RocketChat/Rocket.Chat

import type { IMessage, IRoom } from '@rocket.chat/core-typings';
import type { ServerMethods } from '@rocket.chat/ddp-client';
import { Subscriptions, Rooms } from '@rocket.chat/models';
import { check } from 'meteor/check';
import { Meteor } from 'meteor/meteor';

import { canAccessRoomAsync, roomAccessAttributes } from '../../app/authorization/server';
import { hasPermissionAsync } from '../../app/authorization/server/functions/hasPermission';
import { loadMessageHistory } from '../../app/lib/server/functions/loadMessageHistory';
import { settings } from '../../app/settings/server';

declare module '@rocket.chat/ddp-client' {
    // eslint-disable-next-line @typescript-eslint/naming-convention
    interface ServerMethods {
        loadHistory(
            rid: IRoom['_id'],
            ts?: Date,
            limit?: number,
            ls?: string | Date,
            showThreadMessages?: boolean,
        ):
            | {
                    messages: IMessage[];
                    firstUnread: IMessage | undefined;
                    unreadNotLoaded: number;
              }
            | false;
    }
}

Meteor.methods<ServerMethods>({
    async loadHistory(rid, end, limit = 20, ls, showThreadMessages = true) {
        check(rid, String);

        if (!Meteor.userId() && settings.get('Accounts_AllowAnonymousRead') === false) {
            throw new Meteor.Error('error-invalid-user', 'Invalid user', {
                method: 'loadHistory',
            });
        }

        const fromId = Meteor.userId();

        const room = await Rooms.findOneById(rid, { projection: { ...roomAccessAttributes, t: 1 } });
        if (!room) {
            return false;
        }

        // this checks the Allow Anonymous Read setting, so no need to check again
        if (!(await canAccessRoomAsync(room, fromId ? { _id: fromId } : undefined))) {
            return false;
        }

        // if fromId is undefined and it passed the previous check, the user is reading anonymously
        if (!fromId) {
            return loadMessageHistory({ rid, end, limit, ls, showThreadMessages });
        }

        const canPreview = await hasPermissionAsync(fromId, 'preview-c-room');

        if (room.t === 'c' && !canPreview && !(await Subscriptions.findOneByRoomIdAndUserId(rid, fromId, { projection: { _id: 1 } }))) {
            return false;
        }

        return loadMessageHistory({ userId: fromId, rid, end, limit, ls, showThreadMessages });
    },
});