const B2_DOMAIN = "totyt0.s3.us-east-005.backblazeb2.com";

addEventListener("fetch", event => {
  event.respondWith(handleRequest(event.request));
});

async function handleRequest(request) {
  const url = new URL(request.url);
  
  // 1. 替换域名为 B2 实际地址
  url.hostname = B2_DOMAIN;
  
  // 2. 创建新请求（保留原始方法和头信息）
  const newRequest = new Request(url, {
    method: request.method,
    headers: request.headers,
    body: request.body,
    redirect: 'follow'
  });

  // 3. 添加必要的安全头（防止B2被直接访问）
  newRequest.headers.set('Host', B2_DOMAIN);
  
  try {
    // 4. 代理请求到 B2
    const response = await fetch(newRequest);
  
    // 5. 修改响应头（可选）
    const newResponse = new Response(response.body, response);
    newResponse.headers.set('X-Proxy-By', 'Cloudflare-Worker');
    newResponse.headers.delete('x-amz-request-id'); // 移除敏感头
  
    return newResponse;
  } catch (error) {
    return new Response(`Proxy Error: ${error.message}`, { status: 500 });
  }
}