// STOREBOUND_STORE_MOCK=http://127.0.0.1:<port>: every request to a store host (App Store Connect, Google APIs, the
// public store pages, the example.com placeholders) goes to that local double instead, as
// <mock>/__host/<host>/<path>. The release acceptance matrix (tools/acceptance.ts) runs the packed npm tarball this
// way against the fake stores of tests/helpers/fake-stores.ts, on every platform and runtime. Only a loopback address
// (with an optional path: the matrix gives every cell its own store) is accepted, so the variable can never send store keys or tokens to another machine. Unset: nothing changes.

const STORE_HOST = /^(?:[a-z0-9-]+\.)*(?:apple\.com|googleapis\.com|google\.com|example\.com)$/i;
const LOOPBACK = /^http:\/\/(?:127\.0\.0\.1|localhost|\[::1\]):\d{1,5}(?:\/[\w.-]+)*$/;

/** The URL a request goes to under the mock (unchanged for hosts that are not store hosts). */
export function mockedUrl(url: string, base: string): string {
  let u: URL;
  try { u = new URL(url); } catch { return url; }
  if (u.protocol !== 'https:' || !STORE_HOST.test(u.hostname)) return url;
  return `${base}/__host/${u.hostname}${u.pathname}${u.search}`;
}

/** Installs the redirect when STOREBOUND_STORE_MOCK is set; throws on a non-loopback value. */
export function installStoreMock(env: Record<string, string | undefined> = process.env): boolean {
  const base = env.STOREBOUND_STORE_MOCK?.replace(/\/+$/, '');
  if (!base) return false;
  if (!LOOPBACK.test(base)) throw new Error(`STOREBOUND_STORE_MOCK must be a loopback address like http://127.0.0.1:8080 (got ${JSON.stringify(base)})`);
  const real = globalThis.fetch;
  globalThis.fetch = ((input: string | URL | Request, init?: RequestInit) => {
    if (input instanceof Request) {
      const to = mockedUrl(input.url, base);
      return real(to === input.url ? input : new Request(to, input), init);
    }
    return real(mockedUrl(String(input), base), init);
  }) as typeof fetch;
  return true;
}