import { StorageKeyType } from './storage-key';
/**
 * Sentinel object returned by middleware to signal that the value has not changed.
 * BaseStorage checks for this by reference equality to skip subscriber notifications.
 */
export declare const VALUE_NOT_CHANGED: unique symbol;
export type StorageActionType = 'get' | 'set' | 'delete' | 'clear' | 'init' | 'keys' | 'update' | 'reset';
export type StorageAction = {
    type: StorageActionType;
    key?: StorageKeyType;
    value?: any;
    metadata?: Record<string, any>;
    source?: string;
    timestamp?: number;
};
export type MiddlewareAPI = {
    dispatch: (action: StorageAction) => Promise<any>;
    getState: () => Promise<Record<string, any>>;
    storage: {
        doGet: (key: StorageKeyType) => Promise<any>;
        doSet: (key: StorageKeyType, value: any) => Promise<void>;
        doUpdate: (updates: Array<{
            key: StorageKeyType;
            value: any;
        }>) => Promise<void>;
        doDelete: (key: StorageKeyType) => Promise<boolean>;
        doClear: () => Promise<void>;
        doKeys: () => Promise<string[]>;
        notifySubscribers: (key: StorageKeyType, value: any) => void;
    };
};
export type NextFunction = (action: StorageAction) => Promise<any>;
export type SetupEventsFunction = (api: MiddlewareAPI) => void;
export type Middleware = {
    name: string;
    setup?: SetupEventsFunction;
    cleanup?: () => Promise<void> | void;
    reducer: (api: MiddlewareAPI) => (next: NextFunction) => (action: StorageAction) => Promise<any>;
};
export type AsyncMiddlewareAPI = MiddlewareAPI;
export type AsyncNextFunction = NextFunction;
export type AsyncMiddleware = Middleware;
export type SyncMiddlewareAPI = {
    dispatch: (action: StorageAction) => any;
    getState: () => Record<string, any>;
    storage: {
        doGet: (key: StorageKeyType) => any;
        doSet: (key: StorageKeyType, value: any) => void;
        doUpdate: (updates: Array<{
            key: StorageKeyType;
            value: any;
        }>) => void;
        doRemove: (key: StorageKeyType) => boolean;
        doClear: () => void;
        doKeys: () => string[];
        notifySubscribers: (key: StorageKeyType, value: any) => void;
    };
};
export type SyncNextFunction = (action: StorageAction) => any;
export type SyncSetupEventsFunction = (api: SyncMiddlewareAPI) => void;
export type SyncMiddleware = {
    name: string;
    setup?: SyncSetupEventsFunction;
    cleanup?: () => void;
    reducer: (api: SyncMiddlewareAPI) => (next: SyncNextFunction) => (action: StorageAction) => any;
};
export declare class AsyncMiddlewareModule {
    private middlewares;
    private api;
    private initialized;
    private dispatchFn;
    constructor(storage: any);
    private baseOperation;
    private initializeMiddlewares;
    use(middleware: Middleware): void;
    dispatch(action: StorageAction): Promise<any>;
}
/** @deprecated Use AsyncMiddlewareModule */
export declare class MiddlewareModule extends AsyncMiddlewareModule {
}
export declare class SyncMiddlewareModule {
    private middlewares;
    private api;
    private initialized;
    private dispatchFn;
    constructor(storage: any);
    private baseOperation;
    private initializeMiddlewares;
    use(middleware: SyncMiddleware): void;
    dispatch(action: StorageAction): any;
}