const fs = require('fs');
const path = require('path');

function walkDir(dir, callback) {
  fs.readdirSync(dir).forEach(f => {
    let dirPath = path.join(dir, f);
    if (fs.statSync(dirPath).isDirectory()) {
      walkDir(dirPath, callback);
    } else {
      callback(dirPath);
    }
  });
}

walkDir('apps/website/src/app/[lang]', (filePath) => {
  if (!filePath.endsWith('.tsx') && !filePath.endsWith('.ts')) return;

  let content = fs.readFileSync(filePath, 'utf8');
  let changed = false;

  // 1. Convert `export const metadata = { title: '...', description: '...' }` to generateMetadata
  // We need to parse:
  // export const metadata = {
  //   title: '...',
  //   description: '...',
  // }
  
  const metadataRegex = /export const metadata\s*(?::\s*Metadata\s*)?=\s*\{([\s\S]*?)\};?/g;
  
  // Exclude layout.tsx because we'll keep its global metadata, and handle it separately.
  if (filePath.endsWith('layout.tsx')) return;

  content = content.replace(metadataRegex, (match, body) => {
    changed = true;
    
    // Extract title and description
    const titleMatch = body.match(/title:\s*['"`](.*?)['"`]/);
    const descMatch = body.match(/description:\s*['"`](.*?)['"`]/);
    
    const title = titleMatch ? titleMatch[1] : '';
    const desc = descMatch ? descMatch[1] : '';
    
    // Determine the route path (e.g. /shop, /about, /checkout)
    // from the filePath. e.g. apps/website/src/app/[lang]/shop/page.tsx -> /shop
    let routePath = '';
    const relPath = filePath.split('app/[lang]/')[1].replace('/page.tsx', '').replace('page.tsx', '');
    if (relPath && !relPath.includes('[') && !relPath.includes(']')) {
      routePath = '/' + relPath;
    } else if (relPath.includes('[') && relPath.includes(']')) {
      // Dynamic route, can't just use string replacement easily. We will leave it to be manually fixed or use params.
      // But wait! If it's a dynamic route, it probably already has `generateMetadata`!
      // Let's check if there are static metadata in dynamic routes.
      // Wait, `/order/[id]/page.tsx` has `generateMetadata`.
    }
    
    if (relPath.includes('[')) {
       // Just fallback to empty for dynamic segments if any static metadata exists
       routePath = '';
    }

    return `export async function generateMetadata({ params }: { params: Promise<{ lang: string }> }) {
  const { lang } = await params;
  return generateSeoMetadata({
    title: '${title}',
    description: '${desc}',
    path: '${routePath}',
    lang,
  });
}`;
  });
  
  if (changed) {
    if (!content.includes('generateSeoMetadata')) {
       // Insert import at the top
       content = `import { generateSeoMetadata } from '@/lib/seo';\n` + content;
    }
    fs.writeFileSync(filePath, content, 'utf8');
    console.log('Converted static metadata in', filePath);
  }
});