/* Render docs/launch/one-pager.html to an A4 PDF.
 *
 *   node docs/launch/build-one-pager.cjs [output.pdf]
 *
 * It asserts the result is a single page, because a one-pager that quietly becomes two is worse
 * than useless — the second sheet is where the contact details end up, and nobody prints it.
 */
const { chromium } = require('playwright');
const path = require('path');

const SRC = path.join(__dirname, 'one-pager.html');
const OUT = process.argv[2] || path.join(process.env.HOME || '.', 'Downloads', 'ThreadCount-one-pager.pdf');
const A4_PX = Math.round((297 / 25.4) * 96); // A4 height at CSS 96dpi

(async () => {
  const b = await chromium.launch();
  const p = await b.newPage();
  await p.goto('file://' + SRC, { waitUntil: 'networkidle' });
  await p.evaluate(() => document.fonts.ready);
  await p.waitForTimeout(800); // let the webfont settle before measuring
  const h = await p.evaluate(() => document.body.getBoundingClientRect().height);
  await p.pdf({ path: OUT, format: 'A4', printBackground: true, margin: { top: 0, right: 0, bottom: 0, left: 0 } });
  await b.close();
  console.log(`content ${Math.round(h)}px against an A4 page of ${A4_PX}px`);
  if (h > A4_PX + 1) {
    console.error('SPILLS ONTO A SECOND PAGE — trim the content or the block spacing, not the type size.');
    process.exit(1);
  }
  console.log('one page ->', OUT);
})();