Merge "Ignore requests to remove a call when there are pending connection attempts." into main
diff --git a/flags/telecom_callaudioroutestatemachine_flags.aconfig b/flags/telecom_callaudioroutestatemachine_flags.aconfig
index 1608869..6cca8f9 100644
--- a/flags/telecom_callaudioroutestatemachine_flags.aconfig
+++ b/flags/telecom_callaudioroutestatemachine_flags.aconfig
@@ -80,3 +80,11 @@
   description: "Clear the requested communication device after the audio operations are completed."
   bug: "315865533"
 }
+
+# OWNER=pmadapurmath TARGET=24Q3
+flag {
+  name: "resolve_switching_bt_devices_computation"
+  namespace: "telecom"
+  description: "Update switching bt devices based on arbitrary device chosen if no device is specified."
+  bug: "333751408"
+}
diff --git a/res/values-vi/strings.xml b/res/values-vi/strings.xml
index 5ae2e79..70f9bfc 100644
--- a/res/values-vi/strings.xml
+++ b/res/values-vi/strings.xml
@@ -133,5 +133,5 @@
     <string name="callendpoint_name_unknown" msgid="2199074708477193852">"Không xác định"</string>
     <string name="call_streaming_notification_body" msgid="502216105683378263">"Đang truyền trực tuyến âm thanh tới thiết bị khác"</string>
     <string name="call_streaming_notification_action_hang_up" msgid="7017663335289063827">"Kết thúc"</string>
-    <string name="call_streaming_notification_action_switch_here" msgid="3524180754186221228">"Chuyển đổi tại đây"</string>
+    <string name="call_streaming_notification_action_switch_here" msgid="3524180754186221228">"Chuyển qua thiết bị này"</string>
 </resources>
diff --git a/src/com/android/server/telecom/CallAudioCommunicationDeviceTracker.java b/src/com/android/server/telecom/CallAudioCommunicationDeviceTracker.java
index 3a05eb5..8130685 100644
--- a/src/com/android/server/telecom/CallAudioCommunicationDeviceTracker.java
+++ b/src/com/android/server/telecom/CallAudioCommunicationDeviceTracker.java
@@ -31,6 +31,8 @@
 import java.util.Arrays;
 import java.util.List;
 import java.util.concurrent.Semaphore;
+import java.util.concurrent.locks.Lock;
+import java.util.concurrent.locks.ReentrantLock;
 
 /**
  * Helper class used to keep track of the requested communication device within Telecom for audio
@@ -47,7 +49,7 @@
     private int mAudioDeviceType = sAUDIO_DEVICE_TYPE_INVALID;
     // Keep track of the locally requested BT audio device if set
     private String mBtAudioDevice = null;
-    private final Semaphore mLock =  new Semaphore(1);
+    private final Lock mLock = new ReentrantLock();
 
     public CallAudioCommunicationDeviceTracker(Context context) {
         mAudioManager = context.getSystemService(AudioManager.class);
@@ -58,11 +60,29 @@
     }
 
     public boolean isAudioDeviceSetForType(int audioDeviceType) {
-        return mAudioDeviceType == audioDeviceType;
+        if (Flags.communicationDeviceProtectedByLock()) {
+            mLock.lock();
+        }
+        try {
+            return mAudioDeviceType == audioDeviceType;
+        } finally {
+            if (Flags.communicationDeviceProtectedByLock()) {
+                mLock.unlock();
+            }
+        }
     }
 
     public int getCurrentLocallyRequestedCommunicationDevice() {
-       return mAudioDeviceType;
+        if (Flags.communicationDeviceProtectedByLock()) {
+            mLock.lock();
+        }
+        try {
+            return mAudioDeviceType;
+        } finally {
+            if (Flags.communicationDeviceProtectedByLock()) {
+                mLock.unlock();
+            }
+        }
     }
 
     @VisibleForTesting
@@ -71,13 +91,22 @@
     }
 
     public void clearBtCommunicationDevice() {
-        if (mBtAudioDevice == null) {
-            Log.i(this, "No bluetooth device was set for communication that can be cleared.");
-            return;
+        if (Flags.communicationDeviceProtectedByLock()) {
+            mLock.lock();
         }
-        // If mBtAudioDevice is set, we know a BT audio device was set for communication so
-        // mAudioDeviceType corresponds to a BT device type (e.g. hearing aid, SCO, LE).
-        clearCommunicationDevice(mAudioDeviceType);
+        try {
+            if (mBtAudioDevice == null) {
+                Log.i(this, "No bluetooth device was set for communication that can be cleared.");
+            } else {
+                // If mBtAudioDevice is set, we know a BT audio device was set for communication so
+                // mAudioDeviceType corresponds to a BT device type (e.g. hearing aid, SCO, LE).
+                processClearCommunicationDevice(mAudioDeviceType);
+            }
+        } finally {
+            if (Flags.communicationDeviceProtectedByLock()) {
+                mLock.unlock();
+            }
+        }
     }
 
     /*
@@ -93,8 +122,19 @@
     public boolean setCommunicationDevice(int audioDeviceType,
             BluetoothDevice btDevice) {
         if (Flags.communicationDeviceProtectedByLock()) {
-            mLock.tryAcquire();
+            mLock.lock();
         }
+        try {
+            return processSetCommunicationDevice(audioDeviceType, btDevice);
+        } finally {
+            if (Flags.communicationDeviceProtectedByLock()) {
+                mLock.unlock();
+            }
+        }
+    }
+
+    private boolean processSetCommunicationDevice(int audioDeviceType,
+            BluetoothDevice btDevice) {
         // There is only one audio device type associated with each type of BT device.
         boolean isBtDevice = BT_AUDIO_DEVICE_INFO_TYPES.contains(audioDeviceType);
         Log.i(this, "setCommunicationDevice: type = %s, isBtDevice = %s, btDevice = %s",
@@ -132,14 +172,14 @@
             Log.i(this, "No active device of type(s) %s available",
                     audioDeviceType == AudioDeviceInfo.TYPE_WIRED_HEADSET
                             ? Arrays.asList(AudioDeviceInfo.TYPE_WIRED_HEADSET,
-                                    AudioDeviceInfo.TYPE_USB_HEADSET)
+                            AudioDeviceInfo.TYPE_USB_HEADSET)
                             : audioDeviceType);
             return false;
         }
 
         // Force clear previous communication device, if one was set, before setting the new device.
         if (mAudioDeviceType != sAUDIO_DEVICE_TYPE_INVALID) {
-            clearCommunicationDevice(mAudioDeviceType);
+            processClearCommunicationDevice(mAudioDeviceType);
         }
 
         // Turn activeDevice ON.
@@ -161,12 +201,8 @@
                 mBtAudioDevice = null;
             }
         }
-        if (Flags.communicationDeviceProtectedByLock()) {
-            mLock.release();
-        }
         return result;
     }
-
     /*
      * Clears the communication device for the passed in audio device types, given that the device
      * has previously been set for communication.
@@ -174,8 +210,23 @@
      */
     public void clearCommunicationDevice(int audioDeviceType) {
         if (Flags.communicationDeviceProtectedByLock()) {
-            mLock.tryAcquire();
+            mLock.lock();
         }
+        try {
+            processClearCommunicationDevice(audioDeviceType);
+        } finally {
+            if (Flags.communicationDeviceProtectedByLock()) {
+                mLock.unlock();
+            }
+        }
+    }
+
+    public void processClearCommunicationDevice(int audioDeviceType) {
+        if (audioDeviceType == sAUDIO_DEVICE_TYPE_INVALID) {
+            Log.i(this, "clearCommunicationDevice: Skip clearing communication device"
+                    + "for invalid audio type (-1).");
+        }
+
         // There is only one audio device type associated with each type of BT device.
         boolean isBtDevice = BT_AUDIO_DEVICE_INFO_TYPES.contains(audioDeviceType);
         Log.i(this, "clearCommunicationDevice: type = %s, isBtDevice = %s",
@@ -184,10 +235,10 @@
         if (audioDeviceType != mAudioDeviceType
                 && !isUsbHeadsetType(audioDeviceType, mAudioDeviceType)) {
             Log.i(this, "Unable to clear communication device of type(s), %s. "
-                    + "Device does not correspond to the locally requested device type.",
+                            + "Device does not correspond to the locally requested device type.",
                     audioDeviceType == AudioDeviceInfo.TYPE_WIRED_HEADSET
                             ? Arrays.asList(AudioDeviceInfo.TYPE_WIRED_HEADSET,
-                                    AudioDeviceInfo.TYPE_USB_HEADSET)
+                            AudioDeviceInfo.TYPE_USB_HEADSET)
                             : audioDeviceType
             );
             return;
@@ -207,13 +258,10 @@
             mBluetoothRouteManager.onAudioLost(mBtAudioDevice);
             mBtAudioDevice = null;
         }
-        if (Flags.communicationDeviceProtectedByLock()) {
-            mLock.release();
-        }
     }
 
     private boolean isUsbHeadsetType(int audioDeviceType, int sourceType) {
-        return audioDeviceType != AudioDeviceInfo.TYPE_WIRED_HEADSET
-                ? false : sourceType == AudioDeviceInfo.TYPE_USB_HEADSET;
+        return audioDeviceType == AudioDeviceInfo.TYPE_WIRED_HEADSET
+                && sourceType == AudioDeviceInfo.TYPE_USB_HEADSET;
     }
 }
diff --git a/src/com/android/server/telecom/CallAudioRouteStateMachine.java b/src/com/android/server/telecom/CallAudioRouteStateMachine.java
index 621ba36..04dae5f 100644
--- a/src/com/android/server/telecom/CallAudioRouteStateMachine.java
+++ b/src/com/android/server/telecom/CallAudioRouteStateMachine.java
@@ -847,6 +847,14 @@
                     if (msg.arg1 == NO_FOCUS) {
                         // Only disconnect audio here instead of routing away from BT entirely.
                         if (mFeatureFlags.transitRouteBeforeAudioDisconnectBt()) {
+                            // Note: We have to turn off mute here rather than when entering the
+                            // QuiescentBluetooth route because setMuteOn will only work when there the
+                            // current state is active.
+                            // We don't need to do this in the unflagged path since reinitialize
+                            // will turn off mute.
+                            if (mFeatureFlags.resetMuteWhenEnteringQuiescentBtRoute()) {
+                                setMuteOn(false);
+                            }
                             transitionTo(mQuiescentBluetoothRoute);
                             mBluetoothRouteManager.disconnectAudio();
                         } else {
@@ -977,9 +985,6 @@
         public void enter() {
             super.enter();
             mHasUserExplicitlyLeftBluetooth = false;
-            if (mFeatureFlags.resetMuteWhenEnteringQuiescentBtRoute()) {
-                setMuteOn(false);
-            }
             updateInternalCallAudioState();
         }
 
diff --git a/src/com/android/server/telecom/bluetooth/BluetoothRouteManager.java b/src/com/android/server/telecom/bluetooth/BluetoothRouteManager.java
index d2686e7..5a44041 100644
--- a/src/com/android/server/telecom/bluetooth/BluetoothRouteManager.java
+++ b/src/com/android/server/telecom/bluetooth/BluetoothRouteManager.java
@@ -28,6 +28,7 @@
 import android.os.Message;
 import android.telecom.Log;
 import android.telecom.Logging.Session;
+import android.util.Pair;
 import android.util.SparseArray;
 
 import com.android.internal.annotations.VisibleForTesting;
@@ -165,10 +166,23 @@
                         removeDevice((String) args.arg2);
                         break;
                     case CONNECT_BT:
-                        String actualAddress = connectBtAudio((String) args.arg2,
-                            false /* switchingBtDevices*/);
+                        String actualAddress;
+                        boolean connected;
+                        if (mFeatureFlags.resolveSwitchingBtDevicesComputation()) {
+                            Pair<String, Boolean> addressInfo = computeAddressToConnectTo(
+                                    (String) args.arg2, false, null);
+                            // See if we need to transition route if the device is already
+                            // connected. If connected, another connection will not occur.
+                            addressInfo = handleDeviceAlreadyConnected(addressInfo);
+                            actualAddress = addressInfo.first;
+                            connected = connectBtAudio(actualAddress, 0,
+                                    false /* switchingBtDevices*/);
+                        } else {
+                            actualAddress = connectBtAudioLegacy((String) args.arg2, false);
+                            connected = actualAddress != null;
+                        }
 
-                        if (actualAddress != null) {
+                        if (connected) {
                             transitionTo(getConnectingStateForAddress(actualAddress,
                                     "AudioOff/CONNECT_BT"));
                         } else {
@@ -181,10 +195,24 @@
                         break;
                     case RETRY_BT_CONNECTION:
                         Log.i(LOG_TAG, "Retrying BT connection to %s", (String) args.arg2);
-                        String retryAddress = connectBtAudio((String) args.arg2, args.argi1,
-                            false /* switchingBtDevices*/);
+                        String retryAddress;
+                        boolean retrySuccessful;
+                        if (mFeatureFlags.resolveSwitchingBtDevicesComputation()) {
+                            Pair<String, Boolean> retryAddressInfo = computeAddressToConnectTo(
+                                    (String) args.arg2, false, null);
+                            // See if we need to transition route if the device is already
+                            // connected. If connected, another connection will not occur.
+                            retryAddressInfo = handleDeviceAlreadyConnected(retryAddressInfo);
+                            retryAddress = retryAddressInfo.first;
+                            retrySuccessful = connectBtAudio(retryAddress, args.argi1,
+                                    false /* switchingBtDevices*/);
+                        } else {
+                            retryAddress = connectBtAudioLegacy((String) args.arg2, args.argi1,
+                                    false /* switchingBtDevices*/);
+                            retrySuccessful = retryAddress != null;
+                        }
 
-                        if (retryAddress != null) {
+                        if (retrySuccessful) {
                             transitionTo(getConnectingStateForAddress(retryAddress,
                                     "AudioOff/RETRY_BT_CONNECTION"));
                         } else {
@@ -255,7 +283,7 @@
             String address = (String) args.arg2;
             boolean switchingBtDevices = !Objects.equals(mDeviceAddress, address);
 
-            if (switchingBtDevices == true) { // check if it is an hearing aid pair
+            if (switchingBtDevices) { // check if it is an hearing aid pair
                 BluetoothAdapter bluetoothAdapter = mDeviceManager.getBluetoothAdapter();
                 if (bluetoothAdapter != null) {
                     List<BluetoothDevice> activeHearingAids =
@@ -272,7 +300,9 @@
                             }
                         }
                     }
-
+                }
+                if (mFeatureFlags.resolveSwitchingBtDevicesComputation()) {
+                    switchingBtDevices &= (mDeviceAddress != null);
                 }
             }
             try {
@@ -288,14 +318,30 @@
                         }
                         break;
                     case CONNECT_BT:
+                        String actualAddress = null;
+                        if (mFeatureFlags.resolveSwitchingBtDevicesComputation()) {
+                            Pair<String, Boolean> addressInfo = computeAddressToConnectTo(address,
+                                    switchingBtDevices, mDeviceAddress);
+                            // See if we need to transition route if the device is already
+                            // connected. If connected, another connection will not occur.
+                            addressInfo = handleDeviceAlreadyConnected(addressInfo);
+                            actualAddress = addressInfo.first;
+                            switchingBtDevices = addressInfo.second;
+                        }
+
                         if (!switchingBtDevices) {
                             // Ignore repeated connection attempts to the same device
                             break;
                         }
 
-                        String actualAddress = connectBtAudio(address,
-                            true /* switchingBtDevices*/);
-                        if (actualAddress != null) {
+                        if (!mFeatureFlags.resolveSwitchingBtDevicesComputation()) {
+                            actualAddress = connectBtAudioLegacy(address,
+                                    true /* switchingBtDevices*/);
+                        }
+                        boolean connected = mFeatureFlags.resolveSwitchingBtDevicesComputation()
+                                ? connectBtAudio(actualAddress, 0, true /* switchingBtDevices*/)
+                                : actualAddress != null;
+                        if (connected) {
                             transitionTo(getConnectingStateForAddress(actualAddress,
                                     "AudioConnecting/CONNECT_BT"));
                         } else {
@@ -307,14 +353,32 @@
                         mDeviceManager.disconnectAudio();
                         break;
                     case RETRY_BT_CONNECTION:
+                        String retryAddress = null;
+                        if (mFeatureFlags.resolveSwitchingBtDevicesComputation()) {
+                            Pair<String, Boolean> retryAddressInfo = computeAddressToConnectTo(
+                                    address, switchingBtDevices, mDeviceAddress);
+                            // See if we need to transition route if the device is already
+                            // connected. If connected, another connection will not occur.
+                            retryAddressInfo = handleDeviceAlreadyConnected(retryAddressInfo);
+                            retryAddress = retryAddressInfo.first;
+                            switchingBtDevices = retryAddressInfo.second;
+                        }
+
                         if (!switchingBtDevices) {
                             Log.d(LOG_TAG, "Retry message came through while connecting.");
                             break;
                         }
 
-                        String retryAddress = connectBtAudio(address, args.argi1,
-                            true /* switchingBtDevices*/);
-                        if (retryAddress != null) {
+                        if (!mFeatureFlags.resolveSwitchingBtDevicesComputation()) {
+                            retryAddress = connectBtAudioLegacy(address, args.argi1,
+                                    true /* switchingBtDevices*/);
+                        }
+                        boolean retrySuccessful = mFeatureFlags
+                                .resolveSwitchingBtDevicesComputation()
+                                ? connectBtAudio(retryAddress, args.argi1,
+                                        true /* switchingBtDevices*/)
+                                : retryAddress != null;
+                        if (retrySuccessful) {
                             transitionTo(getConnectingStateForAddress(retryAddress,
                                     "AudioConnecting/RETRY_BT_CONNECTION"));
                         } else {
@@ -393,6 +457,10 @@
             SomeArgs args = (SomeArgs) msg.obj;
             String address = (String) args.arg2;
             boolean switchingBtDevices = !Objects.equals(mDeviceAddress, address);
+            if (mFeatureFlags.resolveSwitchingBtDevicesComputation()) {
+                switchingBtDevices &= (mDeviceAddress != null);
+            }
+
             try {
                 switch (msg.what) {
                     case NEW_DEVICE_CONNECTED:
@@ -405,6 +473,17 @@
                         }
                         break;
                     case CONNECT_BT:
+                        String actualAddress = null;
+                        if (mFeatureFlags.resolveSwitchingBtDevicesComputation()) {
+                            Pair<String, Boolean> addressInfo = computeAddressToConnectTo(address,
+                                    switchingBtDevices, mDeviceAddress);
+                            // See if we need to transition route if the device is already
+                            // connected. If connected, another connection will not occur.
+                            addressInfo = handleDeviceAlreadyConnected(addressInfo);
+                            actualAddress = addressInfo.first;
+                            switchingBtDevices = addressInfo.second;
+                        }
+
                         if (!switchingBtDevices) {
                             // Ignore connection to already connected device but still notify
                             // CallAudioRouteStateMachine since this might be a switch from other
@@ -413,9 +492,14 @@
                             break;
                         }
 
-                        String actualAddress = connectBtAudio(address,
-                            true /* switchingBtDevices*/);
-                        if (actualAddress != null) {
+                        if (!mFeatureFlags.resolveSwitchingBtDevicesComputation()) {
+                            actualAddress = connectBtAudioLegacy(address,
+                                    true /* switchingBtDevices*/);
+                        }
+                        boolean connected = mFeatureFlags.resolveSwitchingBtDevicesComputation()
+                                ? connectBtAudio(actualAddress, 0, true /* switchingBtDevices*/)
+                                : actualAddress != null;
+                        if (connected) {
                             if (mFeatureFlags.useActualAddressToEnterConnectingState()) {
                                 transitionTo(getConnectingStateForAddress(actualAddress,
                                         "AudioConnected/CONNECT_BT"));
@@ -432,14 +516,32 @@
                         mDeviceManager.disconnectAudio();
                         break;
                     case RETRY_BT_CONNECTION:
+                        String retryAddress = null;
+                        if (mFeatureFlags.resolveSwitchingBtDevicesComputation()) {
+                            Pair<String, Boolean> retryAddressInfo = computeAddressToConnectTo(
+                                    address, switchingBtDevices, mDeviceAddress);
+                            // See if we need to transition route if the device is already
+                            // connected. If connected, another connection will not occur.
+                            retryAddressInfo = handleDeviceAlreadyConnected(retryAddressInfo);
+                            retryAddress = retryAddressInfo.first;
+                            switchingBtDevices = retryAddressInfo.second;
+                        }
+
                         if (!switchingBtDevices) {
                             Log.d(LOG_TAG, "Retry message came through while connected.");
                             break;
                         }
 
-                        String retryAddress = connectBtAudio(address, args.argi1,
-                            true /* switchingBtDevices*/);
-                        if (retryAddress != null) {
+                        if (!mFeatureFlags.resolveSwitchingBtDevicesComputation()) {
+                            retryAddress = connectBtAudioLegacy(address, args.argi1,
+                                    true /* switchingBtDevices*/);
+                        }
+                        boolean retrySuccessful = mFeatureFlags
+                                .resolveSwitchingBtDevicesComputation()
+                                ? connectBtAudio(retryAddress, args.argi1,
+                                        true /* switchingBtDevices*/)
+                                : retryAddress != null;
+                        if (retrySuccessful) {
                             transitionTo(getConnectingStateForAddress(retryAddress,
                                     "AudioConnected/RETRY_BT_CONNECTION"));
                         } else {
@@ -740,8 +842,124 @@
         return false;
     }
 
-    private String connectBtAudio(String address, boolean switchingBtDevices) {
-        return connectBtAudio(address, 0, switchingBtDevices);
+    /**
+     * Determines the address that should be used for the connection attempt. In the case that the
+     * specified address to be used is null, Telecom will try to find an arbitrary address to
+     * connect instead.
+     *
+     * @param address The address that should be prioritized for the connection attempt
+     * @param switchingBtDevices Used when there is existing audio connection to other Bt device.
+     * @param stateAddress The address stored in the state that indicates the connecting/connected
+     *                     device.
+     * @return {@link Pair} containing the address to connect to and whether an existing BT audio
+     *                      connection for a different device exists.
+     */
+    private Pair<String, Boolean> computeAddressToConnectTo(
+            String address, boolean switchingBtDevices, String stateAddress) {
+        Collection<BluetoothDevice> deviceList = mDeviceManager.getConnectedDevices();
+        Optional<BluetoothDevice> matchingDevice = deviceList.stream()
+                .filter(d -> Objects.equals(d.getAddress(), address))
+                .findAny();
+
+        String actualAddress = matchingDevice.isPresent()
+                ? address : getActiveDeviceAddress();
+        if (actualAddress == null) {
+            Log.i(this, "No device specified and BT stack has no active device."
+                    + " Using arbitrary device - except watch");
+            if (deviceList.size() > 0) {
+                for (BluetoothDevice device : deviceList) {
+                    if (mFeatureFlags.ignoreAutoRouteToWatchDevice() && isWatch(device)) {
+                        Log.i(this, "Skipping a watch device: " + device);
+                        continue;
+                    }
+                    actualAddress = device.getAddress();
+                    break;
+                }
+            }
+
+            if (actualAddress == null) {
+                Log.i(this, "No devices available at all. Not connecting.");
+                return new Pair<>(null, false);
+            }
+            if (switchingBtDevices && actualAddress.equals(stateAddress)) {
+                switchingBtDevices = false;
+            }
+        }
+        if (!matchingDevice.isPresent()) {
+            Log.i(this, "No device with address %s available. Using %s instead.",
+                    address, actualAddress);
+        }
+        return new Pair<>(actualAddress, switchingBtDevices);
+    }
+
+    /**
+     * Handles route switching to the connected state for a device. This currently handles the case
+     * for hearing aids when the route manager reports AudioOff since Telecom doesn't treat HA as
+     * the active device outside of a call.
+     *
+     * @param addressInfo A {@link Pair} containing the BT address to connect to as well as if we're
+     *                    handling a switch of BT devices.
+     * @return {@link Pair} indicating the address to connect to as well as if we're handling a
+     *                      switch of BT devices. If the device is already connected, then the
+     *                      return value will be {null, false} to indicate that a connection attempt
+     *                      is not required.
+     */
+    private Pair<String, Boolean> handleDeviceAlreadyConnected(Pair<String, Boolean> addressInfo) {
+        String address = addressInfo.first;
+        BluetoothDevice alreadyConnectedDevice = getBluetoothAudioConnectedDevice();
+        if (alreadyConnectedDevice != null && alreadyConnectedDevice.getAddress().equals(
+                address)) {
+            Log.i(this, "trying to connect to already connected device -- skipping connection"
+                    + " and going into the actual connected state.");
+            transitionToActualState();
+            return new Pair<>(null, false);
+        }
+        return addressInfo;
+    }
+
+    /**
+     * Initiates a connection to the BT address specified.
+     * Note: This method is not synchronized on the Telecom lock, so don't try and call back into
+     * Telecom from within it.
+     * @param address The address that should be tried first. May be null.
+     * @param retryCount The number of times this connection attempt has been retried.
+     * @param switchingBtDevices Used when there is existing audio connection to other Bt device.
+     * @return {@code true} if the connection to the address was successful, otherwise {@code false}
+     *          if the connection fails.
+     *
+     * Note: This should only be used in par with the resolveSwitchingBtDevicesComputation flag.
+     */
+    private boolean connectBtAudio(String address, int retryCount, boolean switchingBtDevices) {
+        if (address == null) {
+            return false;
+        }
+
+        if (switchingBtDevices) {
+            /* When new Bluetooth connects audio, make sure previous one has disconnected audio. */
+            mDeviceManager.disconnectAudio();
+        }
+
+        if (!mDeviceManager.connectAudio(address, switchingBtDevices)) {
+            boolean shouldRetry = retryCount < MAX_CONNECTION_RETRIES;
+            Log.w(LOG_TAG, "Could not connect to %s. Will %s", address,
+                    shouldRetry ? "retry" : "not retry");
+            if (shouldRetry) {
+                SomeArgs args = SomeArgs.obtain();
+                args.arg1 = Log.createSubsession();
+                args.arg2 = address;
+                args.argi1 = retryCount + 1;
+                sendMessageDelayed(RETRY_BT_CONNECTION, args,
+                        mTimeoutsAdapter.getRetryBluetoothConnectAudioBackoffMillis(
+                                mContext.getContentResolver()));
+            }
+            return false;
+        }
+
+        return true;
+    }
+
+    private String connectBtAudioLegacy(String address, boolean switchingBtDevices) {
+        return connectBtAudioLegacy(address, 0, switchingBtDevices);
     }
 
     /**
@@ -754,7 +972,8 @@
      * @return The address of the device that's actually being connected to, or null if no
      * connection was successful.
      */
-    private String connectBtAudio(String address, int retryCount, boolean switchingBtDevices) {
+    private String connectBtAudioLegacy(String address, int retryCount,
+            boolean switchingBtDevices) {
         Collection<BluetoothDevice> deviceList = mDeviceManager.getConnectedDevices();
         Optional<BluetoothDevice> matchingDevice = deviceList.stream()
                 .filter(d -> Objects.equals(d.getAddress(), address))
diff --git a/tests/src/com/android/server/telecom/tests/BluetoothRouteManagerTest.java b/tests/src/com/android/server/telecom/tests/BluetoothRouteManagerTest.java
index 07dd350..1c885c1 100644
--- a/tests/src/com/android/server/telecom/tests/BluetoothRouteManagerTest.java
+++ b/tests/src/com/android/server/telecom/tests/BluetoothRouteManagerTest.java
@@ -21,6 +21,7 @@
 import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.ArgumentMatchers.nullable;
+import static org.mockito.Mockito.never;
 import static org.mockito.Mockito.reset;
 import static org.mockito.Mockito.times;
 import static org.mockito.Mockito.verify;
@@ -249,7 +250,18 @@
 
     @SmallTest
     @Test
-    public void testConnectBtWithoutAddress() {
+    public void testConnectBtWithoutAddress_SwitchingBtDeviceFlag() {
+        when(mFeatureFlags.resolveSwitchingBtDevicesComputation()).thenReturn(true);
+        verifyConnectBtWithoutAddress();
+    }
+
+    @SmallTest
+    @Test
+    public void testConnectBtWithoutAddress_SwitchingBtDeviceFlagDisabled() {
+        verifyConnectBtWithoutAddress();
+    }
+
+    private void verifyConnectBtWithoutAddress() {
         when(mFeatureFlags.useActualAddressToEnterConnectingState()).thenReturn(true);
         BluetoothRouteManager sm = setupStateMachine(
                 BluetoothRouteManager.AUDIO_CONNECTED_STATE_NAME_PREFIX, DEVICE1);
@@ -266,7 +278,15 @@
         waitForHandlerAction(sm.getHandler(), TEST_TIMEOUT);
         waitForHandlerAction(sm.getHandler(), TEST_TIMEOUT);
         waitForHandlerAction(sm.getHandler(), TEST_TIMEOUT);
-        verifyConnectionAttempt(DEVICE1, 1);
+        // We should not expect explicit connection attempt (BluetoothDeviceManager#connectAudio)
+        // as the device is already "connected" as per how the state machine was initialized.
+        if (mFeatureFlags.resolveSwitchingBtDevicesComputation()) {
+            verify(mDeviceManager, never()).disconnectAudio();
+        } else {
+            // Legacy behavior
+            verifyConnectionAttempt(DEVICE1, 1);
+            verify(mDeviceManager, times(1)).disconnectAudio();
+        }
         assertEquals(BluetoothRouteManager.AUDIO_CONNECTED_STATE_NAME_PREFIX
                         + ":" + DEVICE1.getAddress(),
                 sm.getCurrentState().getName());
diff --git a/tests/src/com/android/server/telecom/tests/CallAudioRouteStateMachineTest.java b/tests/src/com/android/server/telecom/tests/CallAudioRouteStateMachineTest.java
index d2da505..e97de2e 100644
--- a/tests/src/com/android/server/telecom/tests/CallAudioRouteStateMachineTest.java
+++ b/tests/src/com/android/server/telecom/tests/CallAudioRouteStateMachineTest.java
@@ -20,6 +20,7 @@
 import static org.junit.Assert.assertNotEquals;
 import static org.junit.Assert.assertNotNull;
 import static org.junit.Assert.assertTrue;
+import static org.mockito.ArgumentMatchers.anyInt;
 import static org.mockito.ArgumentMatchers.anyString;
 import static org.mockito.ArgumentMatchers.eq;
 import static org.mockito.ArgumentMatchers.nullable;
@@ -1230,8 +1231,9 @@
 
     @SmallTest
     @Test
-    public void testQuiescentBluetoothRouteResetMute() {
+    public void testQuiescentBluetoothRouteResetMute() throws Exception {
         when(mFeatureFlags.resetMuteWhenEnteringQuiescentBtRoute()).thenReturn(true);
+        when(mFeatureFlags.transitRouteBeforeAudioDisconnectBt()).thenReturn(true);
         CallAudioRouteStateMachine stateMachine = new CallAudioRouteStateMachine(
                 mContext,
                 mockCallsManager,
@@ -1264,6 +1266,7 @@
                 CallAudioState.ROUTE_BLUETOOTH, CallAudioState.ROUTE_SPEAKER
                 | CallAudioState.ROUTE_EARPIECE | CallAudioState.ROUTE_BLUETOOTH);
         assertEquals(expectedState, stateMachine.getCurrentCallAudioState());
+        when(mockAudioManager.isMicrophoneMute()).thenReturn(true);
 
         stateMachine.sendMessageWithSessionInfo(CallAudioRouteStateMachine.SWITCH_FOCUS,
                 CallAudioRouteStateMachine.NO_FOCUS);
@@ -1272,9 +1275,8 @@
         expectedState = new CallAudioState(false,
                 CallAudioState.ROUTE_BLUETOOTH, CallAudioState.ROUTE_SPEAKER
                 | CallAudioState.ROUTE_EARPIECE | CallAudioState.ROUTE_BLUETOOTH);
-        // TODO: Re-enable this part of the test; this is now failing because we have to
-        // revert ag/23783145.
-        // assertEquals(expectedState, stateMachine.getCurrentCallAudioState());
+        assertEquals(expectedState, stateMachine.getCurrentCallAudioState());
+        verify(mockAudioService).setMicrophoneMute(eq(false), anyString(), anyInt(), eq(null));
     }
 
     @SmallTest