#!/usr/bin/env node
// Render each slide of a ThothII-style HTML deck to a high-res PNG.
// Assumes the deck exposes .slide sections navigable via #N hash routes.
//
// Usage:
//   node render.mjs <deck.html> <outdir> [--hide "sel1,sel2"] [--scale 2] [--width 1600] [--height 900]
//
// Output: <outdir>/01.png .. NN.png + <outdir>/notes.json (slide number -> title text)
import { createRequire } from 'node:module';
import { execSync } from 'node:child_process';
import { mkdirSync, writeFileSync } from 'node:fs';
import path from 'node:path';

const require = createRequire(import.meta.url);
function req(name) {
  try { return require(name); } catch {}
  const g = execSync('npm root -g').toString().trim();
  return require(path.join(g, name));
}

const args = process.argv.slice(2);
const html = path.resolve(args[0]);
const outdir = path.resolve(args[1]);
if (!args[0] || !args[1]) {
  console.error('usage: node render.mjs <deck.html> <outdir> [--hide "sel1,sel2"] [--scale 2] [--width 1600] [--height 900]');
  process.exit(1);
}
const opt = (f, d) => { const i = args.indexOf(f); return i >= 0 ? args[i + 1] : d; };
const hide = (opt('--hide', '') || '').split(',').map(s => s.trim()).filter(Boolean);
const scale = Number(opt('--scale', '2'));
const width = Number(opt('--width', '1600'));
const height = Number(opt('--height', '900'));

const { chromium } = req('playwright');
mkdirSync(outdir, { recursive: true });

const browser = await chromium.launch();
const page = await browser.newPage({
  viewport: { width, height },
  deviceScaleFactor: scale,
  reducedMotion: 'reduce',
});
await page.goto('file://' + html, { waitUntil: 'networkidle' });
await page.evaluate(() => document.fonts.ready);
if (hide.length) {
  await page.addStyleTag({ content: hide.map(s => `${s}{display:none!important}`).join('\n') });
}

const count = await page.locator('.slide').count();
const notes = {};
for (let i = 1; i <= count; i++) {
  await page.evaluate(n => { location.hash = '#' + n; }, i);
  await page.waitForFunction(n => {
    const s = document.querySelectorAll('.slide')[n - 1];
    return !!s && s.classList.contains('on');
  }, i);
  await page.waitForTimeout(450); // let the crossfade settle
  const file = path.join(outdir, String(i).padStart(2, '0') + '.png');
  await page.screenshot({ path: file });
  notes[i] = await page.evaluate(n => {
    const s = document.querySelectorAll('.slide')[n - 1];
    const t = s.querySelector('.title, .cover-mark');
    const txt = t ? t.innerText.trim().replace(/\s+/g, ' ') : '';
    return txt || s.getAttribute('aria-label') || '';
  }, i);
  console.log('rendered', file);
}
await browser.close();
writeFileSync(path.join(outdir, 'notes.json'), JSON.stringify(notes, null, 2));
console.log('done:', count, 'slides ->', outdir);