Subscribe to AudioManager to listen to currently selected device

Bug: b/255495104
Test: manually tested
Change-Id: I360b1ef592e30f4ad39136ec0def2f3fa74df912
diff --git a/services/core/java/com/android/server/media/AudioAttributesUtils.java b/services/core/java/com/android/server/media/AudioAttributesUtils.java
new file mode 100644
index 0000000..b9c9bae
--- /dev/null
+++ b/services/core/java/com/android/server/media/AudioAttributesUtils.java
@@ -0,0 +1,112 @@
+/*
+ * Copyright (C) 2023 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+package com.android.server.media;
+
+import android.annotation.NonNull;
+import android.annotation.Nullable;
+import android.media.AudioAttributes;
+import android.media.AudioDeviceAttributes;
+import android.media.AudioDeviceInfo;
+import android.media.MediaRoute2Info;
+
+/* package */ final class AudioAttributesUtils {
+
+    /* package */ static final AudioAttributes ATTRIBUTES_MEDIA = new AudioAttributes.Builder()
+            .setUsage(AudioAttributes.USAGE_MEDIA)
+            .build();
+
+    private AudioAttributesUtils() {
+        // no-op to prevent instantiation.
+    }
+
+    @MediaRoute2Info.Type
+    /* package */ static int mapToMediaRouteType(
+            @NonNull AudioDeviceAttributes audioDeviceAttributes) {
+        switch (audioDeviceAttributes.getType()) {
+            case AudioDeviceInfo.TYPE_BUILTIN_EARPIECE:
+            case AudioDeviceInfo.TYPE_BUILTIN_SPEAKER:
+                return MediaRoute2Info.TYPE_BUILTIN_SPEAKER;
+            case AudioDeviceInfo.TYPE_WIRED_HEADSET:
+                return MediaRoute2Info.TYPE_WIRED_HEADSET;
+            case AudioDeviceInfo.TYPE_WIRED_HEADPHONES:
+                return MediaRoute2Info.TYPE_WIRED_HEADPHONES;
+            case AudioDeviceInfo.TYPE_DOCK:
+            case AudioDeviceInfo.TYPE_DOCK_ANALOG:
+                return MediaRoute2Info.TYPE_DOCK;
+            case AudioDeviceInfo.TYPE_HDMI:
+                return MediaRoute2Info.TYPE_HDMI;
+            case AudioDeviceInfo.TYPE_USB_DEVICE:
+                return MediaRoute2Info.TYPE_USB_DEVICE;
+            case AudioDeviceInfo.TYPE_BLUETOOTH_A2DP:
+                return MediaRoute2Info.TYPE_BLUETOOTH_A2DP;
+            case AudioDeviceInfo.TYPE_BLE_HEADSET:
+                return MediaRoute2Info.TYPE_BLE_HEADSET;
+            case AudioDeviceInfo.TYPE_HEARING_AID:
+                return MediaRoute2Info.TYPE_HEARING_AID;
+            default:
+                return MediaRoute2Info.TYPE_UNKNOWN;
+        }
+    }
+
+
+    /* package */ static boolean isDeviceOutputAttributes(
+            @Nullable AudioDeviceAttributes audioDeviceAttributes) {
+        if (audioDeviceAttributes == null) {
+            return false;
+        }
+
+        if (audioDeviceAttributes.getRole() != AudioDeviceAttributes.ROLE_OUTPUT) {
+            return false;
+        }
+
+        switch (audioDeviceAttributes.getType()) {
+            case AudioDeviceInfo.TYPE_BUILTIN_EARPIECE:
+            case AudioDeviceInfo.TYPE_BUILTIN_SPEAKER:
+            case AudioDeviceInfo.TYPE_WIRED_HEADSET:
+            case AudioDeviceInfo.TYPE_WIRED_HEADPHONES:
+            case AudioDeviceInfo.TYPE_DOCK:
+            case AudioDeviceInfo.TYPE_DOCK_ANALOG:
+            case AudioDeviceInfo.TYPE_HDMI:
+            case AudioDeviceInfo.TYPE_USB_DEVICE:
+                return true;
+            default:
+                return false;
+        }
+    }
+
+    /* package */ static boolean isBluetoothOutputAttributes(
+            @Nullable AudioDeviceAttributes audioDeviceAttributes) {
+        if (audioDeviceAttributes == null) {
+            return false;
+        }
+
+        if (audioDeviceAttributes.getRole() != AudioDeviceAttributes.ROLE_OUTPUT) {
+            return false;
+        }
+
+        switch (audioDeviceAttributes.getType()) {
+            case AudioDeviceInfo.TYPE_BLUETOOTH_A2DP:
+            case AudioDeviceInfo.TYPE_BLE_HEADSET:
+            case AudioDeviceInfo.TYPE_BLE_SPEAKER:
+            case AudioDeviceInfo.TYPE_HEARING_AID:
+                return true;
+            default:
+                return false;
+        }
+    }
+
+}
diff --git a/services/core/java/com/android/server/media/SystemMediaRoute2Provider.java b/services/core/java/com/android/server/media/SystemMediaRoute2Provider.java
index 6619e6c..5d5c621 100644
--- a/services/core/java/com/android/server/media/SystemMediaRoute2Provider.java
+++ b/services/core/java/com/android/server/media/SystemMediaRoute2Provider.java
@@ -16,11 +16,14 @@
 
 package com.android.server.media;
 
+import android.annotation.NonNull;
 import android.content.BroadcastReceiver;
 import android.content.ComponentName;
 import android.content.Context;
 import android.content.Intent;
 import android.content.IntentFilter;
+import android.media.AudioAttributes;
+import android.media.AudioDeviceAttributes;
 import android.media.AudioManager;
 import android.media.MediaRoute2Info;
 import android.media.MediaRoute2ProviderInfo;
@@ -37,6 +40,7 @@
 
 import com.android.internal.annotations.GuardedBy;
 
+import java.util.List;
 import java.util.Objects;
 
 /**
@@ -71,6 +75,26 @@
     private final AudioManagerBroadcastReceiver mAudioReceiver =
             new AudioManagerBroadcastReceiver();
 
+    private final AudioManager.OnDevicesForAttributesChangedListener
+            mOnDevicesForAttributesChangedListener =
+            new AudioManager.OnDevicesForAttributesChangedListener() {
+                @Override
+                public void onDevicesForAttributesChanged(@NonNull AudioAttributes attributes,
+                        @NonNull List<AudioDeviceAttributes> devices) {
+                    if (attributes.getUsage() != AudioAttributes.USAGE_MEDIA) {
+                        return;
+                    }
+
+                    mHandler.post(() -> {
+                        updateSelectedAudioDevice(devices);
+                        notifyProviderState();
+                        if (updateSessionInfosIfNeeded()) {
+                            notifySessionInfoUpdated();
+                        }
+                    });
+                }
+            };
+
     private final Object mRequestLock = new Object();
     @GuardedBy("mRequestLock")
     private volatile SessionCreationRequest mPendingSessionCreationRequest;
@@ -100,8 +124,15 @@
             });
         });
 
+        mAudioManager.addOnDevicesForAttributesChangedListener(
+                AudioAttributesUtils.ATTRIBUTES_MEDIA, mContext.getMainExecutor(),
+                mOnDevicesForAttributesChangedListener);
+
         // These methods below should be called after all fields are initialized, as they
         // access the fields inside.
+        List<AudioDeviceAttributes> devices =
+                mAudioManager.getDevicesForAttributes(AudioAttributesUtils.ATTRIBUTES_MEDIA);
+        updateSelectedAudioDevice(devices);
         updateProviderState();
         updateSessionInfosIfNeeded();
     }
@@ -239,6 +270,26 @@
         }
     }
 
+    private void updateSelectedAudioDevice(@NonNull List<AudioDeviceAttributes> devices) {
+        if (devices.isEmpty()) {
+            Slog.w(TAG, "The list of preferred devices was empty.");
+            return;
+        }
+
+        AudioDeviceAttributes audioDeviceAttributes = devices.get(0);
+
+        if (AudioAttributesUtils.isDeviceOutputAttributes(audioDeviceAttributes)) {
+            mDeviceRouteController.selectRoute(
+                    AudioAttributesUtils.mapToMediaRouteType(audioDeviceAttributes));
+            mBluetoothRouteController.selectRoute(null);
+        } else if (AudioAttributesUtils.isBluetoothOutputAttributes(audioDeviceAttributes)) {
+            mDeviceRouteController.selectRoute(null);
+            mBluetoothRouteController.selectRoute(audioDeviceAttributes.getAddress());
+        } else {
+            Slog.w(TAG, "Unknown audio attributes: " + audioDeviceAttributes);
+        }
+    }
+
     private void updateProviderState() {
         MediaRoute2ProviderInfo.Builder builder = new MediaRoute2ProviderInfo.Builder();