type StorageValue = null | string | number | boolean | object;
type WatchEvent = "update" | "remove";
type WatchCallback = (event: WatchEvent, key: string) => any;
type MaybePromise<T> = T | Promise<T>;
type MaybeDefined<T> = T extends any ? T : any;
type Unwatch = () => MaybePromise<void>;
interface StorageMeta {
    atime?: Date;
    mtime?: Date;
    [key: string]: StorageValue | Date | undefined;
}
type TransactionOptions = Record<string, any>;
interface Driver {
    name?: string;
    options?: any;
    hasItem: (key: string, opts: TransactionOptions) => MaybePromise<boolean>;
    getItem: (key: string, opts?: TransactionOptions) => MaybePromise<StorageValue>;
    /** @experimental */
    getItems?: (items: {
        key: string;
        options?: TransactionOptions;
    }[], commonOptions?: TransactionOptions) => MaybePromise<{
        key: string;
        value: StorageValue;
    }[]>;
    /** @experimental */
    getItemRaw?: (key: string, opts: TransactionOptions) => MaybePromise<unknown>;
    setItem?: (key: string, value: string, opts: TransactionOptions) => MaybePromise<void>;
    /** @experimental */
    setItems?: (items: {
        key: string;
        value: string;
        options?: TransactionOptions;
    }[], commonOptions?: TransactionOptions) => MaybePromise<void>;
    /** @experimental */
    setItemRaw?: (key: string, value: any, opts: TransactionOptions) => MaybePromise<void>;
    removeItem?: (key: string, opts: TransactionOptions) => MaybePromise<void>;
    getMeta?: (key: string, opts: TransactionOptions) => MaybePromise<StorageMeta | null>;
    getKeys: (base: string, opts: TransactionOptions) => MaybePromise<string[]>;
    clear?: (base: string, opts: TransactionOptions) => MaybePromise<void>;
    dispose?: () => MaybePromise<void>;
    watch?: (callback: WatchCallback) => MaybePromise<Unwatch>;
}
interface Storage<T extends StorageValue = StorageValue> {
    hasItem: (key: string, opts?: TransactionOptions) => Promise<boolean>;
    getItem: <U extends T>(key: string, opts?: TransactionOptions) => Promise<U | null>;
    /** @experimental */
    getItems: (items: (string | {
        key: string;
        options?: TransactionOptions;
    })[], commonOptions?: TransactionOptions) => Promise<{
        key: string;
        value: StorageValue;
    }[]>;
    /** @experimental See https://github.com/unjs/unstorage/issues/142 */
    getItemRaw: <T = any>(key: string, opts?: TransactionOptions) => Promise<MaybeDefined<T> | null>;
    setItem: <U extends T>(key: string, value: U, opts?: TransactionOptions) => Promise<void>;
    /** @experimental */
    setItems: (items: {
        key: string;
        value: string;
        options?: TransactionOptions;
    }[], commonOptions?: TransactionOptions) => Promise<void>;
    /** @experimental See https://github.com/unjs/unstorage/issues/142 */
    setItemRaw: <T = any>(key: string, value: MaybeDefined<T>, opts?: TransactionOptions) => Promise<void>;
    removeItem: (key: string, opts?: (TransactionOptions & {
        removeMeta?: boolean;
    }) | boolean) => Promise<void>;
    getMeta: (key: string, opts?: (TransactionOptions & {
        nativeOnly?: boolean;
    }) | boolean) => MaybePromise<StorageMeta>;
    setMeta: (key: string, value: StorageMeta, opts?: TransactionOptions) => Promise<void>;
    removeMeta: (key: string, opts?: TransactionOptions) => Promise<void>;
    getKeys: (base?: string, opts?: TransactionOptions) => Promise<string[]>;
    clear: (base?: string, opts?: TransactionOptions) => Promise<void>;
    dispose: () => Promise<void>;
    watch: (callback: WatchCallback) => Promise<Unwatch>;
    unwatch: () => Promise<void>;
    mount: (base: string, driver: Driver) => Storage;
    unmount: (base: string, dispose?: boolean) => Promise<void>;
    getMount: (key?: string) => {
        base: string;
        driver: Driver;
    };
    getMounts: (base?: string, options?: {
        parents?: boolean;
    }) => {
        base: string;
        driver: Driver;
    }[];
}

export { Driver as D, StorageValue as S, TransactionOptions as T, Unwatch as U, WatchEvent as W, Storage as a, WatchCallback as b, StorageMeta as c };