/**
 * kosha-discovery — File-based JSON cache with TTL.
 *
 * Stores discovered provider data as individual JSON files on disk
 * to avoid re-fetching from provider APIs on every startup.
 * Each cache key maps to a `{key}.json` file inside the cache directory.
 * @module
 */
interface CacheEntry<T> {
    data: T;
    timestamp: number;
}
/**
 * Simple file-based JSON cache with TTL support.
 * Stores discovered provider data to avoid re-fetching on every startup.
 *
 * Each cache key maps to a `{key}.json` file inside the cache directory.
 */
export declare class KoshaCache {
    private readonly cacheDir;
    constructor(cacheDir?: string);
    /**
     * Retrieve cached data by key.
     * Returns null if the entry is missing or the file cannot be read.
     */
    get<T>(key: string): Promise<CacheEntry<T> | null>;
    /**
     * Write data to the cache under the given key.
     *
     * Uses atomic write (temp file + rename) so a crash mid-write
     * cannot leave a corrupted cache file behind.
     */
    set<T>(key: string, data: T): Promise<void>;
    /**
     * Remove a single cached entry by key.
     */
    invalidate(key: string): Promise<void>;
    /**
     * Remove all cache files from the cache directory.
     */
    clear(): Promise<void>;
    /**
     * Check whether a cached timestamp has exceeded the given TTL.
     */
    isExpired(timestamp: number, ttlMs: number): boolean;
    /**
     * Sanitize a cache key into a safe filename and return the full path.
     * Replaces any character that is not alphanumeric, dash, or underscore with an underscore.
     */
    private keyToPath;
    /**
     * Ensure the cache directory exists, creating it recursively if needed.
     */
    private ensureDir;
}
export {};
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