RocketChat/Rocket.Chat

import type { IMessage, IRoom, IUser } from '@rocket.chat/core-typings';
import { isEditedMessage } from '@rocket.chat/core-typings';
import { Messages } from '@rocket.chat/models';
import { Meteor } from 'meteor/meteor';

import { callbacks } from '../../../../lib/callbacks';
import { notifyOnMessageChange } from '../../../lib/server/lib/notifyListener';
import { updateThreadUsersSubscriptions, getMentions } from '../../../lib/server/lib/notifyUsersOnMessage';
import { sendMessageNotifications } from '../../../lib/server/lib/sendNotificationsOnMessage';
import { settings } from '../../../settings/server';
import { reply } from '../functions';

async function notifyUsersOnReply(message: IMessage, replies: IUser['_id'][]) {
    // skips this callback if the message was edited
    if (isEditedMessage(message)) {
        return message;
    }

    await updateThreadUsersSubscriptions(message, replies);

    return message;
}

async function metaData(message: IMessage, parentMessage: IMessage, followers: string[]) {
    await reply({ tmid: message.tmid }, message, parentMessage, followers);

    return message;
}

const notification = async (message: IMessage, room: IRoom, replies: string[]) => {
    // skips this callback if the message was edited
    if (isEditedMessage(message)) {
        return message;
    }

    // will send a notification to everyone who replied/followed the thread except the owner of the message
    await sendMessageNotifications(message, room, replies);

    return message;
};

export async function processThreads(message: IMessage, room: IRoom) {
    if (!message.tmid) {
        return message;
    }

    const parentMessage = await Messages.findOneById(message.tmid);
    if (!parentMessage) {
        return message;
    }

    const { mentionIds } = await getMentions(message);

    const replies = [
        ...new Set([
            ...((!parentMessage.tcount ? [parentMessage.u._id] : parentMessage.replies) || []),
            ...(!parentMessage.tcount && room.t === 'd' && room.uids ? room.uids : []),
            ...mentionIds,
        ]),
    ].filter((userId) => userId !== message.u._id);

    await notifyUsersOnReply(message, replies);
    await metaData(message, parentMessage, replies);
    await notification(message, room, replies);
    void notifyOnMessageChange({
        id: message.tmid,
    });

    return message;
}

Meteor.startup(() => {
    settings.watch<boolean>('Threads_enabled', (value) => {
        if (!value) {
            callbacks.remove('afterSaveMessage', 'threads-after-save-message');
            return;
        }
        callbacks.add(
            'afterSaveMessage',
            async (message, { room }) => {
                return processThreads(message, room);
            },
            callbacks.priority.LOW,
            'threads-after-save-message',
        );
    });
});