module.exports = function(options = {}) {
  let security = {}
  security.options = options

  security.setHeaders = function(req, res, next) {
    if(!this.options) options = {}
    else options = this.options

    if (typeof options.CacheControl === 'undefined') {
      options.CacheControl = 'no-cache, no-store, must-revalidate'
    }
    if (options.CacheControl !== false) {
      res.set('Cache-Control', options.CacheControl)
    }

    if (typeof options.Pragma === 'undefined') {
      options.Pragma = 'no-cache'
    }
    if (options.Pragma !== false) {
      res.set('Pragma', options.Pragma)
    }

    if (typeof options.Expires === 'undefined') {
      options.Expires = '0'
    }
    if (options.Expires !== false) {
      res.set('Expires', options.Expires)
    }

    if (typeof options.ContentSecurityPolicy === 'undefined') {
      options.ContentSecurityPolicy = 'default-src \'self\'; frame-ancestors \'none\''
    }
    if (options.ContentSecurityPolicy !== false) {
      res.set('Content-Security-Policy', options.ContentSecurityPolicy )
    }

    if (typeof options.XXSSProtection === 'undefined') {
      options.XXSSProtection = '1; mode=block'
    }
    if (options.XXSSProtection !== false) {
      res.set('X-XSS-Protection', options.XXSSProtection)
    }

    if (typeof options.XDNSPrefetchControl === 'undefined') {
      options.XDNSPrefetchControl = 'off'
    }
    if (options.XDNSPrefetchControl !== false) {
      res.set('X-DNS-Prefetch-Control', options.XDNSPrefetchControl)
    }

    if (typeof options.ExpectCT === 'undefined') {
      options.ExpectCT = 'enforce; max-age=30; report-uri="/_report"'
    }
    if (options.ExpectCT !== false) {
      res.set('Expect-CT', options.ExpectCT)
    }

    if (typeof options.XFrameOptions === 'undefined') {
      options.XFrameOptions = 'deny'
    }
    if (options.XFrameOptions !== false) {
      res.set('X-Frame-Options', options.XFrameOptions)
    }

    if (typeof options.XPoweredBy === 'undefined') {
      options.XPoweredBy = true
    }
    if (options.XPoweredBy !== false) {
      res.removeHeader('X-Powered-By')
    }

    if (typeof options.StrictTransportSecurity === 'undefined') {
      options.StrictTransportSecurity = 'max-age=30'
    }
    if (options.StrictTransportSecurity !== false) {
      res.set('Strict-Transport-Security', options.StrictTransportSecurity)
    }

    if (typeof options.XDownloadOptions === 'undefined') {
      options.XDownloadOptions = 'noopen'
    }
    if (options.XDownloadOptions !== false) {
      res.set('X-Download-Options', options.XDownloadOptions)
    }

    if (typeof options.XContentTypeOptions === 'undefined') {
      options.XContentTypeOptions = 'nosniff'
    }
    if (options.XContentTypeOptions !== false) {
      res.set('X-Content-Type-Options', options.XContentTypeOptions )
    }

    if (typeof options.XPermittedCrossDomainPolicies === 'undefined') {
      options.XPermittedCrossDomainPolicies = 'none'
    }
    if (options.XPermittedCrossDomainPolicies !== false) {
      res.set('X-Permitted-Cross-Domain-Policies', options.XPermittedCrossDomainPolicies)
    }

    if (typeof options.ReferrerPolicy === 'undefined') {
      options.ReferrerPolicy = 'no-referrer'
    }
    if (options.ReferrerPolicy !== false) {
      res.set('Referrer-Policy', options.ReferrerPolicy)
    }


    if (typeof options.allowedMethods === 'undefined') {
      options.allowedMethods = ['GET', 'POST', 'PUT', 'DELETE']
    }
    if (!options.allowedMethods.includes(req.method)) {
      res.status(405).end()
    }

    if (typeof options.onlyDefinedRoutes === 'undefined') {
      options.onlyDefinedRoutes = false
    }
    if (options.onlyDefinedRoutes) {
      if (!options.definedRoutes) {
        options.definedRoutes = []
      }
      let isAllowed = false;
      for (const allowedRoute of options.definedRoutes) {
        if (allowedRoute.startsWith('REGEX:')) {
          let regexString = allowedRoute.split('REGEX:')[1];
          let regexp = new RegExp(regexString);
          if (regexp.test(req.originalUrl)) {
            isAllowed= true;
          }
        } else {
          if (req.originalUrl === allowedRoute) {
            isAllowed = true;
          }
        }
      }
      if (!isAllowed) { 
        res.status(405).end()
      }
    }

    next()
  }

  return security;
}