Authentication.scala

package wrappers

import play.api._
import play.api.mvc._
import scala.concurrent._
import scala.concurrent.Future
import play.mvc.Http.Status
import ExecutionContext.Implicits.global
import play.libs.Akka
import akka.actor.{Actor, Props}
import akka.pattern.ask
import akka.util.Timeout
import scala.concurrent.duration._
import play.api.libs.json.{JsObject, Json}

// Authenticated action builder
object Authenticated extends ActionBuilder[AuthenticatedRequest] {
  val authenticationActor = Akka.system.actorOf(Props[Authenticator], name = "authentication")
  implicit val timeout = Timeout(1 second)

  def invokeBlock[A](request: Request[A], block: (AuthenticatedRequest[A]) => Future[SimpleResult]) = {
    (authenticationActor ask Authenticate(request)).mapTo[AuthenticationResult] flatMap { result =>
      if(result.valid)
        block(AuthenticatedRequest[A](result.user, request))
      else
        block(AuthenticatedRequest[A](None, request))
    } recover {
      case e => Results.Status(Status.INTERNAL_SERVER_ERROR)
    }
  }
}

// Authorised helpers
object Authorised {
  def async[T](request: Request[T], user: Option[JsObject]) = (block: Future[SimpleResult]) => new Authorised[T](request, user, block)
  def apply[T](request: Request[T], user: Option[JsObject]) = (block: SimpleResult) => new Authorised[T](request, user, future{block})
  val authorisationActor = Akka.system.actorOf(Props[Authorisor], name = "authorisation")
}
class Authorised[T](request: Request[T], user: Option[JsObject], success: Future[SimpleResult]) {
  implicit val timeout = Timeout(1 second)

  def authorised = {
    (Authorised.authorisationActor ask Authorise(request)).mapTo[AuthorisationResult] map { result =>
      result.valid
    } recover {
      case e => false
    }
  }
  def otherwise(block: => Future[SimpleResult]) : Future[SimpleResult] = authorised.flatMap { valid => if (valid) success else block }
  def otherwise(block: => SimpleResult) : SimpleResult = if(authorised.value.get.get) success.value.get.get else block
}

// AuthenticatedRequest wrapper
trait AuthenticatedRequest[+A] extends Request[A] {
  val user: Option[JsObject]
}
object AuthenticatedRequest {
 def apply[A](u: Option[JsObject], r: Request[A]) = new AuthenticatedRequest[A] {
   def id = r.id
   def tags = r.tags
   def uri = r.uri
   def path = r.path
   def method = r.method
   def version = r.version
   def queryString = r.queryString
   def headers = r.headers
   lazy val remoteAddress = r.remoteAddress
   def username = None
   val body = r.body
   val user = u
 }
}

// Case classes for communication using Akka
case class Authenticate[A](request: Request[A])
case class AuthenticationResult(valid: Boolean = false, user: Option[JsObject] = None)
case class Authorise[A](request: Request[A])
case class AuthorisationResult(valid: Boolean = false)

// Actor responsible for authentication
class Authenticator extends Actor {
  def receive = {
    case Authenticate(request) => sender ! AuthenticationResult(valid = true, user = Some(Json.obj()))
    case _ => sender ! AuthenticationResult
  }
}

// Actor responsible for authorisation
class Authorisor extends Actor {
  def receive = {
    case Authorise(request) => sender ! AuthorisationResult(valid = true)
    case _ => sender ! AuthorisationResult
  }
}