import fs from 'fs';
import path from 'path';

export default function sigproRouter() {
  const virtualModuleId = 'virtual:sigpro-routes';
  const resolvedVirtualModuleId = '\0' + virtualModuleId;

  function getFiles(dir) {
    let results = [];
    if (!fs.existsSync(dir)) return results;
    const list = fs.readdirSync(dir);
    list.forEach(file => {
      const fullPath = path.resolve(dir, file);
      const stat = fs.statSync(fullPath);
      if (stat && stat.isDirectory()) {
        results = results.concat(getFiles(fullPath));
      } else if (file.endsWith('.js')) {
        results.push(fullPath);
      }
    });
    return results;
  }

  return {
    name: 'sigpro-router',
    resolveId(id) {
      if (id === virtualModuleId) return resolvedVirtualModuleId;
    },
    load(id) {
      if (id === resolvedVirtualModuleId) {
        const pagesDir = path.resolve(process.cwd(), 'src/pages');
        let files = getFiles(pagesDir);

        files = files.sort((a, b) => {
          const aDyn = a.includes('[');
          const bDyn = b.includes('[');
          if (aDyn !== bDyn) return aDyn ? 1 : -1;
          return a.length - b.length;
        });

        let imports = '';
        let routeArray = 'export const routes = [\n';

        console.log('\n🚀 [SigPro Router] Mapa de rutas generado:');

        files.forEach((fullPath, i) => {
          const relativePath = path.relative(pagesDir, fullPath).replace(/\\/g, '/');
          const fileName = relativePath.replace('.js', '');
          const varName = `Page_${i}`;
          
          let urlPath = '/' + fileName.toLowerCase();
          if (urlPath.endsWith('/index')) urlPath = urlPath.replace('/index', '') || '/';

          const isDynamic = urlPath.includes('[') && urlPath.includes(']');
          let finalPathValue = `'${urlPath}'`;
          let paramName = null;

          if (isDynamic) {
            // Extraemos el nombre del parámetro (ej: de [id] extraemos 'id')
            const match = urlPath.match(/\[([^\]]+)\]/);
            paramName = match ? match[1] : 'id';

            // CORRECCIÓN: Usamos Grupos Nombrados de JS (?<nombre>...)
            // Esto permite que el router haga path.match(regex).groups
            const regexStr = urlPath
              .replace(/\//g, '\\/')
              .replace(/\[([^\]]+)\]/, '(?<$1>[^/]+)'); // Reemplaza [id] por (?<id>[^/]+)
            
            finalPathValue = `new RegExp("^${regexStr}$")`;
          }

          console.log(`   ${isDynamic ? '🔗' : '📄'} ${urlPath.padEnd(20)} -> ${relativePath}`);

          imports += `import ${varName} from './src/pages/${relativePath}';\n`;
          routeArray += `  { path: ${finalPathValue}, component: ${varName}, isDynamic: ${isDynamic}, paramName: ${paramName ? `'${paramName}'` : 'null'} },\n`;
        });

        routeArray += '];';
        return `${imports}\n${routeArray}`;
      }
    }
  };
}