export type PermissionState = 'granted' | 'denied' | 'prompt' | 'unavailable';
export declare class PermissionManager {
    private static instance;
    private cameraState;
    private microphoneState;
    private cameraListeners;
    private microphoneListeners;
    private constructor();
    static getInstance(): PermissionManager;
    private init;
    getCameraState(): PermissionState;
    getMicrophoneState(): PermissionState;
    addCameraListener(listener: (state: PermissionState) => void): void;
    addMicrophoneListener(listener: (state: PermissionState) => void): void;
    private notifyCameraListeners;
    private notifyMicrophoneListeners;
    private checkCameraPermission;
    private checkMicrophonePermission;
    requestCameraPermission(): Promise<PermissionState>;
    requestMicrophonePermission(): Promise<PermissionState>;
}