import { getPreLockFetch } from './navigation-testing-lock'

/**
 * Internal `fetch` used by the Next.js client router.
 *
 * When the Instant Navigation Testing API is enabled, the navigation lock may
 * install a blocking override on `window.fetch` for the duration of a lock
 * scope. To let internal fetches bypass the lock, callers go through a wrapper
 * that falls back to the pre-lock fetch captured at lock-acquire time.
 *
 * When the testing API is not enabled, this calls window.fetch directly.
 */
function fetchInternal(
  input: RequestInfo | URL,
  init?: RequestInit
): Promise<Response> {
  if (process.env.__NEXT_EXPOSE_TESTING_API) {
    const preLockFetch = getPreLockFetch()
    if (preLockFetch !== null) {
      return preLockFetch(input, init)
    }
  }
  return fetch(input, init)
}

export { fetchInternal as fetch }