'use server';

import { revalidatePath } from 'next/cache';
import { cookies } from 'next/headers';

import { isLocale, type Locale } from '@sport/types';

import { LOCALE_COOKIE } from './request';

/**
 * Persists the operator's language choice.
 *
 * A Server Action rather than a client-side cookie write, so the very next
 * render already has the new locale — no flash of the previous language, and no
 * need to duplicate the cookie name in client code.
 */
export async function setLocale(locale: Locale): Promise<void> {
  if (!isLocale(locale)) return;

  const store = await cookies();
  store.set(LOCALE_COOKIE, locale, {
    path: '/',
    maxAge: 60 * 60 * 24 * 365,
    sameSite: 'lax',
    // Not httpOnly: this is a display preference, not a credential, and reading
    // it client-side is occasionally useful.
    httpOnly: false,
  });

  // Every admin screen renders translated text, so the whole tree is stale.
  revalidatePath('/', 'layout');
}