ViewController.does not work version 4.swift

// does NOT resume play at all
// what's different = no .MixWithOthers at all

/* console output:
  AVAudioSession Category Playback OK
  AVAudioSession is Active
  handleInterruption
  began
  audioPlayer.playing false
  AVAudioSession is inactive
  handleInterruption
  ended
  should resume
  The operation couldn’t be completed. (OSStatus error 560557684.)
 */


//
//  ViewController.swift
//  test audio interruption
//

import UIKit
import AVFoundation

class ViewController: UIViewController {
    
    var player = AVAudioPlayer()
    
    let audioPath = NSBundle.mainBundle().pathForResource("rachmaninov-romance-sixhands-alianello", ofType: "mp3")!
    
    let theSession = AVAudioSession.sharedInstance()
    
    /*
     func handleInterruption(notification: NSNotification) {
     
     //guard let interruptionType = notification.userInfo?[AVAudioSessionInterruptionTypeKey] as? AVAudioSessionInterruptionType else { print("wrong type"); return }
     
     if notification.name != AVAudioSessionInterruptionNotification
     || notification.userInfo == nil{
     return
     }
     
     var info = notification.userInfo!
     var intValue: UInt = 0
     (info[AVAudioSessionInterruptionTypeKey] as! NSValue).getValue(&intValue)
     if let interruptionType = AVAudioSessionInterruptionType(rawValue: intValue) {
     
     switch interruptionType {
     
     case .Began:
     print("began")
     // player is paused and session is inactive. need to update UI)
     player.pause()
     print("audio paused")
     
     default:
     print("ended")
     /** /
     if let option = notification.userInfo?[AVAudioSessionInterruptionOptionKey] as? AVAudioSessionInterruptionOptions where option == .ShouldResume {
     // ok to resume playing, re activate session and resume playing
     // need to update UI
     player.play()
     print("audio resumed")
     }
     / **/
     player.play()
     print("audio resumed")
     }
     }
     }
     */
    
    /*
     func handleInterruption(notification: NSNotification) {
     // new from Leo Dabus http://stackoverflow.com/a/38800403/1827488
     print("handleInterruption")
     guard let value = (notification.userInfo?[AVAudioSessionInterruptionTypeKey] as? NSNumber)?.unsignedIntegerValue,
     let interruptionType =  AVAudioSessionInterruptionType(rawValue: value)
     else {
     print("notification.userInfo?[AVAudioSessionInterruptionTypeKey]", notification.userInfo?[AVAudioSessionInterruptionTypeKey])
     return }
     switch interruptionType {
     case .Began:
     print("began")
     print("audioPlayer.playing", player.playing)
     // player is paused and session is inactive. need to update UI)
     default :
     print("ended")
     if let optionValue = (notification.userInfo?[AVAudioSessionInterruptionOptionKey] as? NSNumber)?.unsignedIntegerValue where AVAudioSessionInterruptionOptions(rawValue: optionValue) == .ShouldResume {
     print("should resume")
     // ok to resume playing, re activate session and resume playing
     // need to update UI
     do {
     try theSession.setActive(true)
     player.play()
     } catch let error as NSError {
     print(error.localizedDescription)
     }
     }
     }
     }
     */
    
    func handleInterruption(notification: NSNotification) {
        print("handleInterruption")
        guard let value = (notification.userInfo?[AVAudioSessionInterruptionTypeKey] as? NSNumber)?.unsignedIntegerValue,
            let interruptionType =  AVAudioSessionInterruptionType(rawValue: value)
            else {
                print("notification.userInfo?[AVAudioSessionInterruptionTypeKey]", notification.userInfo?[AVAudioSessionInterruptionTypeKey])
                return }
        switch interruptionType {
        case .Began:
            print("began")
            player.pause()
            print("audioPlayer.playing", player.playing)
            /**/
            do {
                try theSession.setActive(false)
                print("AVAudioSession is inactive")
            } catch let error as NSError {
                print(error.localizedDescription)
            }
            /**/
        // player is paused and session is inactive. need to update UI)
        default :
            print("ended")
            if let optionValue = (notification.userInfo?[AVAudioSessionInterruptionOptionKey] as? NSNumber)?.unsignedIntegerValue where AVAudioSessionInterruptionOptions(rawValue: optionValue) == .ShouldResume {
                print("should resume")
                // ok to resume playing, re activate session and resume playing
                /**/
                do {
                    try theSession.setActive(true)
                    print("AVAudioSession is Active again")
                    player.play()
                } catch let error as NSError {
                    print(error.localizedDescription)
                }
                /**/
                // need to update UI
                
                //player.play()
            }
        }
    }
    
    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        
        do {
            try player = AVAudioPlayer(contentsOfURL: NSURL(fileURLWithPath: audioPath))
            player.numberOfLoops = -1 // play indefinitely
            player.prepareToPlay()
            //player.delegate = player
            
        } catch {
            // process error here
        }
        
        // enable play in background http://stackoverflow.com/a/30280699/1827488 but this audio still gets interrupted by alerts
        do {
            try theSession.setCategory(AVAudioSessionCategoryPlayback)
            //try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback)
            print("AVAudioSession Category Playback OK")
            do {
                try theSession.setActive(true)
                //try AVAudioSession.sharedInstance().setActive(true)
                print("AVAudioSession is Active")
            } catch let error as NSError {
                print(error.localizedDescription)
            }
        } catch let error as NSError {
            print(error.localizedDescription)
        }
        
        // will this resume play? http://stackoverflow.com/a/32635113/1827488
        /** /
        do {
            try AVAudioSession.sharedInstance().setCategory(AVAudioSessionCategoryPlayback, withOptions: AVAudioSessionCategoryOptions.MixWithOthers)
            //try theSession.setCategory(AVAudioSessionCategoryPlayback, withOptions: AVAudioSessionCategoryOptions.MixWithOthers)
            
        } catch {
            
        }
        / **/
        
        // add observer to handle audio interruptions
        // using 'object: nil' does not have a noticeable effect
        //let theSession = AVAudioSession.sharedInstance()
        NSNotificationCenter.defaultCenter().addObserver(self, selector: #selector(ViewController.handleInterruption(_:)), name: AVAudioSessionInterruptionNotification, object: theSession)
        
        // start playing audio
        player.play()
    }
    
    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }
}