/** The PKCE + state material minted once per login attempt. */
export interface PkceMaterial {
    /** Opaque anti-CSRF token echoed back on the loopback callback; verified constant-time. */
    state: string;
    /** The secret the CLI keeps; sent to /exchange. Never leaves the machine until then. */
    codeVerifier: string;
    /** base64url(SHA-256(codeVerifier)); sent to the browser/console, binds the exchange. */
    codeChallenge: string;
}
/** SHA-256 → base64url. Exported for the exchange-binding assertion in tests. */
export declare function s256(input: string): string;
/**
 * Mint fresh `state` + PKCE `code_verifier`/`code_challenge` (S256). The verifier is a
 * high-entropy 32-byte value (well within RFC 7636's 43–128 char range once base64url'd).
 */
export declare function makePkceMaterial(): PkceMaterial;
/**
 * Constant-time equality for the returned `state` vs the expected one. Length-mismatched
 * inputs return false without leaking timing (timingSafeEqual throws on unequal lengths).
 */
export declare function stateMatches(expected: string, actual: string | null): boolean;
/** Prefix a scheme when the user passed a bare host; localhost defaults to http. */
export declare function normalizeBaseUrl(u: string): string;
/**
 * The console URL the browser opens: `/cli-auth?redirect_uri=<loopback>&state=…&code_challenge=…`.
 * The console signs the user in (passwordless), shows the Grant CLI access consent screen,
 * POSTs /access-tokens {code_challenge, state}, and redirects the resulting auth_code to the
 * loopback. The code_verifier is NOT in this URL — only its challenge.
 */
export declare function buildCliAuthUrl(consoleBase: string, redirectUri: string, material: PkceMaterial): string;
/** A compact, human-copyable fallback URL for the "if it doesn't open" line. */
export declare function shortenUrl(url: string, max?: number): string;
export type CallbackResult = {
    ok: true;
    code: string;
} | {
    ok: false;
    reason: "state_mismatch" | "denied" | "missing_code";
    message: string;
};
/**
 * Interpret the loopback redirect (`127.0.0.1:PORT?code=…&state=…`). State is verified
 * constant-time FIRST, always — a mismatch rejects before the code is even read, so a
 * forged/stray callback can never drive an exchange (QA-F1-C3). The console signals a
 * user cancel via `?error=access_denied`.
 */
export declare function parseCallback(params: URLSearchParams, expectedState: string): CallbackResult;