package example

import scala.io._
import akka.actor.{Actor,ActorSystem,Props}

object PageLoader {
    def getPageSize(url : String) : Int = {
        try {
            return Source.fromURL(url).mkString.length
        } catch {
            case e:Exception =>
                return -1
        }
    }
}

class ConcurrentActor extends Actor {
    def receive = {
        case (url, size) => println("Size for " + url + ": " + size)
    }
}

object Main {
    val urls = List(
        "https://www.amazon.com/",
        "https://twitter.com/",
        "https://www.google.co.uk/",
        "https://www.bbc.co.uk/news/"
    )

    val system = ActorSystem("MySystem")
    val actor = system.actorOf(Props[ConcurrentActor], name="concurrent-actor")

    def timeMethod(method: () => Unit) = {
        val start = System.nanoTime
        method()
        val end = System.nanoTime
        println("+++ Method took " + (end - start) / 1000000000.0 + " seconds.")
    }

    def getPageSizeSequentially() = {
        for (url <- urls) {
            println("Size for " + url +": " + PageLoader.getPageSize(url))
        }
    }

    def getPageSizeConcurrently() = {
        for (url <- urls) {
            // Send a message to the actor (which won't arrive until the PageLoader call completes)
            println(s"Sending message for $url")
            actor ! (url, PageLoader.getPageSize(url))
        }
    }

    def main(args: Array[String]) {
        println("Sequential:")
        timeMethod { getPageSizeSequentially }

        println("Concurrent:")
        timeMethod { getPageSizeConcurrently }
        system.stop(actor)
        system.terminate()
    }
}