RocketChat/Rocket.Chat

import { api, Room } from '@rocket.chat/core-services';
import type { SlashCommandCallbackParams } from '@rocket.chat/core-typings';
import { Rooms, Subscriptions } from '@rocket.chat/models';
import { Meteor } from 'meteor/meteor';

import { i18n } from '../../../server/lib/i18n';
import { settings } from '../../settings/server';
import { slashCommands } from '../../utils/server/slashCommand';

slashCommands.add({
    command: 'join',
    callback: async ({ params, message, userId }: SlashCommandCallbackParams<'join'>): Promise<void> => {
        let channel = params.trim();
        if (channel === '') {
            return;
        }

        if (!userId) {
            return;
        }

        channel = channel.replace('#', '');

        const room = await Rooms.findOneByNameAndType(channel, 'c');
        if (!room) {
            void api.broadcast('notify.ephemeralMessage', userId, message.rid, {
                msg: i18n.t('Channel_doesnt_exist', {
                    postProcess: 'sprintf',
                    sprintf: [channel],
                    lng: settings.get('Language') || 'en',
                }),
            });
            return;
        }

        const subscription = await Subscriptions.findOneByRoomIdAndUserId(room._id, userId, {
            projection: { _id: 1 },
        });

        if (subscription) {
            throw new Meteor.Error('error-user-already-in-room', 'You are already in the channel', {
                method: 'slashCommands',
            });
        }

        await Room.join({ room, user: { _id: userId } });
    },
    options: {
        description: 'Join_the_given_channel',
        params: '#channel',
        permission: 'view-c-room',
    },
});