import { IncomingMessage, Server, ServerResponse } from "node:http";
/** Configures the loopback callback server. */
export interface CallbackServerOptions {
    expectedState: string;
    timeoutMs?: number;
    signal?: AbortSignal;
}
/** Authorization-code and state pair captured from a successful redirect. */
export interface CallbackResult {
    code: string;
    state: string;
}
/** Live handle to a running callback server. */
export interface CallbackServerHandle {
    redirectURI: string;
    result: Promise<CallbackResult>;
    close: () => Promise<void>;
}
type RequestHandler = (req: IncomingMessage, res: ServerResponse) => void;
type LoopbackListener = (handler: RequestHandler, host: string) => Promise<Server>;
/**
 * Binds an HTTP server to the loopback interface, preferring IPv4.
 *
 * RFC 8252 §7.3: "use whichever is available". Prefer IPv4; fall back to
 * IPv6 only when the IPv4 loopback isn't configured on this host. `listenFn`
 * is an injection seam for tests — production callers use the default.
 */
export declare function bindLoopback(handler: RequestHandler, listenFn?: LoopbackListener): Promise<{
    server: Server;
    host: "127.0.0.1" | "::1";
}>;
/** Starts a loopback HTTP server that captures the OAuth redirect. */
export declare function startCallbackServer(opts: CallbackServerOptions): Promise<CallbackServerHandle>;
export {};