/**
 * passkeys-firefox-relay.ts — extension-world relay for the MAIN-world
 * passkey proxy (passkeys-firefox.ts).
 *
 * The MAIN-world script cannot call chrome.runtime.sendMessage — it lives in
 * the page's JS context, not the extension's. This relay listens for the
 * MAIN-world's PEACH_PASSKEY_REQUEST window messages, forwards each payload
 * to the background, and posts the result back as PEACH_PASSKEY_RESPONSE
 * with the same request id.
 *
 * Trust boundary: anything the page can synthesize on `window.message` lands
 * here. The `type` and `id` fields gate dispatch; the `payload` is forwarded
 * verbatim to the background, which validates required fields and runs the
 * Pro/vault checks before performing any cryptographic work. Vault data is
 * never sent the other direction over postMessage — only the credential
 * shape the RP needs.
 *
 * Removal: deleted alongside the MAIN-world proxy when Firefox ships
 * chrome.webAuthenticationProxy. See src/shared/passkey-flags.ts.
 */

window.addEventListener("message", async (event: MessageEvent) => {
  if (event.source !== window) return;
  const data = event.data as
    | { type?: string; id?: string; payload?: unknown }
    | undefined;
  if (!data || data.type !== "PEACH_PASSKEY_REQUEST") return;
  const { id, payload } = data;
  if (typeof id !== "string" || !payload || typeof payload !== "object") return;

  const reply = (replyPayload: unknown) => {
    window.postMessage(
      { type: "PEACH_PASSKEY_RESPONSE", id, payload: replyPayload },
      window.location.origin
    );
  };

  try {
    const response = await chrome.runtime.sendMessage(payload);
    reply(response);
  } catch {
    // The background may be momentarily unreachable (service worker spin-up,
    // extension reload). Tell the proxy to fall through to the platform
    // rather than throwing into the page.
    reply({ ok: false, error: "extension_error" });
  }
});