create generateInitialPreNotifyProps function

apps/app/src/server/service/preNotify.ts

@@ -1,7 +1,24 @@
-import type { IUser } from '@growi/core';
+import type { IPage, IUser, Ref } from '@growi/core';
+
+import { ActivityDocument } from '../models/activity';
+import Subscription from '../models/subscription';
+import { getModelSafely } from '../util/mongoose-utils';
 
 export type PreNotifyProps = {
   notificationTargetUsers?: IUser[],
 }
 
 export type PreNotify = (props: PreNotifyProps) => Promise<void>;
+
+export const generateInitialPreNotifyProps = async(activity: ActivityDocument): Promise<IUser[]> => {
+  const User = getModelSafely('User') || require('~/server/models/user')();
+  const actionUser = activity.user;
+  const target = activity.target;
+  const subscribedUsers = await Subscription.getSubscription(target as unknown as Ref<IPage>);
+  const notificationUsers = subscribedUsers.filter(item => (item.toString() !== actionUser._id.toString()));
+  const activeNotificationUsers = await User.find({
+    _id: { $in: notificationUsers },
+    status: User.STATUS_ACTIVE,
+  }).distinct('_id');
+  return activeNotificationUsers;
+};