export default {
  async fetch(request, env) {
    const url = new URL(request.url);
    const path = url.pathname.split('/');
    
    // 处理CORS
    if (request.method === 'OPTIONS') {
      return new Response(null, {
        headers: {
          'Access-Control-Allow-Origin': '*',
          'Access-Control-Allow-Methods': 'GET, POST, DELETE, OPTIONS',
          'Access-Control-Allow-Headers': 'Content-Type, Authorization'
        }
      });
    }
    
    // 文件上传
    if (path[1] === 'upload' && request.method === 'POST') {
      try {
        const formData = await request.formData();
        const file = formData.get('file');
        const password = formData.get('password') || null;
        const expiresAt = formData.get('expires') ? new Date(formData.get('expires')) : null;
        
        if (!file) {
          return new Response(JSON.stringify({ error: 'No file provided' }), {
            status: 400,
            headers: {
              'Content-Type': 'application/json',
              'Access-Control-Allow-Origin': '*'
            }
          });
        }
        
        // 生成唯一文件ID
        const fileId = crypto.randomUUID();
        
        // 上传文件到R2，将 FILES_BUCKET 改为 file_share_bucket
        await env.file_share_bucket.put(fileId, file);
        
        // 存储文件元数据到D1
        await env.DB.prepare(
          'INSERT INTO files (id, name, type, size, password, created_at, expires_at) VALUES (?, ?, ?, ?, ?, ?, ?)'
        ).bind(
          fileId,
          file.name,
          file.type,
          file.size,
          password,
          new Date().toISOString(),
          expiresAt ? expiresAt.toISOString() : null
        ).run();
        
        return new Response(JSON.stringify({
          success: true,
          fileId: fileId,
          url: `${url.origin}/file/${fileId}`
        }), {
          headers: {
            'Content-Type': 'application/json',
            'Access-Control-Allow-Origin': '*'
          }
        });
      } catch (error) {
        return new Response(JSON.stringify({ error: error.message }), {
          status: 500,
          headers: {
            'Content-Type': 'application/json',
            'Access-Control-Allow-Origin': '*'
          }
        });
      }
    }
    
    // 文件下载
    if (path[1] === 'file' && path[2]) {
      const fileId = path[2];
      const password = url.searchParams.get('password') || null;
      
      try {
        // 获取文件元数据
        const fileInfo = await env.DB.prepare(
          'SELECT * FROM files WHERE id = ?'
        ).bind(fileId).first();
        
        if (!fileInfo) {
          return new Response(JSON.stringify({ error: 'File not found' }), {
            status: 404,
            headers: {
              'Content-Type': 'application/json',
              'Access-Control-Allow-Origin': '*'
            }
          });
        }
        
        // 检查文件是否过期
        if (fileInfo.expires_at && new Date(fileInfo.expires_at) < new Date()) {
          return new Response(JSON.stringify({ error: 'File has expired' }), {
            status: 410,
            headers: {
              'Content-Type': 'application/json',
              'Access-Control-Allow-Origin': '*'
            }
          });
        }
        
        // 检查密码
        if (fileInfo.password && fileInfo.password !== password) {
          return new Response(JSON.stringify({ error: 'Invalid password' }), {
            status: 401,
            headers: {
              'Content-Type': 'application/json',
              'Access-Control-Allow-Origin': '*'
            }
          });
        }
        
        // 从R2获取文件，将 FILES_BUCKET 改为 file_share_bucket
        const file = await env.file_share_bucket.get(fileId);
        
        if (!file) {
          return new Response(JSON.stringify({ error: 'File not found in storage' }), {
            status: 404,
            headers: {
              'Content-Type': 'application/json',
              'Access-Control-Allow-Origin': '*'
            }
          });
        }
        
        // 更新下载计数
        await env.DB.prepare(
          'UPDATE files SET downloads = downloads + 1 WHERE id = ?'
        ).bind(fileId).run();
        
        // 返回文件
        return new Response(file.body, {
          headers: {
            'Content-Type': file.httpMetadata.contentType || 'application/octet-stream',
            'Content-Disposition': `attachment; filename="${fileInfo.name}"`,
            'Access-Control-Allow-Origin': '*'
          }
        });
      } catch (error) {
        return new Response(JSON.stringify({ error: error.message }), {
          status: 500,
          headers: {
            'Content-Type': 'application/json',
            'Access-Control-Allow-Origin': '*'
          }
        });
      }
    }
    
    // 修改默认响应
    const apiDoc = {
      message: "\u26a0\ufe0f \u8fd9\u662fAPI\u4e13\u7528\u7aef\u53e3\uff0c\u7981\u6b62\u76f4\u63a5\u8bbf\u95ee",
      description: "\u8fd9\u662f\u4e00\u4e2a\u6587\u4ef6\u5b58\u50a8\u548c\u5206\u4eab\u7cfb\u7edf\u7684API\u670d\u52a1",
      frontend: "https://fileshare.ssplus.cn",
      api_endpoints: {
        upload: {
          method: "POST",
          path: "/upload",
          description: "\u4e0a\u4f20\u6587\u4ef6"
        },
        download: {
          method: "GET",
          path: "/file/:fileId",
          description: "\u4e0b\u8f7d\u6587\u4ef6"
        }
      }
    };

    return new Response(JSON.stringify(apiDoc, null, 2), {
      headers: {
        'Content-Type': 'application/json; charset=utf-8',
        'Access-Control-Allow-Origin': '*'
      }
    });
  }
};