export type LivenessCallbacks = {
    onChallengeChanged?: (stepIndex: number, stepLabel: string) => void;
    onFailure?: (reason: string) => void;
    onSuccess?: (imageBase64: string) => void;
    onFaceInOval?: (inside: boolean, reason?: string) => void;
    onDebugFrame?: (info: {
        hasFace: boolean;
        metrics: Metrics | null;
        step: string;
    }) => void;
};
export type LivenessSoundOptions = {
    baseUrl?: string;
    left?: string;
    blink?: string;
    right?: string;
    nod?: string;
    mouth?: string;
    good?: string;
    capture?: string;
};
export type LivenessOptions = {
    videoElement: HTMLVideoElement;
    canvasElement: HTMLCanvasElement;
    modelUrl?: string;
    wasmUrl?: string;
    callbacks?: LivenessCallbacks;
    sounds?: LivenessSoundOptions;
    /** Subset of challenges to run. Default: all 5. Empty array, duplicates and unknown keys fall back to all 5. */
    steps?: LivenessStepKey[];
    /** Shuffle the selected step order. Default true. */
    shuffleSteps?: boolean;
};
/** Identifier for a liveness challenge step. Lowercase, matches the sound-key form. */
export type LivenessStepKey = "left" | "blink" | "right" | "nod" | "mouth";
export declare const DEFAULT_MODEL_URL = "https://storage.googleapis.com/mediapipe-models/face_landmarker/face_landmarker/float16/1/face_landmarker.task";
export declare const DEFAULT_WASM_URL = "https://cdn.jsdelivr.net/npm/@mediapipe/tasks-vision@latest/wasm";
/** Error code when CDN/assets are unavailable after retries (internet confirmed). */
export declare const LIVENESS_ERROR_CDN_NOT_AVAILABLE: "cdnNotAvailable";
/** Error code when the user has no internet connection. */
export declare const LIVENESS_ERROR_OFFLINE: "offline";
export declare function isCdnNotAvailableError(reason: string): boolean;
export declare function isOfflineError(reason: string): boolean;
export declare class LivenessError extends Error {
    readonly code: typeof LIVENESS_ERROR_CDN_NOT_AVAILABLE | typeof LIVENESS_ERROR_OFFLINE;
    constructor(code: typeof LIVENESS_ERROR_CDN_NOT_AVAILABLE | typeof LIVENESS_ERROR_OFFLINE, message: string);
}
export type Metrics = {
    yaw: number;
    pitch: number;
    ear: number;
    mar: number;
    blinkScore: number;
    mouthScore: number;
    faceCx: number;
    faceCy: number;
    faceSize: number;
};
/** Resolve a caller-supplied step-key array into the corresponding display labels.
 *  Empty / undefined / all-invalid → default to all 5 steps. Duplicates are dropped. */
export declare function resolveStepLabels(keys?: readonly LivenessStepKey[] | null): string[];
/** Default step count (5). The active session may have fewer if `options.steps` is set. */
export declare const LIVENESS_STEP_COUNT: number;
export declare class LivenessEngine {
    private opts;
    private landmarker;
    private running;
    private rafId;
    private stream;
    private steps;
    private stepIndex;
    private stepStart;
    private baselineYaw;
    private baselinePitch;
    private baselineSamples;
    private blinkState;
    private blinkCloseTs;
    private blinkSeenOpen;
    private nodState;
    private holdStart;
    private latestMetrics;
    private nodPeakDPitch;
    private lastDetectTs;
    private lastOvalState;
    private stepSoundPlayedForCurrentStep;
    private currentAudio;
    private currentAudioCleanup;
    private currentAudioToken;
    private sessionTimeoutId;
    constructor(opts: LivenessOptions);
    private playSound;
    private getSoundUrl;
    private playStepSound;
    private stopAllSounds;
    private clearSessionTimeout;
    private playGoodSound;
    private playCaptureSound;
    /** Number of challenge steps in the active session (after applying `options.steps`). */
    get stepCount(): number;
    start(): Promise<void>;
    stop(): void;
    private stopDetectionOnly;
    private ensureVideo;
    private createLandmarker;
    private loop;
    private checkFaceInOval;
    private resetStepState;
    private updateState;
    private advanceStep;
    private fail;
    private scheduleCapture;
    private captureImage;
}