import sharp from 'sharp'
import { NextRequest, NextResponse } from 'next/server'
import { getServerSession } from 'next-auth'
import { authOptions } from '@/lib/auth'

const ALLOWED_IMAGE_HOST_SUFFIXES = [
  'alicdn.com',
  'taobaocdn.com',
  'tbcdn.cn',
]

function isAllowedImageHost(hostname: string): boolean {
  return ALLOWED_IMAGE_HOST_SUFFIXES.some(
    (suffix) => hostname === suffix || hostname.endsWith(`.${suffix}`),
  )
}

export async function GET(request: NextRequest) {
  try {
    const session = await getServerSession(authOptions)
    if (!session) {
      return NextResponse.json(
        {
          success: false,
          error: {
            code: 'UNAUTHORIZED',
            message: '请先登录后再导出图片',
          },
        },
        { status: 401 },
      )
    }

    const rawUrl = request.nextUrl.searchParams.get('url')
    if (!rawUrl) {
      return NextResponse.json(
        {
          success: false,
          error: {
            code: 'MISSING_URL',
            message: '缺少图片地址',
          },
        },
        { status: 400 },
      )
    }

    let targetUrl: URL
    try {
      targetUrl = new URL(rawUrl)
    } catch {
      return NextResponse.json(
        {
          success: false,
          error: {
            code: 'INVALID_URL',
            message: '图片地址不正确',
          },
        },
        { status: 400 },
      )
    }

    if (!['http:', 'https:'].includes(targetUrl.protocol) || !isAllowedImageHost(targetUrl.hostname)) {
      return NextResponse.json(
        {
          success: false,
          error: {
            code: 'IMAGE_HOST_NOT_ALLOWED',
            message: '图片来源不允许导出',
          },
        },
        { status: 400 },
      )
    }

    const upstream = await fetch(targetUrl.toString(), {
      method: 'GET',
      cache: 'no-store',
      headers: {
        'User-Agent': 'Mozilla/5.0 Codex Taobao Image Proxy',
        Referer: 'https://item.taobao.com/',
      },
    })

    if (!upstream.ok) {
      return NextResponse.json(
        {
          success: false,
          error: {
            code: 'UPSTREAM_IMAGE_FETCH_FAILED',
            message: `图片下载失败，上游返回 ${upstream.status}`,
          },
        },
        { status: 502 },
      )
    }

    const buffer = Buffer.from(await upstream.arrayBuffer())
    const pngBuffer = await sharp(buffer, { failOn: 'none' })
      .flatten({ background: '#ffffff' })
      .png()
      .toBuffer()
    const metadata = await sharp(pngBuffer).metadata()

    return new NextResponse(Uint8Array.from(pngBuffer), {
      status: 200,
      headers: {
        'Content-Type': 'image/png',
        'Cache-Control': 'private, max-age=300',
        'X-Image-Width': String(metadata.width || 0),
        'X-Image-Height': String(metadata.height || 0),
      },
    })
  } catch (error) {
    console.error('[api/taobao-detail-plus/image-proxy] GET error:', error)
    return NextResponse.json(
      {
        success: false,
        error: {
          code: 'IMAGE_PROXY_ERROR',
          message: '图片处理失败，请稍后再试',
        },
      },
      { status: 500 },
    )
  }
}