addEventListener('fetch', event => {
    event.respondWith(handle58imgRequest(event.request));
  })
  
  async function handle58imgRequest(request) {
    // 确认请求方法为 POST 并且内容类型正确
    if (request.method !== 'POST' || !request.headers.get('Content-Type').includes('multipart/form-data')) {
      return new Response('Invalid request', { status: 400 });
    }
  
    // 解析表单数据
    const formData = await request.formData();
    const imageFile = formData.get('image'); // 假设字段名为 'image'
    if (!imageFile) return new Response('Image file not found', { status: 400 });
  
    // 将文件数据转换为 ArrayBuffer
    const arrayBuffer = await imageFile.arrayBuffer();
  
    // 将 ArrayBuffer 转换为 Base64
    const base64EncodedData = bufferToBase64(arrayBuffer);
  
    // 构建请求负载
    const payload = {
      "Pic-Size": "0*0",
      "Pic-Encoding": "base64",
      "Pic-Path": "/nowater/webim/big/",
      "Pic-Data": base64EncodedData
    };
  
    // 目标URL
    const targetUrl = "https://upload.58cdn.com.cn/json/nowater/webim/big/";
  
    // 发送POST请求
    const response = await fetch(targetUrl, {
      method: 'POST',
      headers: { 'Content-Type': 'application/json' },
      body: JSON.stringify(payload)
    });
  
    // 处理响应
    if (response.ok) {
      const result = await response.text();
      // 随机生成1到8之间的数字
      const random_number = Math.floor(Math.random() * 8) + 1;
      const finalUrl = `https://pic${random_number}.58cdn.com.cn/nowater/webim/big/${result}`;
      return new Response(finalUrl);
    } else {
      return new Response("Error: " + await response.text(), { status: response.status });
    }
  }
  
  // ArrayBuffer 转 Base64
  function bufferToBase64(buf) {
    var binary = '';
    var bytes = new Uint8Array(buf);
    var len = bytes.byteLength;
    for (var i = 0; i < len; i++) {
      binary += String.fromCharCode(bytes[i]);
    }
    // 使用 btoa 进行 Base64 编码
    return btoa(binary);
  }