Merge pull request 'refactors design to flutter driven service core.' (#6) from central_flutter_service into main

Reviewed-on: http://192.168.1.74:30008/kfj001/kryz-go-flutter/pulls/6

android/app/src/main/kotlin/com/example/kryz_go_flutter/KryzAutoMediaBrowserService.kt

@@ -3,36 +3,30 @@ package com.example.kryz_go_flutter
 import android.app.Notification
 import android.app.NotificationChannel
 import android.app.NotificationManager
+import android.content.ComponentName
 import android.content.Context
-import android.media.AudioAttributes
+import android.os.Handler
-import android.media.AudioFocusRequest
+import android.os.Looper
-import android.media.AudioManager
+import android.support.v4.media.MediaBrowserCompat
-import android.media.MediaPlayer
 import android.net.Uri
 import android.os.Build
 import android.os.Bundle
 import android.support.v4.media.MediaBrowserCompat.MediaItem
 import android.support.v4.media.MediaDescriptionCompat
 import android.support.v4.media.MediaMetadataCompat
+import android.support.v4.media.session.MediaControllerCompat
 import android.support.v4.media.session.MediaSessionCompat
 import android.support.v4.media.session.PlaybackStateCompat
 import android.util.Log
 import androidx.core.app.NotificationCompat
 import androidx.media.MediaBrowserServiceCompat
+import com.ryanheise.audioservice.AudioService
 
 /**
  * MediaBrowserService for Android Auto.
  *
- * Android Auto connects to this service to browse content and control playback.
+ * Android Auto connects to this service to browse content and send transport
- *
+ * controls. Playback execution is delegated to Flutter's audio_service session.
- * Two playback modes:
- *  1. Cold start (Flutter not running): the service plays the stream directly via
- *     MediaPlayer. This avoids the unreliable startActivity → Flutter bridge.
- *  2. Warm start (Flutter running): MainActivity registers play/stop callbacks so
- *     Auto commands are forwarded through the method channel to just_audio.
- *
- * When the Flutter app opens while the service is playing, MainActivity stops the
- * service's MediaPlayer and Flutter takes over seamlessly.
  *
  * Brand color (#E36A18) is declared on this service via KryzAutoTheme in styles.xml
  * so Android Auto accents its media UI with the KRYZ orange.
@@ -46,45 +40,55 @@ class KryzAutoMediaBrowserService : MediaBrowserServiceCompat() {
         private const val STREAM_URL = "https://kryz.out.airtime.pro/kryz_a"
         private const val NOTIFICATION_CHANNEL_ID = "com.kryzgoflutter.auto.channel"
         private const val NOTIFICATION_ID = 1001
-
-        private var instance: KryzAutoMediaBrowserService? = null
-
-        // Called by MainActivity to mirror Flutter playback state into the MediaSession.
-        fun updatePlaybackState(isPlaying: Boolean, isBuffering: Boolean) {
-            instance?.applyPlaybackState(isPlaying, isBuffering)
-        }
-
-        // Called by MainActivity when Flutter is alive and taking over from the service player.
-        fun stopServicePlayer() {
-            instance?.stopServicePlayback()
-        }
-
-        fun isServicePlaying(): Boolean {
-            return try {
-                instance?.serviceMediaPlayer?.isPlaying == true
-            } catch (_: IllegalStateException) {
-                false
-            }
-        }
-
-        // Flutter-side play/stop callbacks registered by MainActivity when Flutter is ready.
-        private var directPlayCallback: (() -> Unit)? = null
-        private var directStopCallback: (() -> Unit)? = null
-
-        fun registerDirectCallbacks(play: () -> Unit, stop: () -> Unit) {
-            directPlayCallback = play
-            directStopCallback = stop
-        }
-
-        fun unregisterDirectCallbacks() {
-            directPlayCallback = null
-            directStopCallback = null
-        }
     }
 
     private lateinit var mediaSession: MediaSessionCompat
-    private var serviceMediaPlayer: MediaPlayer? = null
+    private var audioServiceBrowser: MediaBrowserCompat? = null
-    private var audioFocusRequest: AudioFocusRequest? = null
+    private var audioServiceController: MediaControllerCompat? = null
+    private val mainHandler = Handler(Looper.getMainLooper())
+    private var pendingPlayRequest: Boolean = false
+    private var pendingStopRequest: Boolean = false
+    private var reconnectScheduled: Boolean = false
+
+    private val mediaControllerCallback = object : MediaControllerCompat.Callback() {
+        override fun onPlaybackStateChanged(state: PlaybackStateCompat?) {
+            applyPlaybackStateFromFlutter(state)
+        }
+
+        override fun onMetadataChanged(metadata: MediaMetadataCompat?) {
+            applyNowPlayingMetadataFromFlutter(metadata)
+        }
+    }
+
+    private val browserConnectionCallback = object : MediaBrowserCompat.ConnectionCallback() {
+        override fun onConnected() {
+            val browser = audioServiceBrowser ?: return
+            try {
+                val controller = MediaControllerCompat(this@KryzAutoMediaBrowserService, browser.sessionToken)
+                audioServiceController?.unregisterCallback(mediaControllerCallback)
+                audioServiceController = controller
+                controller.registerCallback(mediaControllerCallback)
+                applyPlaybackStateFromFlutter(controller.playbackState)
+                applyNowPlayingMetadataFromFlutter(controller.metadata)
+                consumePendingTransportCommands()
+                Log.d(TAG, "Connected to Flutter audio_service session")
+            } catch (error: Exception) {
+                Log.e(TAG, "Unable to bind media controller: ${error.message}")
+            }
+        }
+
+        override fun onConnectionSuspended() {
+            Log.w(TAG, "audio_service browser connection suspended")
+            handleControllerDisconnected()
+            scheduleBrowserReconnect()
+        }
+
+        override fun onConnectionFailed() {
+            Log.e(TAG, "audio_service browser connection failed")
+            handleControllerDisconnected()
+            scheduleBrowserReconnect()
+        }
+    }
 
     private val mediaSessionCallback = object : MediaSessionCompat.Callback() {
         override fun onPlay() {
@@ -94,12 +98,7 @@ class KryzAutoMediaBrowserService : MediaBrowserServiceCompat() {
 
         override fun onStop() {
             Log.d(TAG, "onStop()")
-            val stop = directStopCallback
+            dispatchStopCommand()
-            if (stop != null) {
-                stop()
-            } else {
-                stopServicePlayback()
-            }
         }
 
         override fun onPlayFromMediaId(mediaId: String?, extras: Bundle?) {
@@ -114,20 +113,11 @@ class KryzAutoMediaBrowserService : MediaBrowserServiceCompat() {
     }
 
     private fun triggerPlay() {
-        val play = directPlayCallback
+        dispatchPlayCommand()
-        if (play != null) {
-            // Flutter is running — signal buffering then let Flutter handle audio.
-            applyPlaybackState(isPlaying = false, isBuffering = true)
-            play()
-        } else {
-            // Flutter is not running — play directly via MediaPlayer.
-            startServicePlayback()
-        }
     }
 
     override fun onCreate() {
         super.onCreate()
-        instance = this
         Log.d(TAG, "onCreate()")
         createNotificationChannel()
 
@@ -154,6 +144,7 @@ class KryzAutoMediaBrowserService : MediaBrowserServiceCompat() {
         }
         sessionToken = mediaSession.sessionToken
         Log.d(TAG, "MediaSession created, sessionToken set")
+        connectToFlutterAudioService()
     }
 
     override fun onGetRoot(
@@ -187,78 +178,11 @@ class KryzAutoMediaBrowserService : MediaBrowserServiceCompat() {
 
     override fun onDestroy() {
         Log.d(TAG, "onDestroy()")
-        stopServicePlayback()
+        disconnectFromFlutterAudioService()
-        instance = null
         if (::mediaSession.isInitialized) mediaSession.release()
         super.onDestroy()
     }
 
-    // Direct MediaPlayer playback used when Flutter is not running (cold Auto start).
-    private fun startServicePlayback() {
-        Log.d(TAG, "startServicePlayback()")
-        stopServicePlayback()
-        applyPlaybackState(isPlaying = false, isBuffering = true)
-        startForeground(NOTIFICATION_ID, buildNotification(isPlaying = false))
-        requestAudioFocus()
-
-        val player = MediaPlayer()
-        try {
-            player.setAudioAttributes(
-                AudioAttributes.Builder()
-                    .setUsage(AudioAttributes.USAGE_MEDIA)
-                    .setContentType(AudioAttributes.CONTENT_TYPE_MUSIC)
-                    .build()
-            )
-            player.setDataSource(STREAM_URL)
-            player.setOnPreparedListener { mp ->
-                Log.d(TAG, "MediaPlayer prepared → starting")
-                mp.start()
-                applyPlaybackState(isPlaying = true, isBuffering = false)
-                startForeground(NOTIFICATION_ID, buildNotification(isPlaying = true))
-            }
-            player.setOnInfoListener { _, what, _ ->
-                when (what) {
-                    MediaPlayer.MEDIA_INFO_BUFFERING_START ->
-                        applyPlaybackState(isPlaying = false, isBuffering = true)
-                    MediaPlayer.MEDIA_INFO_BUFFERING_END ->
-                        applyPlaybackState(isPlaying = true, isBuffering = false)
-                }
-                true
-            }
-            player.setOnErrorListener { _, what, extra ->
-                Log.e(TAG, "MediaPlayer error what=$what extra=$extra")
-                applyPlaybackState(isPlaying = false, isBuffering = false)
-                @Suppress("DEPRECATION")
-                stopForeground(true)
-                true
-            }
-            player.prepareAsync()
-            serviceMediaPlayer = player
-        } catch (e: Exception) {
-            Log.e(TAG, "Failed to start service playback: ${e.message}")
-            player.release()
-            applyPlaybackState(isPlaying = false, isBuffering = false)
-            @Suppress("DEPRECATION")
-            stopForeground(true)
-        }
-    }
-
-    private fun stopServicePlayback() {
-        val player = serviceMediaPlayer ?: return
-        Log.d(TAG, "stopServicePlayback()")
-        serviceMediaPlayer = null
-        try {
-            if (player.isPlaying) player.stop()
-            player.release()
-        } catch (e: Exception) {
-            Log.e(TAG, "Error releasing MediaPlayer: ${e.message}")
-        }
-        abandonAudioFocus()
-        applyPlaybackState(isPlaying = false, isBuffering = false)
-        @Suppress("DEPRECATION")
-        stopForeground(true)
-    }
-
     private fun applyPlaybackState(isPlaying: Boolean, isBuffering: Boolean) {
         if (!::mediaSession.isInitialized) return
         val state = when {
@@ -279,34 +203,66 @@ class KryzAutoMediaBrowserService : MediaBrowserServiceCompat() {
                 .setState(state, PlaybackStateCompat.PLAYBACK_POSITION_UNKNOWN, 1f)
                 .build()
         )
+        startForeground(NOTIFICATION_ID, buildNotification(isPlaying = isPlaying, isBuffering = isBuffering))
         Log.d(TAG, "applyPlaybackState: playing=$isPlaying buffering=$isBuffering")
     }
 
-    private fun requestAudioFocus() {
+    private fun dispatchPlayCommand() {
-        val audioManager = getSystemService(Context.AUDIO_SERVICE) as AudioManager
+        val controller = audioServiceController
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+        if (controller != null) {
-            val req = AudioFocusRequest.Builder(AudioManager.AUDIOFOCUS_GAIN)
+            pendingPlayRequest = false
-                .setAudioAttributes(
+            pendingStopRequest = false
-                    AudioAttributes.Builder()
+            applyPlaybackState(isPlaying = false, isBuffering = true)
-                        .setUsage(AudioAttributes.USAGE_MEDIA)
+            controller.transportControls.play()
-                        .setContentType(AudioAttributes.CONTENT_TYPE_MUSIC)
+            return
-                        .build()
+        }
-                )
+
-                .build()
+        pendingStopRequest = false
-            audioFocusRequest = req
+        pendingPlayRequest = true
-            audioManager.requestAudioFocus(req)
+        applyPlaybackState(isPlaying = false, isBuffering = true)
-        } else {
+        connectToFlutterAudioService()
-            @Suppress("DEPRECATION")
+    }
-            audioManager.requestAudioFocus(null, AudioManager.STREAM_MUSIC, AudioManager.AUDIOFOCUS_GAIN)
+
+    private fun dispatchStopCommand() {
+        val controller = audioServiceController
+        if (controller != null) {
+            pendingPlayRequest = false
+            pendingStopRequest = false
+            controller.transportControls.stop()
+            return
+        }
+
+        pendingPlayRequest = false
+        pendingStopRequest = true
+        applyPlaybackState(isPlaying = false, isBuffering = false)
+        connectToFlutterAudioService()
+    }
+
+    private fun consumePendingTransportCommands() {
+        val controller = audioServiceController ?: return
+
+        if (pendingStopRequest) {
+            pendingStopRequest = false
+            controller.transportControls.stop()
+        }
+
+        if (pendingPlayRequest) {
+            pendingPlayRequest = false
+            controller.transportControls.play()
         }
     }
 
-    private fun abandonAudioFocus() {
+    private fun applyPlaybackStateFromFlutter(state: PlaybackStateCompat?) {
-        val audioManager = getSystemService(Context.AUDIO_SERVICE) as AudioManager
+        if (state == null) {
-        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            applyPlaybackState(isPlaying = false, isBuffering = false)
-            audioFocusRequest?.let { audioManager.abandonAudioFocusRequest(it) }
+            return
-            audioFocusRequest = null
         }
+
+        val isPlaying = state.state == PlaybackStateCompat.STATE_PLAYING
+        val isBuffering = state.state == PlaybackStateCompat.STATE_BUFFERING ||
+            state.state == PlaybackStateCompat.STATE_CONNECTING
+
+        applyPlaybackState(isPlaying = isPlaying, isBuffering = isBuffering)
     }
 
     private fun createNotificationChannel() {
@@ -324,16 +280,126 @@ class KryzAutoMediaBrowserService : MediaBrowserServiceCompat() {
         }
     }
 
-    private fun buildNotification(isPlaying: Boolean): Notification {
+    private fun buildNotification(isPlaying: Boolean, isBuffering: Boolean): Notification {
+        val statusText = when {
+            isPlaying -> "Playing from Flutter audio handler"
+            isBuffering -> "Connecting via Flutter audio handler..."
+            else -> "Stopped"
+        }
         return NotificationCompat.Builder(this, NOTIFICATION_CHANNEL_ID)
             .setContentTitle("KRYZ Radio")
-            .setContentText(if (isPlaying) "Playing via Android Auto" else "Connecting…")
+            .setContentText(statusText)
             .setSmallIcon(R.mipmap.ic_launcher)
-            .setOngoing(isPlaying)
+            .setOngoing(isPlaying || isBuffering)
             .setSilent(true)
             .build()
     }
 
+    private fun applyNowPlayingMetadata(
+        title: String?,
+        subtitle: String?,
+        album: String?,
+        mediaUri: String?,
+    ) {
+        if (!::mediaSession.isInitialized) return
+
+        val iconUri = Uri.parse("android.resource://${packageName}/drawable/kryz_auto_art")
+        mediaSession.setMetadata(
+            MediaMetadataCompat.Builder()
+                .putString(MediaMetadataCompat.METADATA_KEY_TITLE, title ?: "KRYZ Live Stream")
+                .putString(MediaMetadataCompat.METADATA_KEY_ARTIST, subtitle ?: "KRYZ Radio")
+                .putString(MediaMetadataCompat.METADATA_KEY_ALBUM, album ?: "Live")
+                .putString(MediaMetadataCompat.METADATA_KEY_MEDIA_ID, MEDIA_ID_LIVE)
+                .putString(MediaMetadataCompat.METADATA_KEY_MEDIA_URI, mediaUri ?: STREAM_URL)
+                .putString(MediaMetadataCompat.METADATA_KEY_ALBUM_ART_URI, iconUri.toString())
+                .putString(MediaMetadataCompat.METADATA_KEY_DISPLAY_ICON_URI, iconUri.toString())
+                .build()
+        )
+    }
+
+    private fun applyNowPlayingMetadataFromFlutter(metadata: MediaMetadataCompat?) {
+        if (metadata == null) {
+            applyNowPlayingMetadata(
+                title = "KRYZ Live Stream",
+                subtitle = "KRYZ Radio",
+                album = "Live",
+                mediaUri = STREAM_URL,
+            )
+            return
+        }
+
+        applyNowPlayingMetadata(
+            title = metadata.getString(MediaMetadataCompat.METADATA_KEY_TITLE),
+            subtitle = metadata.getString(MediaMetadataCompat.METADATA_KEY_ARTIST),
+            album = metadata.getString(MediaMetadataCompat.METADATA_KEY_ALBUM),
+            mediaUri = metadata.getString(MediaMetadataCompat.METADATA_KEY_MEDIA_URI),
+        )
+    }
+
+    private fun connectToFlutterAudioService() {
+        if (audioServiceController != null) {
+            return
+        }
+
+        val existing = audioServiceBrowser
+        if (existing?.isConnected == true) {
+            return
+        }
+
+        if (existing != null) {
+            try {
+                existing.connect()
+            } catch (error: Exception) {
+                Log.w(TAG, "Failed reconnect attempt: ${error.message}")
+            }
+            return
+        }
+
+        val browser = MediaBrowserCompat(
+            this,
+            ComponentName(this, AudioService::class.java),
+            browserConnectionCallback,
+            null,
+        )
+
+        audioServiceBrowser = browser
+        browser.connect()
+    }
+
+    private fun disconnectFromFlutterAudioService() {
+        reconnectScheduled = false
+        mainHandler.removeCallbacksAndMessages(null)
+
+        handleControllerDisconnected()
+
+        audioServiceBrowser?.let { browser ->
+            if (browser.isConnected) {
+                browser.disconnect()
+            }
+        }
+        audioServiceBrowser = null
+    }
+
+    private fun handleControllerDisconnected() {
+        audioServiceController?.unregisterCallback(mediaControllerCallback)
+        audioServiceController = null
+    }
+
+    private fun scheduleBrowserReconnect() {
+        if (reconnectScheduled) {
+            return
+        }
+
+        reconnectScheduled = true
+        mainHandler.postDelayed(
+            {
+                reconnectScheduled = false
+                connectToFlutterAudioService()
+            },
+            1200,
+        )
+    }
+
     private fun buildLiveStreamMetadata(): MediaMetadataCompat {
         val iconUri = Uri.parse("android.resource://${packageName}/mipmap/ic_launcher")
         return MediaMetadataCompat.Builder()

android/app/src/main/kotlin/com/example/kryz_go_flutter/MainActivity.kt

@@ -27,7 +27,6 @@ class MainActivity : AudioServiceActivity(), MethodChannel.MethodCallHandler, Ev
 	companion object {
 		private const val METHOD_CHANNEL = "kryz_go_flutter/casting/methods"
 		private const val EVENT_CHANNEL = "kryz_go_flutter/casting/events"
-		private const val PLAYBACK_METHOD_CHANNEL = "kryz_go_flutter/playback/methods"
 	}
 
 	private var castContext: CastContext? = null
@@ -35,9 +34,6 @@ class MainActivity : AudioServiceActivity(), MethodChannel.MethodCallHandler, Ev
 	private var chooserDialog: MediaRouteChooserDialog? = null
 	private val mainHandler = Handler(Looper.getMainLooper())
     private var activeRemoteMediaClient: RemoteMediaClient? = null
-	private var playbackMethodChannel: MethodChannel? = null
-	private var flutterReady = false
-	private var pendingAutoPlay = false
 
 	private var statusPayload: MutableMap<String, Any?> = mutableMapOf(
 		"status" to "idle",
@@ -106,38 +102,6 @@ class MainActivity : AudioServiceActivity(), MethodChannel.MethodCallHandler, Ev
 		EventChannel(flutterEngine.dartExecutor.binaryMessenger, EVENT_CHANNEL)
 			.setStreamHandler(this)
 
-		playbackMethodChannel = MethodChannel(
-			flutterEngine.dartExecutor.binaryMessenger,
-			PLAYBACK_METHOD_CHANNEL,
-		)
-
-		playbackMethodChannel?.setMethodCallHandler { call, result ->
-			when (call.method) {
-				"flutterReady" -> {
-					flutterReady = true
-					// Stop the service's MediaPlayer and hand off to Flutter.
-					val wasServicePlaying = KryzAutoMediaBrowserService.isServicePlaying()
-					KryzAutoMediaBrowserService.stopServicePlayer()
-					KryzAutoMediaBrowserService.registerDirectCallbacks(
-						play = { mainHandler.post { invokeFlutterPlay() } },
-						stop = { mainHandler.post { playbackMethodChannel?.invokeMethod("stop", null) } },
-					)
-					if (pendingAutoPlay || wasServicePlaying) {
-						pendingAutoPlay = false
-						invokeFlutterPlay()
-					}
-					result.success(null)
-				}
-				"updatePlaybackState" -> {
-					val isPlaying = call.argument<Boolean>("isPlaying") ?: false
-					val isBuffering = call.argument<Boolean>("isBuffering") ?: false
-					KryzAutoMediaBrowserService.updatePlaybackState(isPlaying, isBuffering)
-					result.success(null)
-				}
-				else -> result.notImplemented()
-			}
-		}
-
 		initializeCastContext()
 	}
 
@@ -181,8 +145,6 @@ class MainActivity : AudioServiceActivity(), MethodChannel.MethodCallHandler, Ev
 		chooserDialog?.dismiss()
 		chooserDialog = null
 
-		KryzAutoMediaBrowserService.unregisterDirectCallbacks()
-
 		castContext?.sessionManager?.removeSessionManagerListener(
 			castSessionManagerListener,
 			CastSession::class.java,
@@ -192,16 +154,6 @@ class MainActivity : AudioServiceActivity(), MethodChannel.MethodCallHandler, Ev
 		super.onDestroy()
 	}
 
-	private fun invokeFlutterPlay() {
-		if (!flutterReady) {
-			pendingAutoPlay = true
-			return
-		}
-		mainHandler.post {
-			playbackMethodChannel?.invokeMethod("play", null)
-		}
-	}
-
 	private fun initializeCastContext() {
 		try {
 			castContext = CastContext.getSharedInstance(this)

ios/Runner/AppDelegate.swift

@@ -178,99 +178,3 @@ import AVKit
     NotificationCenter.default.removeObserver(self)
   }
 }
-
-  private func handleCastingMethod(call: FlutterMethodCall, result: @escaping FlutterResult) {
-    switch call.method {
-    case "getStatus":
-      updateCastingStatusForCurrentRoute()
-      result(castingStatus)
-    case "showDevicePicker":
-      showAirPlayPicker()
-      result(nil)
-    case "startCastingLiveStream":
-      // AirPlay route selection controls where iOS outputs audio. No explicit load call needed.
-      result(nil)
-    case "disconnect":
-      // iOS does not expose direct route disconnect. Users select route via picker.
-      showAirPlayPicker()
-      result(nil)
-    default:
-      result(FlutterMethodNotImplemented)
-    }
-  }
-
-  private func showAirPlayPicker() {
-    DispatchQueue.main.async {
-      guard let rootViewController = self.activeRootViewController() else {
-        self.emitCastingEvent(status: "error", message: "Unable to open AirPlay picker")
-        return
-      }
-
-      let routePickerView = AVRoutePickerView(frame: CGRect(x: 0, y: 0, width: 1, height: 1))
-      routePickerView.alpha = 0.01
-      rootViewController.view.addSubview(routePickerView)
-
-      for subview in routePickerView.subviews {
-        if let button = subview as? UIButton {
-          button.sendActions(for: .touchUpInside)
-          break
-        }
-      }
-
-      DispatchQueue.main.asyncAfter(deadline: .now() + 0.25) {
-        routePickerView.removeFromSuperview()
-      }
-    }
-  }
-
-  private func activeRootViewController() -> UIViewController? {
-    let activeScene = UIApplication.shared.connectedScenes
-      .first { $0.activationState == .foregroundActive } as? UIWindowScene
-    let keyWindow = activeScene?.windows.first { $0.isKeyWindow }
-    return keyWindow?.rootViewController
-  }
-
-  private func updateCastingStatusForCurrentRoute() {
-    let currentOutputs = AVAudioSession.sharedInstance().currentRoute.outputs
-    if let airPlayOutput = currentOutputs.first(where: { $0.portType == .airPlay }) {
-      castingStatus = [
-        "status": "connected",
-        "platform": "ios",
-        "deviceName": airPlayOutput.portName
-      ]
-    } else {
-      castingStatus = [
-        "status": "idle",
-        "platform": "ios"
-      ]
-    }
-
-    castingEventSink?(castingStatus)
-  }
-
-  private func emitCastingEvent(status: String, message: String) {
-    let event: [String: Any] = [
-      "status": status,
-      "platform": "ios",
-      "message": message
-    ]
-
-    castingStatus = event
-    castingEventSink?(event)
-  }
-
-  func onListen(withArguments arguments: Any?, eventSink events: @escaping FlutterEventSink) -> FlutterError? {
-    castingEventSink = events
-    events(castingStatus)
-    return nil
-  }
-
-  func onCancel(withArguments arguments: Any?) -> FlutterError? {
-    castingEventSink = nil
-    return nil
-  }
-
-  deinit {
-    NotificationCenter.default.removeObserver(self)
-  }
-}

lib/kryz_audio_handler.dart

@@ -0,0 +1,222 @@
+import 'dart:async';
+import 'dart:convert';
+
+import 'package:audio_service/audio_service.dart';
+import 'package:audio_session/audio_session.dart';
+import 'package:http/http.dart' as http;
+import 'package:just_audio/just_audio.dart';
+
+import 'live_info_business_object.dart';
+
+class KryzAudioHandler extends BaseAudioHandler with SeekHandler {
+  KryzAudioHandler() {
+    mediaItem.add(_defaultMediaItem);
+    _playerStateSubscription = _player.playerStateStream.listen(
+      _onPlayerStateChanged,
+    );
+  }
+
+  static const String streamUrl = 'https://kryz.out.airtime.pro/kryz_a';
+  static const String mediaId = 'kryz-live-stream';
+  static const String _liveInfoEndpoint = 'http://kryz.airtime.pro/api/live-info';
+  static const Duration _liveInfoTimeout = Duration(seconds: 8);
+  static const Duration _metadataRefreshInterval = Duration(seconds: 20);
+
+  static const MediaItem _defaultMediaItem = MediaItem(
+    id: mediaId,
+    title: 'KRYZ Live Stream',
+    artist: 'KRYZ Radio',
+    album: 'Live',
+    extras: <String, dynamic>{
+      'isLive': true,
+      'seekable': false,
+    },
+  );
+
+  final AudioPlayer _player = AudioPlayer();
+  late final StreamSubscription<PlayerState> _playerStateSubscription;
+  Timer? _metadataRefreshTimer;
+  bool _isAudioSessionConfigured = false;
+  bool _isSourceLoaded = false;
+  bool _playRequested = false;
+
+  Future<void> updateMetadataFromLiveInfo(LiveInfoSnapshot? snapshot) async {
+    final current = snapshot?.current;
+    if (current == null || current.type != 'track') {
+      mediaItem.add(_defaultMediaItem);
+      return;
+    }
+
+    final String subtitle = current.displaySubtitle.trim();
+    mediaItem.add(
+      MediaItem(
+        id: mediaId,
+        title: current.displayTitle,
+        artist: subtitle.isEmpty ? 'KRYZ Radio' : subtitle,
+        album: 'Live',
+        extras: <String, dynamic>{
+          'isLive': true,
+          'seekable': false,
+          'starts': current.starts,
+          'ends': current.ends,
+          'schedulerTime': snapshot?.schedulerTime,
+        },
+      ),
+    );
+  }
+
+  @override
+  Future<void> play() async {
+    _playRequested = true;
+    playbackState.add(
+      playbackState.value.copyWith(
+        controls: const <MediaControl>[MediaControl.stop],
+        systemActions: const <MediaAction>{},
+        processingState: AudioProcessingState.buffering,
+        playing: false,
+      ),
+    );
+
+    await _configureAudioSessionIfNeeded();
+
+    try {
+      if (!_isSourceLoaded) {
+        await _player.setAudioSource(
+          AudioSource.uri(
+            Uri.parse(streamUrl),
+            tag: mediaItem.value,
+          ),
+        );
+        _isSourceLoaded = true;
+      }
+
+      final session = await AudioSession.instance;
+      await session.setActive(true);
+      await _player.play();
+      await _refreshMetadataFromApi();
+      _startMetadataRefreshTimer();
+    } catch (_) {
+      _playRequested = false;
+      playbackState.add(
+        playbackState.value.copyWith(
+          controls: const <MediaControl>[MediaControl.play],
+          systemActions: const <MediaAction>{},
+          processingState: AudioProcessingState.idle,
+          playing: false,
+        ),
+      );
+      rethrow;
+    }
+  }
+
+  @override
+  Future<void> stop() async {
+    _playRequested = false;
+    _isSourceLoaded = false;
+    _metadataRefreshTimer?.cancel();
+    _metadataRefreshTimer = null;
+    await _player.stop();
+    playbackState.add(
+      playbackState.value.copyWith(
+        controls: const <MediaControl>[MediaControl.play],
+        systemActions: const <MediaAction>{},
+        processingState: AudioProcessingState.idle,
+        playing: false,
+      ),
+    );
+  }
+
+  @override
+  Future<void> seek(Duration position) async {
+    // Live stream is intentionally non-seekable.
+  }
+
+  @override
+  Future<void> playFromMediaId(String mediaId, [Map<String, dynamic>? extras]) {
+    return play();
+  }
+
+  @override
+  Future<void> playFromSearch(String query, [Map<String, dynamic>? extras]) {
+    return play();
+  }
+
+  Future<void> dispose() async {
+    _metadataRefreshTimer?.cancel();
+    await _playerStateSubscription.cancel();
+    await _player.dispose();
+  }
+
+  Future<void> _configureAudioSessionIfNeeded() async {
+    if (_isAudioSessionConfigured) {
+      return;
+    }
+
+    final session = await AudioSession.instance;
+    await session.configure(const AudioSessionConfiguration.music());
+    _isAudioSessionConfigured = true;
+  }
+
+  void _onPlayerStateChanged(PlayerState state) {
+    final AudioProcessingState processingState = switch (state.processingState) {
+      ProcessingState.idle => AudioProcessingState.idle,
+      ProcessingState.loading => AudioProcessingState.loading,
+      ProcessingState.buffering => AudioProcessingState.buffering,
+      ProcessingState.ready => AudioProcessingState.ready,
+      ProcessingState.completed => AudioProcessingState.completed,
+    };
+
+    final bool isPlaying = state.playing && state.processingState == ProcessingState.ready;
+    final bool isBuffering = (state.playing && state.processingState != ProcessingState.ready) ||
+        (_playRequested && !state.playing && state.processingState != ProcessingState.completed);
+
+    playbackState.add(
+      playbackState.value.copyWith(
+        controls: <MediaControl>[
+          if (isPlaying || isBuffering) MediaControl.stop else MediaControl.play,
+        ],
+        systemActions: const <MediaAction>{},
+        processingState: isBuffering ? AudioProcessingState.buffering : processingState,
+        playing: isPlaying,
+      ),
+    );
+
+    if (isPlaying || isBuffering) {
+      _startMetadataRefreshTimer();
+    } else {
+      _metadataRefreshTimer?.cancel();
+      _metadataRefreshTimer = null;
+    }
+  }
+
+  void _startMetadataRefreshTimer() {
+    if (_metadataRefreshTimer != null) {
+      return;
+    }
+
+    _metadataRefreshTimer = Timer.periodic(_metadataRefreshInterval, (_) {
+      _refreshMetadataFromApi();
+    });
+  }
+
+  Future<void> _refreshMetadataFromApi() async {
+    try {
+      final response = await http
+          .get(Uri.parse(_liveInfoEndpoint))
+          .timeout(_liveInfoTimeout);
+      if (response.statusCode < 200 || response.statusCode >= 300) {
+        return;
+      }
+
+      final dynamic decoded = jsonDecode(response.body);
+      if (decoded is! Map<String, dynamic>) {
+        return;
+      }
+
+      final snapshot = LiveInfoSnapshot.fromJson(decoded);
+      await updateMetadataFromLiveInfo(snapshot);
+    } catch (_) {
+      // Keep existing metadata if live-info fetch fails.
+    }
+  }
+}

lib/main.dart

@@ -1,6 +1,7 @@
+import 'dart:async';
+
 import 'package:flutter/material.dart';
 import 'package:flutter/foundation.dart';
-import 'package:just_audio_background/just_audio_background.dart';
 import 'package:flutter/services.dart';
 import 'package:timezone/data/latest.dart' as tz;
 import 'app_theme_business_object.dart';
@@ -12,19 +13,16 @@ import 'streaming_audio_business_object.dart';
 Future<void> main() async {
   WidgetsFlutterBinding.ensureInitialized();
   tz.initializeTimeZones();
-  await JustAudioBackground.init(
-    androidNotificationChannelId: 'com.kryzgoflutter.audio.channel',
-    androidNotificationChannelName: 'KRYZ Audio Playback',
-    androidNotificationOngoing: true,
-  );
-
-  WidgetsFlutterBinding.ensureInitialized();
-  await SystemChrome.setPreferredOrientations([
-    DeviceOrientation.portraitUp,
-    DeviceOrientation.portraitDown,
-  ]);
-
   runApp(const MyApp());
+
+  // Keep startup non-blocking so UI can render even if background media
+  // services are initializing after an Android Auto cold start.
+  unawaited(
+    SystemChrome.setPreferredOrientations([
+      DeviceOrientation.portraitUp,
+      DeviceOrientation.portraitDown,
+    ]),
+  );
 }
 
 class MyApp extends StatefulWidget {
@@ -41,6 +39,7 @@ class _MyAppState extends State<MyApp> {
   @override
   void initState() {
     super.initState();
+    unawaited(_audio.ensureInitialized());
     _casting.initialize();
   }
 
@@ -139,11 +138,6 @@ class _MainPageState extends State<MainPage> {
     _liveInfo.addListener(_handleLiveInfoChanged);
     _liveInfo.start();
     _playbackChannel.setMethodCallHandler(_handlePlaybackMethodCall);
-    // Tell native that Flutter is ready to receive method calls.
-    // On Android this unblocks any pending auto_play from Android Auto.
-    if (defaultTargetPlatform == TargetPlatform.android) {
-      _playbackChannel.invokeMethod<void>('flutterReady');
-    }
   }
 
   Future<void> _handlePlaybackMethodCall(MethodCall call) async {
@@ -163,19 +157,11 @@ class _MainPageState extends State<MainPage> {
     setState(() {
       // Rebuild when playback state changes from the player.
     });
-
-    _syncAutoPlaybackState();
-  }
-
-  void _syncAutoPlaybackState() {
-    if (defaultTargetPlatform != TargetPlatform.android) return;
-    _playbackChannel.invokeMethod<void>('updatePlaybackState', {
-      'isPlaying': _audio.isPlaying,
-      'isBuffering': _audio.isBuffering,
-    });
   }
 
   void _handleLiveInfoChanged() {
+    _audio.updateMetadataFromLiveInfo(_liveInfo.snapshot);
+
     if (!mounted) {
       return;
     }
@@ -213,8 +199,8 @@ class _MainPageState extends State<MainPage> {
     try {
       await _casting.startCastingLiveStream(
         streamUrl: _audio.streamUrl,
-        title: 'KRYZ Live Stream',
+        title: _audio.currentTitle,
-        subtitle: 'KRYZ Radio',
+        subtitle: _audio.currentSubtitle,
       );
 
       _castStreamStartedForActiveSession = true;

lib/streaming_audio_business_object.dart

@@ -1,48 +1,94 @@
 import 'dart:async';
 
-import 'package:audio_session/audio_session.dart';
+import 'package:audio_service/audio_service.dart';
 import 'package:flutter/foundation.dart';
-import 'package:just_audio_background/just_audio_background.dart';
+
-import 'package:just_audio/just_audio.dart';
+import 'kryz_audio_handler.dart';
+import 'live_info_business_object.dart';
 
 enum StreamingPlaybackStatus { stopped, buffering, playing }
 
 class StreamingAudioBusinessObject extends ChangeNotifier {
-  StreamingAudioBusinessObject({
+  StreamingAudioBusinessObject() {
-    this.streamUrl = 'https://kryz.out.airtime.pro/kryz_a',
+    final initFuture = _audioHandlerInitFuture;
-  }) {
+    if (initFuture != null) {
-    _playerStateSubscription = _player.playerStateStream.listen((state) {
+      initFuture.then((handler) {
-      _setPlaybackStatus(_mapPlayerStateToStatus(state));
+        if (_isDisposed) {
-    });
+          return;
+        }
+        _attachHandler(handler);
+      });
+    }
+
+    final handler = _audioHandler;
+    if (handler != null) {
+      _attachHandler(handler);
+    }
   }
 
-  final String streamUrl;
+  static AudioHandler? _audioHandler;
-  final AudioPlayer _player = AudioPlayer();
+  static Future<AudioHandler>? _audioHandlerInitFuture;
-  late final StreamSubscription<PlayerState> _playerStateSubscription;
+
-  bool _isSourceLoaded = false;
+  static Future<void> initializeBackgroundAudio() async {
+    if (_audioHandler != null) {
+      return;
+    }
+
+    _audioHandlerInitFuture ??= AudioService.init(
+      builder: () => KryzAudioHandler(),
+      config: const AudioServiceConfig(
+        androidNotificationChannelId: 'com.kryzgoflutter.audio.channel',
+        androidNotificationChannelName: 'KRYZ Audio Playback',
+        androidNotificationOngoing: true,
+        androidStopForegroundOnPause: true,
+      ),
+    ).then((handler) {
+      _audioHandler = handler;
+      return handler;
+    }).catchError((error) {
+      _audioHandlerInitFuture = null;
+      throw error;
+    });
+
+    await _audioHandlerInitFuture;
+  }
+
+  String get streamUrl => KryzAudioHandler.streamUrl;
+
+  StreamSubscription<PlaybackState>? _playbackStateSubscription;
+  StreamSubscription<MediaItem?>? _mediaItemSubscription;
   StreamingPlaybackStatus _playbackStatus = StreamingPlaybackStatus.stopped;
-  bool _isAudioSessionConfigured = false;
+  bool _isDisposed = false;
-  bool _playRequested = false;
+  bool _isAttached = false;
+  String _currentTitle = 'KRYZ Live Stream';
+  String _currentSubtitle = 'KRYZ Radio';
 
   StreamingPlaybackStatus get playbackStatus => _playbackStatus;
   bool get isPlaying => _playbackStatus == StreamingPlaybackStatus.playing;
   bool get isBuffering => _playbackStatus == StreamingPlaybackStatus.buffering;
   bool get isStopped => _playbackStatus == StreamingPlaybackStatus.stopped;
+  String get currentTitle => _currentTitle;
+  String get currentSubtitle => _currentSubtitle;
 
-  StreamingPlaybackStatus _mapPlayerStateToStatus(PlayerState state) {
+  Future<void> ensureInitialized() async {
-    if (state.processingState == ProcessingState.completed) {
+    await initializeBackgroundAudio();
+  }
+
+  StreamingPlaybackStatus _mapPlaybackStateToStatus(PlaybackState state) {
+    if (state.processingState == AudioProcessingState.completed) {
       return StreamingPlaybackStatus.stopped;
     }
 
     if (state.playing) {
-      if (state.processingState == ProcessingState.ready) {
+      if (state.processingState == AudioProcessingState.ready) {
         return StreamingPlaybackStatus.playing;
       }
 
       return StreamingPlaybackStatus.buffering;
     }
 
-    if (_playRequested && state.processingState != ProcessingState.completed) {
+    if (state.processingState == AudioProcessingState.buffering ||
+        state.processingState == AudioProcessingState.loading) {
       return StreamingPlaybackStatus.buffering;
     }
 
@@ -58,58 +104,66 @@ class StreamingAudioBusinessObject extends ChangeNotifier {
     notifyListeners();
   }
 
-  Future<void> _configureAudioSessionIfNeeded() async {
-    if (_isAudioSessionConfigured) {
-      return;
-    }
-
-    final session = await AudioSession.instance;
-    await session.configure(const AudioSessionConfiguration.music());
-    _isAudioSessionConfigured = true;
-  }
-
   Future<void> play() async {
-    _playRequested = true;
-    await _configureAudioSessionIfNeeded();
     _setPlaybackStatus(StreamingPlaybackStatus.buffering);
-
+    final handler = await _requireHandler();
-    try {
+    await handler.play();
-      if (!_isSourceLoaded) {
-        await _player.setAudioSource(
-          AudioSource.uri(
-            Uri.parse(streamUrl),
-            tag: const MediaItem(
-              id: 'kryz-live-stream',
-              title: 'KRYZ Live Stream',
-              artist: 'KRYZ Radio',
-              album: 'Live',
-            ),
-          ),
-        );
-        _isSourceLoaded = true;
-      }
-
-      final session = await AudioSession.instance;
-      await session.setActive(true);
-      await _player.play();
-    } catch (_) {
-      _playRequested = false;
-      _setPlaybackStatus(StreamingPlaybackStatus.stopped);
-      rethrow;
-    }
   }
 
   Future<void> stop() async {
-    _playRequested = false;
+    final handler = await _requireHandler();
-    _isSourceLoaded = false;
+    await handler.stop();
     _setPlaybackStatus(StreamingPlaybackStatus.stopped);
-    await _player.stop();
+  }
+
+  Future<void> updateMetadataFromLiveInfo(LiveInfoSnapshot? snapshot) async {
+    final handler = await _requireHandler();
+    await handler.updateMetadataFromLiveInfo(snapshot);
+  }
+
+  Future<KryzAudioHandler> _requireHandler() async {
+    await initializeBackgroundAudio();
+    final handler = _audioHandler;
+    if (handler is! KryzAudioHandler) {
+      throw StateError('KryzAudioHandler is not initialized');
+    }
+    _attachHandler(handler);
+    return handler;
+  }
+
+  void _attachHandler(AudioHandler handler) {
+    if (_isAttached) {
+      return;
+    }
+
+    _isAttached = true;
+    _playbackStateSubscription = handler.playbackState.listen((state) {
+      _setPlaybackStatus(_mapPlaybackStateToStatus(state));
+    });
+    _mediaItemSubscription = handler.mediaItem.listen((item) {
+      if (item == null) {
+        return;
+      }
+
+      final title = item.title.trim().isEmpty ? 'KRYZ Live Stream' : item.title;
+      final subtitle =
+          (item.artist ?? '').trim().isEmpty ? 'KRYZ Radio' : item.artist!.trim();
+
+      if (title == _currentTitle && subtitle == _currentSubtitle) {
+        return;
+      }
+
+      _currentTitle = title;
+      _currentSubtitle = subtitle;
+      notifyListeners();
+    });
   }
 
   @override
   void dispose() {
-    _playerStateSubscription.cancel();
+    _isDisposed = true;
-    _player.dispose();
+    _playbackStateSubscription?.cancel();
+    _mediaItemSubscription?.cancel();
     super.dispose();
   }
 }

pubspec.yaml

@@ -36,6 +36,7 @@ dependencies:
   cupertino_icons: ^1.0.8
   just_audio: ^0.10.5
   just_audio_background: ^0.0.1-beta.17
+  audio_service: ^0.18.18
   audio_session: ^0.2.2
   webview_flutter: ^4.13.0
   http: ^1.5.0

test/widget_test.dart

@@ -11,20 +11,12 @@ import 'package:flutter_test/flutter_test.dart';
 import 'package:kryz_go_flutter/main.dart';
 
 void main() {
-  testWidgets('Counter increments smoke test', (WidgetTester tester) async {
+  testWidgets('App renders title and controls', (WidgetTester tester) async {
-    // Build our app and trigger a frame.
     await tester.pumpWidget(const MyApp());
-
-    // Verify that our counter starts at 0.
-    expect(find.text('0'), findsOneWidget);
-    expect(find.text('1'), findsNothing);
-
-    // Tap the '+' icon and trigger a frame.
-    await tester.tap(find.byIcon(Icons.add));
     await tester.pump();
 
-    // Verify that our counter has incremented.
+    expect(find.text('KRYZ Go!'), findsWidgets);
-    expect(find.text('0'), findsNothing);
+    expect(find.widgetWithIcon(ElevatedButton, Icons.play_arrow_rounded), findsOneWidget);
-    expect(find.text('1'), findsOneWidget);
+    expect(find.widgetWithIcon(ElevatedButton, Icons.stop_rounded), findsOneWidget);
   });
 }