import { type TArg, type TRet } from '@scure/base';
/** HOTP/TOTP configuration. */
export type OTPOpts = {
    /** HMAC hash name: `sha1`, `sha256`, or `sha512`. */
    algorithm: string;
    /** Number of digits to keep from the generated OTP code (6 through 16). */
    digits: number;
    /** TOTP step size in seconds. */
    interval: number;
    /** Decoded OTP secret bytes. */
    secret: Uint8Array;
};
/**
 * Parses a raw base32 secret or `otpauth://totp/...` URL.
 * @param otp - Base32 secret or otpauth URL.
 * @returns Normalized OTP settings.
 * @throws If the secret is shorter than 128 bits or the URL requests unsupported settings. {@link Error}
 * @example
 * Parse either a base32 secret or an otpauth URL before generating codes.
 * ```ts
 * import { parse, totp } from 'micro-key-producer/otp.js';
 * const opts = parse('ZYTYYE5FOAGW5ML7LRWUL4WTZLNJAMZS');
 * totp(opts, 0);
 * ```
 */
export declare function parse(otp: string): TRet<OTPOpts>;
/**
 * Serializes OTP settings into an `otpauth://totp/...` URL.
 * @param opts - Parsed OTP settings. See {@link OTPOpts}.
 * @returns OTP URL string.
 * @example
 * Rebuild the otpauth URL after normalizing or editing the parsed settings.
 * ```ts
 * import { parse, buildURL } from 'micro-key-producer/otp.js';
 * const opts = parse('ZYTYYE5FOAGW5ML7LRWUL4WTZLNJAMZS');
 * buildURL(opts);
 * ```
 */
export declare function buildURL(opts: TArg<OTPOpts>): string;
/**
 * Computes an HOTP code for the supplied moving factor.
 * @param opts - OTP settings and secret. See {@link OTPOpts}.
 * @param counter - HOTP counter value.
 * @returns Numeric HOTP code as a zero-padded string.
 * @throws If the secret is shorter than 128 bits or the configuration is unsupported. {@link Error}
 * @example
 * Generate an HOTP code for an explicit moving counter value.
 * ```ts
 * import { parse, hotp } from 'micro-key-producer/otp.js';
 * const opts = parse('ZYTYYE5FOAGW5ML7LRWUL4WTZLNJAMZS');
 * hotp(opts, 0);
 * ```
 */
export declare function hotp(opts: TArg<OTPOpts>, counter: number | bigint): string;
/**
 * Computes a TOTP code for the supplied timestamp.
 * @param opts - OTP settings and secret. See {@link OTPOpts}.
 * @param ts - UNIX time in milliseconds.
 * @returns Numeric TOTP code as a zero-padded string.
 * @throws If the secret is shorter than 128 bits or the configuration is unsupported. {@link Error}
 * @example
 * Generate a TOTP code for a specific timestamp.
 * ```ts
 * import { parse, totp } from 'micro-key-producer/otp.js';
 * const opts = parse('ZYTYYE5FOAGW5ML7LRWUL4WTZLNJAMZS');
 * totp(opts, 0);
 * ```
 */
export declare function totp(opts: TArg<OTPOpts>, ts?: number): string;