
+      "GET /users",
+      "GET /users/discover",
+      "GET /users/:userId",
+      "GET /users/:userId/presence",
+      "GET /users/:userId/profile-overview",
+      "GET /users/:userId/posts",
+      "POST /users/:userId/follow",
+      "DELETE /users/:userId/follow",
+      "GET /users/:userId/follow-status",
+      "GET /users/:userId/followers",
+      "GET /users/:userId/following",
+      "GET /users/me/followers",
+      "GET /users/me/following",
       "GET /users/admin",
       "GET /users/admin/admins",
       "GET /users/admin/:userId",
@@ -31,6 +48,23 @@
       "PATCH /superadmin/users/:userId/status"
     ],
     "posts": [
+      "POST /posts",
+      "POST /posts/reels",
+      "GET /posts/reels",
+      "GET /posts/:postId",
+      "GET /posts/user/:userId",
+      "PATCH /posts/:postId",
+      "POST /posts/:postId/repost",
+      "PATCH /posts/:postId/comment-settings",
+      "PATCH /posts/:postId/pin-profile",
+      "PATCH /posts/:postId/unpin-profile",
+      "PATCH /posts/:postId/archive",
+      "PATCH /posts/:postId/restore-archive",
+      "DELETE /posts/:postId",
+      "POST /posts/:postId/view",
+      "POST /posts/:postId/play",
+      "POST /posts/:postId/share",
+      "POST /posts/:postId/collaboration-requests",
       "GET /posts/admin/moderation",
       "DELETE /posts/admin/:postId",
       "PATCH /superadmin/posts/:postId/status"
@@ -41,8 +75,32 @@
       "PATCH /superadmin/comments/:commentId/status"
     ],
     "notifications": [
+      "GET /notifications",
+      "GET /notifications/unread-count",
+      "PATCH /notifications/:notificationId/read",
+      "PATCH /notifications/read-all",
       "GET /notifications/superadmin"
     ],
+    "follows": [
+      "POST /follows/toggle",
+      "GET /follows/followers/:userId",
+      "GET /follows/following/:userId",
+      "GET /follows/status/:targetUserId",
+      "GET /follows/suggestions",
+      "GET /follows/requests",
+      "PATCH /follows/requests/:requestId/approve",
+      "PATCH /follows/requests/:requestId/reject"
+    ],
+    "devices": [
+      "POST /devices/register",
+      "POST /devices/unregister"
+    ],
+    "collaborationRequests": [
+      "POST /posts/:postId/collaboration-requests",
+      "GET /collaboration-requests",
+      "PATCH /collaboration-requests/:requestId/approve",
+      "PATCH /collaboration-requests/:requestId/reject"
+    ],
     "marketplace": [
       "GET /marketplace/home",
       "GET /marketplace/listings",

oudelaa_dashboard/types/api.ts

@@ -210,8 +210,69 @@ export type SaveStatusResponse = {
 export type FollowStatusResponse = {
   following?: boolean;
   isFollowing?: boolean;
+  isFollowedBy?: boolean;
+  isMutual?: boolean;
 };
 
+export type FollowListItem = {
+  _id?: string;
+  user?: ApiUser;
+  followerId?: ApiUser | string;
+  followingId?: ApiUser | string;
+  status?: "pending" | "accepted" | "rejected";
+  createdAt?: string;
+  updatedAt?: string;
+};
+
+export type FollowListResponse = PaginatedResponse<FollowListItem>;
+
+export type PresenceResponse = {
+  userId: string;
+  isOnline: boolean;
+  lastSeenAt?: string | null;
+};
+
+export type RegisterDevicePayload = {
+  fcmToken: string;
+  platform: "android" | "ios" | "web";
+  deviceId?: string;
+  appVersion?: string;
+  locale?: string;
+};
+
+export type UnregisterDevicePayload = {
+  fcmToken?: string;
+  deviceId?: string;
+};
+
+export type DeviceItem = {
+  _id: string;
+  userId: string;
+  fcmToken: string;
+  platform: "android" | "ios" | "web";
+  deviceId?: string;
+  appVersion?: string;
+  locale?: string;
+  isActive?: boolean;
+  lastSeenAt?: string;
+  createdAt?: string;
+  updatedAt?: string;
+};
+
+export type CollaborationRequestStatus = "pending" | "approved" | "rejected";
+
+export type CollaborationRequestItem = {
+  _id: string;
+  postId: ApiPost | string;
+  requesterId: ApiUser | string;
+  targetUserId: ApiUser | string;
+  status: CollaborationRequestStatus;
+  createdAt?: string;
+  updatedAt?: string;
+};
+
+export type CollaborationRequestsResponse = PaginatedResponse<CollaborationRequestItem>;
+
 export type NotificationType =
   | "like"
   | "comment"
@@ -219,7 +280,10 @@ export type NotificationType =
   | "message"
   | "save"
   | "share"
-  | "mention";
+  | "mention"
+  | "reply"
+  | "system"
+  | "collaboration_request";
 
 export type NotificationItem = {
   _id: string;

src/app.module.ts

@@ -16,6 +16,8 @@ import { AuditModule } from './modules/audit/audit.module';
 import { BlocksModule } from './modules/blocks/blocks.module';
 import { ChatModule } from './modules/chat/chat.module';
 import { CommentsModule } from './modules/comments/comments.module';
+import { CollaborationRequestsModule } from './modules/collaboration-requests/collaboration-requests.module';
+import { DevicesModule } from './modules/devices/devices.module';
 import { FeedModule } from './modules/feed/feed.module';
 import { FollowsModule } from './modules/follows/follows.module';
 import { LikesModule } from './modules/likes/likes.module';
@@ -50,6 +52,8 @@ import { ThrottleGuard } from './common/guards/throttle.guard';
     AuthModule,
     PostsModule,
     CommentsModule,
+    CollaborationRequestsModule,
+    DevicesModule,
     LikesModule,
     FollowsModule,
     FeedModule,

src/common/enums/notification-type.enum.ts

@@ -6,4 +6,7 @@ export enum NotificationType {
   SAVE = 'save',
   SHARE = 'share',
   MENTION = 'mention',
+  REPLY = 'reply',
+  SYSTEM = 'system',
+  COLLABORATION_REQUEST = 'collaboration_request',
 }

src/modules/chat/chat.gateway.ts

@@ -14,6 +14,7 @@ import { Server, Socket } from 'socket.io';
 import { ChatRealtimeService } from './chat-realtime.service';
 import { ChatService } from './chat.service';
 import { SendMessageDto } from './dto/send-message.dto';
+import { UsersService } from '../users/users.service';
 
 type SocketWithUser = Socket & { data: { userId?: string } };
 
@@ -21,12 +22,14 @@ type SocketWithUser = Socket & { data: { userId?: string } };
 export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewayDisconnect {
   @WebSocketServer()
   server!: Server;
+  private readonly connectionCountsByUser = new Map<string, number>();
 
   constructor(
     private readonly chatService: ChatService,
     private readonly chatRealtimeService: ChatRealtimeService,
     private readonly jwtService: JwtService,
     private readonly configService: ConfigService,
+    private readonly usersService: UsersService,
   ) {}
 
   afterInit(server: Server) {
@@ -49,6 +52,8 @@ export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewa
         return;
       }
       client.data.userId = payload.sub;
+      this.incrementUserConnection(payload.sub);
+      await this.usersService.setPresence(payload.sub, true);
       await client.join(this.userRoom(payload.sub));
       this.server.to(this.userRoom(payload.sub)).emit('presence', { userId: payload.sub, online: true });
     } catch {
@@ -59,7 +64,11 @@ export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewa
   handleDisconnect(client: SocketWithUser) {
     const userId = client.data.userId;
     if (userId) {
-      this.server.to(this.userRoom(userId)).emit('presence', { userId, online: false });
+      const remainingConnections = this.decrementUserConnection(userId);
+      if (remainingConnections === 0) {
+        void this.usersService.setPresence(userId, false);
+        this.server.to(this.userRoom(userId)).emit('presence', { userId, online: false });
+      }
     }
   }
 
@@ -140,4 +149,18 @@ export class ChatGateway implements OnGatewayInit, OnGatewayConnection, OnGatewa
   private conversationRoom(conversationId: string): string {
     return `conversation:${conversationId}`;
   }
+
+  private incrementUserConnection(userId: string): void {
+    this.connectionCountsByUser.set(userId, (this.connectionCountsByUser.get(userId) ?? 0) + 1);
+  }
+
+  private decrementUserConnection(userId: string): number {
+    const nextCount = Math.max(0, (this.connectionCountsByUser.get(userId) ?? 1) - 1);
+    if (nextCount === 0) {
+      this.connectionCountsByUser.delete(userId);
+      return 0;
+    }
+    this.connectionCountsByUser.set(userId, nextCount);
+    return nextCount;
+  }
 }

src/modules/collaboration-requests/collaboration-requests.controller.ts

@@ -0,0 +1,39 @@
+import { Body, Controller, Get, Param, Patch, Post, Query, UseGuards } from '@nestjs/common';
+import { ApiBearerAuth, ApiTags } from '@nestjs/swagger';
+import { CurrentUser } from '../../common/decorators/current-user.decorator';
+import { PaginationQueryDto } from '../../common/dto/pagination-query.dto';
+import { JwtAuthGuard } from '../../common/guards/jwt-auth.guard';
+import { JwtPayload } from '../../common/interfaces/jwt-payload.interface';
+import { CollaborationRequestsService } from './collaboration-requests.service';
+import { CreateCollaborationRequestDto } from './dto/create-collaboration-request.dto';
+
+@ApiTags('Collaboration Requests')
+@ApiBearerAuth()
+@UseGuards(JwtAuthGuard)
+export class CollaborationRequestsController {
+  constructor(private readonly collaborationRequestsService: CollaborationRequestsService) {}
+
+  @Post('posts/:postId/collaboration-requests')
+  async create(
+    @CurrentUser() user: JwtPayload,
+    @Param('postId') postId: string,
+    @Body() dto: CreateCollaborationRequestDto,
+  ) {
+    return this.collaborationRequestsService.create(user.sub, postId, dto.targetUserId);
+  }
+
+  @Get('collaboration-requests')
+  async mine(@CurrentUser() user: JwtPayload, @Query() query: PaginationQueryDto) {
+    return this.collaborationRequestsService.getMine(user.sub, query);
+  }
+
+  @Patch('collaboration-requests/:requestId/approve')
+  async approve(@CurrentUser() user: JwtPayload, @Param('requestId') requestId: string) {
+    return this.collaborationRequestsService.approve(user.sub, requestId);
+  }
+
+  @Patch('collaboration-requests/:requestId/reject')
+  async reject(@CurrentUser() user: JwtPayload, @Param('requestId') requestId: string) {
+    return this.collaborationRequestsService.reject(user.sub, requestId);
+  }
+}

src/modules/collaboration-requests/collaboration-requests.module.ts

@@ -0,0 +1,25 @@
+import { Module } from '@nestjs/common';
+import { MongooseModule } from '@nestjs/mongoose';
+import { BlocksModule } from '../blocks/blocks.module';
+import { NotificationsModule } from '../notifications/notifications.module';
+import { PostsModule } from '../posts/posts.module';
+import { UsersModule } from '../users/users.module';
+import { CollaborationRequestsController } from './collaboration-requests.controller';
+import { CollaborationRequestsService } from './collaboration-requests.service';
+import {
+  CollaborationRequest,
+  CollaborationRequestSchema,
+} from './schemas/collaboration-request.schema';
+
+@Module({
+  imports: [
+    BlocksModule,
+    NotificationsModule,
+    PostsModule,
+    UsersModule,
+    MongooseModule.forFeature([{ name: CollaborationRequest.name, schema: CollaborationRequestSchema }]),
+  ],
+  controllers: [CollaborationRequestsController],
+  providers: [CollaborationRequestsService],
+})
+export class CollaborationRequestsModule {}

src/modules/collaboration-requests/collaboration-requests.service.ts

@@ -0,0 +1,136 @@
+import { BadRequestException, ForbiddenException, Injectable, NotFoundException } from '@nestjs/common';
+import { InjectModel } from '@nestjs/mongoose';
+import { Model, Types } from 'mongoose';
+import { PaginationQueryDto } from '../../common/dto/pagination-query.dto';
+import { buildPaginatedResponse } from '../../common/utils/pagination.util';
+import { BlocksRepository } from '../blocks/blocks.repository';
+import { NotificationsService } from '../notifications/notifications.service';
+import { PostsRepository } from '../posts/posts.repository';
+import { UsersRepository } from '../users/users.repository';
+import {
+  CollaborationRequest,
+  CollaborationRequestDocument,
+} from './schemas/collaboration-request.schema';
+
+@Injectable()
+export class CollaborationRequestsService {
+  constructor(
+    @InjectModel(CollaborationRequest.name)
+    private readonly collaborationRequestModel: Model<CollaborationRequestDocument>,
+    private readonly postsRepository: PostsRepository,
+    private readonly usersRepository: UsersRepository,
+    private readonly blocksRepository: BlocksRepository,
+    private readonly notificationsService: NotificationsService,
+  ) {}
+
+  async create(requesterId: string, postId: string, targetUserId: string) {
+    if (!Types.ObjectId.isValid(postId) || !Types.ObjectId.isValid(targetUserId)) {
+      throw new BadRequestException('Invalid collaboration request');
+    }
+    if (requesterId === targetUserId) {
+      throw new BadRequestException('You cannot invite yourself');
+    }
+
+    const [post, targetUser, block] = await Promise.all([
+      this.postsRepository.findById(postId),
+      this.usersRepository.findById(targetUserId),
+      this.blocksRepository.findAnyBetween(requesterId, targetUserId),
+    ]);
+    if (!post) {
+      throw new NotFoundException('Post not found');
+    }
+    if (post.authorId.toString() !== requesterId) {
+      throw new ForbiddenException('Only the post owner can invite collaborators');
+    }
+    if (!targetUser || targetUser.isDisabled) {
+      throw new NotFoundException('Target user not found');
+    }
+    if (block) {
+      throw new BadRequestException('You cannot invite this user');
+    }
+
+    const filter = {
+      postId: new Types.ObjectId(postId),
+      requesterId: new Types.ObjectId(requesterId),
+      targetUserId: new Types.ObjectId(targetUserId),
+      status: 'pending',
+    };
+    const existing = await this.collaborationRequestModel.findOne(filter).exec();
+    const request = existing ?? await this.collaborationRequestModel
+      .findOneAndUpdate(
+        filter,
+        {
+          $setOnInsert: {
+            postId: new Types.ObjectId(postId),
+            requesterId: new Types.ObjectId(requesterId),
+            targetUserId: new Types.ObjectId(targetUserId),
+            status: 'pending',
+          },
+        },
+        { new: true, upsert: true, setDefaultsOnInsert: true },
+      )
+      .exec();
+
+    if (!existing) {
+      await this.notificationsService.create({
+        actorId: requesterId,
+        recipientId: targetUserId,
+        type: 'collaboration_request',
+        referenceId: postId,
+        resourceType: 'post',
+        deepLink: `/posts/${postId}`,
+      });
+    }
+
+    return { message: 'Collaboration request sent', request };
+  }
+
+  async getMine(targetUserId: string, query: PaginationQueryDto) {
+    const page = query.page ?? 1;
+    const limit = query.limit ?? 20;
+    const skip = (page - 1) * limit;
+    const filter = { targetUserId: new Types.ObjectId(targetUserId), status: 'pending' };
+    const [items, total] = await Promise.all([
+      this.collaborationRequestModel
+        .find(filter)
+        .populate({ path: 'requesterId', select: 'name username stageName avatar isVerified isDisabled' })
+        .populate({ path: 'postId' })
+        .sort({ createdAt: -1 })
+        .skip(skip)
+        .limit(limit)
+        .exec(),
+      this.collaborationRequestModel.countDocuments(filter).exec(),
+    ]);
+    return buildPaginatedResponse(items, { page, limit, total, offset: skip });
+  }
+
+  async approve(targetUserId: string, requestId: string) {
+    const request = await this.updateStatus(targetUserId, requestId, 'approved');
+    await this.postsRepository.updateById(request.postId.toString(), {
+      $addToSet: { collaboratorIds: request.targetUserId },
+    });
+    return { approved: true, request };
+  }
+
+  async reject(targetUserId: string, requestId: string) {
+    const request = await this.updateStatus(targetUserId, requestId, 'rejected');
+    return { rejected: true, request };
+  }
+
+  private async updateStatus(targetUserId: string, requestId: string, status: 'approved' | 'rejected') {
+    if (!Types.ObjectId.isValid(requestId)) {
+      throw new BadRequestException('Invalid collaboration request id');
+    }
+    const request = await this.collaborationRequestModel
+      .findOneAndUpdate(
+        { _id: new Types.ObjectId(requestId), targetUserId: new Types.ObjectId(targetUserId), status: 'pending' },
+        { status },
+        { new: true },
+      )
+      .exec();
+    if (!request) {
+      throw new NotFoundException('Collaboration request not found');
+    }
+    return request;
+  }
+}

src/modules/collaboration-requests/dto/create-collaboration-request.dto.ts

@@ -0,0 +1,6 @@
+import { IsMongoId } from 'class-validator';
+
+export class CreateCollaborationRequestDto {
+  @IsMongoId()
+  targetUserId!: string;
+}

src/modules/collaboration-requests/schemas/collaboration-request.schema.ts

@@ -0,0 +1,25 @@
+import { Prop, Schema, SchemaFactory } from '@nestjs/mongoose';
+import { HydratedDocument, Types } from 'mongoose';
+import { Post } from '../../posts/schemas/post.schema';
+import { User } from '../../users/schemas/user.schema';
+
+export type CollaborationRequestDocument = HydratedDocument<CollaborationRequest>;
+
+@Schema({ timestamps: true, versionKey: false })
+export class CollaborationRequest {
+  @Prop({ type: Types.ObjectId, ref: Post.name, required: true, index: true })
+  postId!: Types.ObjectId;
+
+  @Prop({ type: Types.ObjectId, ref: User.name, required: true, index: true })
+  requesterId!: Types.ObjectId;
+
+  @Prop({ type: Types.ObjectId, ref: User.name, required: true, index: true })
+  targetUserId!: Types.ObjectId;
+
+  @Prop({ enum: ['pending', 'approved', 'rejected'], default: 'pending', index: true })
+  status!: 'pending' | 'approved' | 'rejected';
+}
+
+export const CollaborationRequestSchema = SchemaFactory.createForClass(CollaborationRequest);
+CollaborationRequestSchema.index({ postId: 1, targetUserId: 1, status: 1 });
+CollaborationRequestSchema.index({ targetUserId: 1, status: 1, createdAt: -1 });

src/modules/devices/devices.controller.ts

@@ -0,0 +1,26 @@
+import { Body, Controller, Post, UseGuards } from '@nestjs/common';
+import { ApiBearerAuth, ApiTags } from '@nestjs/swagger';
+import { CurrentUser } from '../../common/decorators/current-user.decorator';
+import { JwtAuthGuard } from '../../common/guards/jwt-auth.guard';
+import { JwtPayload } from '../../common/interfaces/jwt-payload.interface';
+import { RegisterDeviceDto } from './dto/register-device.dto';
+import { UnregisterDeviceDto } from './dto/unregister-device.dto';
+import { DevicesService } from './devices.service';
+
+@ApiTags('Devices')
+@ApiBearerAuth()
+@UseGuards(JwtAuthGuard)
+@Controller('devices')
+export class DevicesController {
+  constructor(private readonly devicesService: DevicesService) {}
+
+  @Post('register')
+  async register(@CurrentUser() user: JwtPayload, @Body() dto: RegisterDeviceDto) {
+    return this.devicesService.register(user.sub, dto);
+  }
+
+  @Post('unregister')
+  async unregister(@CurrentUser() user: JwtPayload, @Body() dto: UnregisterDeviceDto) {
+    return this.devicesService.unregister(user.sub, dto);
+  }
+}

src/modules/devices/devices.module.ts

@@ -0,0 +1,14 @@
+import { Module } from '@nestjs/common';
+import { MongooseModule } from '@nestjs/mongoose';
+import { DevicesController } from './devices.controller';
+import { DevicesRepository } from './devices.repository';
+import { DevicesService } from './devices.service';
+import { Device, DeviceSchema } from './schemas/device.schema';
+
+@Module({
+  imports: [MongooseModule.forFeature([{ name: Device.name, schema: DeviceSchema }])],
+  controllers: [DevicesController],
+  providers: [DevicesService, DevicesRepository],
+  exports: [DevicesService, DevicesRepository],
+})
+export class DevicesModule {}

src/modules/devices/devices.repository.ts

@@ -0,0 +1,45 @@
+import { Injectable } from '@nestjs/common';
+import { InjectModel } from '@nestjs/mongoose';
+import { Model, Types } from 'mongoose';
+import { Device, DeviceDocument } from './schemas/device.schema';
+
+@Injectable()
+export class DevicesRepository {
+  constructor(@InjectModel(Device.name) private readonly deviceModel: Model<DeviceDocument>) {}
+
+  async upsert(userId: string, payload: Omit<Partial<Device>, 'userId'>): Promise<DeviceDocument> {
+    const filter = payload.deviceId
+      ? { userId: new Types.ObjectId(userId), deviceId: payload.deviceId }
+      : { userId: new Types.ObjectId(userId), fcmToken: payload.fcmToken };
+
+    return this.deviceModel
+      .findOneAndUpdate(
+        filter,
+        {
+          $set: {
+            ...payload,
+            userId: new Types.ObjectId(userId),
+            isActive: true,
+            lastSeenAt: new Date(),
+          },
+        },
+        { new: true, upsert: true, setDefaultsOnInsert: true },
+      )
+      .exec();
+  }
+
+  async deactivate(userId: string, payload: { fcmToken?: string; deviceId?: string }): Promise<DeviceDocument | null> {
+    const filter: Record<string, unknown> = { userId: new Types.ObjectId(userId) };
+    if (payload.deviceId) {
+      filter.deviceId = payload.deviceId;
+    } else if (payload.fcmToken) {
+      filter.fcmToken = payload.fcmToken;
+    } else {
+      return null;
+    }
+
+    return this.deviceModel
+      .findOneAndUpdate(filter, { isActive: false, lastSeenAt: new Date() }, { new: true })
+      .exec();
+  }
+}

src/modules/devices/devices.service.ts

@@ -0,0 +1,45 @@
+import { BadRequestException, Injectable } from '@nestjs/common';
+import { RegisterDeviceDto } from './dto/register-device.dto';
+import { UnregisterDeviceDto } from './dto/unregister-device.dto';
+import { DevicesRepository } from './devices.repository';
+
+@Injectable()
+export class DevicesService {
+  constructor(private readonly devicesRepository: DevicesRepository) {}
+
+  async register(userId: string, dto: RegisterDeviceDto) {
+    const fcmToken = dto.fcmToken.trim();
+    if (!fcmToken) {
+      throw new BadRequestException('fcmToken is required');
+    }
+
+    const device = await this.devicesRepository.upsert(userId, {
+      fcmToken,
+      platform: dto.platform,
+      deviceId: dto.deviceId?.trim() ?? '',
+      appVersion: dto.appVersion?.trim() ?? '',
+      locale: dto.locale?.trim() ?? '',
+    });
+
+    return {
+      message: 'Device registered successfully',
+      device,
+    };
+  }
+
+  async unregister(userId: string, dto: UnregisterDeviceDto) {
+    if (!dto.deviceId?.trim() && !dto.fcmToken?.trim()) {
+      throw new BadRequestException('deviceId or fcmToken is required');
+    }
+
+    const device = await this.devicesRepository.deactivate(userId, {
+      deviceId: dto.deviceId?.trim(),
+      fcmToken: dto.fcmToken?.trim(),
+    });
+
+    return {
+      message: 'Device unregistered successfully',
+      device,
+    };
+  }
+}

src/modules/devices/dto/register-device.dto.ts

@@ -0,0 +1,25 @@
+import { IsEnum, IsOptional, IsString, MaxLength } from 'class-validator';
+
+export class RegisterDeviceDto {
+  @IsString()
+  @MaxLength(4096)
+  fcmToken!: string;
+
+  @IsEnum(['android', 'ios', 'web'])
+  platform!: 'android' | 'ios' | 'web';
+
+  @IsOptional()
+  @IsString()
+  @MaxLength(160)
+  deviceId?: string;
+
+  @IsOptional()
+  @IsString()
+  @MaxLength(60)
+  appVersion?: string;
+
+  @IsOptional()
+  @IsString()
+  @MaxLength(20)
+  locale?: string;
+}

src/modules/devices/dto/unregister-device.dto.ts

@@ -0,0 +1,13 @@
+import { IsOptional, IsString, MaxLength } from 'class-validator';
+
+export class UnregisterDeviceDto {
+  @IsOptional()
+  @IsString()
+  @MaxLength(4096)
+  fcmToken?: string;
+
+  @IsOptional()
+  @IsString()
+  @MaxLength(160)
+  deviceId?: string;
+}

src/modules/devices/schemas/device.schema.ts

@@ -0,0 +1,36 @@
+import { Prop, Schema, SchemaFactory } from '@nestjs/mongoose';
+import { HydratedDocument, Types } from 'mongoose';
+import { User } from '../../users/schemas/user.schema';
+
+export type DeviceDocument = HydratedDocument<Device>;
+
+@Schema({ timestamps: true, versionKey: false })
+export class Device {
+  @Prop({ type: Types.ObjectId, ref: User.name, required: true, index: true })
+  userId!: Types.ObjectId;
+
+  @Prop({ required: true, trim: true, index: true })
+  fcmToken!: string;
+
+  @Prop({ enum: ['android', 'ios', 'web'], required: true, index: true })
+  platform!: 'android' | 'ios' | 'web';
+
+  @Prop({ default: '', trim: true, index: true })
+  deviceId!: string;
+
+  @Prop({ default: '', trim: true })
+  appVersion!: string;
+
+  @Prop({ default: '', trim: true })
+  locale!: string;
+
+  @Prop({ default: true, index: true })
+  isActive!: boolean;
+
+  @Prop({ type: Date, default: null })
+  lastSeenAt?: Date | null;
+}
+
+export const DeviceSchema = SchemaFactory.createForClass(Device);
+DeviceSchema.index({ userId: 1, fcmToken: 1 }, { unique: true });
+DeviceSchema.index({ userId: 1, deviceId: 1 }, { sparse: true });

src/modules/follows/follows-users.controller.ts

@@ -0,0 +1,58 @@
+import { Controller, Delete, Get, Param, Post, Query, UseGuards } from '@nestjs/common';
+import { ApiBearerAuth, ApiTags } from '@nestjs/swagger';
+import { CurrentUser } from '../../common/decorators/current-user.decorator';
+import { PaginationQueryDto } from '../../common/dto/pagination-query.dto';
+import { JwtAuthGuard } from '../../common/guards/jwt-auth.guard';
+import { JwtPayload } from '../../common/interfaces/jwt-payload.interface';
+import { FollowsService } from './follows.service';
+
+@ApiTags('Users')
+@ApiBearerAuth()
+@UseGuards(JwtAuthGuard)
+@Controller('users')
+export class FollowsUsersController {
+  constructor(private readonly followsService: FollowsService) {}
+
+  @Get('me/followers')
+  async myFollowers(@CurrentUser() user: JwtPayload, @Query() query: PaginationQueryDto) {
+    return this.followsService.getFollowers(user.sub, query, user.sub);
+  }
+
+  @Get('me/following')
+  async myFollowing(@CurrentUser() user: JwtPayload, @Query() query: PaginationQueryDto) {
+    return this.followsService.getFollowing(user.sub, query, user.sub);
+  }
+
+  @Post(':userId/follow')
+  async followUser(@CurrentUser() user: JwtPayload, @Param('userId') targetUserId: string) {
+    return this.followsService.followUser(user.sub, targetUserId);
+  }
+
+  @Delete(':userId/follow')
+  async unfollowUser(@CurrentUser() user: JwtPayload, @Param('userId') targetUserId: string) {
+    return this.followsService.unfollowUser(user.sub, targetUserId);
+  }
+
+  @Get(':userId/follow-status')
+  async followStatus(@CurrentUser() user: JwtPayload, @Param('userId') targetUserId: string) {
+    return this.followsService.getFollowStatus(user.sub, targetUserId);
+  }
+
+  @Get(':userId/followers')
+  async followers(
+    @CurrentUser() user: JwtPayload,
+    @Param('userId') targetUserId: string,
+    @Query() query: PaginationQueryDto,
+  ) {
+    return this.followsService.getFollowers(targetUserId, query, user.sub);
+  }
+
+  @Get(':userId/following')
+  async following(
+    @CurrentUser() user: JwtPayload,
+    @Param('userId') targetUserId: string,
+    @Query() query: PaginationQueryDto,
+  ) {
+    return this.followsService.getFollowing(targetUserId, query, user.sub);
+  }
+}

src/modules/follows/follows.controller.ts

@@ -24,15 +24,23 @@ export class FollowsController {
   @ApiBearerAuth()
   @UseGuards(JwtAuthGuard)
   @Get('followers/:userId')
-  async followers(@Param('userId') userId: string, @Query() query: PaginationQueryDto) {
-    return this.followsService.getFollowers(userId, query);
+  async followers(
+    @CurrentUser() user: JwtPayload,
+    @Param('userId') userId: string,
+    @Query() query: PaginationQueryDto,
+  ) {
+    return this.followsService.getFollowers(userId, query, user.sub);
   }
 
   @ApiBearerAuth()
   @UseGuards(JwtAuthGuard)
   @Get('following/:userId')
-  async following(@Param('userId') userId: string, @Query() query: PaginationQueryDto) {
-    return this.followsService.getFollowing(userId, query);
+  async following(
+    @CurrentUser() user: JwtPayload,
+    @Param('userId') userId: string,
+    @Query() query: PaginationQueryDto,
+  ) {
+    return this.followsService.getFollowing(userId, query, user.sub);
   }
 
   @ApiBearerAuth()

src/modules/follows/follows.module.ts

@@ -1,8 +1,10 @@
 import { Module } from '@nestjs/common';
 import { MongooseModule } from '@nestjs/mongoose';
+import { BlocksModule } from '../blocks/blocks.module';
 import { OutboxModule } from '../outbox/outbox.module';
 import { UsersModule } from '../users/users.module';
 import { FollowsController } from './follows.controller';
+import { FollowsUsersController } from './follows-users.controller';
 import { FollowsService } from './follows.service';
 import { FollowsRepository } from './follows.repository';
 import { FollowRequest, FollowRequestSchema } from './schemas/follow-request.schema';
@@ -10,6 +12,7 @@ import { Follow, FollowSchema } from './schemas/follow.schema';
 
 @Module({
   imports: [
+    BlocksModule,
     UsersModule,
     OutboxModule,
     MongooseModule.forFeature([
@@ -23,7 +26,7 @@ import { Follow, FollowSchema } from './schemas/follow.schema';
       },
     ]),
   ],
-  controllers: [FollowsController],
+  controllers: [FollowsController, FollowsUsersController],
   providers: [FollowsService, FollowsRepository],
   exports: [FollowsService, FollowsRepository],
 })

src/modules/follows/follows.repository.ts

@@ -39,6 +39,15 @@ export class FollowsRepository {
     return follow;
   }
 
+  isDuplicateKeyError(error: unknown): boolean {
+    return (
+      typeof error === 'object' &&
+      error !== null &&
+      'code' in error &&
+      (error as { code?: number }).code === 11000
+    );
+  }
+
   async deleteById(id: string, session?: ClientSession): Promise<void> {
     await this.followModel.findByIdAndDelete(id, { session }).exec();
   }
@@ -83,6 +92,28 @@ export class FollowsRepository {
       .exec();
   }
 
+  async findFollowerUserIds(followingId: string, skip: number, limit: number, sort: Record<string, 1 | -1>) {
+    return this.followModel
+      .find({ followingId: new Types.ObjectId(followingId) })
+      .select({ followerId: 1 })
+      .sort(sort)
+      .skip(skip)
+      .limit(limit)
+      .lean()
+      .exec();
+  }
+
+  async findFollowingUserIds(followerId: string, skip: number, limit: number, sort: Record<string, 1 | -1>) {
+    return this.followModel
+      .find({ followerId: new Types.ObjectId(followerId) })
+      .select({ followingId: 1 })
+      .sort(sort)
+      .skip(skip)
+      .limit(limit)
+      .lean()
+      .exec();
+  }
+
   async upsertPendingRequest(requesterId: string, targetUserId: string): Promise<FollowRequestDocument> {
     return this.followRequestModel
       .findOneAndUpdate(

src/modules/follows/follows.service.spec.ts

@@ -21,12 +21,16 @@ describe('FollowsService', () => {
     const outboxService = {
       enqueueFollowNotification: jest.fn().mockRejectedValue(new Error('socket down')),
     };
+    const blocksRepository = {
+      findAnyBetween: jest.fn().mockResolvedValue(null),
+    };
 
     const service = new FollowsService(
       followsRepository as any,
       usersRepository as any,
       outboxService as any,
       { bumpGlobalVersion: jest.fn().mockResolvedValue(1) } as any,
+      blocksRepository as any,
     );
 
     await expect(service.toggleFollow(currentUserId, { targetUserId })).resolves.toEqual({
@@ -40,4 +44,51 @@ describe('FollowsService', () => {
       'follow-1',
     );
   });
+
+  it('prevents users from following themselves', async () => {
+    const userId = '507f1f77bcf86cd799439011';
+    const service = new FollowsService(
+      {} as any,
+      {} as any,
+      {} as any,
+      { bumpGlobalVersion: jest.fn() } as any,
+      { findAnyBetween: jest.fn() } as any,
+    );
+
+    await expect(service.followUser(userId, userId)).rejects.toThrow('You cannot follow yourself');
+  });
+
+  it('returns already-following response without creating duplicate notification', async () => {
+    const currentUserId = '507f1f77bcf86cd799439011';
+    const targetUserId = '507f191e810c19729de860ea';
+    const followsRepository = {
+      findOne: jest.fn().mockResolvedValue({ id: 'existing-follow' }),
+      count: jest.fn().mockResolvedValueOnce(1).mockResolvedValueOnce(2),
+      create: jest.fn(),
+    };
+    const usersRepository = {
+      findById: jest.fn().mockResolvedValue({ id: targetUserId, isDisabled: false, isPrivate: false }),
+      setFollowingCount: jest.fn(),
+      setFollowersCount: jest.fn(),
+    };
+    const outboxService = {
+      enqueueFollowNotification: jest.fn(),
+    };
+    const service = new FollowsService(
+      followsRepository as any,
+      usersRepository as any,
+      outboxService as any,
+      { bumpGlobalVersion: jest.fn() } as any,
+      { findAnyBetween: jest.fn().mockResolvedValue(null) } as any,
+    );
+
+    await expect(service.followUser(currentUserId, targetUserId)).resolves.toMatchObject({
+      message: 'Already following user',
+      isFollowing: true,
+      followersCount: 2,
+      followingCount: 1,
+    });
+    expect(followsRepository.create).not.toHaveBeenCalled();
+    expect(outboxService.enqueueFollowNotification).not.toHaveBeenCalled();
+  });
 });

src/modules/follows/follows.service.ts

@@ -4,6 +4,7 @@ import { PaginationQueryDto } from '../../common/dto/pagination-query.dto';
 import { buildPaginatedResponse } from '../../common/utils/pagination.util';
 import { resolveMongoSortDirection } from '../../common/utils/sort.util';
 import { FeedVersionService } from '../../infrastructure/cache/feed-version.service';
+import { BlocksRepository } from '../blocks/blocks.repository';
 import { OutboxService } from '../outbox/outbox.service';
 import { UsersRepository } from '../users/users.repository';
 import { UserDocument } from '../users/schemas/user.schema';
@@ -19,23 +20,19 @@ export class FollowsService {
     private readonly usersRepository: UsersRepository,
     private readonly outboxService: OutboxService,
     private readonly feedVersionService: FeedVersionService,
+    private readonly blocksRepository: BlocksRepository,
   ) {}
 
   async toggleFollow(currentUserId: string, dto: ToggleFollowDto) {
     const targetUserId = dto.targetUserId;
-
     if (!Types.ObjectId.isValid(targetUserId)) {
       throw new BadRequestException('Invalid target user id');
     }
-
     if (currentUserId === targetUserId) {
       throw new BadRequestException('You cannot follow yourself');
     }
 
-    const targetUser = await this.usersRepository.findById(targetUserId);
-    if (!targetUser) {
-      throw new NotFoundException('Target user not found');
-    }
+    const targetUser = await this.findActiveTargetUser(targetUserId);
 
     const existing = await this.followsRepository.findOne(currentUserId, targetUserId);
 
@@ -46,37 +43,107 @@ export class FollowsService {
       return { following: false };
     }
 
+    const block = await this.blocksRepository.findAnyBetween(currentUserId, targetUserId);
+    if (block) {
+      throw new BadRequestException('You cannot follow this user');
+    }
+
     if (targetUser.isPrivate) {
       const request = await this.followsRepository.upsertPendingRequest(currentUserId, targetUserId);
       return { following: false, requested: true, requestId: request.id };
     }
 
-    const follow = await this.followsRepository.create(currentUserId, targetUserId);
+    let followId: string | null = null;
+    try {
+      const follow = await this.followsRepository.create(currentUserId, targetUserId);
+      followId = follow.id;
+    } catch (error) {
+      if (!this.followsRepository.isDuplicateKeyError(error)) {
+        throw error;
+      }
+    }
     await this.syncFollowCounts(currentUserId, targetUserId);
     await this.feedVersionService.bumpGlobalVersion();
 
-    try {
-      await this.outboxService.enqueueFollowNotification(currentUserId, targetUserId, follow.id);
-    } catch (error) {
-      this.logger.warn(
-        `Follow notification failed for actor=${currentUserId} recipient=${targetUserId}: ${
-          error instanceof Error ? error.message : 'unknown error'
-        }`,
-      );
+    if (followId) {
+      await this.enqueueFollowNotification(currentUserId, targetUserId, followId);
     }
 
     return { following: true };
   }
 
-  async getFollowers(userId: string, query: PaginationQueryDto) {
+  async followUser(currentUserId: string, targetUserId: string) {
+    await this.assertCanFollowTarget(currentUserId, targetUserId);
+    const targetUser = await this.findActiveTargetUser(targetUserId);
+
+    const existing = await this.followsRepository.findOne(currentUserId, targetUserId);
+    if (existing) {
+      const counts = await this.syncFollowCounts(currentUserId, targetUserId);
+      return this.buildFollowActionResponse('Already following user', true, targetUserId, counts);
+    }
+
+    if (targetUser.isPrivate) {
+      const request = await this.followsRepository.upsertPendingRequest(currentUserId, targetUserId);
+      const counts = await this.getFollowCounts(currentUserId, targetUserId);
+      return {
+        ...this.buildFollowActionResponse('Follow request sent', false, targetUserId, counts),
+        requested: true,
+        requestId: request.id,
+      };
+    }
+
+    let followId: string | null = null;
+    try {
+      const follow = await this.followsRepository.create(currentUserId, targetUserId);
+      followId = follow.id;
+    } catch (error) {
+      if (!this.followsRepository.isDuplicateKeyError(error)) {
+        throw error;
+      }
+    }
+
+    const counts = await this.syncFollowCounts(currentUserId, targetUserId);
+    await this.feedVersionService.bumpGlobalVersion();
+
+    if (followId) {
+      await this.enqueueFollowNotification(currentUserId, targetUserId, followId);
+    }
+
+    return this.buildFollowActionResponse('User followed successfully', true, targetUserId, counts);
+  }
+
+  async unfollowUser(currentUserId: string, targetUserId: string) {
+    if (!Types.ObjectId.isValid(targetUserId)) {
+      throw new BadRequestException('Invalid target user id');
+    }
+    if (currentUserId === targetUserId) {
+      throw new BadRequestException('You cannot follow yourself');
+    }
+
+    const existing = await this.followsRepository.findOne(currentUserId, targetUserId);
+    if (existing) {
+      await this.followsRepository.deleteById(existing.id);
+      await this.feedVersionService.bumpGlobalVersion();
+    }
+
+    const counts = await this.syncFollowCounts(currentUserId, targetUserId);
+    return this.buildFollowActionResponse('User unfollowed successfully', false, targetUserId, counts);
+  }
+
+  async getFollowers(userId: string, query: PaginationQueryDto, viewerUserId?: string) {
+    await this.assertListTargetExists(userId);
     const page = query.page ?? 1;
     const limit = query.limit ?? 20;
     const skip = (page - 1) * limit;
     const sort = { createdAt: resolveMongoSortDirection(query.sortOrder) } as Record<string, 1 | -1>;
-    const [items, total] = await Promise.all([
-      this.followsRepository.findMany({ followingId: userId }, skip, limit, sort),
+    const [followRows, total] = await Promise.all([
+      this.followsRepository.findFollowerUserIds(userId, skip, limit, sort),
       this.followsRepository.count({ followingId: userId }),
     ]);
+    const items = await this.decorateFollowUsers(
+      followRows.map((row) => row.followerId.toString()),
+      viewerUserId,
+    );
 
     return buildPaginatedResponse(items, {
       page,
@@ -86,15 +153,20 @@ export class FollowsService {
     });
   }
 
-  async getFollowing(userId: string, query: PaginationQueryDto) {
+  async getFollowing(userId: string, query: PaginationQueryDto, viewerUserId?: string) {
+    await this.assertListTargetExists(userId);
     const page = query.page ?? 1;
     const limit = query.limit ?? 20;
     const skip = (page - 1) * limit;
     const sort = { createdAt: resolveMongoSortDirection(query.sortOrder) } as Record<string, 1 | -1>;
-    const [items, total] = await Promise.all([
-      this.followsRepository.findMany({ followerId: userId }, skip, limit, sort),
+    const [followRows, total] = await Promise.all([
+      this.followsRepository.findFollowingUserIds(userId, skip, limit, sort),
       this.followsRepository.count({ followerId: userId }),
     ]);
+    const items = await this.decorateFollowUsers(
+      followRows.map((row) => row.followingId.toString()),
+      viewerUserId,
+    );
 
     return buildPaginatedResponse(items, {
       page,
@@ -110,16 +182,28 @@ export class FollowsService {
     }
 
     if (currentUserId === targetUserId) {
-      return { following: false, targetUserId };
+      return {
+        following: false,
+        isFollowing: false,
+        isFollowedBy: false,
+        isMutual: false,
+        targetUserId,
+      };
     }
 
-    const existing = await this.followsRepository.findOne(currentUserId, targetUserId);
+    const [existing, reverseExisting] = await Promise.all([
+      this.followsRepository.findOne(currentUserId, targetUserId),
+      this.followsRepository.findOne(targetUserId, currentUserId),
+    ]);
     const pendingRequest =
       currentUserId === targetUserId
         ? null
         : await this.followsRepository.findPendingRequest(currentUserId, targetUserId);
     return {
       following: !!existing,
+      isFollowing: !!existing,
+      isFollowedBy: !!reverseExisting,
+      isMutual: !!existing && !!reverseExisting,
       requested: !!pendingRequest,
       targetUserId,
     };
@@ -282,7 +366,10 @@ export class FollowsService {
     return count;
   }
 
-  private async syncFollowCounts(currentUserId: string, targetUserId: string): Promise<void> {
+  private async syncFollowCounts(
+    currentUserId: string,
+    targetUserId: string,
+  ): Promise<{ followingCount: number; followersCount: number }> {
     const [followingCount, followersCount] = await Promise.all([
       this.followsRepository.count({ followerId: currentUserId }),
       this.followsRepository.count({ followingId: targetUserId }),
@@ -292,5 +379,102 @@ export class FollowsService {
       this.usersRepository.setFollowingCount(currentUserId, followingCount),
       this.usersRepository.setFollowersCount(targetUserId, followersCount),
     ]);
+
+    return { followingCount, followersCount };
+  }
+
+  private async getFollowCounts(
+    currentUserId: string,
+    targetUserId: string,
+  ): Promise<{ followingCount: number; followersCount: number }> {
+    const [followingCount, followersCount] = await Promise.all([
+      this.followsRepository.count({ followerId: currentUserId }),
+      this.followsRepository.count({ followingId: targetUserId }),
+    ]);
+
+    return { followingCount, followersCount };
+  }
+
+  private async assertCanFollowTarget(currentUserId: string, targetUserId: string): Promise<void> {
+    if (!Types.ObjectId.isValid(targetUserId)) {
+      throw new BadRequestException('Invalid target user id');
+    }
+
+    if (currentUserId === targetUserId) {
+      throw new BadRequestException('You cannot follow yourself');
+    }
+
+    const block = await this.blocksRepository.findAnyBetween(currentUserId, targetUserId);
+    if (block) {
+      throw new BadRequestException('You cannot follow this user');
+    }
+  }
+
+  private async findActiveTargetUser(targetUserId: string): Promise<UserDocument> {
+    const targetUser = await this.usersRepository.findById(targetUserId);
+    if (!targetUser || targetUser.isDisabled) {
+      throw new NotFoundException('Target user not found');
+    }
+    return targetUser;
+  }
+
+  private async assertListTargetExists(userId: string): Promise<void> {
+    if (!Types.ObjectId.isValid(userId)) {
+      throw new BadRequestException('Invalid user id');
+    }
+    await this.findActiveTargetUser(userId);
+  }
+
+  private async enqueueFollowNotification(actorId: string, recipientId: string, followId: string): Promise<void> {
+    try {
+      await this.outboxService.enqueueFollowNotification(actorId, recipientId, followId);
+    } catch (error) {
+      this.logger.warn(
+        `Follow notification failed for actor=${actorId} recipient=${recipientId}: ${
+          error instanceof Error ? error.message : 'unknown error'
+        }`,
+      );
+    }
+  }
+
+  private buildFollowActionResponse(
+    message: string,
+    isFollowing: boolean,
+    targetUserId: string,
+    counts: { followingCount: number; followersCount: number },
+  ) {
+    return {
+      message,
+      following: isFollowing,
+      isFollowing,
+      targetUserId,
+      followersCount: counts.followersCount,
+      followingCount: counts.followingCount,
+    };
+  }
+
+  private async decorateFollowUsers(userIds: string[], viewerUserId?: string) {
+    const users = await this.usersRepository.findManyByIds(userIds);
+    const usersById = new Map(users.map((user) => [user.id, user]));
+    const viewerFollowingIds = viewerUserId ? new Set(await this.followsRepository.findFollowingIds(viewerUserId)) : new Set();
+
+    return userIds
+      .map((id) => usersById.get(id))
+      .filter((user): user is UserDocument => !!user)
+      .map((user) => {
+        const object = user.toObject();
+        return {
+          _id: object._id,
+          name: object.name,
+          stageName: object.stageName,
+          username: object.username,
+          avatar: object.avatar,
+          isVerified: object.isVerified,
+          isDisabled: object.isDisabled,
+          followersCount: object.followersCount ?? 0,
+          followingCount: object.followingCount ?? 0,
+          isFollowing: viewerFollowingIds.has(user.id),
+        };
+      });
   }
 }

src/modules/follows/schemas/follow.schema.ts

@@ -15,3 +15,5 @@ export class Follow {
 
 export const FollowSchema = SchemaFactory.createForClass(Follow);
 FollowSchema.index({ followerId: 1, followingId: 1 }, { unique: true });
+FollowSchema.index({ followerId: 1, createdAt: -1 });
+FollowSchema.index({ followingId: 1, createdAt: -1 });

src/modules/notifications/notifications.repository.ts

@@ -92,22 +92,28 @@ export class NotificationsRepository {
   }
 
   async markRead(recipientId: string, notificationId: string): Promise<NotificationDocument | null> {
-    const updated = await this.notificationModel
-      .findOneAndUpdate(
-        {
-          _id: new Types.ObjectId(notificationId),
-          recipientId: new Types.ObjectId(recipientId),
-        },
-        {
-          read: true,
-          readAt: new Date(),
-        },
-        { new: true },
-      )
-      .populate({ path: 'actorId', select: 'name username stageName avatar isVerified isDisabled' })
+    const notification = await this.notificationModel
+      .findOne({
+        _id: new Types.ObjectId(notificationId),
+        recipientId: new Types.ObjectId(recipientId),
+      })
       .exec();
 
-    return updated;
+    if (!notification) {
+      return null;
+    }
+
+    if (notification.read) {
+      await notification.populate({ path: 'actorId', select: 'name username stageName avatar isVerified isDisabled' });
+      return notification;
+    }
+
+    notification.read = true;
+    notification.readAt = notification.readAt ?? new Date();
+    await notification.save();
+    await notification.populate({ path: 'actorId', select: 'name username stageName avatar isVerified isDisabled' });
+
+    return notification;
   }
 
   async markAllRead(recipientId: string): Promise<number> {

src/modules/notifications/notifications.service.spec.ts

@@ -47,6 +47,7 @@ describe('NotificationsService', () => {
 
     await expect(service.markAllRead('user-1')).resolves.toEqual({
       message: 'All notifications marked as read',
+      modifiedCount: 4,
       updatedCount: 4,
       unreadCount: 2,
     });
@@ -70,4 +71,68 @@ describe('NotificationsService', () => {
     await expect(service.markRead('user-1', 'invalid-id')).rejects.toBeInstanceOf(NotFoundException);
     expect(notificationsRepository.markRead).not.toHaveBeenCalled();
   });
+
+  it('returns total unread count for the current user in the notifications list', async () => {
+    const notificationsRepository = {
+      findMine: jest.fn().mockResolvedValue([{ id: 'notification-1' }]),
+      countMine: jest.fn().mockResolvedValue(30),
+      countUnread: jest.fn().mockResolvedValue(7),
+    };
+    const notificationsGateway = {
+      emitUnreadCount: jest.fn(),
+    };
+
+    const service = new NotificationsService(
+      notificationsRepository as any,
+      notificationsGateway as any,
+    );
+
+    await expect(
+      service.getMine('507f1f77bcf86cd799439011', {
+        page: 1,
+        limit: 20,
+        sortOrder: 'desc' as any,
+      }),
+    ).resolves.toMatchObject({
+      count: 1,
+      page: 1,
+      limit: 20,
+      total: 30,
+      unreadCount: 7,
+      pagination: {
+        mode: 'offset',
+        hasNextPage: true,
+      },
+    });
+    expect(notificationsRepository.countUnread).toHaveBeenCalledWith('507f1f77bcf86cd799439011');
+  });
+
+  it('creates system notifications with system resource mapping when requested', async () => {
+    const notificationsRepository = {
+      create: jest.fn().mockResolvedValue({ toJSON: () => ({ _id: 'notification-1' }) }),
+      countUnread: jest.fn().mockResolvedValue(1),
+    };
+    const notificationsGateway = {
+      emitCreated: jest.fn(),
+    };
+
+    const service = new NotificationsService(
+      notificationsRepository as any,
+      notificationsGateway as any,
+    );
+
+    await service.create({
+      actorId: '507f1f77bcf86cd799439011',
+      recipientId: '507f191e810c19729de860ea',
+      type: 'system',
+    });
+
+    expect(notificationsRepository.create).toHaveBeenCalledWith(
+      expect.objectContaining({
+        type: 'system',
+        resourceType: 'system',
+        deepLink: '',
+      }),
+    );
+  });
 });

src/modules/notifications/notifications.service.ts

@@ -206,10 +206,13 @@ export class NotificationsService {
 
     const sort = { createdAt: resolveMongoSortDirection(query.sortOrder) } as Record<string, 1 | -1>;
 
+    const unreadFilter = { ...filter };
+    delete unreadFilter.read;
+
     const [items, total, unreadCount] = await Promise.all([
       this.notificationsRepository.findMany(filter, skip, limit, sort),
       this.notificationsRepository.count(filter),
-      this.notificationsRepository.countUnreadAll(filter),
+      this.notificationsRepository.countUnreadAll(unreadFilter),
     ]);
 
     return {
@@ -250,13 +253,14 @@ export class NotificationsService {
   }
 
   async markAllRead(recipientId: string) {
-    const updatedCount = await this.notificationsRepository.markAllRead(recipientId);
+    const modifiedCount = await this.notificationsRepository.markAllRead(recipientId);
     const unreadCount = await this.notificationsRepository.countUnread(recipientId);
     this.notificationsGateway.emitUnreadCount(recipientId, unreadCount);
 
     return {
       message: 'All notifications marked as read',
-      updatedCount,
+      modifiedCount,
+      updatedCount: modifiedCount,
       unreadCount,
     };
   }
@@ -277,6 +281,12 @@ export class NotificationsService {
         return 'Post shared';
       case 'mention':
         return 'New mention';
+      case 'reply':
+        return 'New reply';
+      case 'system':
+        return 'Notification';
+      case 'collaboration_request':
+        return 'Collaboration request';
       default:
         return 'Notification';
     }
@@ -288,6 +298,10 @@ export class NotificationsService {
         return 'user';
       case 'message':
         return 'conversation';
+      case 'system':
+        return 'system';
+      case 'collaboration_request':
+        return 'post';
       default:
         return 'post';
     }
@@ -306,8 +320,8 @@ export class NotificationsService {
       return `/users/${referenceId}`;
     }
 
-    if (resourceType === 'comment' && referenceId) {
-      return `/comments/${referenceId}`;
+    if (resourceType === 'system') {
+      return '';
     }
 
     if (referenceId) {

src/modules/notifications/schemas/notification.schema.ts

@@ -4,7 +4,18 @@ import { User } from '../../users/schemas/user.schema';
 
 export type NotificationDocument = HydratedDocument<Notification>;
 
-export const NOTIFICATION_TYPES = ['like', 'comment', 'follow', 'message', 'save', 'share', 'mention'] as const;
+export const NOTIFICATION_TYPES = [
+  'like',
+  'comment',
+  'follow',
+  'message',
+  'save',
+  'share',
+  'mention',
+  'reply',
+  'system',
+  'collaboration_request',
+] as const;
 export type NotificationType = (typeof NOTIFICATION_TYPES)[number];
 
 @Schema({ timestamps: true, versionKey: false })
@@ -47,4 +58,6 @@ export const NotificationSchema = SchemaFactory.createForClass(Notification);
 NotificationSchema.index({ recipientId: 1, createdAt: -1 });
 NotificationSchema.index({ recipientId: 1, read: 1, createdAt: -1 });
 NotificationSchema.index({ recipientId: 1, read: 1, type: 1, createdAt: -1 });
+NotificationSchema.index({ recipientId: 1, type: 1, createdAt: -1 });
 NotificationSchema.index({ recipientId: 1, resourceType: 1, createdAt: -1 });
+NotificationSchema.index({ referenceId: 1 });

src/modules/posts/posts-users.controller.ts

@@ -0,0 +1,24 @@
+import { Controller, Get, Param, Query, UseGuards } from '@nestjs/common';
+import { ApiBearerAuth, ApiTags } from '@nestjs/swagger';
+import { CurrentUser } from '../../common/decorators/current-user.decorator';
+import { JwtAuthGuard } from '../../common/guards/jwt-auth.guard';
+import { JwtPayload } from '../../common/interfaces/jwt-payload.interface';
+import { PostQueryDto } from './dto/post-query.dto';
+import { PostsService } from './posts.service';
+
+@ApiTags('Users')
+@ApiBearerAuth()
+@UseGuards(JwtAuthGuard)
+@Controller('users')
+export class PostsUsersController {
+  constructor(private readonly postsService: PostsService) {}
+
+  @Get(':userId/posts')
+  async findUserPosts(
+    @CurrentUser() user: JwtPayload,
+    @Param('userId') userId: string,
+    @Query() query: PostQueryDto,
+  ) {
+    return this.postsService.findUserPosts(userId, query, user.sub);
+  }
+}

src/modules/posts/posts.controller.ts

@@ -106,8 +106,12 @@ export class PostsController {
   @ApiBearerAuth()
   @UseGuards(JwtAuthGuard)
   @Get('user/:userId')
-  async findUserPosts(@Param('userId') userId: string, @Query() query: PostQueryDto) {
-    return this.postsService.findUserPosts(userId, query);
+  async findUserPosts(
+    @CurrentUser() user: JwtPayload,
+    @Param('userId') userId: string,
+    @Query() query: PostQueryDto,
+  ) {
+    return this.postsService.findUserPosts(userId, query, user.sub);
   }
 
   @ApiBearerAuth()

src/modules/posts/posts.module.ts

@@ -5,6 +5,7 @@ import { NotificationsModule } from '../notifications/notifications.module';
 import { UsersModule } from '../users/users.module';
 import { Post, PostSchema } from './schemas/post.schema';
 import { PostsController } from './posts.controller';
+import { PostsUsersController } from './posts-users.controller';
 import { PostsRepository } from './posts.repository';
 import { PostsService } from './posts.service';
 
@@ -20,7 +21,7 @@ import { PostsService } from './posts.service';
     NotificationsModule,
     UsersModule,
   ],
-  controllers: [PostsController],
+  controllers: [PostsController, PostsUsersController],
   providers: [PostsService, PostsRepository],
   exports: [PostsService, PostsRepository],
 })

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;
+  }
 }

src/modules/users/schemas/user.schema.ts

@@ -99,6 +99,12 @@ export class User {
   @Prop({ default: false })
   isEmailVerified!: boolean;
 
+  @Prop({ default: false, index: true })
+  isOnline!: boolean;
+
+  @Prop({ type: Date, default: null })
+  lastSeenAt?: Date | null;
+
   @Prop({ default: '', trim: true, maxlength: 120 })
   shopName!: string;
 

src/modules/users/users.controller.ts

@@ -288,11 +288,18 @@ export class UsersController {
     return this.usersService.getProfileOverview(id, user.sub);
   }
 
+  @ApiBearerAuth()
+  @UseGuards(JwtAuthGuard)
+  @Get(':id/presence')
+  async getPresence(@Param('id') id: string) {
+    return this.usersService.getPresence(id);
+  }
+
   @ApiBearerAuth()
   @UseGuards(JwtAuthGuard)
   @Get(':id')
-  async findOne(@Param('id') id: string) {
-    return this.usersService.findPublicByIdOrFail(id);
+  async findOne(@CurrentUser() user: JwtPayload, @Param('id') id: string) {
+    return this.usersService.findPublicByIdForViewer(id, user.sub);
   }
 
   @ApiBearerAuth()

src/modules/users/users.repository.ts

@@ -1,6 +1,6 @@
 import { Injectable } from '@nestjs/common';
 import { InjectModel } from '@nestjs/mongoose';
-import { ClientSession, FilterQuery, Model, UpdateQuery } from 'mongoose';
+import { ClientSession, FilterQuery, Model, Types, UpdateQuery } from 'mongoose';
 import { User, UserDocument } from './schemas/user.schema';
 
 @Injectable()
@@ -69,6 +69,12 @@ export class UsersRepository {
     await this.userModel.findByIdAndUpdate(userId, { followingCount }, { new: false }).exec();
   }
 
+  async setPresence(userId: string, isOnline: boolean, lastSeenAt: Date): Promise<void> {
+    await this.userModel
+      .findByIdAndUpdate(userId, { isOnline, lastSeenAt }, { new: false })
+      .exec();
+  }
+
   async findMany(
     filter: FilterQuery<UserDocument>,
     skip: number,
@@ -78,6 +84,16 @@ export class UsersRepository {
     return this.userModel.find(filter).sort(sort).skip(skip).limit(limit).exec();
   }
 
+  async findManyByIds(ids: string[]): Promise<UserDocument[]> {
+    if (!ids.length) {
+      return [];
+    }
+
+    return this.userModel
+      .find({ _id: { $in: ids.map((id) => new Types.ObjectId(id)) } })
+      .exec();
+  }
+
   async findByUsernames(usernames: string[]): Promise<UserDocument[]> {
     if (!usernames.length) {
       return [];

src/modules/users/users.service.ts

@@ -237,6 +237,40 @@ export class UsersService {
     return user;
   }
 
+  async findPublicByIdForViewer(userId: string, viewerUserId: string) {
+    const user = await this.findPublicByIdOrFail(userId);
+    const isFollowing =
+      viewerUserId === userId
+        ? false
+        : (await this.connection.collection('follows').countDocuments({
+            followerId: new Types.ObjectId(viewerUserId),
+            followingId: new Types.ObjectId(userId),
+          })) > 0;
+
+    return {
+      ...user.toObject(),
+      isFollowing,
+      following: isFollowing,
+      isOwnProfile: viewerUserId === userId,
+    };
+  }
+
+  async getPresence(userId: string) {
+    const user = await this.findPublicByIdOrFail(userId);
+    return {
+      userId: user.id,
+      isOnline: user.isOnline ?? false,
+      lastSeenAt: user.lastSeenAt ?? null,
+    };
+  }
+
+  async setPresence(userId: string, isOnline: boolean): Promise<void> {
+    if (!Types.ObjectId.isValid(userId)) {
+      return;
+    }
+    await this.usersRepository.setPresence(userId, isOnline, new Date());
+  }
+
   async findByEmailWithPassword(email: string): Promise<UserDocument | null> {
     return this.usersRepository.findOneWithPassword({ email: email.toLowerCase() });
   }
@@ -737,6 +771,7 @@ export class UsersService {
       viewerState: {
         isOwnProfile: viewerUserId === userId,
         following: followingState,
+        isFollowing: followingState,
         canMessage: viewerUserId !== userId,
       },
     };
@@ -749,6 +784,7 @@ export class UsersService {
       viewerState: {
         isOwnProfile: false,
         following: false,
+        isFollowing: false,
         canMessage: false,
       },
     };