import { networkInterfaces } from 'node:os';
export type StableHostKind = 'tailscale-magicdns' | 'mdns-local' | 'gateway-interface' | 'loopback';
export interface TailscaleState {
    /** BackendState === 'Running'. */
    readonly up: boolean;
    /** Self.DNSName from `tailscale status --json`, trailing dot stripped. */
    readonly magicDnsName?: string | undefined;
}
export interface StableHostInputs {
    /** os.hostname(), possibly an FQDN, the `.local` name derives from its first label. */
    readonly hostname: string;
    /** The routable IPv4 on the default-route interface, when known. */
    readonly gatewayInterfaceIp?: string | undefined;
    /** First non-internal IPv4 in enumeration order, the last-resort address. */
    readonly firstNonInternalIp?: string | undefined;
    /** Tailscale state, when the CLI is present and answered in time. */
    readonly tailscale?: TailscaleState | undefined;
}
export interface ResolvedStableHost {
    readonly host: string;
    readonly kind: StableHostKind;
    /** True when `host` is a name that survives a DHCP lease change. */
    readonly stable: boolean;
}
/** `<hostname>.local` from the first label of a hostname, or null when there is no usable label. */
export declare function mdnsLocalName(host: string): string | null;
/**
 * Resolve the stable host from injected inputs. Pure, no I/O, so the ladder is
 * exercised directly under mocked interface / tailscale states.
 */
export declare function resolveStableHost(inputs: StableHostInputs): ResolvedStableHost;
/** First non-internal IPv4 in enumeration order, the last-resort address. */
export declare function firstNonInternalIpv4(nets: ReturnType<typeof networkInterfaces>): string | undefined;
/** Parse the `src <ip>` field out of a Linux `ip route get` line. */
export declare function parseIpRouteSrc(output: string): string | undefined;
/** Parse `Self.DNSName` + running state out of `tailscale status --json` output. */
export declare function parseTailscaleStatus(json: string): TailscaleState | undefined;
/** Gather the impure inputs the resolver needs, each bounded and failure-tolerant. */
export declare function probeStableHostInputs(): StableHostInputs;
/**
 * The stable host for a printed/QR link given the endpoint's bind host. A
 * wildcard bind (0.0.0.0 / ::) resolves through the ladder; an explicit bind
 * host is honored as-is (loopback stays loopback). `probe` is injectable for
 * tests.
 */
export declare function stableUrlHostForBindHost(host: string, probe?: () => StableHostInputs): ResolvedStableHost;
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