cherrypick/src/api/common/notify.ts

import * as mongo from 'mongodb';
import Notification from '../models/notification';
import Mute from '../models/mute';
import event from '../event';
import serialize from '../serializers/notification';

export default (
	notifiee: mongo.ObjectID,
	notifier: mongo.ObjectID,
	type: string,
	content?: any
) => new Promise<any>(async (resolve, reject) => {
	if (notifiee.equals(notifier)) {
		return resolve();
	}

	// Create notification
	const notification = await Notification.insert(Object.assign({
		created_at: new Date(),
		notifiee_id: notifiee,
		notifier_id: notifier,
		type: type,
		is_read: false
	}, content));

	resolve(notification);

	// Publish notification event
	event(notifiee, 'notification',
		await serialize(notification));

	// 3秒経っても(今回作成した)通知が既読にならなかったら「未読の通知がありますよ」イベントを発行する
	setTimeout(async () => {
		const fresh = await Notification.findOne({ _id: notification._id }, { is_read: true });
		if (!fresh.is_read) {
			//#region ただしミュートしているユーザーからの通知なら無視
			const mute = await Mute.find({
				muter_id: notifiee,
				deleted_at: { $exists: false }
			});
			const mutedUserIds = mute.map(m => m.mutee_id.toString());
			if (mutedUserIds.indexOf(notifier.toHexString()) != -1) {
				return;
			}
			//#endregion

			event(notifiee, 'unread_notification', await serialize(notification));
		}
	}, 3000);
});