import { spawn } from 'node:child_process';
import { access, copyFile, mkdir, readdir, readFile, rm, writeFile } from 'node:fs/promises';
import path from 'node:path';
import { fileURLToPath } from 'node:url';

const siteRoot = path.resolve(fileURLToPath(new URL('..', import.meta.url)));
const repoRoot = path.resolve(siteRoot, '..');
const frontendRoot = path.join(repoRoot, 'frontend');
const runtimeDir = path.join(siteRoot, 'public', 'demo', 'runtime');
const templatesDir = path.join(repoRoot, 'backend', 'bot', 'app', 'web', 'templates');
const themesDir = path.join(repoRoot, 'backend', 'bot', 'app', 'web', 'themes');
const localesDir = path.join(repoRoot, 'locales');
const runtimeBase = '/demo/runtime';
const installGuidesConfigUrl =
  'https://raw.githubusercontent.com/legiz-ru/my-remnawave/main/sub-page/subpage-config/multiapp.json';
const isWindows = process.platform === 'win32';
const npmExecPath = process.env.npm_execpath || '';

function run(command, args, options = {}) {
  return new Promise((resolve, reject) => {
    const child = spawn(command, args, {
      cwd: repoRoot,
      stdio: 'inherit',
      shell: false,
      ...options,
    });
    child.on('error', reject);
    child.on('exit', (code) => {
      if (code === 0) {
        resolve();
        return;
      }
      reject(new Error(`${command} ${args.join(' ')} exited with code ${code}`));
    });
  });
}

function runNpm(args) {
  if (npmExecPath) {
    return run(process.execPath, [npmExecPath, ...args]);
  }
  return run(isWindows ? 'npm.cmd' : 'npm', args, { shell: isWindows });
}

async function pathExists(targetPath) {
  try {
    await access(targetPath);
    return true;
  } catch (_error) {
    return false;
  }
}

async function ensureFrontendDependencies() {
  const viteBin = isWindows
    ? path.join(frontendRoot, 'node_modules', '.bin', 'vite.cmd')
    : path.join(frontendRoot, 'node_modules', '.bin', 'vite');
  if (await pathExists(viteBin)) return;
  await runNpm(['--prefix', frontendRoot, 'ci']);
}

async function copyDirectory(sourceDir, targetDir, transform = null) {
  await mkdir(targetDir, { recursive: true });
  const entries = await readdir(sourceDir, { withFileTypes: true });
  for (const entry of entries) {
    const sourcePath = path.join(sourceDir, entry.name);
    const targetPath = path.join(targetDir, entry.name);
    if (entry.isDirectory()) {
      await copyDirectory(sourcePath, targetPath, transform);
      continue;
    }
    if (!entry.isFile()) continue;
    if (transform) {
      const handled = await transform(sourcePath, targetPath);
      if (handled) continue;
    }
    await mkdir(path.dirname(targetPath), { recursive: true });
    await copyFile(sourcePath, targetPath);
  }
}

async function copyThemeFile(sourcePath, targetPath) {
  if (path.extname(sourcePath).toLowerCase() !== '.css') return false;
  const css = await readFile(sourcePath, 'utf8');
  const rewritten = css.replace(/\/webapp-theme-assets\//g, `${runtimeBase}/themes/`);
  await mkdir(path.dirname(targetPath), { recursive: true });
  await writeFile(targetPath, rewritten, 'utf8');
  return true;
}

async function copyRuntimeAsset(name) {
  await copyFile(path.join(templatesDir, name), path.join(runtimeDir, name));
}

function jsonScriptPayload(value) {
  return JSON.stringify(value).replace(/</g, '\\u003c');
}

async function demoI18nPayload() {
  const [ru, en] = await Promise.all([
    readFile(path.join(localesDir, 'ru.json'), 'utf8'),
    readFile(path.join(localesDir, 'en.json'), 'utf8'),
  ]);
  return jsonScriptPayload({ ru: JSON.parse(ru), en: JSON.parse(en) });
}

async function installGuidesConfigPayload() {
  const response = await fetch(installGuidesConfigUrl, {
    headers: { accept: 'application/json' },
  });
  if (!response.ok) {
    throw new Error(
      `Unable to download demo install guides config (${response.status} ${response.statusText})`,
    );
  }
  const config = await response.json();
  return `${JSON.stringify(config, null, 2)}\n`;
}

async function appHtml() {
  const i18n = await demoI18nPayload();
  return `<!doctype html>
<html lang="ru">
  <head>
    <meta charset="utf-8" />
    <meta
      name="viewport"
      content="width=device-width, initial-scale=1, maximum-scale=1, user-scalable=no, viewport-fit=cover"
    />
    <meta name="robots" content="noindex, nofollow" />
    <meta name="theme-color" content="#03070b" />
    <title>Remnawave Minishop Demo</title>
    <link rel="stylesheet" href="${runtimeBase}/subscription_webapp_docs_demo.css" />
  </head>
  <body>
    <main id="app">
      <div class="app-boot-fallback" role="status" aria-label="Loading demo"></div>
    </main>
    <script id="i18n" type="application/json">${i18n}</script>
    <script src="${runtimeBase}/subscription_webapp_docs_demo.js" defer></script>
  </body>
</html>
`;
}

await ensureFrontendDependencies();
await runNpm(['--prefix', frontendRoot, 'run', 'build:docs-demo']);

await rm(runtimeDir, { recursive: true, force: true });
await mkdir(runtimeDir, { recursive: true });

const html = await appHtml();

await Promise.all([
  copyRuntimeAsset('subscription_webapp_docs_demo.js'),
  copyRuntimeAsset('subscription_webapp_docs_demo.css'),
  copyRuntimeAsset('subscription_webapp_admin.js'),
  copyRuntimeAsset('subscription_webapp_admin.css'),
  copyDirectory(path.join(templatesDir, 'default-brand'), path.join(runtimeDir, 'default-brand')),
  copyDirectory(themesDir, path.join(runtimeDir, 'themes'), copyThemeFile),
  writeFile(path.join(runtimeDir, 'app.html'), html, 'utf8'),
  installGuidesConfigPayload().then((payload) =>
    writeFile(path.join(runtimeDir, 'subscription-guides-config.json'), payload, 'utf8'),
  ),
]);

console.log(`Built static docs demo runtime at ${path.relative(repoRoot, runtimeDir)}`);