/**
 * Service-worker configuration for `@serwist/next`. Extracted from
 * `sw.ts` so unit tests can pin the choices without booting up a
 * service-worker scope.
 *
 * The choices we care about — and why they're the way they are:
 *
 *   skipWaiting + clientsClaim
 *     A new worker takes over open tabs on the next navigation
 *     instead of waiting for every tab to close. Operators tend to
 *     live in one tab; faster updates win.
 *
 *   navigationPreload
 *     Tells the browser it can race the network fetch for navigations
 *     alongside the worker boot, cutting first-paint when the worker
 *     is cold.
 *
 *   runtimeCaching
 *     Serwist's stock recipe — HTML network-first with offline
 *     fallback, static assets cache-first, image / font caches with
 *     sensible TTLs. Easy to swap if we want bespoke strategies later.
 *
 *   precacheEntries
 *     Whatever `__SW_MANIFEST` the build pipeline injected. We pass
 *     it through unchanged.
 */

type PrecacheEntry = string | { url: string; revision: string | null };

/**
 * The runtime-caching shape is generic on purpose. Serwist's own
 * `RuntimeCaching` type pulls in WebWorker DOM lib refs that
 * vitest's plain Node env doesn't ship; using a generic preserves
 * the type at the call site (sw.ts passes Serwist's
 * `RuntimeCaching[]` and gets it back unchanged) without forcing
 * the lib import here.
 */
export interface ServiceWorkerConfig<R> {
  precacheEntries: PrecacheEntry[];
  skipWaiting: boolean;
  clientsClaim: boolean;
  navigationPreload: boolean;
  runtimeCaching: R;
}

export function serviceWorkerConfig<R>(
  precacheEntries: PrecacheEntry[],
  runtimeCaching: R,
): ServiceWorkerConfig<R> {
  return {
    precacheEntries,
    skipWaiting: true,
    clientsClaim: true,
    navigationPreload: true,
    runtimeCaching,
  };
}