import os from 'os'
import crypto from 'crypto'
import path from 'path'
import http from 'http'
import stream from 'stream'
import fs from 'fs/promises'
import fsSync from 'fs'
import { URL } from 'url'
import { Buffer } from 'buffer'
import zlib from 'zlib'

function getDb() {
  // Take from @thi-ng/mime which is a reduced mime-db
  let MimeTypeDbRaw = Buffer.from('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', 'base64')
  let inbetween = JSON.parse(zlib.brotliDecompressSync(MimeTypeDbRaw).toString())

  let res = {}
  for (let groupID in inbetween) {
    const group = inbetween[groupID];
    for (let type in group) {
        const mime = groupID + "/" + type;
        for (let e of group[type].split(",")) {
            const isLowPri = e[0] === "*";
            const ext = isLowPri ? e.substr(1) : e;
            let coll = res[ext];
            !coll && (coll = res[ext] = []);
            isLowPri ? coll.push(mime) : coll.unshift(mime);
        }
    }
  }
  return res
}

export const MimeTypeDb = getDb()

/**
 * Router
 */

class Branch {
  constructor() {
    this.children = new Map()
    this.paramName = null
    this.fullparamName = null
    this.handler = null
    this.middlewares = []
  }
}

export const ErrorCodes = {
  ERR_CONNECTION_ABORTED: 'ERR_CON_ABORTED'
}

// Taken from https://github.com/nfp-projects/koa-lite/blob/master/lib/statuses.js
const statuses = {
  100: 'Continue', 101: 'Switching Protocols', 102: 'Processing', 103: 'Early Hints',
  200: 'OK', 201: 'Created', 202: 'Accepted', 203: 'Non-Authoritative Information', 204: 'No Content', 205: 'Reset Content', 206: 'Partial Content', 207: 'Multi-Status', 208: 'Already Reported', 226: 'IM Used',
  300: 'Multiple Choices', 301: 'Moved Permanently', 302: 'Found', 303: 'See Other', 304: 'Not Modified', 305: 'Use Proxy', 306: '(Unused)', 307: 'Temporary Redirect', 308: 'Permanent Redirect',
  400: 'Bad Request', 401: 'Unauthorized', 402: 'Payment Required', 403: 'Forbidden', 404: 'Not Found', 405: 'Method Not Allowed', 406: 'Not Acceptable', 407: 'Proxy Authentication Required', 408: 'Request Timeout', 409: 'Conflict', 410: 'Gone', 411: 'Length Required', 412: 'Precondition Failed', 413: 'Payload Too Large', 414: 'URI Too Long', 415: 'Unsupported Media Type', 416: 'Range Not Satisfiable', 417: 'Expectation Failed', 418: 'I\'m a teapot', 421: 'Misdirected Request', 422: 'Unprocessable Entity', 423: 'Locked', 424: 'Failed Dependency', 425: 'Too Early', 426: 'Upgrade Required', 428: 'Precondition Required', 429: 'Too Many Requests', 431: 'Request Header Fields Too Large', 451: 'Unavailable For Legal Reasons',
  500: 'Internal Server Error', 501: 'Not Implemented', 502: 'Bad Gateway', 503: 'Service Unavailable', 504: 'Gateway Timeout', 505: 'HTTP Version Not Supported', 506: 'Variant Also Negotiates', 507: 'Insufficient Storage', 508: 'Loop Detected', 509: 'Bandwidth Limit Exceeded', 510: 'Not Extended', 511: 'Network Authentication Required',
  redirect: {
    300: true,
    301: true,
    302: true,
    303: true,
    305: true,
    307: true,
    308: true
  },
  empty: {
    204: true,
    205: true,
    304: true
  }
}
const __paramMapName = '__param'
const __fullParamMapName = '__fullparam'

function assertIsHandler(handler, name) {
  if (typeof(handler) !== 'function') {
    throw new Error(`${name} was called with a handler that was not a function`)
  }
}

export function QueryHandler() {
  return function(ctx) {
    ctx.query = (new URL(ctx.req.url, 'http://localhost')).searchParams
  }
}

export function JsonHandler(org = {}) {
  let opts = {
    sizeLimit: org.sizeLimit || (10 * 1024)
  }
  return function(ctx) {
    const buffers = [];
    let size = 0

    return new Promise(function(res, rej) {
      ctx.req.on('data', chunk => {
        size += chunk.length
        if (size > opts.sizeLimit) {
          return rej(new HttpError(413, `Body limit of ${opts.sizeLimit} bytes reached with ${size} bytes`))
        }

        buffers.push(chunk)
      })
      ctx.req.on('end', () => {
        res()
      })
    })
    .then(function() {
      if (!buffers.length) {
        ctx.req.body = {}
        return
      }
  
      const data = Buffer.concat(buffers).toString();
  
      try {
        ctx.req.body = JSON.parse(data)
      } catch (err) {
        return Promise.reject(new HttpError(400, `Invalid JSON: ${err.message}`, {
          status: 400,
          message: `Invalid JSON: ${err.message}`,
          request: data,
        }))
      }
    })
  }
}

export function CorsHandler(opts = {}) {
  const options = {
    allowedMethods: opts.allowedMethods || 'GET,HEAD,PUT,POST,DELETE,PATCH',
    allowedOrigins: opts.allowedOrigins || [],
    allowedHeaders: opts.allowedHeaders,
    credentials: opts.credentials || false,
    exposeHeaders: opts.exposeHeaders || '',
    maxAge: opts.maxAge || '',
  }
  const allowAll = options.allowedOrigins.includes('*')

  return function(ctx) {
    // Always add vary header on origin. Prevent caches from
    // accidentally caching wrong preflight request
    ctx.headers['Vary'] = 'Origin'
    
    // Set status to 204 if OPTIONS. Just handy for flaska and
    // other checking.
    if (ctx.method === 'OPTIONS') {
      ctx.status = 204
    }

    // Check origin is specified. Nothing needs to be done if
    // there is no origin or it doesn't match
    let origin = ctx.req.headers['origin']
    if (!origin || (!allowAll && !options.allowedOrigins.includes(origin))) {
      return
    }

    // Set some extra headers if this is a pre-flight. Most of
    // these are not needed during a normal request.
    if (ctx.method === 'OPTIONS') {
      if (!ctx.req.headers['access-control-request-method']) {
        return
      }

      if (options.maxAge) {
        ctx.headers['Access-Control-Max-Age'] = options.maxAge
      }

      let reqHeaders = options.allowedHeaders
                  || ctx.req.headers['access-control-request-headers']
      if (reqHeaders && options.allowedHeaders !== false) {
        ctx.headers['Access-Control-Allow-Headers'] = reqHeaders
      }
      ctx.headers['Access-Control-Allow-Methods'] = options.allowedMethods
    } else {
      if (options.exposeHeaders) {
        ctx.headers['Access-Control-Expose-Headers'] = options.exposeHeaders
      }
    }

    ctx.headers['Access-Control-Allow-Origin'] = origin

    if (options.credentials) {
      ctx.headers['Access-Control-Allow-Credentials'] = 'true'
    }
  }
}

export function FormidableHandler(formidable, org = {}) {
  let lastDateString = ''
  let incrementor = 1

  let opts = {
    rename: true,
    parseFields: org.parseFields || false,
    uploadDir: org.uploadDir || os.tmpdir(),
    filename: org.filename || function(file) {
      let prefix = new Date()
        .toISOString()
        .replace(/-/g, '')
        .replace('T', '_')
        .replace(/:/g, '')
        .replace(/\..+/, '_')

      // Prevent accidental overwriting if two file uploads with
      // same name get uploaded at exact same second.
      if (prefix === lastDateString) {
        prefix += incrementor.toString().padStart('2', '0') + '_'
        incrementor++
      } else {
        lastDateString = prefix
        incrementor
      }

      return prefix + file.name
    },
    maxFileSize: org.maxFileSize || 8 * 1024 * 1024,
    maxFieldsSize: org.maxFieldsSize || 10 * 1024,
    maxFields: org.maxFields || 50,
  }
  if (org.rename != null) {
    opts.rename = org.rename
  }

  // For testing/stubbing purposes
  let rename = formidable.fsRename || fs.rename
  
  return function(ctx) {
    let form = formidable.IncomingForm()
    form.uploadDir = opts.uploadDir
    form.maxFileSize = opts.maxFileSize
    form.maxFieldsSize = opts.maxFieldsSize
    form.maxFields = opts.maxFields

    return new Promise(function(res, rej) {
      form.parse(ctx.req, function(err, fields, files) {
        if (err) return rej(new HttpError(400, err.message))

        if (opts.parseFields) {
          Object.keys(fields).forEach(function(key) {
            try {
              fields[key] = JSON.parse(fields[key])
            } catch { }
          })
        }

        ctx.req.body = fields
        ctx.req.files = files
        ctx.req.file = null


        if (!ctx.req.files) {
          return res()
        }

        let keys = Object.keys(files).filter(key => Boolean(ctx.req.files[key]))

        Promise.all(
          keys.map(key => {
            let filename
            let target
    
            try {
              filename = opts.filename(ctx.req.files[key]) || ctx.req.files[key].name
              target = path.join(opts.uploadDir, filename)
            } catch (err) {
              return Promise.reject(err)
            }

            return rename(ctx.req.files[key].path, target)
            .then(function() {
              if (!ctx.req.files[key].type || ctx.req.files[key].type === 'application/octet-stream') {
                let found = MimeTypeDb[path.extname(filename).slice(1)]
                ctx.req.files[key].type = found && found[0] || 'application/octet-stream'
              }
              ctx.req.files[key].path = target
              ctx.req.files[key].filename = filename
            })
          })
        )
        .then(() => {
          if (keys.length === 1 && keys[0] === 'file') {
            ctx.req.file = ctx.req.files.file
          }
          res()
        }, rej)
      })
    })
  }
}

export class HttpError extends Error {
  constructor(statusCode, message, body = null) {
    super(message);

    Error.captureStackTrace(this, HttpError);

    let proto = Object.getPrototypeOf(this);
    proto.name = 'HttpError';

    this.status = statusCode
    this.body = body
  }
}

const RangeRegexTester = /bytes=(\d+)-(\d+)?/

export class FileResponse {
  constructor(filepath, stat) {
    this.filepath = filepath
    this.stat = stat
  }

  handleRequest(ctx, useFs = fsSync) {
    let etag = '"' + this.stat.ino + '-' + this.stat.size + '-' + this.stat.mtime.getTime() + '"'
    let lastModified = this.stat.mtime.toUTCString()
    let lastModifiedRounded = Date.parse(lastModified)

    if (ctx.req.headers['if-match'] && ctx.req.headers['if-match'] !== etag) {
      throw new HttpError(412, `Request if-match pre-condition failed`)
    }
    if (ctx.req.headers['if-unmodified-since']) {
      let check = Date.parse(ctx.req.headers['if-unmodified-since'])
      if (!check || check < lastModifiedRounded) {
        throw new HttpError(412, `Request if-unmodified-since pre-condition failed`)
      }
    }

    ctx.headers['Etag'] = etag

    if (ctx.req.headers['if-none-match']) {
      let split = ctx.req.headers['if-none-match'].split(',')
      for (let check of split) {
        if (check.trim() === etag) {
          ctx.status = 304
          return null
        }
      }
    } else if (ctx.req.headers['if-modified-since']) {
      let check = Date.parse(ctx.req.headers['if-modified-since'])
      if (check >= lastModifiedRounded) {
        ctx.status = 304
        return null
      }
    }

    let readOptions = {}
    let size = this.stat.size

    if (ctx.req.headers['range']) {
      let match = RangeRegexTester.exec(ctx.req.headers['range'])

      let ifRange = ctx.req.headers['if-range']
      if (ifRange) {
        if (ifRange[0] === '"' && ifRange !== etag) {
          match = null
        } else if (ifRange[0] !== '"') {
          let check = Date.parse(ifRange)
          if (!check || check < lastModifiedRounded) {
            match = null
          }
        }
      }

      if (match) {
        let start = Number(match[1])
        let end = size - 1
        if (match[2]) {
          end = Math.min(Number(match[2]), size - 1)
        }

        if (start >= size) {
          throw new HttpError(416, `Out of range start ${start} outside of ${size} bounds`)
        }

        if (start <= end) {
          size = end - start + 1
          readOptions.start = start
          readOptions.end = end
          ctx.headers['Content-Range'] = start + '-' + end + '/' + this.stat.size
          ctx.status = 206
        }
      }
    }
    
    let ext = path.extname(this.filepath).slice(1)
    let found = MimeTypeDb[ext]
    if (found) {
      ctx.type = found[found.length - 1]
    }

    ctx.headers['Last-Modified'] = lastModified
    ctx.headers['Content-Length'] = size
    if (ctx.method !== 'HEAD') {
      let stream = useFs.createReadStream(this.filepath, readOptions)
      return stream
    }
    return null
  }
}

export class FlaskaRouter {
  constructor() {
    this.root = new Branch()
  }

  addRoute(route, orgMiddlewares, orgHandler) {
    if (route[0] !== '/')
      throw new Error(`route "${route}" must start with forward slash`)
  
    let middlewares = orgMiddlewares
    let handler = orgHandler
    if (!orgHandler) {
      handler = orgMiddlewares
      middlewares = []
    }
    if (middlewares && typeof(middlewares) === 'function') {
      middlewares = [middlewares]
    }
    assertIsHandler(handler, 'addRoute()')
  
    let start = 1
    let end = 1
    let name = ''
    let param = ''
    let isParam = false
    let isFullParam = false
    let branch = this.root
  
    if (route.indexOf(':') < 0) {
      let name = route
      if (name.length > 1 && name[name.length - 1] === '/') {
        name = name.slice(0, -1)
      }
      let child = new Branch()
      branch.children.set(name, child)
      child.handler = handler
      child.middlewares = middlewares
    }
  
    for (let i = 1; i <= route.length; i++) {
      if ((i === route.length || route[i] === '/') && end > start) {
        if (branch.fullparamName) {
          throw new Error(`route "${route}" conflicts with a sub-branch that has a full param child`)
        }
        let child
        name = route.substring(start, end)
        if (isFullParam) {
          param = name
          name = __fullParamMapName
        } else if (isParam) {
          param = name
          name = __paramMapName
        }
        if (branch.children.has(name)) {
          child = branch.children.get(name)
        }
        else if (isParam && !isFullParam && branch.children.has(__fullParamMapName)) {
          throw new Error(`route "${route}" conflicts with a sub-branch that has a full param child`)
        }
        else if (isFullParam && branch.children.has(__paramMapName)) {
          throw new Error(`route "${route}" conflicts with a sub-branch that has a partial param child`)
        }
        else {
          child = new Branch()
          branch.children.set(name, child)
        }
        branch = child
        end = i
        start = i
        if (isParam) {
          if (branch.paramName && branch.paramName !== param) {
            throw new Error(`route "${route}" conflicts with pre-existing param name of ${branch.paramName} instead of ${param}`)
          }
          if (isFullParam) {
            branch.fullparamName = param
          } else {
            branch.paramName = param
          }
          isParam = false
        }
      } else if (route[i] === '/' && end === start) {
        throw new Error(`route "${route}" has missing path name inbetween slashes`)
      }
      if (i === route.length) {
        branch.handler = handler
        branch.middlewares = middlewares
        continue
      }
      if (route[i] === ':') {
        if (isParam) {
          isFullParam = true
        }
        isParam = true
        end = start = i + 1
      }
      else if (route[i] === '/') {
        end = start = i + 1
      }
      else {
        end++
      }
    }
  }

  match(orgUrl) {
    let url = orgUrl
    if (url.length > 1 && url[url.length - 1] === '/') {
      url = url.slice(0, -1)
    }
    let branch = this.root
    let start = 1
    let end = 1
    let output
    let name
    let char
    let params = {}
    if (output = branch.children.get(url)) {
      return {
        handler: output.handler,
        middlewares: output.middlewares,
        params: params,
      }
    }
    for (let i = 1; i <= url.length; i++) {
      char = url[i]
      if ((i === url.length || char === '/') && end > start) {
        name = url.slice(start, end)
        if (output = branch.children.get(name)) {
          branch = output
        }
        else if (output = branch.children.get(__paramMapName)) {
          branch = output
          params[branch.paramName] = name
        }
        else if (output = branch.children.get(__fullParamMapName)) {
          params[output.fullparamName] = url.slice(start)
          return {
            handler: output.handler,
            middlewares: output.middlewares,
            params: params,
          }
        } else {
          if (output = this.root.children.get(__fullParamMapName)) {
            params = {
              [output.fullparamName]: url.slice(1)
            }
            return {
              handler: output.handler,
              middlewares: output.middlewares,
              params: params,
            }
          }
          return null
        }
        i++
        end = start = i
        char = url[i]
      }
      // Check branch.handler. This can happen if route /::path is added
      // and request is '/' it will attempt to match root which will fail
      if (i >= url.length && branch.handler) {
        return {
          handler: branch.handler,
          middlewares: branch.middlewares,
          params: params,
        }
      }
      if (char === '/') {
        end = start = i + 1
      } else {
        end++
      }
    }
    if (output = this.root.children.get(__fullParamMapName)) {
      params = {
        [output.fullparamName]: url.slice(1)
      }
      return {
        handler: output.handler,
        middlewares: output.middlewares,
        params: params,
      }
    }
    return null
  }
}

/**
 * Flaska
 */
export class Flaska {
  constructor(opts = {}, orgHttp = http, orgStream = stream) {
    this._before = []
    this._beforeCompiled = null
    this._beforeAsync = []
    this._beforeAsyncCompiled = null
    this._after = []
    this._afterCompiled = null
    this._afterAsync = []
    this._afterAsyncCompiled = null
    this._on404 = function(ctx) {
      if (ctx.body == null && ctx.status !== 204) {
        ctx.status = 404
        ctx.body = {
          status: 404,
          message: statuses[404],
        }
      }
    }
    this._backuperror = this._onerror = function(err, ctx) {
      ctx.log.error(err)
      if (err instanceof HttpError) {
        ctx.status = err.status
        ctx.body = err.body || {
          status: err.status,
          message: statuses[err.status] || statuses[500],
        }
      } else {
        ctx.status = 500
        ctx.body = {
          status: 500,
          message: statuses[500],
        }
      }
    }
    this._onreqerror = function(err, ctx) {
      if (err.message !== 'aborted') {
        ctx.log.error(err)
        ctx.res.statusCode = ctx.statusCode = 400
      }
      ctx.res.end()
    }
    this._onreserror = function(err, ctx) {
      ctx.log.error(err)
    }

    let options = {
      defaultHeaders: opts.defaultHeaders || {
        'Server': 'Flaska',
        'X-Content-Type-Options': 'nosniff',
        'Content-Security-Policy': `default-src 'self'; style-src 'self' 'unsafe-inline'; img-src * data: blob:; font-src 'self' data:; object-src 'none'; frame-ancestors 'none'`,
        'Cross-Origin-Opener-Policy': 'same-origin',
        'Cross-Origin-Resource-Policy': 'same-origin',
        'Cross-Origin-Embedder-Policy': 'require-corp',
      },
      log: opts.log || {
        fatal: console.error.bind(console),
        error: console.error.bind(console),
        warn: console.log.bind(console),
        info: console.log.bind(console),
        debug: console.debug.bind(console),
        trace: console.debug.bind(console),
        log: console.log.bind(console),
      },
      nonce: opts.nonce || [],
      nonceCacheLength: opts.nonceCacheLength || 25
    }

    if (opts.appendHeaders) {
      let appendKeys = Object.keys(opts.appendHeaders)
      for (let key of appendKeys) {
        options.defaultHeaders[key] = opts.appendHeaders[key]
      }
    }

    if (!options.defaultHeaders && options.nonce.length) {
      // throw error
    }

    let headerKeys = Object.keys(options.defaultHeaders)
    let constructFunction = ''

    if (options.nonce.length) {
      this._nonces = new Array(options.nonceCacheLength)
      this._noncesIndex = this._nonces.length - 1

      for (let i = 0; i < this._nonces.length; i++) {
        this._nonces[i] = crypto.randomBytes(16).toString('base64')
      }
      
      constructFunction += `
let nonce = this._nonces[this._noncesIndex] || crypto.randomBytes(16).toString('base64');
this._noncesIndex--;
ctx.state.nonce = nonce;
`
    }

    constructFunction += 'ctx.headers = {'
    constructFunction += `'Date': new Date().toUTCString(),`
    for (let key of headerKeys) { 
      if (key === 'Content-Security-Policy' && options.nonce.length) {
        let groups = options.defaultHeaders[key].split(';')
        for (let ni = 0; ni < options.nonce.length; ni++) {
          let found = false
          for (let x = 0; x < groups.length; x++) {
            if (groups[x].trim().startsWith(options.nonce[ni])) {
              groups[x] = groups[x].trimEnd() + ` 'nonce-$'`
              found = true
              break
            }
          }
          if (!found) {
            groups.push(` ${options.nonce[ni]} 'nonce-$'`)
          }
        }
        groups = groups.join(';').replace(/\'/g, "\\'").split('$')
        constructFunction += `'${key}': '${groups.join(`' + nonce + '`)}',`
      } else {
        constructFunction += `'${key}': '${options.defaultHeaders[key].replace(/\'/g, "\\'")}',`
      }
    }
    constructFunction += '};'

    // console.log(constructFunction)

    if (options.nonce.length) {
      this.before(new Function('crypto', 'ctx', constructFunction).bind(this, crypto))
      this.after(new Function('crypto', 'ctx', `
        this._noncesIndex = Math.max(this._noncesIndex, -1);
        if (this._noncesIndex < this._nonces.length - 1) {
          this._noncesIndex++;
          this._nonces[this._noncesIndex] = crypto.randomBytes(16).toString('base64');
        }
      `).bind(this, crypto))
    } else {
      this.before(new Function('ctx', constructFunction).bind(this))
    }

    this.log = options.log
    this.http = orgHttp
    this.stream = orgStream
    this.server = null
    this.routers = {
      'GET': new FlaskaRouter(),
      'POST': new FlaskaRouter(),
      'PUT': new FlaskaRouter(),
      'DELETE': new FlaskaRouter(),
      'OPTIONS': new FlaskaRouter(),
      'PATCH': new FlaskaRouter(),
    }
    // HEAD and GET should be identical
    this.routers['HEAD'] = this.routers['GET']

    this.get = this.routers.GET.addRoute.bind(this.routers.GET)
    this.post = this.routers.POST.addRoute.bind(this.routers.POST)
    this.put = this.routers.PUT.addRoute.bind(this.routers.PUT)
    this.delete = this.routers.DELETE.addRoute.bind(this.routers.DELETE)
    this.options = this.routers.OPTIONS.addRoute.bind(this.routers.OPTIONS)
    this.patch = this.routers.PATCH.addRoute.bind(this.routers.PATCH)
  }

  _assertIsHandler(handler, name) {
    if (typeof(handler) !== 'function') {
      throw new Error(`${name} was called with a handler that was not a function`)
    }
  }

  devMode() {
    this._backuperror = this._onerror = function(err, ctx) {
      ctx.log.error(err)
      if (err instanceof HttpError) {
        ctx.status = err.status
        ctx.body = err.body || {
          status: err.status,
          message: `${statuses[err.status] || statuses[500]}: ${err.message}`,
          stack: err.stack || '',
        }
      } else {
        ctx.status = 500
        ctx.body = {
          status: 500,
          message: `${statuses[500]}: ${err.message}`,
          stack: err.stack || '',
        }
      }
    }
  }

  on404(handler) {
    assertIsHandler(handler, 'on404()')
    this._on404 = handler
  }

  onerror(handler) {
    assertIsHandler(handler, 'onerror()')
    this._onerror = handler
  }

  onreqerror(handler) {
    assertIsHandler(handler, 'onreqerror()')
    this._onreqerror = handler
  }
  
  onreserror(handler) {
    assertIsHandler(handler, 'onreserror()')
    this._onreserror = handler
  }

  before(handler) {
    assertIsHandler(handler, 'before()')
    this._before.push(handler)
  }

  beforeAsync(handler) {
    assertIsHandler(handler, 'beforeAsync()')
    this._beforeAsync.push(handler)
  }
  
  after(handler) {
    assertIsHandler(handler, 'after()')
    this._after.push(handler)
  }

  afterAsync(handler) {
    assertIsHandler(handler, 'afterAsync()')
    this._afterAsync.push(handler)
  }
  
  requestStart(req, res) {
    let url = req.url
    let search = ''
    let hasSearch = url.indexOf('?')

    if (hasSearch > 0) {
      search = url.slice(hasSearch)
      url = url.slice(0, hasSearch)
    }

    let ctx = {
      log: this.log,
      req: req,
      res: res,
      method: req.method,
      url: url,
      search: search,
      state: {},
      status: 200,
      query: new Map(),
      body: null,
      type: null,
      length: null,
    }

    req.on('error', (err) => {
      if (err.message === 'aborted') {
        ctx.aborted = true
      }
      this._onreqerror(err, ctx)
      this.requestEnded(ctx)
    })
    res.on('error', (err) => {
      this._onreserror(err, ctx)
    })

    res.on('finish', () => {
      this.requestEnded(ctx)
    })

    try {
      this._beforeCompiled(ctx)
      if (this._beforeAsyncCompiled) {
        return this._beforeAsyncCompiled(ctx)
          .then(() => {
            this.requestStartInternal(ctx)
          }).catch(err => {
            this.requestEnd(err, ctx)
          })
      }
      this.requestStartInternal(ctx)
    }
    catch (err) {
      this.requestEnd(err, ctx)
    }
  }

  requestStartInternal(ctx) {
    let route = this.routers[ctx.method].match(ctx.url)
    if (!route) {
      let middle = this._on404(ctx)
      if (middle && middle.then) {
        return middle.then(() => {
          this.requestEnd(null, ctx)
        }, err => {
          this.requestEnd(err, ctx)
        })
      }
      return this.requestEnd(null, ctx)
    }

    ctx.params = route.params

    if (route.middlewares.length) {
      let middle = this.handleMiddleware(ctx, route.middlewares, 0)

      if (middle && middle.then) {
        return middle.then(() => {
          return route.handler(ctx)
        })
        .then(() => {
          this.requestEnd(null, ctx)
        }, err => {
          this.requestEnd(err, ctx)
        })
      }
    }
    let handler = route.handler(ctx)
    if (handler && handler.then) {
      return handler.then(() => {
        this.requestEnd(null, ctx)
      }, err => {
        this.requestEnd(err, ctx)
      })
    }
    this.requestEnd(null, ctx)
  }

  handleMiddleware(ctx, middles, index) {
    for (let i = index; i < middles.length; i++) {
      let res = middles[i](ctx)
      if (res && res.then) {
        return res.then(() => {
          return this.handleMiddleware(ctx, middles, i + 1)
        })
      }
    }
  }

  requestEnd(orgErr, ctx) {
    let err = orgErr
    let handleUsed = Boolean(ctx.body && ctx.body.handleRequest)
    if (handleUsed) {
      try {
        ctx.body = ctx.body.handleRequest(ctx)
      } catch (newErr) {
        err = newErr
      }
    }
    if (err) {
      try {
        this._onerror(err, ctx)
      } catch (err) {
        this._backuperror(err, ctx)
      }
    }

    if (ctx.res.writableEnded) {
      return
    }

    if (ctx.body === null && !handleUsed && ctx.status === 200) {
      ctx.status = 204
    }

    if (statuses.empty[ctx.status]) {
      ctx.res.writeHead(ctx.status, ctx.headers)
      return ctx.res.end()
    }

    let body = ctx.body

    // Special handling for files
    if (body && typeof(body.pipe) === 'function') {
      // Be smart when handling file handles, auto detect mime-type
      // based off of the extension of the file.
      if (!ctx.type && body.path) {
        let ext = path.extname(body.path).slice(1)
        if (ext && MimeTypeDb[ext]) {
          let found = MimeTypeDb[ext]
          ctx.type = found[found.length - 1]
        }
      }
      ctx.headers['Content-Type'] = ctx.type || 'application/octet-stream'

      ctx.res.writeHead(ctx.status, ctx.headers)

      if (ctx.method !== 'HEAD') {
        return this.stream.pipeline(body, ctx.res, function() { })
      } else {
        try {
          body.destroy()
        } catch { }
        return ctx.res.end()
      }
    }

    let length = 0
    
    if (body instanceof Buffer) {
      length = body.byteLength
      ctx.type = ctx.type || 'application/octet-stream'
    } else if (typeof(body) === 'object' && body) {
      body = JSON.stringify(body)
      length = Buffer.byteLength(body)
      ctx.type = 'application/json; charset=utf-8'
    } else if (body) {
      body = body.toString()
      length = Buffer.byteLength(body)
      ctx.type = ctx.type || 'text/plain; charset=utf-8'
    }

    if (ctx.type) {
      ctx.headers['Content-Type'] = ctx.type
    }
    if (!ctx.headers['Content-Length']) {
      ctx.headers['Content-Length'] = length
    }

    ctx.res.writeHead(ctx.status, ctx.headers)
    if (body && ctx.method !== 'HEAD') {
      ctx.res.end(body)
    } else {
      ctx.res.end()
    }
  }

  requestEnded(ctx) {
    if (ctx.finished) return
    ctx.finished = true

    // Prevent accidental leaking
    if (ctx.body && ctx.body.pipe && !ctx.body.closed) {
      ctx.body.destroy()
    }
    this._afterCompiled(ctx)
    if (this._afterAsyncCompiled) {
      return this._afterAsyncCompiled(ctx).then()
    }
  }

  compile() {
    let types = ['before', 'after']
    for (let i = 0; i < types.length; i++) {
      let type = types[i]
      let args = ''
      let body = ''
      for (let i = 0; i < this['_' + type].length; i++) {
        args += `a${i}, `
        body += `a${i}(ctx);`
      }
      args += 'ctx'

      let func = new Function(args, body)
      this[`_${type}Compiled`] = func.bind(this, ...this['_' + type])

      if (this[`_${type}Async`].length) {
        args = ''
        body = 'return Promise.all(['
        for (let i = 0; i < this[`_${type}Async`].length; i++) {
          args += `a${i}, `
          body += `a${i}(ctx),`
        }
        args += 'ctx'
        body += '])'
        func = new Function(args, body)
        this[`_${type}AsyncCompiled`] = func.bind(this, ...this[`_${type}Async`])
      }
    }
  }

  create() {
    this.compile()
    this.server = this.http.createServer(this.requestStart.bind(this))

    this.server.on('connection', function (socket) {
      // Set socket idle timeout in milliseconds
      socket.setTimeout(1000 * 60 * 5) // 5 minutes
  
      // Wait for timeout event (socket will emit it when idle timeout elapses)
      socket.on('timeout', function () {
        // Call destroy again
        socket.destroy();
      })
    })
  }

  listen(port, orgIp, orgcb) {
    let ip = orgIp
    let cb = orgcb
    if (!cb && typeof(orgIp) === 'function') {
      ip = '::'
      cb = orgIp
    }
    if (typeof(port) !== 'number') {
      throw new Error('Flaska.listen() called with non-number in port')
    }

    this.create()
    
    this.server.listen(port, ip, cb)
  }

  listenAsync(port, ip = '::') {
    if (typeof(port) !== 'number') {
      return Promise.reject(new Error('Flaska.listen() called with non-number in port'))
    }

    this.create()

    if (this.server.listenAsync && typeof(this.server.listenAsync) === 'function') {
      return this.server.listenAsync(port, ip)
    }

    return new Promise((res, rej) => {
      this.server.listen(port, ip, function(err) {
        if (err) return rej(err)
        return res()
      })
    })
  }

  closeAsync() {
    if (!this.server) return Promise.resolve()

    return new Promise((res, rej) => {
      this.server.close(function(err) {
        if (err) { return rej(err) }

        // Waiting 0.1 second for it to close down
        setTimeout(function() { res() }, 100)
      })
    })
  }
}