/**
 * Message-state transitions for a streaming turn — start, append, end, fail.
 *
 * Deliberately does NOT parse frames or extract tokens any more. It used to
 * carry its own `parseStreamPayload` and a 10-path `extractTokenText` that was
 * byte-for-byte identical to the one in `streaming/sse-parser.ts` (whose
 * docstring records that it was lifted from here). The widget now consumes
 * parsed events from `stream-runner`, so the second copy was deleted rather than
 * kept in sync by hand.
 */
import type { MessageType } from '@/widget/types';
type StreamingDeps = {
    setMessages: (fn: (prev: MessageType[]) => MessageType[]) => void;
    appendToken: (text: string) => void;
};
export declare const useStreamingChat: (deps: StreamingDeps) => {
    startStream: () => void;
    ensureStreamMessage: () => void;
    appendStreamChunk: (chunk: string) => void;
    endStream: () => void;
    failStream: (errorMessage: string) => void;
};
export {};