// AbortSignal/AbortController through fetch, differentially against Node's
// undici: pre-aborted signals, mid-flight aborts, mid-stream aborts (the
// pending read rejects), AbortSignal.timeout, AbortSignal.any, custom
// abort reasons, and the no-abort quiet path — byte-exact output both
// sides, so the error SHAPES (DOMException, name, message, Error
// inheritance, legacy code) are pinned to Node's exactly.
const out = (line) => process.stdout.write(line + "\n");
const show = (tag, e) =>
  out(`${tag} dom=${e instanceof DOMException} err=${e instanceof Error} code=${e.code} ${e.name}: ${e.message}`);

export function runAbort(base) {
  (async () => {
    // an already-aborted signal rejects before any request happens
    try {
      await fetch(base + "/text", { signal: AbortSignal.abort() });
      out("pre no-throw");
    } catch (e) {
      show("pre", e);
    }
    // a custom abort reason is carried verbatim
    try {
      await fetch(base + "/text", { signal: AbortSignal.abort("my custom reason") });
      out("custom no-throw");
    } catch (e) {
      out(`custom typeof=${typeof e} ${e}`);
    }
    // abort mid-flight, before any response arrives
    {
      const c = new AbortController();
      const p = fetch(base + "/slow", { signal: c.signal });
      c.abort();
      try {
        await p;
        out("mid no-throw");
      } catch (e) {
        show("mid", e);
      }
    }
    // abort mid-stream: the pending read rejects with the reason
    {
      const c = new AbortController();
      const res = await fetch(base + "/drip", { signal: c.signal });
      const reader = res.body.getReader();
      const first = await reader.read();
      out(`drip-first ${new TextDecoder().decode(first.value)}`);
      const pending = reader.read();
      c.abort();
      try {
        await pending;
        out("stream no-throw");
      } catch (e) {
        show("stream", e);
      }
    }
    // AbortSignal.timeout fires while the transfer is in flight
    try {
      await fetch(base + "/slow", { signal: AbortSignal.timeout(100) });
      out("timeout no-throw");
    } catch (e) {
      show("timeout", e);
    }
    // AbortSignal.any follows its first-aborting member (the AI-SDK
    // combine-signals shape: a user controller plus a timeout)
    {
      const c = new AbortController();
      const combined = AbortSignal.any([c.signal, AbortSignal.timeout(4000)]);
      const p = fetch(base + "/slow", { signal: combined });
      c.abort();
      try {
        await p;
        out("any no-throw");
      } catch (e) {
        show("any", e);
      }
    }
    // a Request-carried signal aborts the fetch built from it
    {
      const c = new AbortController();
      const req = new Request(base + "/slow", { signal: c.signal });
      const p = fetch(req);
      c.abort();
      try {
        await p;
        out("request no-throw");
      } catch (e) {
        show("request", e);
      }
    }
    // the quiet path: a signal that never aborts changes nothing, and an
    // abort AFTER the body was consumed is a no-op
    {
      const c = new AbortController();
      const res = await fetch(base + "/text", { signal: c.signal });
      out(`quiet ${res.status} ${JSON.stringify(await res.text())}`);
      c.abort();
      out(`quiet-after aborted=${c.signal.aborted} reason=${c.signal.reason.name}`);
    }
    // signal surface: state, listener order, once, throwIfAborted
    {
      const c = new AbortController();
      const s = c.signal;
      out(`surface aborted=${s.aborted} reason=${s.reason}`);
      const seen = [];
      s.onabort = () => seen.push("onabort");
      s.addEventListener("abort", () => seen.push("first"));
      const twice = () => seen.push("once");
      s.addEventListener("abort", twice, { once: true });
      c.abort();
      c.abort(); // second abort is a no-op
      out(`surface fired=${seen.join(",")}`);
      try {
        s.throwIfAborted();
        out("surface no-throw");
      } catch (e) {
        show("surface-throw", e);
      }
    }
    out("done");
  })().catch((e) => {
    out(`FATAL ${e}`);
  });
}