// Minimal CDP helper with HARD timeouts so scripts can never hang.
// Usage:
//   import { connectTab, screenshot, close } from './cdp.mjs';
//   const c = await connectTab();   // finds a booted game tab on :8080
//   const v = await c.eval('1+1');
//   await c.screenshot('/tmp/x.png');
//   c.close();
const CDP = '127.0.0.1:9333';
const GLOBAL_MS = 45000;
const watchdog = setTimeout(() => {
  console.error('[cdp] GLOBAL TIMEOUT — force exiting');
  process.exit(130);
}, GLOBAL_MS);

function toTimeout(promise, ms, label) {
  return Promise.race([
    promise,
    new Promise((_, rej) => setTimeout(() => rej(new Error(`timeout: ${label} (${ms}ms)`)), ms)),
  ]);
}

async function listTargets() {
  const r = await toTimeout(fetch(`http://${CDP}/json`), 5000, 'fetch /json');
  return r.json();
}

export async function connectTab() {
  const list = await listTargets();
  const tabs = list.filter(x => x.type === 'page' && x.url.includes(':8080'));
  if (!tabs.length) throw new Error('no :8080 page target');
  for (const cand of tabs) {
    let ws = null;
    try {
      ws = new WebSocket(cand.webSocketDebuggerUrl);
      await toTimeout(new Promise((res, rej) => {
        ws.onopen = res;
        ws.onerror = () => rej(new Error('ws open error'));
      }), 3000, 'ws open');

      let seq = 0;
      const pending = new Map();
      ws.onmessage = m => {
        const q = JSON.parse(m.data);
        if (q.id && pending.has(q.id)) {
          const o = pending.get(q.id); pending.delete(q.id);
          q.error ? o.rej(new Error(q.error.message)) : o.res(q.result);
        }
      };
      const send = (method, params = {}) =>
        toTimeout(new Promise((res, rej) => {
          const id = ++seq;
          pending.set(id, { res, rej });
          ws.send(JSON.stringify({ id, method, params }));
          setTimeout(() => {
            if (pending.has(id)) { pending.delete(id); rej(new Error('send timeout ' + method)); }
          }, 8000);
        }), 12000, 'send ' + method);

      await send('Runtime.enable');
      const probe = await send('Runtime.evaluate', {
        expression: 'Boolean(window.__ORBIT_COMBAT__ && window.game?.scene?.getScene("GameScene")?.ship)',
        returnByValue: true,
      });
      if (!probe.result?.value) { ws.close(); continue; }

      return {
        ws,
        async eval(expression) {
          const r = await send('Runtime.evaluate', { expression, returnByValue: true });
          if (r.exceptionDetails) throw new Error(r.exceptionDetails.exception?.description || 'eval error');
          return r.result?.value;
        },
        async screenshot(path) {
          const r = await send('Page.captureScreenshot', { format: 'png' });
          const fs = await import('node:fs');
          fs.writeFileSync(path, Buffer.from(r.data, 'base64'));
          return path;
        },
        close() { try { ws.close(); } catch {} },
      };
    } catch (e) {
      try { ws?.close(); } catch {}
      continue;
    }
  }
  throw new Error('no booted game tab found: ' + tabs.map(t => t.url).join(' | '));
}