fix error

Source/Engine/AudioEngine.swift

@@ -239,5 +239,6 @@ class AudioEngine: AudioEngineProtocol {
         if let audioModifiers = audioModifiers, audioModifiers.count > 0 {
             audioModifiers.forEach { engine.detach($0) }
         }
+        Log.info("invalidated engine for key \(key)")
     }
 }

Source/SAPlayerHelpers.swift

@@ -55,10 +55,10 @@ public struct SALockScreenInfo {
  Use to add audio to be queued for playback.
  */
 public struct SAAudioQueueItem {
-    var loc: Location
-    var url: URL
-    var mediaInfo: SALockScreenInfo?
-    var bitrate: SAPlayerBitrate
+    public var loc: Location
+    public var url: URL
+    public var mediaInfo: SALockScreenInfo?
+    public var bitrate: SAPlayerBitrate
     
     /**
      Use to add audio to be queued for playback.
@@ -68,7 +68,7 @@ public struct SAAudioQueueItem {
      - Parameter mediaInfo: Relevant lockscreen media info for the queued audio.
      - Parameter bitrate: For streamed remote audio specifiy a bitrate if different from high. Use low bitrate for radio streams.
      */
-    init(loc: Location, url: URL, mediaInfo: SALockScreenInfo?, bitrate: SAPlayerBitrate = .high) {
+    public init(loc: Location, url: URL, mediaInfo: SALockScreenInfo?, bitrate: SAPlayerBitrate = .high) {
         self.loc = loc
         self.url = url
         self.mediaInfo = mediaInfo
@@ -78,7 +78,7 @@ public struct SAAudioQueueItem {
     /**
      Where the queued audio is sourced. Remote to be streamed or locally saved on device.
      */
-    enum Location {
+    public enum Location {
         case remote
         case saved
     }

Source/SAPlayerPresenter.swift

@@ -144,13 +144,16 @@ class SAPlayerPresenter {
                 return
             }
             
-            self.isPlaying = isPlaying
-            
-            if(self.isPlaying == .paused && self.shouldPlayImmediately) {
+            if(isPlaying == .paused && self.shouldPlayImmediately) {
                 self.shouldPlayImmediately = false
                 self.handlePlay()
             }
             
+            // solves bug nil == owningEngine || GetEngine() == owningEngine where too many
+            // ended statuses were notified to cause 2 engines to be initialized and causes an error.
+            guard isPlaying != self.isPlaying else { return }
+            self.isPlaying = isPlaying
+            
             if(self.isPlaying == .ended) {
                 self.playNextAudioIfExists()
             }
@@ -246,19 +249,15 @@ extension SAPlayerPresenter {
         
         delegate?.mediaInfo = nextAudioURL.mediaInfo
         
-        // We need to give a second to clean up the previous engine properly. Deinit takes some time.
-        Timer.scheduledTimer(withTimeInterval: 1.0, repeats: false) { [weak self] (_) in
-            guard let self = self else { return }
-            
-            switch nextAudioURL.loc {
-            case .remote:
-                self.handlePlayStreamedAudio(withRemoteUrl: nextAudioURL.url, bitrate: nextAudioURL.bitrate)
-                break
-            case .saved:
-                self.handlePlaySavedAudio(withSavedUrl: nextAudioURL.url)
-            }
-            
-            self.shouldPlayImmediately = true
+        switch nextAudioURL.loc {
+        case .remote:
+            handlePlayStreamedAudio(withRemoteUrl: nextAudioURL.url, bitrate: nextAudioURL.bitrate)
+            break
+        case .saved:
+            handlePlaySavedAudio(withSavedUrl: nextAudioURL.url)
+            break
         }
+        
+        shouldPlayImmediately = true
     }
 }