// Downloads the app's Google fonts once (latin + latin-ext subsets) into
// frontend/fonts/ and writes frontend/fonts/fonts.css pointing at them.
// Re-run only when the font list changes.
const fs = require('node:fs');
const path = require('node:path');
const CSS_URL = 'https://fonts.googleapis.com/css2?family=Bricolage+Grotesque:opsz,wght@12..96,600..800&family=Hanken+Grotesk:wght@400..700&family=JetBrains+Mono:wght@400..700&display=swap';
const UA = 'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/126.0 Safari/537.36';
const OUT = path.join(__dirname, '..', 'frontend', 'fonts');
(async () => {
  fs.mkdirSync(OUT, { recursive: true });
  const css = await (await fetch(CSS_URL, { headers: { 'User-Agent': UA } })).text();
  // parts[k] ends with the "/* <subset> */" comment of the block in parts[k+1].
  const parts = css.split('@font-face');
  let out = '/* Generated by scripts/fetch-fonts.js — do not edit by hand. */\n';
  let n = 0;
  for (let k = 1; k < parts.length; k++) {
    const subset = (parts[k - 1].match(/\/\*\s*([\w-]+)\s*\*\/\s*$/) || [])[1];
    const b = parts[k].slice(0, parts[k].indexOf('}') + 1); // just this block
    if (subset !== 'latin' && subset !== 'latin-ext') continue;
    const url = (b.match(/url\((https:[^)]+\.woff2)\)/) || [])[1];
    const fam = (b.match(/font-family:\s*'([^']+)'/) || [])[1];
    if (!url || !fam) continue;
    const file = `${fam.replace(/\s+/g, '')}-${subset}.woff2`;
    const buf = Buffer.from(await (await fetch(url)).arrayBuffer());
    fs.writeFileSync(path.join(OUT, file), buf);
    out += '@font-face' + b.replace(url, file).trimEnd() + '\n';
    n++;
  }
  fs.writeFileSync(path.join(OUT, 'fonts.css'), out);
  console.log(`wrote ${n} font files + fonts.css`);
})().catch((e) => { console.error(e); process.exit(1); });