import { NextRequest, NextResponse } from 'next/server'
import { readFile } from 'fs/promises'
import { join } from 'path'
import { existsSync } from 'fs'

export async function GET(
  request: NextRequest,
  { params }: { params: Promise<{ filename: string }> }
) {
  try {
    const { filename } = await params
    
    // 构建文件路径
    const filePath = join(process.cwd(), 'public', 'uploads', filename)
    
    // 检查文件是否存在
    if (!existsSync(filePath)) {
      return new NextResponse('File not found', { status: 404 })
    }
    
    // 读取文件
    const fileBuffer = await readFile(filePath)
    
    // 根据文件扩展名设置 Content-Type
    const ext = filename.split('.').pop()?.toLowerCase()
    const contentTypeMap: Record<string, string> = {
      // 图片
      'jpg': 'image/jpeg',
      'jpeg': 'image/jpeg',
      'png': 'image/png',
      'gif': 'image/gif',
      'webp': 'image/webp',
      'svg': 'image/svg+xml',
      // 视频
      'mp4': 'video/mp4',
      'webm': 'video/webm',
      'ogg': 'video/ogg',
      'mov': 'video/quicktime',
      'avi': 'video/x-msvideo',
      'mkv': 'video/x-matroska',
    }
    
    const contentType = contentTypeMap[ext || ''] || 'application/octet-stream'
    
    // 返回文件
    return new NextResponse(fileBuffer, {
      status: 200,
      headers: {
        'Content-Type': contentType,
        'Cache-Control': 'public, max-age=31536000, immutable',
      },
    })
  } catch (error) {
    console.error('读取文件失败:', error)
    return new NextResponse('Internal Server Error', { status: 500 })
  }
}