// Headless-chromium CDP driver for the jigsaw initial-image test page.
// Loads the page repeatedly; each load must end PASS, and the initial image
// index (document.__initIndex) must vary across fresh loads.
// Usage: node tools/__jig_init_driver.mjs <url> [loads=8]
import { spawn } from 'node:child_process';
import { setTimeout as sleep } from 'node:timers/promises';

const url = process.argv[2];
const loads = Math.max(2, parseInt(process.argv[3] || '8', 10));
if (!url) { console.error('usage: driver <url> [loads]'); process.exit(2); }

const BIN = process.env.HOME + '/.cache/ms-playwright/chromium_headless_shell-1234/chrome-headless-shell-linux64/chrome-headless-shell';
const PORT = 9333;
const chrome = spawn(BIN, [
  '--headless', '--no-sandbox', '--disable-gpu',
  `--remote-debugging-port=${PORT}`,
  'about:blank',
], { stdio: ['ignore', 'pipe', 'pipe'] });
chrome.stderr.on('data', (d) => { const s = d.toString(); if (!/Fontconfig|dbus|DBus|ozone/i.test(s)) process.stderr.write(s); });

async function httpJson(path) {
  const r = await fetch(`http://127.0.0.1:${PORT}${path}`);
  return r.json();
}

let ws, idc = 0;
const pending = new Map();
const send = (method, params = {}) => new Promise((resolve, reject) => {
  const id = ++idc;
  pending.set(id, { resolve, reject });
  ws.send(JSON.stringify({ id, method, params }));
});

try {
  let targets = null;
  for (let i = 0; i < 60; i++) {
    try { targets = await httpJson('/json/list'); break; } catch { await sleep(250); }
  }
  if (!targets) throw new Error('chrome devtools endpoint never came up');
  const page = targets.find((t) => t.type === 'page');
  if (!page) throw new Error('no page target');
  ws = new WebSocket(page.webSocketDebuggerUrl);
  await new Promise((res, rej) => { ws.onopen = res; ws.onerror = rej; });
  ws.onmessage = (m) => {
    const msg = JSON.parse(m.data);
    if (msg.id && pending.has(msg.id)) {
      const { resolve, reject } = pending.get(msg.id);
      pending.delete(msg.id);
      if (msg.error) reject(new Error(msg.error.message)); else resolve(msg.result);
    }
  };

  await send('Runtime.enable');
  await send('Page.enable');

  const ev = (expression) => send('Runtime.evaluate', { expression, returnByValue: true }).then((r) => r.result.value);

  const indexes = [];
  for (let k = 0; k < loads; k++) {
    await send('Page.navigate', { url });
    const t0 = Date.now();
    let title = '';
    while (Date.now() - t0 < 60000) {
      title = (await ev('document.title')) || '';
      if (title === 'PASS' || title.startsWith('FAIL')) break;
      await sleep(500);
    }
    if (title !== 'PASS') throw new Error(`load #${k}: ${title || 'TIMEOUT'}`);
    indexes.push(await ev('document.__initIndex'));
  }

  const valid = indexes.every((i) => Number.isInteger(i) && i >= 0 && i < 5);
  const distinct = new Set(indexes).size;
  console.log('initial indexes across fresh loads:', indexes.join(', '));
  console.log(`all valid: ${valid}, distinct images: ${distinct}/${loads}`);
  if (!valid || distinct < 2) { console.log('FAIL'); process.exitCode = 1; }
  else console.log('ALL PASS');
} finally {
  try { ws && ws.close(); } catch {}
  chrome.kill('SIGKILL');
}