/**
 * 图片上传API
 * 支持上传图片到public/assets目录
 */

import { NextRequest, NextResponse } from 'next/server'
import { writeFile, mkdir } from 'fs/promises'
import { existsSync } from 'fs'
import path from 'path'

// 支持的图片格式
const ALLOWED_TYPES = ['image/jpeg', 'image/png', 'image/gif', 'image/webp', 'image/svg+xml']
const MAX_SIZE = 5 * 1024 * 1024 // 5MB

/**
 * POST - 上传图片
 */
export async function POST(request: NextRequest) {
  try {
    const formData = await request.formData()
    const file = formData.get('file') as File | null
    const folder = formData.get('folder') as string || 'uploads'
    
    if (!file) {
      return NextResponse.json({
        success: false,
        error: '请选择要上传的文件'
      }, { status: 400 })
    }
    
    // 验证文件类型
    if (!ALLOWED_TYPES.includes(file.type)) {
      return NextResponse.json({
        success: false,
        error: '不支持的文件格式，仅支持 JPG、PNG、GIF、WebP、SVG'
      }, { status: 400 })
    }
    
    // 验证文件大小
    if (file.size > MAX_SIZE) {
      return NextResponse.json({
        success: false,
        error: '文件大小不能超过5MB'
      }, { status: 400 })
    }
    
    // 生成唯一文件名
    const timestamp = Date.now()
    const randomStr = Math.random().toString(36).substring(2, 8)
    const ext = file.name.split('.').pop() || 'jpg'
    const fileName = `${timestamp}_${randomStr}.${ext}`
    
    // 确保上传目录存在
    const uploadDir = path.join(process.cwd(), 'public', 'assets', folder)
    if (!existsSync(uploadDir)) {
      await mkdir(uploadDir, { recursive: true })
    }
    
    // 写入文件
    const filePath = path.join(uploadDir, fileName)
    const bytes = await file.arrayBuffer()
    const buffer = Buffer.from(bytes)
    await writeFile(filePath, buffer)
    
    // 返回可访问的URL
    const url = `/assets/${folder}/${fileName}`
    
    return NextResponse.json({
      success: true,
      data: {
        url,
        fileName,
        size: file.size,
        type: file.type
      }
    })
    
  } catch (error) {
    console.error('[Upload API] 上传失败:', error)
    return NextResponse.json({
      success: false,
      error: '上传失败: ' + (error as Error).message
    }, { status: 500 })
  }
}

/**
 * DELETE - 删除图片
 */
export async function DELETE(request: NextRequest) {
  try {
    const { searchParams } = new URL(request.url)
    const filePath = searchParams.get('path')
    
    if (!filePath) {
      return NextResponse.json({
        success: false,
        error: '请指定要删除的文件路径'
      }, { status: 400 })
    }
    
    // 安全检查：确保只能删除assets目录下的文件
    if (!filePath.startsWith('/assets/')) {
      return NextResponse.json({
        success: false,
        error: '无权限删除此文件'
      }, { status: 403 })
    }
    
    const fullPath = path.join(process.cwd(), 'public', filePath)
    
    if (!existsSync(fullPath)) {
      return NextResponse.json({
        success: false,
        error: '文件不存在'
      }, { status: 404 })
    }
    
    const { unlink } = await import('fs/promises')
    await unlink(fullPath)
    
    return NextResponse.json({
      success: true,
      message: '文件删除成功'
    })
    
  } catch (error) {
    console.error('[Upload API] 删除失败:', error)
    return NextResponse.json({
      success: false,
      error: '删除失败: ' + (error as Error).message
    }, { status: 500 })
  }
}