import { createHash } from 'node:crypto'

// 重试函数
const fetchWithRetry = async (url: string, options: any, maxRetries = 3): Promise<Response> => {
  let lastError: Error

  for (let attempt = 1; attempt <= maxRetries; attempt++) {
    try {
      console.log(`尝试获取图片 (${attempt}/${maxRetries}): ${url}`)

      // 创建AbortController用于超时控制
      const controller = new AbortController()
      const timeoutId = setTimeout(() => controller.abort(), 10000) // 10秒超时

      const response = await fetch(url, {
        ...options,
        signal: controller.signal
      })

      clearTimeout(timeoutId)

      if (response.ok) {
        console.log(`图片获取成功 (尝试 ${attempt})`)
        return response
      } else {
        throw new Error(`HTTP ${response.status}: ${response.statusText}`)
      }
    } catch (error: any) {
      lastError = error
      console.warn(`图片获取失败 (尝试 ${attempt}/${maxRetries}):`, error.message)

      // 如果不是最后一次尝试，等待一段时间后重试
      if (attempt < maxRetries) {
        const delay = Math.min(1000 * Math.pow(2, attempt - 1), 5000) // 指数退避，最大5秒
        console.log(`等待 ${delay}ms 后重试...`)
        await new Promise((resolve) => setTimeout(resolve, delay))
      }
    }
  }

  throw lastError
}

export default defineEventHandler(async (event) => {
  const query = getQuery(event)
  const imageUrl = query.url as string
  const quality = query.quality as string

  if (!imageUrl) {
    throw createError({
      statusCode: 400,
      statusMessage: 'Missing image URL parameter'
    })
  }

  try {
    // 验证URL是否为有效的图片URL
    const url = new URL(imageUrl)
    if (!url.protocol.startsWith('http')) {
      throw new Error('Invalid protocol')
    }

    // 确定 Referer
    let referer = url.origin
    // 针对 Bilibili 图片的特殊处理
    if (url.hostname.includes('hdslb.com') || url.hostname.includes('bilibili.com')) {
      referer = 'https://www.bilibili.com/'
    }

    // 优化的请求头
    const headers = {
      'User-Agent':
        'Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36',
      Accept: 'image/webp,image/apng,image/svg+xml,image/*,*/*;q=0.8',
      'Accept-Language': 'zh-CN,zh;q=0.9,en;q=0.8',
      'Accept-Encoding': 'gzip, deflate, br',
      'Sec-Fetch-Dest': 'image',
      'Sec-Fetch-Mode': 'no-cors',
      'Sec-Fetch-Site': 'cross-site',
      Referer: referer
    }

    // 使用重试机制获取图片
    const response = await fetchWithRetry(imageUrl, { headers })

    // 检查内容类型
    const contentType = response.headers.get('content-type')
    if (!contentType || !contentType.startsWith('image/')) {
      throw new Error('Response is not an image')
    }

    // 获取图片数据
    const imageBuffer = await response.arrayBuffer()
    const etag = `"${createHash('sha1').update(Buffer.from(imageBuffer)).digest('hex')}"`

    if (getHeader(event, 'if-none-match') === etag) {
      setResponseStatus(event, 304)
      setHeader(event, 'ETag', etag)
      setHeader(event, 'Cache-Control', 'public, max-age=86400, s-maxage=86400, stale-while-revalidate=604800')
      setHeader(event, 'Access-Control-Allow-Origin', '*')
      setHeader(event, 'Access-Control-Allow-Methods', 'GET, OPTIONS')
      setHeader(event, 'Access-Control-Allow-Headers', 'Content-Type')
      return ''
    }

    // 设置响应头
    setHeader(event, 'Content-Type', contentType)
    setHeader(event, 'ETag', etag)
    setHeader(event, 'Cache-Control', 'public, max-age=86400, s-maxage=86400, stale-while-revalidate=604800')
    setHeader(event, 'Access-Control-Allow-Origin', '*')
    setHeader(event, 'Access-Control-Allow-Methods', 'GET, OPTIONS')
    setHeader(event, 'Access-Control-Allow-Headers', 'Content-Type')

    console.log(`图片代理成功: ${imageUrl}, 大小: ${imageBuffer.byteLength} bytes`)
    return new Uint8Array(imageBuffer)
  } catch (error: any) {
    console.error('Image proxy error:', {
      url: imageUrl,
      error: error.message,
      code: error.code,
      cause: error.cause
    })

    // 提供更详细的错误信息
    let errorMessage = 'Failed to fetch image'
    if (error.code === 'ECONNRESET') {
      errorMessage = '网络连接被重置，请稍后重试'
    } else if (error.code === 'ETIMEDOUT' || error.name === 'AbortError') {
      errorMessage = '请求超时，请检查网络连接'
    } else if (error.code === 'ENOTFOUND') {
      errorMessage = '无法解析域名，请检查URL是否正确'
    } else if (error.message.includes('HTTP')) {
      errorMessage = `服务器返回错误: ${error.message}`
    }

    throw createError({
      statusCode: 500,
      statusMessage: `${errorMessage}: ${error.message}`
    })
  }
})