const Router = require('koa-router')
const multer = require('@koa/multer')
const path = require('path')
const fs = require('fs')

const router = new Router()

const ALLOWED_TYPES = ['image/jpeg', 'image/png', 'image/gif', 'image/webp']
const MAX_SIZE = 5 * 1024 * 1024

const uploadDir = path.join(__dirname, '..', 'public', 'uploads')

const storage = multer.diskStorage({
  destination: (req, file, cb) => {
    const type = (req.query && req.query.type) || 'goods'
    const dir = path.join(uploadDir, type)
    if (!fs.existsSync(dir)) {
      fs.mkdirSync(dir, { recursive: true })
    }
    cb(null, dir)
  },
  filename: (req, file, cb) => {
    const uniqueSuffix = Date.now() + '-' + Math.round(Math.random() * 1e9)
    const ext = path.extname(file.originalname)
    cb(null, uniqueSuffix + ext)
  }
})

const upload = multer({
  storage,
  limits: { fileSize: MAX_SIZE },
  fileFilter: (req, file, cb) => {
    if (ALLOWED_TYPES.includes(file.mimetype)) {
      cb(null, true)
    } else {
      cb(new Error('不支持的文件类型，仅支持 jpg/png/gif/webp'))
    }
  }
})

router.post('/', upload.single('file'), async (ctx) => {
  if (!ctx.file) {
    ctx.status = 400
    ctx.body = { code: 400, message: '没有上传文件' }
    return
  }

  const type = ctx.query.type || 'goods'
  const fileUrl = `/uploads/${type}/${ctx.file.filename}`
  ctx.body = {
    code: 200,
    message: '上传成功',
    url: fileUrl
  }
})

module.exports = router.routes()