import fs from 'node:fs/promises';
import { fileURLToPath } from 'node:url';

const escapeText = value => value.replaceAll('&', '&amp;').replaceAll('<', '&lt;').replaceAll('>', '&gt;');

// Populate the checked-in German fallback while retaining all runtime i18n markers.
export function localizeHtml(source, translate) {
  const result = source.replaceAll(/(<[^>]+\bdata-i18n="([^"]+)"[^>]*>)([^<]*)(<\/)/g,
    (_match, opening, key, _text, closing) => opening + escapeText(translate(key)) + closing);
  return result.replaceAll(/<[^>]+>/g, opening => {
    let translated = opening;
    for (const attribute of ['title', 'aria-label', 'placeholder', 'alt']) {
      const key = new RegExp(`data-i18n-${attribute}="([^"]+)"`).exec(opening)?.[1];
      if (!key) continue;
      const value = escapeText(translate(key)).replaceAll('"', '&quot;');
      // Match an actual attribute, never the suffix of its data-i18n marker.
      translated = translated.replaceAll(new RegExp(`(\\s)${attribute}="[^"]*"`, 'g'), (_match, space) => `${space}${attribute}="${value}"`);
    }
    return translated;
  });
}

if (process.argv[1] === fileURLToPath(import.meta.url)) {
  await import('../public/js/texts-de.js');
  await import('../public/js/i18n.js');
  const file = new URL('../public/index.html', import.meta.url);
  const source = await fs.readFile(file, 'utf8');
  const translated = localizeHtml(source, key => globalThis.Wegwichtel.I18n.t(key));
  await fs.writeFile(file, translated);
}