/**
 * @typedef {'hex' | 'base64url' | 'base58' | 'crockford' | 'ulid' | 'uuid4' | 'uuid7' | 'alphanumeric' | 'prefixed' | 'structured'} OpaqueTokenFormat
 */
/**
 * @typedef {object} GenerateOptions
 * @property {OpaqueTokenFormat} format
 * @property {number}  [bytes=32]      Entropy size for byte-based generators (`hex`, `base64url`, `base58`).
 * @property {number}  [length]        Output length for `alphanumeric` — defaults to `bytes` if omitted.
 * @property {keyof typeof GENERATORS} [generator='hex']  Which generator produces the entropy segment of a `prefixed` / `structured` token.
 * @property {string}  [prefix]        Required for `format: 'prefixed'` — e.g. `'usr'`.
 * @property {string}  [version]      Required for `format: 'structured'` — e.g. `'v1'`.
 * @property {string}  [type]         Required for `format: 'structured'` — a literal label embedded in the token, e.g. `'ref'`.
 * @property {string}  [separator='_'] Joins the segments of `prefixed` / `structured` tokens.
 */
/**
 * Generate an opaque token. `format` is either a bare generator name
 * (`'hex'`, `'uuid4'`, …) or a composite shape (`'prefixed'`,
 * `'structured'`) that wraps a generator's output with a literal label.
 *
 * @param {GenerateOptions} options
 * @returns {string}
 *
 * @example
 * generate({ format: 'hex', bytes: 32 })
 * // → '3f9a...'  (64 hex chars)
 *
 * generate({ format: 'prefixed', prefix: 'usr' })
 * // → 'usr_3f9a...'  (generator defaults to 'hex')
 *
 * generate({ format: 'structured', version: 'v1', type: 'ref', generator: 'ulid', separator: '.' })
 * // → 'v1.ref.01ARZ3NDEKTSV4RRFFQ69G5FAV'
 */
export function generate(options: GenerateOptions): string;
export type OpaqueTokenFormat = "hex" | "base64url" | "base58" | "crockford" | "ulid" | "uuid4" | "uuid7" | "alphanumeric" | "prefixed" | "structured";
export type GenerateOptions = {
    format: OpaqueTokenFormat;
    /**
     * Entropy size for byte-based generators (`hex`, `base64url`, `base58`).
     */
    bytes?: number | undefined;
    /**
     * Output length for `alphanumeric` — defaults to `bytes` if omitted.
     */
    length?: number | undefined;
    /**
     * Which generator produces the entropy segment of a `prefixed` / `structured` token.
     */
    generator?: string | undefined;
    /**
     * Required for `format: 'prefixed'` — e.g. `'usr'`.
     */
    prefix?: string | undefined;
    /**
     * Required for `format: 'structured'` — e.g. `'v1'`.
     */
    version?: string | undefined;
    /**
     * Required for `format: 'structured'` — a literal label embedded in the token, e.g. `'ref'`.
     */
    type?: string | undefined;
    /**
     * Joins the segments of `prefixed` / `structured` tokens.
     */
    separator?: string | undefined;
};