import { readFile } from 'node:fs/promises';
import path from 'node:path';
import process from 'node:process';
import { pathToFileURL } from 'node:url';

/**
 * 校验路由表里每个 renderLazyComponent(X) 用到的组件 X 都在同文件里
 * 用 `const X = lazy(() => import(...))` 声明过。
 *
 * 为什么要这个检查（2026-10-22 生产事故）：
 *   PR #74 新增「缺货补货监控」时，router/index.jsx 里写了
 *   `element: renderLazyComponent(BinReplenishMonitor)` 却漏了 lazy 声明。
 *   这行在模块顶层执行 → 加载即抛 `ReferenceError: BinReplenishMonitor is not defined`
 *   → 整个 React 应用挂掉、**全站白屏，连登录页都渲染不出来**。
 *   而 `vite build` 完全能构建成功（未声明标识符在 JS 里是合法语法），
 *   所以必须在构建期用静态扫描拦住。
 */
export async function verifyRouterLazy(routerPath = path.resolve(process.cwd(), 'src/router/index.jsx')) {
  const source = await readFile(routerPath, 'utf8');

  const used = new Set();
  for (const match of source.matchAll(/renderLazyComponent\s*\(\s*([A-Za-z_$][\w$]*)/g)) {
    used.add(match[1]);
  }

  const declared = new Set();
  for (const match of source.matchAll(/const\s+([A-Za-z_$][\w$]*)\s*=\s*lazy\s*\(/g)) {
    declared.add(match[1]);
  }

  const missing = [...used].filter((name) => !declared.has(name)).sort();

  if (missing.length > 0) {
    const lines = missing.map((name) => {
      const idx = source.indexOf(`renderLazyComponent(${name}`);
      const line = idx === -1 ? '?' : source.slice(0, idx).split('\n').length;
      return `  - ${name}  (router/index.jsx:${line} 使用，缺少 const ${name} = lazy(() => import('...')) 声明)`;
    });
    throw new Error(
      'router/index.jsx 有组件被 renderLazyComponent 使用但未声明为 lazy，' +
        '这会导致运行时 ReferenceError 并让整站白屏：\n' +
        lines.join('\n'),
    );
  }

  return { routerPath, used: [...used].sort(), declared: [...declared].sort() };
}

async function main() {
  const routerArg = process.argv[2];
  const routerPath = routerArg
    ? path.resolve(process.cwd(), routerArg)
    : path.resolve(process.cwd(), 'src/router/index.jsx');
  const result = await verifyRouterLazy(routerPath);
  process.stdout.write(
    `Verified router lazy declarations: ${result.used.length} used, ${result.declared.length} declared ` +
      `(${path.relative(process.cwd(), result.routerPath)})\n`,
  );
}

const isDirectExecution = process.argv[1]
  ? pathToFileURL(path.resolve(process.argv[1])).href === import.meta.url
  : false;

if (isDirectExecution) {
  main().catch((error) => {
    process.stderr.write(`${error.message}\n`);
    process.exitCode = 1;
  });
}