Fix chat unread counter map updates

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;