import { ref, readonly } from 'vue';
import { TTSProvider } from '../providers/types.js';
export interface UseVoiceQueueOptions {
    /** Override the injected provider for this queue instance */
    provider?: TTSProvider;
}
export interface UseVoiceQueueReturn {
    /** Items waiting to be spoken (does not include the currently-speaking item) */
    readonly queue: ReturnType<typeof readonly<ReturnType<typeof ref<string[]>>>>;
    /** The text currently being spoken, or null if idle */
    readonly currentItem: ReturnType<typeof readonly<ReturnType<typeof ref<string | null>>>>;
    /** Whether the queue is currently speaking something */
    readonly isPlaying: ReturnType<typeof readonly<ReturnType<typeof ref<boolean>>>>;
    /** Add a text item to the end of the queue. Starts speaking immediately if idle */
    enqueue(text: string): void;
    /**
     * Manually pop the next item from the queue without speaking it.
     * Useful for manual queue management; does NOT affect auto-advance behaviour.
     */
    dequeue(): string | undefined;
    /** Stop the current utterance and discard all pending items */
    clear(): void;
    /**
     * Stop the current utterance immediately.
     * Auto-advance fires the next item via `onEnd`.
     */
    skip(): void;
}
/**
 * Reactive voice queue — auto-advances to the next item when each utterance ends.
 *
 * The queue relies on the provider's `onEnd` hook (added in Sprint 2, I-2.1)
 * to advance automatically. The `isPlaying` flag guards against double-advance
 * when multiple composables share the same provider instance.
 *
 * All providers (WebSpeech + AI) consistently emit `onEnd` after every speak()
 * call, whether it ended normally or via an error.
 */
export declare function useVoiceQueue(options?: UseVoiceQueueOptions): UseVoiceQueueReturn;