import { type Locale } from '@urbicon-ui/i18n';
import type { AuthLocale, PartialAuthLocale } from './keys.js';
/**
 * Make an `AuthLocale` bundle available to every auth component and to the
 * server-side mail builders, paired with the locale's subpath import:
 *
 * ```ts
 * import { registerAuthLocale } from '@urbicon-ui/auth';
 * import { de } from '@urbicon-ui/auth/i18n/de';
 * registerAuthLocale('de', de);
 * ```
 *
 * **At app start** is the recommendation, not a requirement: the registry is
 * reactive, so a registration after mount re-renders the components that are
 * already on screen. Registering at start is what makes the *first* server
 * render already correct — put the lines in a module that both the server and
 * the client evaluate (e.g. a `src/lib/locales.ts` imported from
 * `hooks.server.ts` **and** from the root `+layout.ts`), or a locale registered
 * on only one side renders German HTML that hydrates into English.
 *
 * Only `en` is built in; without a registration an auth component under
 * `<I18nProvider locale="de">` renders English. Registering `en` replaces the
 * built-in English bundle — the way to restyle the whole surface at once rather
 * than per component through the `t` prop. It replaces rather than merges, so
 * build the full bundle from the shipped one:
 *
 * ```ts
 * import { en } from '@urbicon-ui/auth/i18n/en';
 * registerAuthLocale('en', mergeAuthLocale(en, { auth: { login: { title: 'Welcome back' } } }));
 * ```
 *
 * Write-strict, because a bundle that is wrong here is wrong for every
 * component at once: throws on a locale `@urbicon-ui/i18n` does not support, on
 * a non-object bundle, and on a bundle missing any key the built-in `en` has.
 * TypeScript already refuses an incomplete literal, but a JSON file, a
 * JavaScript caller and an `as AuthLocale` cast do not — and a partial bundle
 * under `en` would make every other locale's fallback throw at render.
 */
export declare function registerAuthLocale(locale: Locale, bundle: AuthLocale): void;
/**
 * Context-scoped hook for the full AuthLocale object at the active locale. Call
 * during component initialisation, then read it inside a `$derived` so it stays
 * reactive and resolves against the nearest `<I18nProvider>`:
 *
 * ```svelte
 * const authLocale = useAuthLocale();
 * const t = $derived(mergeAuthLocale(authLocale(), tProp));
 * ```
 *
 * Resolves to the bundle registered for the provider's locale, or to English
 * when that locale has none — {@link registerAuthLocale} is how a locale other
 * than `en` gets one. Read inside a `$derived` as above, a registration that
 * lands after the component mounted re-renders it; read once into a `const`, it
 * does not.
 *
 * Replaces the former free `getAuthLocale()`, which read the global locale
 * singleton and so could not be request-scoped (SSR-unsafe).
 */
export declare function useAuthLocale(): () => AuthLocale;
/**
 * Deep-merge consumer locale `overrides` over a complete `base` bundle — THE
 * single place a `PartialAuthLocale` becomes a full `AuthLocale`.
 * Every component resolves its `t` prop through this, so overriding one string
 * (`{ auth: { login: { title: 'Welcome back' } } }`) keeps every other key from
 * the active bundle instead of blanking whole subtrees. Objects merge
 * recursively, string leaves replace, `undefined` entries are skipped. Returns
 * `base` itself when there is nothing to merge.
 *
 * Kind-preserving: an entry whose kind mismatches the base (`null`/array/
 * primitive where the bundle has a subtree, an object where it has a string)
 * is skipped, keeping the base value. TypeScript rules those out, but JSON is
 * the natural carrier for consumer override files and cannot express
 * `undefined` — a hand-written `null` must not blank a whole subtree the
 * postcondition promises to be complete.
 */
export declare function mergeAuthLocale(base: AuthLocale, overrides?: PartialAuthLocale): AuthLocale;
export type { AuthLocale, DeepPartial, PartialAuthLocale } from './keys.js';