import { type EnvConfig } from '../config/env.js';
import { type ProjectCache, type ArtifactRecord, type VerifiedDeviceRecord } from './types.js';
/**
 * SQLite-backed persistent storage for the MCP server.
 *
 * Manages project cache entries, generic key/value cache with TTL,
 * and artifact records. Uses WAL mode and foreign keys for safety.
 * All public methods are safe — errors are logged internally and
 * never thrown to the caller.
 */
export declare class Storage {
    private db;
    private config;
    private initialized;
    constructor(config: EnvConfig);
    /** Initialise the schema (tables + indexes). Safe to call multiple times. */
    initialize(): void;
    /** Retrieve a cached value by key. Returns `null` when missing or expired. */
    cacheGet(key: string): string | null;
    /**
     * Store a value in the cache.
     * @param ttlSec Time-to-live in seconds. 0 means never expire.
     */
    cacheSet(key: string, value: string, ttlSec?: number): void;
    /** Remove a single cache entry by key. */
    cacheDelete(key: string): void;
    /** Remove all cache entries. */
    cacheClear(): void;
    /** Look up a project cache entry by its hash. Returns `null` if not found. */
    getProjectCache(hash: string): ProjectCache | null;
    /** Insert or replace a project cache entry. */
    upsertProjectCache(cache: ProjectCache): void;
    /** Store a new artifact record (gerber, bom, pdf, etc.). */
    insertArtifact(artifact: ArtifactRecord): void;
    /**
     * List artifact records for a project, optionally filtered by type.
     * Results are ordered by creation date descending.
     */
    getArtifacts(projectHash: string, type?: string): ArtifactRecord[];
    /** Insert or replace a verified-device cache entry, keyed by LCSC id. */
    upsertVerifiedDevice(record: Omit<VerifiedDeviceRecord, 'createdAt' | 'updatedAt'>): void;
    /** Look up a cached verified-device entry by LCSC id. Returns `null` if not found. */
    getVerifiedDevice(lcscId: string): VerifiedDeviceRecord | null;
    /** List cached verified devices, optionally filtered by status, newest first. */
    listVerifiedDevices(status?: VerifiedDeviceRecord['status']): VerifiedDeviceRecord[];
    /** Remove a cached verified-device entry by LCSC id. */
    deleteVerifiedDevice(lcscId: string): void;
    /** Reclaim storage by running VACUUM. */
    vacuum(): void;
    /** Close the database connection. */
    close(): void;
}