Fix chat unread counter map updates

src/modules/chat/chat.controller.ts

@@ -1,4 +1,5 @@
 import {
+  BadRequestException,
   Body,
   Controller,
   Get,
@@ -40,6 +41,11 @@ export class ChatController {
     return this.chatService.getMyConversations(user.sub, query);
   }
 
+  @Get('conversations/messages')
+  async messagesMissingConversationId() {
+    throw new BadRequestException('conversationId is required. Use /chat/conversations/:conversationId/messages');
+  }
+
   @Get('conversations/:conversationId/messages')
   async messages(
     @CurrentUser() user: JwtPayload,

src/modules/chat/chat.repository.spec.ts

@@ -0,0 +1,91 @@
+import { Types } from 'mongoose';
+import { ChatRepository } from './chat.repository';
+
+const queryResult = <T>(value: T) => ({
+  exec: jest.fn().mockResolvedValue(value),
+});
+
+describe('ChatRepository unread counters', () => {
+  let conversationModel: Record<string, jest.Mock>;
+  let repository: ChatRepository;
+
+  beforeEach(() => {
+    conversationModel = {
+      create: jest.fn(),
+      findById: jest.fn(),
+      findByIdAndUpdate: jest.fn(),
+      updateOne: jest.fn(),
+    };
+    repository = new ChatRepository(conversationModel as any, {} as any, {} as any);
+  });
+
+  it('creates conversations with string user ids as unread counter keys', async () => {
+    const userA = new Types.ObjectId().toString();
+    const userB = new Types.ObjectId().toString();
+    conversationModel.create.mockResolvedValue({ id: 'conversation-1' });
+
+    await repository.createConversation({
+      participantIds: [userA, userB],
+      isGroup: false,
+      createdBy: userA,
+    });
+
+    expect(conversationModel.create).toHaveBeenCalledWith(
+      expect.objectContaining({
+        unreadCountByUser: {
+          [userA]: 0,
+          [userB]: 0,
+        },
+      }),
+    );
+  });
+
+  it('increments unread count for recipients and resets sender with atomic updates', async () => {
+    const conversationId = new Types.ObjectId().toString();
+    const messageId = new Types.ObjectId().toString();
+    const senderId = new Types.ObjectId().toString();
+    const recipientId = new Types.ObjectId().toString();
+    const updatedConversation = { id: conversationId };
+
+    conversationModel.findById.mockReturnValue(
+      queryResult({
+        participantIds: [new Types.ObjectId(senderId), new Types.ObjectId(recipientId)],
+      }),
+    );
+    conversationModel.findByIdAndUpdate.mockReturnValue(queryResult(updatedConversation));
+
+    await repository.updateConversationAfterNewMessage(conversationId, messageId, senderId, 'hello');
+
+    expect(conversationModel.findByIdAndUpdate).toHaveBeenCalledWith(
+      conversationId,
+      expect.objectContaining({
+        $set: expect.objectContaining({
+          lastMessageId: expect.any(Types.ObjectId),
+          lastMessageText: 'hello',
+          [`unreadCountByUser.${senderId}`]: 0,
+        }),
+        $inc: {
+          [`unreadCountByUser.${recipientId}`]: 1,
+        },
+      }),
+      { new: true },
+    );
+  });
+
+  it('clears unread count for current user without saving a Mongoose Map', async () => {
+    const conversationId = new Types.ObjectId().toString();
+    const userId = new Types.ObjectId().toString();
+    conversationModel.updateOne.mockReturnValue(queryResult({ modifiedCount: 1 }));
+
+    await repository.clearConversationUnreadForUser(conversationId, userId);
+
+    expect(conversationModel.updateOne).toHaveBeenCalledWith(
+      { _id: new Types.ObjectId(conversationId) },
+      {
+        $set: {
+          [`unreadCountByUser.${userId}`]: 0,
+        },
+      },
+    );
+  });
+});

src/modules/chat/chat.repository.ts

@@ -35,9 +35,10 @@ export class ChatRepository {
     title?: string;
     createdBy: string;
   }): Promise<ConversationDocument> {
-    const participantIds = payload.participantIds.map((id) => new Types.ObjectId(id));
+    const participantIdStrings = payload.participantIds.map((id) => id.toString());
+    const participantIds = participantIdStrings.map((id) => new Types.ObjectId(id));
     const unreadCountByUser: Record<string, number> = {};
-    payload.participantIds.forEach((id) => {
+    participantIdStrings.forEach((id) => {
       unreadCountByUser[id] = 0;
     });
 
@@ -141,7 +142,7 @@ export class ChatRepository {
     return this.messageModel
       .findByIdAndUpdate(
         messageId,
-        { $set: { [`reactionsByUser.${userId}`]: reactionType } },
+        { $set: { [`reactionsByUser.${userId.toString()}`]: reactionType } },
         { new: true },
       )
       .populate({ path: 'senderId', select: 'name username stageName avatar isVerified' })
@@ -165,40 +166,41 @@ export class ChatRepository {
       return null;
     }
 
-    const unreadMap = new Map<string, number>(
-      Object.entries((conversation.unreadCountByUser as unknown as Record<string, number>) ?? {}),
-    );
-
+    const senderKey = senderId.toString();
+    const incrementUnreadCounts: Record<string, number> = {};
     for (const participantId of conversation.participantIds) {
       const id = participantId.toString();
-      if (id === senderId) {
-        unreadMap.set(id, 0);
-      } else {
-        unreadMap.set(id, (unreadMap.get(id) ?? 0) + 1);
+      if (id !== senderKey) {
+        incrementUnreadCounts[`unreadCountByUser.${id}`] = 1;
       }
     }
 
-    conversation.lastMessageId = new Types.ObjectId(messageId);
-    conversation.lastMessageText = messageText.slice(0, 4000);
-    conversation.lastMessageAt = new Date();
-    conversation.unreadCountByUser = unreadMap as unknown as Map<string, number>;
-    await conversation.save();
+    const update: Record<string, unknown> = {
+      $set: {
+        lastMessageId: new Types.ObjectId(messageId),
+        lastMessageText: messageText.slice(0, 4000),
+        lastMessageAt: new Date(),
+        [`unreadCountByUser.${senderKey}`]: 0,
+      },
+    };
+    if (Object.keys(incrementUnreadCounts).length > 0) {
+      update.$inc = incrementUnreadCounts;
+    }
 
-    return conversation;
+    return this.conversationModel.findByIdAndUpdate(conversationId, update, { new: true }).exec();
   }
 
   async clearConversationUnreadForUser(conversationId: string, userId: string): Promise<void> {
-    const conversation = await this.conversationModel.findById(conversationId).exec();
-    if (!conversation) {
-      return;
-    }
-
-    const unreadMap = new Map<string, number>(
-      Object.entries((conversation.unreadCountByUser as unknown as Record<string, number>) ?? {}),
-    );
-    unreadMap.set(userId, 0);
-    conversation.unreadCountByUser = unreadMap as unknown as Map<string, number>;
-    await conversation.save();
+    await this.conversationModel
+      .updateOne(
+        { _id: new Types.ObjectId(conversationId) },
+        {
+          $set: {
+            [`unreadCountByUser.${userId.toString()}`]: 0,
+          },
+        },
+      )
+      .exec();
   }
 
   async unsendMessage(messageId: string, senderId: string): Promise<MessageDocument | null> {

src/modules/chat/chat.service.ts

@@ -82,9 +82,11 @@ export class ChatService {
     ]);
 
     const mappedItems = items.map((conversation) => {
-      const unreadMap = (conversation.unreadCountByUser as unknown as Record<string, number>) ?? {};
+      const conversationObject = conversation.toObject();
+      const unreadMap = this.normalizeUnreadCountByUser(conversationObject.unreadCountByUser);
       return {
-        ...conversation.toObject(),
+        ...conversationObject,
+        unreadCountByUser: unreadMap,
         unreadCount: unreadMap[currentUserId] ?? 0,
         lastMessageAt: conversation.lastMessageAt ?? null,
       };
@@ -104,6 +106,10 @@ export class ChatService {
   }
 
   async getMessages(currentUserId: string, conversationId: string, query: MessageQueryDto) {
+    if (!conversationId?.trim()) {
+      throw new BadRequestException('conversationId is required');
+    }
+
     const conversation = await this.assertConversationMember(currentUserId, conversationId);
     const page = query.page ?? 1;
     const limit = query.limit ?? 20;
@@ -326,6 +332,28 @@ export class ChatService {
     }
   }
 
+  private normalizeUnreadCountByUser(value: unknown): Record<string, number> {
+    if (!value) {
+      return {};
+    }
+
+    if (value instanceof Map) {
+      return Object.fromEntries(
+        Array.from(value.entries()).map(([key, count]) => [key.toString(), Number(count) || 0]),
+      );
+    }
+
+    if (typeof value === 'object') {
+      return Object.fromEntries(
+        Object.entries(value as Record<string, unknown>)
+          .filter(([key]) => !key.startsWith('$__') && key !== '$isMongooseMap')
+          .map(([key, count]) => [key, Number(count) || 0]),
+      );
+    }
+
+    return {};
+  }
+
   private async resolveReplyToMessageId(replyToMessageId: string | undefined, conversationId: string) {
     if (!replyToMessageId) {
       return null;

src/modules/chat/schemas/conversation.schema.ts

@@ -29,10 +29,39 @@ export class Conversation {
 
   @Prop({ type: Map, of: Number, default: {} })
   unreadCountByUser!: Map<string, number>;
-
 }
 
 export const ConversationSchema = SchemaFactory.createForClass(Conversation);
 ConversationSchema.index({ participantIds: 1, updatedAt: -1 });
 ConversationSchema.index({ lastMessageAt: -1, updatedAt: -1 });
 ConversationSchema.index({ participantIds: 1, isGroup: 1, lastMessageAt: -1 });
+
+const normalizeUnreadCountByUser = (value: unknown): Record<string, number> => {
+  if (!value) {
+    return {};
+  }
+
+  if (value instanceof Map) {
+    return Object.fromEntries(
+      Array.from(value.entries()).map(([key, count]) => [key.toString(), Number(count) || 0]),
+    );
+  }
+
+  if (typeof value === 'object') {
+    return Object.fromEntries(
+      Object.entries(value as Record<string, unknown>)
+        .filter(([key]) => !key.startsWith('$__') && key !== '$isMongooseMap')
+        .map(([key, count]) => [key, Number(count) || 0]),
+    );
+  }
+
+  return {};
+};
+
+const transformConversation = (_doc: unknown, ret: any) => {
+  ret.unreadCountByUser = normalizeUnreadCountByUser(ret.unreadCountByUser);
+  return ret;
+};
+
+ConversationSchema.set('toJSON', { transform: transformConversation });
+ConversationSchema.set('toObject', { transform: transformConversation });