/**
 * 通过 CDP 读取运行中的 Electron 页面：文本、节点数量与控制台错误。
 * 用法：node scripts/cdp-probe.mjs [expression]
 */
const endpoint = process.env.CDP_ENDPOINT || "http://127.0.0.1:9223";
const targets = await (await fetch(`${endpoint}/json/list`)).json();
const page = targets.find((item) => item.type === "page");
if (!page) throw new Error("no page target");

const ws = new WebSocket(page.webSocketDebuggerUrl);
const pending = new Map();
const events = [];
let seq = 0;

function send(method, params = {}) {
  return new Promise((resolve, reject) => {
    const id = ++seq;
    pending.set(id, { resolve, reject });
    ws.send(JSON.stringify({ id, method, params }));
  });
}

await new Promise((resolve, reject) => {
  ws.onopen = resolve;
  ws.onerror = reject;
});

ws.onmessage = (event) => {
  const message = JSON.parse(event.data);
  if (message.id && pending.has(message.id)) {
    const { resolve, reject } = pending.get(message.id);
    pending.delete(message.id);
    if (message.error) reject(new Error(JSON.stringify(message.error)));
    else resolve(message.result);
  } else {
    events.push(message);
  }
};

await send("Runtime.enable");
await send("Log.enable");

const expression = process.argv[2] || "document.body.innerText.slice(0, 6000)";
const result = await send("Runtime.evaluate", {
  expression,
  returnByValue: true,
  awaitPromise: true
});

console.log("=== result ===");
console.log(JSON.stringify(result.result?.value ?? result, null, 2));

const errors = events.filter(
  (item) =>
    item.method === "Runtime.exceptionThrown" ||
    (item.method === "Log.entryAdded" && ["error", "warning"].includes(item.params?.entry?.level))
);
console.log("\n=== errors/warnings ===");
console.log(JSON.stringify(errors.map((item) => item.params), null, 2).slice(0, 6000));

ws.close();