RocketChat/Rocket.Chat

import type {
    IMessage,
    SlashCommand,
    SlashCommandOptions,
    RequiredField,
    SlashCommandPreviewItem,
    SlashCommandPreviews,
} from '@rocket.chat/core-typings';

import { InvalidCommandUsage, InvalidPreview } from '../../../client/lib/errors';

interface ISlashCommandAddParams<T extends string> {
    command: string;
    callback?: SlashCommand<T>['callback'];
    options?: SlashCommandOptions;
    result?: SlashCommand['result'];
    providesPreview?: boolean;
    previewer?: SlashCommand['previewer'];
    previewCallback?: SlashCommand['previewCallback'];
    appId?: string;
    description?: string;
}

export const slashCommands = {
    commands: {} as Record<string, SlashCommand>,
    add<T extends string>({
        command,
        callback,
        options = {},
        result,
        providesPreview = false,
        previewer,
        previewCallback,
        appId,
        description = '',
    }: ISlashCommandAddParams<T>): void {
        if (this.commands[command]) {
            return;
        }
        this.commands[command] = {
            command,
            callback,
            params: options.params,
            description: options.description || description,
            permission: options.permission,
            clientOnly: options.clientOnly || false,
            result,
            providesPreview: Boolean(providesPreview),
            previewer,
            previewCallback,
            appId,
        } as SlashCommand;
    },
    async run({
        command,
        message,
        params,
        triggerId,
        userId,
    }: {
        command: string;
        params: string;
        message: RequiredField<Partial<IMessage>, 'rid' | '_id'>;
        userId: string;
        triggerId?: string | undefined;
    }): Promise<unknown> {
        const cmd = this.commands[command];
        if (typeof cmd?.callback !== 'function') {
            return;
        }

        if (!message?.rid) {
            throw new InvalidCommandUsage();
        }

        return cmd.callback({ command, params, message, triggerId, userId });
    },
    async getPreviews(
        command: string,
        params: string,
        message: RequiredField<Partial<IMessage>, 'rid'>,
    ): Promise<SlashCommandPreviews | undefined> {
        const cmd = this.commands[command];
        if (typeof cmd?.previewer !== 'function') {
            return;
        }

        if (!message?.rid) {
            throw new InvalidCommandUsage();
        }

        const previewInfo = await cmd.previewer(command, params, message);

        if (!previewInfo?.items?.length) {
            return;
        }

        // A limit of ten results, to save time and bandwidth
        if (previewInfo.items.length >= 10) {
            previewInfo.items = previewInfo.items.slice(0, 10);
        }

        return previewInfo;
    },
    async executePreview(
        command: string,
        params: string,
        message: Pick<IMessage, 'rid'> & Partial<Omit<IMessage, 'rid'>>,
        preview: SlashCommandPreviewItem,
        triggerId?: string,
    ) {
        const cmd = this.commands[command];
        if (typeof cmd?.previewCallback !== 'function') {
            return;
        }

        if (!message?.rid) {
            throw new InvalidCommandUsage();
        }

        // { id, type, value }
        if (!preview.id || !preview.type || !preview.value) {
            throw new InvalidPreview();
        }

        return cmd.previewCallback(command, params, message, preview, triggerId);
    },
};

declare module '@rocket.chat/ddp-client' {
    // eslint-disable-next-line @typescript-eslint/naming-convention
    interface ServerMethods {
        slashCommand(params: { cmd: string; params: string; msg: IMessage; triggerId: string }): unknown;
    }
}