/**
 * Facial expression detection utilities (optional, requires user permission)
 */
export interface FacialExpression {
    emotion: 'happy' | 'sad' | 'angry' | 'surprised' | 'neutral' | 'confused';
    confidence: number;
    features: {
        smiling: number;
        eyebrowsRaised: number;
        eyesWide: number;
    };
}
/**
 * Facial expression analyzer using webcam
 * Note: This is a simplified implementation. For production, consider using
 * libraries like face-api.js or TensorFlow.js with face detection models
 */
export declare class FacialAnalyzer {
    private video;
    private canvas;
    private stream;
    private animationFrame;
    private callback;
    start(callback: (result: FacialExpression) => void): Promise<boolean>;
    private analyze;
    stop(): void;
}
/**
 * Check if facial detection is supported
 */
export declare function isFacialDetectionSupported(): boolean;
/**
 * Request camera permission
 */
export declare function requestCameraPermission(): Promise<boolean>;