// Builds dist/index.html: one self-contained page (ttyd --index serves a single
// file and nothing else), with CSS, JS, fonts and the favicon all inlined.
import { build, transform } from 'esbuild';
import { readFile, writeFile, mkdir } from 'node:fs/promises';
import { dirname, join } from 'node:path';
import { fileURLToPath } from 'node:url';

const root = join(dirname(fileURLToPath(import.meta.url)), '..');
const at = (...parts) => join(root, ...parts);
const read = (...parts) => readFile(at(...parts), 'utf8');

// Version: $DEVDESK_VERSION (CI) or the top entry of debian/changelog.
async function version() {
  if (process.env.DEVDESK_VERSION) return process.env.DEVDESK_VERSION;
  const changelog = await read('debian', 'changelog');
  return /^devdesk \(([^)]+)\)/.exec(changelog)?.[1] ?? 'dev';
}

// JetBrains Mono (OFL-1.1) from @fontsource: keep the latin + latin-ext faces
// of the given weights and inline their woff2 files.
async function fontFaces(weights) {
  const pkg = at('node_modules', '@fontsource', 'jetbrains-mono');
  const faces = [];
  for (const weight of weights) {
    const css = await readFile(join(pkg, `${weight}.css`), 'utf8');
    for (const block of css.match(/\/\* jetbrains-mono-latin(-ext)?-\d+-normal \*\/\s*@font-face\s*{[^}]*}/g) ?? []) {
      const file = /url\(\.\/files\/([^)]+\.woff2)\)/.exec(block)[1];
      const data = (await readFile(join(pkg, 'files', file))).toString('base64');
      faces.push(block.replace(/src:[^;]*;/, `src: url(data:font/woff2;base64,${data}) format('woff2');`));
    }
  }
  if (!faces.length) throw new Error('no JetBrains Mono faces found');
  return faces.join('\n');
}

async function main() {
  const ver = await version();

  const js = await build({
    entryPoints: [at('web', 'src', 'main.js')],
    bundle: true,
    minify: true,
    format: 'iife',
    target: ['es2020'],
    write: false,
    legalComments: 'eof',
    define: { __DEVDESK_VERSION__: JSON.stringify(ver) },
  });

  const css = await transform([
    await read('vendor', 'web_template', 'base.css'),
    await read('node_modules', '@xterm', 'xterm', 'css', 'xterm.css'),
    await fontFaces([400, 700]),
    await read('web', 'styles.css'),
  ].join('\n'), { loader: 'css', minify: true, legalComments: 'eof' });

  const { FAVICON: favicon } = await import('./src/icon.js');

  const script = js.outputFiles[0].text.replace(/<\/script/gi, '<\\/script');
  const style = css.code.replace(/<\/style/gi, '<\\/style');
  const template = await read('web', 'index.template.html');
  const html = template
    .replace('__FAVICON__', () => favicon)
    .replace('<!--STYLES-->', () => `<style>${style}</style>`)
    .replace('<!--SCRIPT-->', () => `<script>${script}</script>`);

  await mkdir(at('dist'), { recursive: true });
  await writeFile(at('dist', 'index.html'), html);
  console.log(`dist/index.html  ${(html.length / 1024).toFixed(0)} KiB  (devdesk ${ver})`);
}

main().catch((err) => {
  console.error(err);
  process.exit(1);
});