import { networkInterfaces } from "node:os";
/**
 * Stable per-installation identifier, persisted on first run.
 *
 * Read from `~/.jdcodec/machine-id` if present. Otherwise derive from
 * the hostname and the first non-internal network MAC, hash, persist
 * (mode 0600), and return. Persisting matters because the MAC-lookup
 * fallback can shift between runs in sandboxed environments — without
 * the file, the derivation would re-randomise on the affected systems
 * and defeat client-side dedup.
 *
 * The `py-node-` prefix is part of the file format and stays stable
 * across releases. Other JD Codec clients on the same machine read the
 * same file; rebranding the prefix would invalidate existing IDs and
 * fragment a single user across multiple identifiers.
 *
 * Telemetry-only — not a credential. The file is written 0600 as a
 * defensive default; on Windows `chmod` is a no-op (acceptable).
 */
export declare const MACHINE_ID_PATH: string;
export interface MachineIdSource {
    /** Override for tests. */
    path?: string;
    /** Override hostname for tests. */
    hostname?: () => string;
    /** Override network interfaces for tests. */
    networkInterfaces?: () => ReturnType<typeof networkInterfaces>;
}
export declare function stableMachineId(source?: MachineIdSource): string;