Use MPNowPlayingInfoCenter to player info

This means that the notications bar media player will show track &
artist title, as well as artwork for the album.

It also means that Play/Pause/Next/Previous work without needing
accessibility access

Mac/App.swift

@@ -12,6 +12,8 @@ struct App {
   static let store = Store<AppState>(reducer: appReducer, state: nil)
   static let trackTimer = TrackTimer()
   static let userNotificationsController = UserNotificationsController()
+  static let mediaInfoController = MediaInfoController()
+  static let playerStateInfoController = PlayerStateInfoController()
   static let mpdServerDelegate = MPDServerDelegate()
   static let mpdServerController = MPDServerController(delegate: mpdServerDelegate)
   static var mpdClient: MPDClient!

Mac/AppDelegate.swift

@@ -40,6 +40,8 @@ class AppDelegate: NSObject,
     }
     
     _ = App.userNotificationsController
+    _ = App.mediaInfoController
+    _ = App.playerStateInfoController
     
     _ = App.mpdServerController
   }

Mac/Components/Shared/MediaInfoController.swift

@@ -0,0 +1,76 @@
+//
+//  MediaInfoController.swift
+//  Persephone
+//
+//  Created by Alan Harper on 18/11/20.
+//  Copyright © 2020 Dan Barber. All rights reserved.
+//
+
+import Foundation
+import ReSwift
+import MediaPlayer
+import Kingfisher
+
+class MediaInfoController {
+  init() {
+    App.store.subscribe(self) {
+      $0.select { $0.playerState.currentSong }
+    }
+  }
+
+  func notifyTrack(_ song: Song) {
+    let provider = MPDAlbumArtImageDataProvider(
+      songUri: song.mpdSong.uriString,
+      cacheKey: song.album.hash
+    )
+
+    let infoCenter = MPNowPlayingInfoCenter.default()
+
+    var nowPlayingInfo = [
+      MPMediaItemPropertyTitle: song.title,
+      MPMediaItemPropertyArtist: song.artist,
+      MPMediaItemPropertyAlbumArtist: song.album.artist,
+      MPMediaItemPropertyAlbumTitle: song.album.title,
+      MPMediaItemPropertyPlaybackDuration: NSNumber(value: song.duration.timeInSeconds),
+      MPNowPlayingInfoPropertyMediaType: NSNumber(value: MPNowPlayingInfoMediaType.audio.rawValue),
+      MPNowPlayingInfoPropertyIsLiveStream: NSNumber(value: false),
+    ] as [String : Any]
+      
+    if let elapsedTime = App.store.state.playerState.elapsedTimeMs {
+        nowPlayingInfo[MPNowPlayingInfoPropertyElapsedPlaybackTime] = NSNumber(value: elapsedTime / 1000)
+    }
+      
+    if #available(OSX 10.13.2, *) {
+      _ = KingfisherManager.shared.retrieveImage(
+        with: .provider(provider),
+        options: [
+          .processor(DownsamplingImageProcessor(size: .notificationCoverSize)),
+          .scaleFactor(2),
+        ]
+      ) { result in
+        switch result {
+        case .success(let value):
+          let artwork = MPMediaItemArtwork.init(boundsSize: CGSize(width: 100.0, height: 100.0)) { (size: CGSize) in value.image }
+          nowPlayingInfo[MPMediaItemPropertyArtwork] = artwork
+          infoCenter.nowPlayingInfo = nowPlayingInfo
+        case .failure:
+          infoCenter.nowPlayingInfo = nowPlayingInfo
+          break
+        }
+      }
+    } else {
+      infoCenter.nowPlayingInfo = nowPlayingInfo
+    }
+  }
+}
+
+extension MediaInfoController: StoreSubscriber {
+  typealias StoreSubscriberStateType = Song?
+    
+
+  func newState(state: StoreSubscriberStateType) {
+    guard let song = state else {return}
+
+    notifyTrack(song)
+  }
+}

Mac/Components/Shared/PlayerStateInfoController.swift

@@ -0,0 +1,72 @@
+//
+//  MediaInfoController.swift
+//  Persephone
+//
+//  Created by Alan Harper on 18/11/20.
+//  Copyright © 2020 Dan Barber. All rights reserved.
+//
+
+import Foundation
+import ReSwift
+import MediaPlayer
+import Kingfisher
+
+class PlayerStateInfoController {
+  init() {
+    App.store.subscribe(self) {
+      $0.select { $0.playerState.state }
+    }
+    let commandCenter = MPRemoteCommandCenter.shared()
+    commandCenter.playCommand.addTarget {  _ in
+      App.mpdClient.playPause()
+      return .success
+    }
+    commandCenter.togglePlayPauseCommand.addTarget { _ in
+      App.mpdClient.playPause()
+      return .success
+    }
+    commandCenter.pauseCommand.addTarget { _ in
+      App.mpdClient.playPause()
+      return .success
+    }
+
+    commandCenter.nextTrackCommand.addTarget {  _ in
+      App.mpdClient.nextTrack()
+      return .success
+    }
+    
+    commandCenter.previousTrackCommand.addTarget { _ in
+      App.mpdClient.prevTrack()
+      return .success
+    }
+  }
+
+  func notifyState(_ state: MPDClient.MPDStatus.State?) {
+    let infoCenter = MPNowPlayingInfoCenter.default()
+
+    switch(state) {
+    case .unknown:
+      infoCenter.playbackState = .unknown
+      break;
+    case .paused:
+      infoCenter.playbackState = .paused
+      break;
+    case .stopped:
+      infoCenter.playbackState = .stopped
+      break;
+    case .playing:
+      infoCenter.playbackState = .playing
+      break;
+    case .none:
+      return
+    }
+  }
+}
+
+extension PlayerStateInfoController: StoreSubscriber {
+  typealias StoreSubscriberStateType = MPDClient.MPDStatus.State?
+
+  func newState(state: StoreSubscriberStateType) {
+    notifyState(state)
+  }
+}

Persephone.xcodeproj/project.pbxproj

@@ -307,6 +307,8 @@
 		E4FF7190227601B400D4C412 /* PreferencesReducer.swift in Sources */ = {isa = PBXBuildFile; fileRef = E4FF718F227601B400D4C412 /* PreferencesReducer.swift */; };
 		E4FF71922276029000D4C412 /* PreferencesActions.swift in Sources */ = {isa = PBXBuildFile; fileRef = E4FF71912276029000D4C412 /* PreferencesActions.swift */; };
 		E4FF71942276043A00D4C412 /* MPDServer.swift in Sources */ = {isa = PBXBuildFile; fileRef = E4FF71932276043A00D4C412 /* MPDServer.swift */; };
+		E72BF0CE2567F45E00419CB0 /* PlayerStateInfoController.swift in Sources */ = {isa = PBXBuildFile; fileRef = E72BF0CD2567F45E00419CB0 /* PlayerStateInfoController.swift */; };
+		E7AF1B642565124D00057784 /* MediaInfoController.swift in Sources */ = {isa = PBXBuildFile; fileRef = E7AF1B632565124D00057784 /* MediaInfoController.swift */; };
 /* End PBXBuildFile section */
 
 /* Begin PBXContainerItemProxy section */
@@ -650,6 +652,8 @@
 		E4FF718F227601B400D4C412 /* PreferencesReducer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PreferencesReducer.swift; sourceTree = "<group>"; };
 		E4FF71912276029000D4C412 /* PreferencesActions.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PreferencesActions.swift; sourceTree = "<group>"; };
 		E4FF71932276043A00D4C412 /* MPDServer.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MPDServer.swift; sourceTree = "<group>"; };
+		E72BF0CD2567F45E00419CB0 /* PlayerStateInfoController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = PlayerStateInfoController.swift; sourceTree = "<group>"; };
+		E7AF1B632565124D00057784 /* MediaInfoController.swift */ = {isa = PBXFileReference; lastKnownFileType = sourcecode.swift; path = MediaInfoController.swift; sourceTree = "<group>"; };
 /* End PBXFileReference section */
 
 /* Begin PBXFrameworksBuildPhase section */
@@ -958,6 +962,8 @@
 				E489E3A222B9D31800CA8CBD /* DraggedSongView.swift */,
 				E489E3A322B9D31800CA8CBD /* DraggedSongView.xib */,
 				E4B11BB52275374B0075461B /* UserNotificationsController.swift */,
+				E7AF1B632565124D00057784 /* MediaInfoController.swift */,
+				E72BF0CD2567F45E00419CB0 /* PlayerStateInfoController.swift */,
 			);
 			path = Shared;
 			sourceTree = "<group>";
@@ -1643,6 +1649,7 @@
 				E48059D82426D73600362CF3 /* database.c in Sources */,
 				E43AC1F522C6A4F4001E483C /* DraggedAlbum.swift in Sources */,
 				E40FE71B221B904300A4223F /* NSEvent.swift in Sources */,
+				E72BF0CE2567F45E00419CB0 /* PlayerStateInfoController.swift in Sources */,
 				E4B11BB62275374B0075461B /* UserNotificationsController.swift in Sources */,
 				E43AC1F622C6AD0B001E483C /* AlbumViewController+NSCollectionViewDelegate.swift in Sources */,
 				E4B11B68226A4FA00075461B /* QueueState.swift in Sources */,
@@ -1674,6 +1681,7 @@
 				E4805A0A2426D73600362CF3 /* sync.c in Sources */,
 				E4DA820623D6236200C1EE58 /* NSSize.swift in Sources */,
 				E408D3B6220DD8970006D9BE /* Notification.swift in Sources */,
+				E7AF1B642565124D00057784 /* MediaInfoController.swift in Sources */,
 				E48059E42426D73600362CF3 /* run.c in Sources */,
 				E4805A1A2426D73600362CF3 /* cmessage.c in Sources */,
 				E48059C42426D73600362CF3 /* replay_gain.c in Sources */,