text: /* eslint-disable import/first, no-return-await */
  import { resolve, join, sep } from 'path'
  import { parse as parseUrl } from 'url'
  import { parse as parseQs } from 'querystring'
  import fs from 'fs'
  import http, { STATUS_CODES } from 'http'
  import {
    renderToHTML,
    renderErrorToHTML,
    sendHTML,
    serveStatic
  } from './render'
  import Router from './router'
  import { isInternalUrl } from './utils'
  import loadConfig from './config'
  import {PHASE_PRODUCTION_SERVER, PHASE_DEVELOPMENT_SERVER, BLOCKED_PAGES, BUILD_ID_FILE, CLIENT_STATIC_FILES_PATH, CLIENT_STATIC_FILES_RUNTIME} from '../lib/constants'
  import * as asset from '../lib/asset'
  import * as envConfig from '../lib/runtime-config'
  import { isResSent } from '../lib/utils'
  
  // We need to go up one more level since we are in the `dist` directory
  import pkg from '../../package'
  
  export default class Server {
    constructor ({ dir = '.', dev = false, staticMarkup = false, quiet = false, conf = null } = {}) {
      this.dir = resolve(dir)
      this.dev = dev
      this.quiet = quiet
      this.router = new Router()
      this.http = null
      const phase = dev ? PHASE_DEVELOPMENT_SERVER : PHASE_PRODUCTION_SERVER
      this.nextConfig = loadConfig(phase, this.dir, conf)
      this.distDir = join(this.dir, this.nextConfig.distDir)
  
      // Only serverRuntimeConfig needs the default
      // publicRuntimeConfig gets it's default in client/index.js
      const {serverRuntimeConfig = {}, publicRuntimeConfig, assetPrefix, generateEtags} = this.nextConfig
  
      if (!dev && !fs.existsSync(resolve(this.distDir, BUILD_ID_FILE))) {
        console.error(`> Could not find a valid build in the '${this.distDir}' directory! Try building your app with 'next build' before starting the server.`)
        process.exit(1)
      }
      this.buildId = this.readBuildId(dev)
      this.hotReloader = dev ? this.getHotReloader(this.dir, { config: this.nextConfig, buildId: this.buildId }) : null
      this.renderOpts = {
        dev,
        staticMarkup,
        distDir: this.distDir,
        hotReloader: this.hotReloader,
        buildId: this.buildId,
        generateEtags
      }
  
      // Only the `publicRuntimeConfig` key is exposed to the client side
      // It'll be rendered as part of __NEXT_DATA__ on the client side
      if (publicRuntimeConfig) {
        this.renderOpts.runtimeConfig = publicRuntimeConfig
      }
  
      // Initialize next/config with the environment configuration
      envConfig.setConfig({
        serverRuntimeConfig,
        publicRuntimeConfig
      })
  
      this.setAssetPrefix(assetPrefix)
    }
  
    getHotReloader (dir, options) {
      const HotReloader = require('./hot-reloader').default
      return new HotReloader(dir, options)
    }
  
    handleRequest (req, res, parsedUrl) {
      // Parse url if parsedUrl not provided
      if (!parsedUrl || typeof parsedUrl !== 'object') {
        parsedUrl = parseUrl(req.url, true)
      }
  
      // Parse the querystring ourselves if the user doesn't handle querystring parsing
      if (typeof parsedUrl.query === 'string') {
        parsedUrl.query = parseQs(parsedUrl.query)
      }
  
      res.statusCode = 200
      return this.run(req, res, parsedUrl)
        .catch((err) => {
          if (!this.quiet) console.error(err)
          res.statusCode = 500
          res.end(STATUS_CODES[500])
        })
    }
  
    getRequestHandler () {
      return this.handleRequest.bind(this)
    }
  
    setAssetPrefix (prefix) {
      this.renderOpts.assetPrefix = prefix ? prefix.replace(/\/$/, '') : ''
      asset.setAssetPrefix(this.renderOpts.assetPrefix)
    }
  
    async prepare () {
      await this.defineRoutes()
      if (this.hotReloader) {
        await this.hotReloader.start()
      }
    }
  
    async close () {
      if (this.hotReloader) {
        await this.hotReloader.stop()
      }
  
      if (this.http) {
        await new Promise((resolve, reject) => {
          this.http.close((err) => {
            if (err) return reject(err)
            return resolve()
          })
        })
      }
    }
  
    async defineRoutes () {
      const routes = {
        '/_next/static/:path*': async (req, res, params) => {
          // The commons folder holds commonschunk files
          // The chunks folder holds dynamic entries
          // The buildId folder holds pages and potentially other assets. As buildId changes per build it can be long-term cached.
          // In development they don't have a hash, and shouldn't be cached by the browser.
          if (params.path[0] === CLIENT_STATIC_FILES_RUNTIME || params.path[0] === 'chunks' || params.path[0] === this.buildId) {
            if (this.dev) {
              res.setHeader('Cache-Control', 'no-store, must-revalidate')
            } else {
              res.setHeader('Cache-Control', 'public, max-age=31536000, immutable')
            }
          }
          const p = join(this.distDir, CLIENT_STATIC_FILES_PATH, ...(params.path || []))
          await this.serveStatic(req, res, p)
        },
  
        // It's very important keep this route's param optional.
        // (but it should support as many as params, seperated by '/')
        // Othewise this will lead to a pretty simple DOS attack.
        // See more: https://github.com/zeit/next.js/issues/2617
        '/static/:path*': async (req, res, params) => {
          const p = join(this.dir, 'static', ...(params.path || []))
          await this.serveStatic(req, res, p)
        }
      }
  
      // In development we expose all compiled files for react-error-overlay's line show feature
      if (this.dev) {
        routes['/_next/development/:path*'] = async (req, res, params) => {
          const p = join(this.distDir, ...(params.path || []))
          console.log('page', p)
          await this.serveStatic(req, res, p)
        }
      }
  
      // This path is needed because `render()` does a check for `/_next` and the calls the routing again
      routes['/_next/:path*'] = async (req, res, params, parsedUrl) => {
        await this.render404(req, res, parsedUrl)
      }
  
      // Makes `next export` exportPathMap work in development mode.
      // So that the user doesn't have to define a custom server reading the exportPathMap
      if (this.dev && this.nextConfig.exportPathMap) {
        console.log('Defining routes from exportPathMap')
        const exportPathMap = await this.nextConfig.exportPathMap({}, {dev: true, dir: this.dir, outDir: null, distDir: this.distDir, buildId: this.buildId}) // In development we can't give a default path mapping
        for (const path in exportPathMap) {
          const {page, query = {}} = exportPathMap[path]
          routes[path] = async (req, res, params, parsedUrl) => {
            const { query: urlQuery } = parsedUrl
  
            Object.keys(urlQuery)
              .filter(key => query[key] === undefined)
              .forEach(key => console.warn(`Url defines a query parameter '${key}' that is missing in exportPathMap`))
  
            const mergedQuery = {...urlQuery, ...query}
  
            await this.render(req, res, page, mergedQuery, parsedUrl)
          }
        }
      }
  
      if (this.nextConfig.useFileSystemPublicRoutes) {
        // It's very important keep this route's param optional.
        // (but it should support as many as params, seperated by '/')
        // Othewise this will lead to a pretty simple DOS attack.
        // See more: https://github.com/zeit/next.js/issues/2617
        routes['/:path*'] = async (req, res, params, parsedUrl) => {
          const { pathname, query } = parsedUrl
          await this.render(req, res, pathname, query, parsedUrl)
        }
      }
  
      for (const method of ['GET', 'HEAD']) {
        for (const p of Object.keys(routes)) {
          this.router.add(method, p, routes[p])
        }
      }
    }
  
    async start (port, hostname) {
      await this.prepare()
      this.http = http.createServer(this.getRequestHandler())
      await new Promise((resolve, reject) => {
        // This code catches EADDRINUSE error if the port is already in use
        this.http.on('error', reject)
        this.http.on('listening', () => resolve())
        this.http.listen(port, hostname)
      })
    }
  
    async run (req, res, parsedUrl) {
      if (this.hotReloader) {
        const {finished} = await this.hotReloader.run(req, res, parsedUrl)
        if (finished) {
          return
        }
      }
  
      const fn = this.router.match(req, res, parsedUrl)
      if (fn) {
        await fn()
        return
      }
  
      if (req.method === 'GET' || req.method === 'HEAD') {
        await this.render404(req, res, parsedUrl)
      } else {
        res.statusCode = 501
        res.end(STATUS_CODES[501])
      }
    }
  
    async render (req, res, pathname, query, parsedUrl) {
      if (isInternalUrl(req.url)) {
        return this.handleRequest(req, res, parsedUrl)
      }
  
      if (BLOCKED_PAGES.indexOf(pathname) !== -1) {
        return await this.render404(req, res, parsedUrl)
      }
  
      const html = await this.renderToHTML(req, res, pathname, query)
      if (isResSent(res)) {
        return
      }
  
      if (this.nextConfig.poweredByHeader) {
        res.setHeader('X-Powered-By', `Next.js ${pkg.version}`)
      }
      return sendHTML(req, res, html, req.method, this.renderOpts)
    }
  
    async renderToHTML (req, res, pathname, query) {
      if (this.dev) {
        const compilationErr = await this.getCompilationError(pathname)
        if (compilationErr) {
          res.statusCode = 500
          return this.renderErrorToHTML(compilationErr, req, res, pathname, query)
        }
      }
  
      try {
        const out = await renderToHTML(req, res, pathname, query, this.renderOpts)
        return out
      } catch (err) {
        if (err.code === 'ENOENT') {
          res.statusCode = 404
          return this.renderErrorToHTML(null, req, res, pathname, query)
        } else {
          if (!this.quiet) console.error(err)
          res.statusCode = 500
          return this.renderErrorToHTML(err, req, res, pathname, query)
        }
      }
    }
  
    async renderError (err, req, res, pathname, query) {
      const html = await this.renderErrorToHTML(err, req, res, pathname, query)
      return sendHTML(req, res, html, req.method, this.renderOpts)
    }
  
    async renderErrorToHTML (err, req, res, pathname, query) {
      if (this.dev) {
        const compilationErr = await this.getCompilationError(pathname)
        if (compilationErr) {
          res.statusCode = 500
          return renderErrorToHTML(compilationErr, req, res, pathname, query, this.renderOpts)
        }
      }
  
      try {
        return await renderErrorToHTML(err, req, res, pathname, query, this.renderOpts)
      } catch (err2) {
        if (this.dev) {
          if (!this.quiet) console.error(err2)
          res.statusCode = 500
          return renderErrorToHTML(err2, req, res, pathname, query, this.renderOpts)
        } else {
          throw err2
        }
      }
    }
  
    async render404 (req, res, parsedUrl = parseUrl(req.url, true)) {
      const { pathname, query } = parsedUrl
      res.statusCode = 404
      res.setHeader('Cache-Control', 'no-cache, no-store, max-age=0, must-revalidate')
      return this.renderError(null, req, res, pathname, query)
    }
  
    async serveStatic (req, res, path) {
      if (!this.isServeableUrl(path)) {
        return this.render404(req, res)
      }
  
      try {
        return await serveStatic(req, res, path)
      } catch (err) {
        if (err.code === 'ENOENT') {
          this.render404(req, res)
        } else {
          throw err
        }
      }
    }
  
    isServeableUrl (path) {
      const resolved = resolve(path)
      if (
        resolved.indexOf(join(this.distDir) + sep) !== 0 &&
        resolved.indexOf(join(this.dir, 'static') + sep) !== 0
      ) {
        // Seems like the user is trying to traverse the filesystem.
        return false
      }
  
      return true
    }
  
    readBuildId (dev) {
      if (dev) {
        return 'development'
      }
      const buildIdPath = join(this.distDir, BUILD_ID_FILE)
      const buildId = fs.readFileSync(buildIdPath, 'utf8')
      return buildId.trim()
    }
  
    async getCompilationError (page) {
      if (!this.hotReloader) return
  
      const errors = await this.hotReloader.getCompilationErrors(page)
      if (errors.length === 0) return
  
      // Return the very first error we found.
      return errors[0]
    }
  }
  