RocketChat/Rocket.Chat

import type { IUser } from '@rocket.chat/core-typings';
import { Meteor } from 'meteor/meteor';
import { Mongo } from 'meteor/mongo';
import { Tracker } from 'meteor/tracker';

import { RoomManager } from '../../../../client/lib/RoomManager';
import { asReactiveSource } from '../../../../client/lib/tracker';
import { Messages } from '../../../models/client';

export const usersFromRoomMessages = new Mongo.Collection<{
    _id: string;
    username: string;
    name: string | undefined;
    ts: Date;
    suggestion?: boolean;
}>(null);

Meteor.startup(() => {
    Tracker.autorun(() => {
        const uid = Meteor.userId();
        const rid = asReactiveSource(
            (cb) => RoomManager.on('changed', cb),
            () => RoomManager.opened,
        );
        const user = uid ? (Meteor.users.findOne(uid, { fields: { username: 1 } }) as IUser | undefined) : undefined;
        if (!rid || !user) {
            return;
        }

        usersFromRoomMessages.remove({});

        const uniqueMessageUsersControl: Record<string, boolean> = {};

        Messages.find(
            {
                rid,
                'u.username': { $ne: user.username },
                't': { $exists: false },
            },
            {
                fields: {
                    'u.username': 1,
                    'u.name': 1,
                    'u._id': 1,
                    'ts': 1,
                },
                sort: { ts: -1 },
            },
        )
            .fetch()
            .filter(({ u: { username } }) => {
                const notMapped = !uniqueMessageUsersControl[username];
                uniqueMessageUsersControl[username] = true;
                return notMapped;
            })
            .forEach(({ u: { username, name, _id }, ts }) =>
                usersFromRoomMessages.upsert(_id, {
                    _id,
                    username,
                    name,
                    ts,
                }),
            );
    });
});