import http from 'http'
import https from 'https'
import { URL } from 'url'

const port = 7860

const CORS_HEADERS = {
  'Access-Control-Allow-Origin': '*',
  'Access-Control-Allow-Methods': 'GET, POST, PUT, DELETE, OPTIONS',
  'Access-Control-Allow-Headers': 'Content-Type, Authorization',
  'Access-Control-Max-Age': '86400'
}

const server = http.createServer((req, res) => {
  // 处理预检请求
  if (req.method === 'OPTIONS') {
    res.writeHead(204, {
      ...CORS_HEADERS,
      'Content-Length': '0'
    })
    return res.end()
  }

  try {
    // 解析代理路径
    const proxyPath = req.url?.replace(/^\/proxy\//i, '')
    const targetUrl = new URL(proxyPath)
    const isHttps = targetUrl.protocol === 'https:'

    // 构建代理请求选项
    const options = {
      hostname: targetUrl.hostname,
      port: targetUrl.port || (isHttps ? 443 : 80),
      path: targetUrl.pathname + targetUrl.search,
      method: req.method,
      headers: { ...req.headers }
    }

    // 清理请求头
    delete options.headers.host
    delete options.headers.origin
    delete options.headers.referer

    // 创建代理请求
    const proxy = (isHttps ? https : http).request(options, (proxyRes) => {
      // 注入CORS头
      const responseHeaders = {
        ...proxyRes.headers,
        ...CORS_HEADERS
      }

      res.writeHead(proxyRes.statusCode || 200, responseHeaders)
      proxyRes.pipe(res, { end: true })
    })

    // 错误处理
    proxy.on('error', (err) => {
      console.error(`Proxy error: ${err.message}`)
      res.writeHead(502, {
        'Content-Type': 'text/plain',
        ...CORS_HEADERS
      })
      res.end('Bad Gateway')
    })

    // 流式传输请求体
    req.pipe(proxy, { end: true })

  } catch (error) {
    res.writeHead(400, {
      'Content-Type': 'text/plain',
      ...CORS_HEADERS
    })
    res.end('Invalid proxy URL')
  }
})

// 启动服务器
server.listen(port, () => {
  console.log(`Proxy server is running on http://localhost:${port}`)
})