import type { DingTalkConfig, DingTalkInboundMessage } from './types.js';
type MessageHandler = (msg: DingTalkInboundMessage) => Promise<void>;
export declare class DingTalkClient {
    private dw;
    private messageHandler?;
    /** Cached robotCode from the most recent inbound (== clientId for
     *  stream-mode internal apps, but we read it from messages so we're
     *  tolerant of multi-bot setups in one app). */
    private lastSeenRobotCode;
    constructor(config: DingTalkConfig);
    onMessage(handler: MessageHandler): void;
    start(): Promise<void>;
    stop(): Promise<void>;
    /** Send a plain-text message to a thread we previously received from
     *  (encoded as `user:<staffId>` for 1:1, `group:<convId>` for groups).
     *  Uses OpenAPI under the bot's access token. */
    sendMessage(threadId: string, text: string): Promise<void>;
    /** Send a markdown-formatted message. DingTalk's `sampleMarkdown` only
     *  takes `title` + `text`; we derive title from the first line so the
     *  user sees something meaningful in the notification preview. */
    sendMarkdown(threadId: string, text: string, title?: string): Promise<void>;
    /** Download an inbound image / voice / file message's binary payload.
     *
     *  DingTalk hands the bot a short-lived `downloadCode` in each media
     *  inbound; we trade it (plus our robotCode) for a presigned downloadUrl
     *  on alibaba CDN, then GET that URL and return the bytes.
     *
     *  Returns null on any error (caller surfaces a "[download failed:...]"
     *  marker instead of silently dropping the user's message). MAX cap is
     *  enforced; oversize payloads throw before allocating the buffer.
     *
     *  Reference: POST /v1.0/robot/messageFiles/download
     *             { downloadCode, robotCode }
     *             header: x-acs-dingtalk-access-token
     *             response: { downloadUrl }   (sometimes nested under .data)
     */
    downloadMessageFile(downloadCode: string): Promise<{
        buffer: Buffer;
        contentType: string;
    } | null>;
    /** Shared POST path. msgKey + msgParam (stringified inner object) is
     *  DingTalk's "templated message" convention — covers text, markdown,
     *  cards via the same endpoint. */
    private sendTemplated;
}
export {};
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