import type { Readable } from 'node:stream'
import { Router } from 'express'

import {
  getStoredFileObject,
  isPublicObjectKey,
} from '../services/file-storage/file-storage-service.js'
import { buildNotFoundPayload, sendRouteError } from '../utils/http.js'

const router = Router()

router.get('/object', async (req, res) => {
  let readerToDestroy: Readable | null = null
  try {
    const rawKey = String(req.query.key || '').trim()
    const isPublic = isPublicObjectKey(rawKey)
    const object = await getStoredFileObject(req.query.key, req.query.variant)
    readerToDestroy = object.reader

    if (object.etag) {
      res.setHeader('ETag', object.etag)
      if (req.headers['if-none-match'] === object.etag) {
        object.reader.destroy()
        readerToDestroy = null
        res.status(304).end()
        return
      }
    }
    if (object.lastModified) {
      res.setHeader('Last-Modified', object.lastModified.toUTCString())
      if (req.headers['if-modified-since']) {
        const ifModifiedSince = new Date(req.headers['if-modified-since'])
        if (!isNaN(ifModifiedSince.getTime()) && object.lastModified <= ifModifiedSince) {
          object.reader.destroy()
          readerToDestroy = null
          res.status(304).end()
          return
        }
      }
    }

    if (object.size > 0) {
      res.setHeader('Content-Length', object.size)
    }
    res.setHeader('Content-Type', object.contentType || 'application/octet-stream')
    res.setHeader('X-Content-Type-Options', 'nosniff')

    if (isPublic) {
      res.setHeader('Cache-Control', 'public, max-age=2592000, stale-while-revalidate=604800')
    } else {
      res.setHeader('Cache-Control', 'private, max-age=300')
    }

    res.on('close', () => {
      if (!res.writableEnded) {
        object.reader.destroy()
      }
    })

    object.reader.on('error', (error) => {
      object.reader.destroy()
      if (!res.headersSent) {
        sendRouteError(res, error, '读取文件失败', '[files/object]')
      } else {
        res.destroy(error)
      }
    })
    object.reader.pipe(res)
    readerToDestroy = null
  } catch (error) {
    if (readerToDestroy) {
      readerToDestroy.destroy()
    }
    sendRouteError(res, error, '读取文件失败', '[files/object]')
  }
})

router.use((req, res) => {
  res.status(404).json(buildNotFoundPayload(req))
})

export default router