Add Voice Helper support for Alexa

app/src/main/AndroidManifest.xml

@@ -40,6 +40,11 @@
     <uses-permission android:name="me.hackerchick.catima.READ_CARDS"/>
     <uses-permission android:name="me.hackerchick.catima.debug.READ_CARDS"/>
 
+    <!-- GB Voice Helper -->
+    <uses-permission android:name="nodomain.freeyourgadget.voice.VOICE_HELPER"/>
+    <uses-permission android:name="nodomain.freeyourgadget.voice.debug.VOICE_HELPER"/>
+    <uses-permission android:name="nodomain.freeyourgadget.voice.nightly.VOICE_HELPER"/>
+
     <uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"
         android:maxSdkVersion="32" />
     <uses-permission android:name="android.permission.READ_CALENDAR" />
@@ -138,6 +143,10 @@
             android:name=".activities.discovery.DiscoveryPairingPreferenceActivity"
             android:label="@string/activity_prefs_discovery_pairing"
             android:parentActivityName=".activities.SettingsActivity" />
+        <activity
+            android:name=".activities.voice.VoiceHelperSettingsActivity"
+            android:label="@string/activity_prefs_voice_helper"
+            android:parentActivityName=".activities.SettingsActivity" />
         <activity
             android:name=".devices.miband.MiBandPreferencesActivity"
             android:label="@string/preferences_miband_1_2_settings"

app/src/main/aidl/nodomain/freeyourgadget/voice/IOpusCodecService.aidl

@@ -0,0 +1,12 @@
+package nodomain.freeyourgadget.voice;
+
+interface IOpusCodecService {
+    int version();
+
+    String create();
+    void destroy(String codec);
+
+    int decoderInit(String codec, int sampleRate, int channels);
+    int decode(String codec, in byte[] data, int len, out byte[] pcm, int frameSize, int decodeFec);
+    void decoderDestroy(String codec);
+}

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/SettingsActivity.java

@@ -64,6 +64,7 @@ import nodomain.freeyourgadget.gadgetbridge.GBApplication;
 import nodomain.freeyourgadget.gadgetbridge.R;
 import nodomain.freeyourgadget.gadgetbridge.activities.charts.ChartsPreferencesActivity;
 import nodomain.freeyourgadget.gadgetbridge.activities.discovery.DiscoveryPairingPreferenceActivity;
+import nodomain.freeyourgadget.gadgetbridge.activities.voice.VoiceHelperSettingsActivity;
 import nodomain.freeyourgadget.gadgetbridge.database.PeriodicExporter;
 import nodomain.freeyourgadget.gadgetbridge.devices.hplus.HPlusSettingsActivity;
 import nodomain.freeyourgadget.gadgetbridge.devices.miband.MiBandPreferencesActivity;
@@ -440,6 +441,15 @@ public class SettingsActivity extends AbstractSettingsActivityV2 {
                 });
             }
 
+            pref = findPreference("pref_voice_helper");
+            if (pref != null) {
+                pref.setOnPreferenceClickListener(preference -> {
+                    Intent enableIntent = new Intent(requireContext(), VoiceHelperSettingsActivity.class);
+                    startActivity(enableIntent);
+                    return true;
+                });
+            }
+
             //fitness app (OpenTracks) package name selection for OpenTracks observer
             pref = findPreference("pref_key_opentracks_packagename");
             if (pref != null) {

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/voice/VoiceHelperSettingsActivity.java

@@ -0,0 +1,70 @@
+/*  Copyright (C) 2023 José Rebelo
+
+    This file is part of Gadgetbridge.
+
+    Gadgetbridge is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published
+    by the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Gadgetbridge is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+package nodomain.freeyourgadget.gadgetbridge.activities.voice;
+
+import android.content.pm.PackageManager;
+
+import androidx.annotation.NonNull;
+import androidx.core.app.ActivityCompat;
+import androidx.fragment.app.Fragment;
+import androidx.fragment.app.FragmentManager;
+import androidx.preference.PreferenceFragmentCompat;
+
+import nodomain.freeyourgadget.gadgetbridge.activities.AbstractSettingsActivityV2;
+
+public class VoiceHelperSettingsActivity extends AbstractSettingsActivityV2 implements
+        PreferenceFragmentCompat.OnPreferenceStartScreenCallback,
+        ActivityCompat.OnRequestPermissionsResultCallback {
+    public static final int PERMISSION_REQUEST_CODE = 0;
+
+    @Override
+    protected String fragmentTag() {
+        return VoiceHelperSettingsFragment.FRAGMENT_TAG;
+    }
+
+    @Override
+    protected PreferenceFragmentCompat newFragment() {
+        return new VoiceHelperSettingsFragment();
+    }
+
+    @Override
+    public void onRequestPermissionsResult(final int requestCode,
+                                           @NonNull final String[] permissions,
+                                           @NonNull final int[] grantResults) {
+        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
+
+        if (requestCode != PERMISSION_REQUEST_CODE) {
+            return;
+        }
+
+        if (grantResults.length == 0) {
+            return;
+        }
+
+        if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
+            final FragmentManager fragmentManager = getSupportFragmentManager();
+            final Fragment fragment = fragmentManager.findFragmentByTag(VoiceHelperSettingsFragment.FRAGMENT_TAG);
+            if (fragment == null) {
+                return;
+            }
+
+            if (fragment instanceof VoiceHelperSettingsFragment) {
+                ((VoiceHelperSettingsFragment) fragment).reloadPreferences(null);
+            }
+        }
+    }
+}

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/voice/VoiceHelperSettingsConst.java

@@ -0,0 +1,24 @@
+/*  Copyright (C) 2022 José Rebelo
+
+    This file is part of Gadgetbridge.
+
+    Gadgetbridge is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published
+    by the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Gadgetbridge is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+package nodomain.freeyourgadget.gadgetbridge.activities.voice;
+
+public final class VoiceHelperSettingsConst {
+    public static final String VOICE_HELPER_PACKAGE = "voice_helper_package";
+    public static final String VOICE_HELPER_NOT_INSTALLED = "voice_helper_not_installed";
+    public static final String VOICE_HELPER_INSTALL = "voice_helper_install";
+    public static final String VOICE_HELPER_PERMISSIONS = "voice_helper_permissions";
+}

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/activities/voice/VoiceHelperSettingsFragment.java

@@ -0,0 +1,130 @@
+/*  Copyright (C) 2023 José Rebelo
+
+    This file is part of Gadgetbridge.
+
+    Gadgetbridge is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published
+    by the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Gadgetbridge is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+package nodomain.freeyourgadget.gadgetbridge.activities.voice;
+
+import static nodomain.freeyourgadget.gadgetbridge.activities.voice.VoiceHelperSettingsConst.VOICE_HELPER_INSTALL;
+import static nodomain.freeyourgadget.gadgetbridge.activities.voice.VoiceHelperSettingsConst.VOICE_HELPER_NOT_INSTALLED;
+import static nodomain.freeyourgadget.gadgetbridge.activities.voice.VoiceHelperSettingsConst.VOICE_HELPER_PACKAGE;
+import static nodomain.freeyourgadget.gadgetbridge.activities.voice.VoiceHelperSettingsConst.VOICE_HELPER_PERMISSIONS;
+
+import android.content.ActivityNotFoundException;
+import android.content.Intent;
+import android.content.pm.PackageManager;
+import android.net.Uri;
+import android.os.Bundle;
+import android.widget.Toast;
+
+import androidx.core.app.ActivityCompat;
+import androidx.core.content.ContextCompat;
+import androidx.preference.ListPreference;
+import androidx.preference.Preference;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.List;
+
+import nodomain.freeyourgadget.gadgetbridge.R;
+import nodomain.freeyourgadget.gadgetbridge.activities.AbstractPreferenceFragment;
+import nodomain.freeyourgadget.gadgetbridge.util.GB;
+import nodomain.freeyourgadget.gadgetbridge.util.StringUtils;
+import nodomain.freeyourgadget.gadgetbridge.voice.VoiceHelper;
+
+public class VoiceHelperSettingsFragment extends AbstractPreferenceFragment {
+    private static final Logger LOG = LoggerFactory.getLogger(VoiceHelperSettingsFragment.class);
+
+    static final String FRAGMENT_TAG = "VOICE_HELPER_SETTINGS_FRAGMENT";
+
+    @Override
+    public void onCreatePreferences(final Bundle savedInstanceState, final String rootKey) {
+        setPreferencesFromResource(R.xml.voice_helper, rootKey);
+
+        reloadPreferences(null);
+    }
+
+    protected void reloadPreferences(final String voiceHelperPackageName) {
+        final List<CharSequence> installedPackages = VoiceHelper.findInstalledPackages(requireContext());
+        final boolean voiceHelperInstalled = !installedPackages.isEmpty();
+
+        final ListPreference packagePreference = findPreference(VOICE_HELPER_PACKAGE);
+
+        if (packagePreference != null) {
+            packagePreference.setEntries(installedPackages.toArray(new CharSequence[0]));
+            packagePreference.setEntryValues(installedPackages.toArray(new CharSequence[0]));
+            packagePreference.setVisible(!installedPackages.isEmpty());
+            packagePreference.setOnPreferenceChangeListener((preference, newValue) -> {
+                LOG.info("Voice Helper package preference changed to {}", newValue);
+                reloadPreferences((String) newValue);
+                return true;
+            });
+
+            if (voiceHelperInstalled) {
+                // Ensure the currently selected value is actually an installed package
+                if (StringUtils.isNullOrEmpty(packagePreference.getValue()) || !installedPackages.contains(packagePreference.getValue())) {
+                    packagePreference.setValue(installedPackages.get(0).toString());
+                }
+            }
+        }
+
+        final String finalPackageName;
+
+        if (voiceHelperPackageName != null) {
+            finalPackageName = voiceHelperPackageName;
+        } else if (packagePreference != null) {
+            finalPackageName = packagePreference.getValue();
+        } else {
+            LOG.warn("This should never happen - package not found");
+            finalPackageName = "this.should.never.happen";
+        }
+
+        final Preference notInstalledPreference = findPreference(VOICE_HELPER_NOT_INSTALLED);
+        if (notInstalledPreference != null) {
+            notInstalledPreference.setVisible(!voiceHelperInstalled);
+        }
+
+        final Preference installPreference = findPreference(VOICE_HELPER_INSTALL);
+        if (installPreference != null) {
+            installPreference.setVisible(!voiceHelperInstalled);
+            installPreference.setOnPreferenceClickListener(preference -> {
+                installVoiceHelper();
+                return true;
+            });
+        }
+
+        final boolean permissionGranted = ContextCompat.checkSelfPermission(requireContext(), VoiceHelper.getPermission(finalPackageName)) == PackageManager.PERMISSION_GRANTED;
+        final Preference permissionsPreference = findPreference(VOICE_HELPER_PERMISSIONS);
+        if (permissionsPreference != null) {
+            permissionsPreference.setVisible(voiceHelperInstalled && !permissionGranted);
+            permissionsPreference.setOnPreferenceClickListener(preference -> {
+                ActivityCompat.requestPermissions(
+                        requireActivity(),
+                        new String[]{VoiceHelper.getPermission(finalPackageName)},
+                        VoiceHelperSettingsActivity.PERMISSION_REQUEST_CODE
+                );
+                return true;
+            });
+        }
+    }
+
+    private void installVoiceHelper() {
+        try {
+            startActivity(new Intent(Intent.ACTION_VIEW, Uri.parse("market://details?id=nodomain.freeyourgadget.voice")));
+        } catch (final ActivityNotFoundException e) {
+            GB.toast(requireContext(), requireContext().getString(R.string.voice_helper_install_fail), Toast.LENGTH_LONG, GB.WARN);
+        }
+    }
+}

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/huami/zeppos/services/ZeppOsAlexaService.java

@@ -17,9 +17,12 @@
 package nodomain.freeyourgadget.gadgetbridge.service.devices.huami.zeppos.services;
 
 import static nodomain.freeyourgadget.gadgetbridge.activities.devicesettings.DeviceSettingsPreferenceConst.PREF_VOICE_SERVICE_LANGUAGE;
-import static nodomain.freeyourgadget.gadgetbridge.activities.devicesettings.DeviceSettingsPreferenceConst.PREF_WATCHFACE;
 
+import android.media.AudioFormat;
+import android.media.AudioManager;
+import android.media.AudioTrack;
 import android.os.Handler;
+import android.os.RemoteException;
 import android.widget.Toast;
 
 import org.slf4j.Logger;
@@ -44,8 +47,10 @@ import nodomain.freeyourgadget.gadgetbridge.service.devices.huami.zeppos.Abstrac
 import nodomain.freeyourgadget.gadgetbridge.util.GB;
 import nodomain.freeyourgadget.gadgetbridge.util.Prefs;
 import nodomain.freeyourgadget.gadgetbridge.util.StringUtils;
+import nodomain.freeyourgadget.gadgetbridge.voice.OpusCodec;
+import nodomain.freeyourgadget.gadgetbridge.voice.VoiceHelper;
 
-public class ZeppOsAlexaService extends AbstractZeppOsService {
+public class ZeppOsAlexaService extends AbstractZeppOsService implements VoiceHelper.Callback {
     private static final Logger LOG = LoggerFactory.getLogger(ZeppOsAlexaService.class);
 
     private static final short ENDPOINT = 0x0011;
@@ -71,14 +76,35 @@ public class ZeppOsAlexaService extends AbstractZeppOsService {
     private static final byte COMPLEX_REPLY_REMINDER = 0x02;
     private static final byte COMPLEX_REPLY_RICH_TEXT = 0x06;
 
+    private static final byte ERROR_TIMEOUT = 0x01;
     private static final byte ERROR_NO_INTERNET = 0x03;
+    private static final byte ERROR_NOT_UNDERSTAND = 0x05;
     private static final byte ERROR_UNAUTHORIZED = 0x06;
 
+    private static final int CHANNELS = 1;
+    private static final int MAX_FRAME_SIZE = 6 * 960;
+
     public static final String PREF_VERSION = "zepp_os_alexa_version";
 
     private final Handler handler = new Handler();
+    private boolean pendingStartAck;
 
-    final ByteArrayOutputStream voiceBuffer = new ByteArrayOutputStream();
+    private VoiceHelper voiceHelper;
+    private OpusCodec opusCodec;
+
+    private final AudioTrack audio = new AudioTrack(AudioManager.STREAM_MUSIC,
+            16000,
+            AudioFormat.CHANNEL_OUT_MONO,
+            AudioFormat.ENCODING_PCM_16BIT,
+            AudioTrack.getMinBufferSize(
+                    16000,
+                    AudioFormat.CHANNEL_OUT_MONO,
+                    AudioFormat.ENCODING_PCM_16BIT
+            ),
+            AudioTrack.MODE_STREAM
+    );
+
+    final ByteBuffer voiceBuffer = ByteBuffer.allocate(4096);
 
     public ZeppOsAlexaService(final Huami2021Support support) {
         super(support);
@@ -349,22 +375,71 @@ public class ZeppOsAlexaService extends AbstractZeppOsService {
         final byte var4 = payload[4];
         final String params = StringUtils.untilNullTerminator(payload, 5);
 
+        // These might be relevant for the remaining connection, but not sure what they mean
+        // On the GTR 4: var1=4, var2=14, var3=2, var4=2, params={"translate":[],"countdown":1440,"thirdMusicApp":0,"ttsTextLimit":0,"suggestions":0,"news":0,"maxAlarmCount":3,"supportDeleteAlert":1,"alexaLanguage":"en-US","audioSize":4096}
         LOG.info("Alexa starting: var1={}, var2={}, var3={}, var4={}, params={}", var1, var2, var3, var4, params);
 
-        // Send the start ack with a slight delay, to give enough time for the connection to switch to fast mode
-        // I can't seem to get the callback for onConnectionUpdated working, and if we reply too soon the watch
-        // will just stay stuck "Connecting...". It seems like it takes ~350ms to switch to fast connection.
-        handler.postDelayed(this::sendStartAck, 700);
+        voiceBuffer.clear();
+
+        if (voiceHelper == null) {
+            // Lazy initialization of the voice helper
+            voiceHelper = new VoiceHelper(getContext(), this);
+        }
+
+        if (!voiceHelper.isConnected()) {
+            pendingStartAck = true;
+            voiceHelper.connect();
+        } else {
+            // Send the start ack with a slight delay, to give enough time for the connection to switch to fast mode
+            // I can't seem to get the callback for onConnectionUpdated working, and if we reply too soon the watch
+            // will just stay stuck "Connecting...". It seems like it takes ~350ms to switch to fast connection.
+            handler.postDelayed(this::sendStartAck, 700);
+        }
+        audio.play();
     }
 
     private void handleEnd(final byte[] payload) {
-        voiceBuffer.reset();
+        voiceBuffer.clear();
+        audio.stop();
         // TODO do something else?
     }
 
     private void handleVoiceData(final byte[] payload) {
         LOG.info("Got {} bytes of voice data", payload.length);
-        // TODO
+        this.voiceBuffer.put(payload, 5, payload.length - 5);
+
+        int frameSize = this.voiceBuffer.get(0) & 0xff;
+
+        while (voiceBuffer.position() > frameSize) {
+            this.voiceBuffer.flip();
+            frameSize = this.voiceBuffer.get() & 0xff;
+            final byte[] frame = new byte[frameSize];
+            this.voiceBuffer.get(frame);
+
+            LOG.debug("Voice Data Frame: {}", GB.hexdump(frame));
+
+            if (opusCodec != null) {
+                try {
+                    final byte[] pcm = new byte[MAX_FRAME_SIZE * CHANNELS * 2];
+                    int ret = opusCodec.decode(frame, frame.length, pcm, MAX_FRAME_SIZE, 0);
+                    LOG.debug("Opus decode: {}", ret);
+                    audio.write(pcm, 0, ret * 2 /* 16 bit */);
+                } catch (final Exception e) {
+                    LOG.error("Failed to process opus frame", e);
+                }
+            }
+
+            final ByteBuffer remaining = this.voiceBuffer.slice();
+            this.voiceBuffer.clear();
+
+            if (remaining.limit() > 0) {
+                LOG.debug("Got {} bytes remaining in the voice buffer", remaining.limit());
+                this.voiceBuffer.put(remaining);
+            }
+
+            frameSize = this.voiceBuffer.get(0) & 0xff;
+            LOG.debug("new frameSize: {}", frameSize);
+        }
     }
 
     private void handleLanguagesResponse(final byte[] payload) {
@@ -392,4 +467,30 @@ public class ZeppOsAlexaService extends AbstractZeppOsService {
     public static boolean isSupported(final Prefs devicePrefs) {
         return devicePrefs.getInt(PREF_VERSION, 0) == 3;
     }
+
+    @Override
+    public void onVoiceHelperConnection(final boolean connected) {
+        if (connected) {
+            try {
+                opusCodec = voiceHelper.createOpusCodec();
+                int ret = opusCodec.decoderInit(16000, 1);
+                if (ret != 0) {
+                    LOG.error("Failed to initialize opus codec, err = {}", ret);
+                    if (pendingStartAck) {
+                        pendingStartAck = false;
+                        handler.postDelayed(() -> sendError(ERROR_TIMEOUT, "Failed to initialize codec"), 700);
+                    }
+                }
+            } catch (final Exception e) {
+                LOG.error("Failed to create opus codec", e);
+                handler.postDelayed(this::sendStartAck, 700);
+            }
+            if (pendingStartAck) {
+                pendingStartAck = false;
+                handler.postDelayed(this::sendStartAck, 700);
+            }
+        } else {
+            opusCodec = null;
+        }
+    }
 }

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/service/devices/qhybrid/adapter/fossil_hr/FossilHRWatchAdapter.java

@@ -42,6 +42,9 @@ import android.graphics.Color;
 import android.graphics.Paint;
 import android.graphics.drawable.Drawable;
 import android.location.Location;
+import android.media.AudioFormat;
+import android.media.AudioManager;
+import android.media.AudioTrack;
 import android.net.Uri;
 import android.os.Bundle;
 import android.os.IBinder;
@@ -175,8 +178,10 @@ import nodomain.freeyourgadget.gadgetbridge.util.Prefs;
 import nodomain.freeyourgadget.gadgetbridge.util.StringUtils;
 import nodomain.freeyourgadget.gadgetbridge.util.UriHelper;
 import nodomain.freeyourgadget.gadgetbridge.util.Version;
+import nodomain.freeyourgadget.gadgetbridge.voice.OpusCodec;
+import nodomain.freeyourgadget.gadgetbridge.voice.VoiceHelper;
 
-public class FossilHRWatchAdapter extends FossilWatchAdapter {
+public class FossilHRWatchAdapter extends FossilWatchAdapter implements VoiceHelper.Callback {
     public static final int MESSAGE_WHAT_VOICE_DATA_RECEIVED = 0;
 
     private byte[] phoneRandomNumber;
@@ -205,24 +210,23 @@ public class FossilHRWatchAdapter extends FossilWatchAdapter {
 
     List<ApplicationInformation> installedApplications = new ArrayList();
 
-    Messenger voiceMessenger = null;
+    private VoiceHelper voiceHelper;
+    private OpusCodec opusCodec;
+
+    private final AudioTrack audio = new AudioTrack(AudioManager.STREAM_MUSIC,
+            48000,
+            AudioFormat.CHANNEL_OUT_MONO,
+            AudioFormat.ENCODING_PCM_16BIT,
+            AudioTrack.getMinBufferSize(
+                    48000,
+                    AudioFormat.CHANNEL_OUT_MONO,
+                    AudioFormat.ENCODING_PCM_16BIT
+            ),
+            AudioTrack.MODE_STREAM
+    );
 
     private Version cleanFirmwareVersion = null;
 
-    ServiceConnection voiceServiceConnection = new ServiceConnection() {
-        @Override
-        public void onServiceConnected(ComponentName name, IBinder service) {
-            GB.log("attached to voice service", GB.INFO, null);
-            voiceMessenger = new Messenger(service);
-        }
-
-        @Override
-        public void onServiceDisconnected(ComponentName name) {
-            GB.log("detached from voice service", GB.INFO, null);
-            voiceMessenger = null;
-        }
-    };
-
     enum CONNECTION_MODE {
         NOT_INITIALIZED,
         AUTHENTICATED,
@@ -362,69 +366,20 @@ public class FossilHRWatchAdapter extends FossilWatchAdapter {
     }
 
     private void attachToVoiceService(){
-        String servicePackage = getDeviceSpecificPreferences().getString("voice_service_package", "");
-        String servicePath = getDeviceSpecificPreferences().getString("voice_service_class", "");
-
-        if(servicePackage.isEmpty()){
-            GB.toast("voice service package is not configured", Toast.LENGTH_LONG, GB.ERROR);
-            respondToAlexa("voice service package not configured on phone", true);
-            return;
-        }
-
-        if(servicePath.isEmpty()){
-            respondToAlexa("voice service class not configured on phone", true);
-            GB.toast("voice service class is not configured", Toast.LENGTH_LONG, GB.ERROR);
-            return;
-        }
-
-        ComponentName component = new ComponentName(servicePackage, servicePath);
-
-        // extract to somewhere
-        Intent voiceIntent = new Intent("nodomain.freeyourgadget.gadgetbridge.VOICE_COMMAND");
-        voiceIntent.setComponent(component);
-
-        int flags = 0;
-
-        flags |= Service.BIND_AUTO_CREATE;
-
-        GB.log("binding to voice service...", GB.INFO, null);
-
-        getContext().bindService(
-                voiceIntent,
-                voiceServiceConnection,
-                flags
-        );
-
-        PackageManager pm = getContext().getPackageManager();
-        boolean serviceEnabled = true;
-        try {
-            int enabledState = pm.getComponentEnabledSetting(component);
-
-            if(enabledState != PackageManager.COMPONENT_ENABLED_STATE_ENABLED && enabledState != PackageManager.COMPONENT_ENABLED_STATE_DEFAULT){
-                respondToAlexa("voice service is disabled on phone", true);
-                GB.toast("voice service is disabled", Toast.LENGTH_LONG, GB.ERROR);
-                serviceEnabled = false;
-            }
-        }catch (IllegalArgumentException e){
-            serviceEnabled = false;
-            respondToAlexa("voice service not found on phone", true);
-            GB.toast("voice service not found", Toast.LENGTH_LONG, GB.ERROR);
-        }
-
-        if(!serviceEnabled){
-            detachFromVoiceService();
-        }
+        voiceHelper.connect();
     }
 
     private void detachFromVoiceService(){
-        getContext().unbindService(voiceServiceConnection);
+        // TODO
     }
 
     private void handleVoiceStatus(byte status){
         if(status == 0x00){
             attachToVoiceService();
+            audio.play();
         }else if(status == 0x01){
             detachFromVoiceService();
+            audio.stop();
         }
     }
 
@@ -434,25 +389,43 @@ public class FossilHRWatchAdapter extends FossilWatchAdapter {
     }
 
     private void handleVoiceDataCharacteristic(BluetoothGattCharacteristic characteristic){
-        if(voiceMessenger == null){
+        if (opusCodec == null){
             return;
         }
-        Message message = Message.obtain(
-                null,
-                MESSAGE_WHAT_VOICE_DATA_RECEIVED
-        );
-        Bundle dataBundle = new Bundle(1);
-        dataBundle.putByteArray("VOICE_DATA", characteristic.getValue());
-        dataBundle.putString("VOICE_ENCODING", "OPUS");
-        message.setData(dataBundle);
-        try {
-            voiceMessenger.send(message);
-        } catch (RemoteException e) {
-            GB.log("error sending voice data to service", GB.ERROR, e);
-            GB.toast("error sending voice data to service", Toast.LENGTH_LONG, GB.ERROR);
-            voiceMessenger = null;
-            detachFromVoiceService();
-            respondToAlexa("error sending voice data to service", true);
+        final int CHANNELS = 1;
+        final int MAX_FRAME_SIZE = 6 * 960;
+
+        final ByteBuffer buf = ByteBuffer.wrap(characteristic.getValue());
+
+        final byte[] frame = new byte[960];
+
+        while (buf.position() < buf.limit()) {
+            buf.get(frame);
+            try {
+                final byte[] pcm = new byte[MAX_FRAME_SIZE * CHANNELS * 2];
+                int ret = opusCodec.decode(frame, frame.length, pcm, MAX_FRAME_SIZE, 0);
+                LOG.debug("Opus decode: {}", ret);
+                audio.write(pcm, 0, ret * 2 /* 16 bit */);
+            } catch (final Exception e) {
+                LOG.error("Failed to process opus frame", e);
+            }
+        }
+    }
+
+    @Override
+    public void onVoiceHelperConnection(boolean connected) {
+        if (connected) {
+            try {
+                opusCodec = voiceHelper.createOpusCodec();
+                int ret = opusCodec.decoderInit(48000, 1);
+                if (ret != 0) {
+                    LOG.error("Failed to initialize opus codec, err = {}", ret);
+                }
+            } catch (final Exception e) {
+                LOG.error("Failed to create opus codec", e);
+            }
+        } else {
+            opusCodec = null;
         }
     }
 

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/voice/OpusCodec.java

@@ -0,0 +1,47 @@
+/*  Copyright (C) 2023 José Rebelo
+
+    This file is part of Gadgetbridge.
+
+    Gadgetbridge is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published
+    by the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Gadgetbridge is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+package nodomain.freeyourgadget.gadgetbridge.voice;
+
+import android.os.RemoteException;
+
+import nodomain.freeyourgadget.voice.IOpusCodecService;
+
+public class OpusCodec {
+    private final IOpusCodecService mOpusCodecService;
+    private final String codec;
+
+    public OpusCodec(final IOpusCodecService opusCodecService) throws RemoteException {
+        this.mOpusCodecService = opusCodecService;
+        this.codec = opusCodecService.create();
+    }
+
+    public void destroy() throws RemoteException {
+        this.mOpusCodecService.destroy(codec);
+    }
+
+    public int decoderInit(final int sampleRate, final int channels) throws RemoteException {
+        return mOpusCodecService.decoderInit(codec, sampleRate, channels);
+    }
+
+    public int decode(final byte[] data, final int len, final byte[] pcm, final int frameSize, final int decodeFec) throws RemoteException {
+        return mOpusCodecService.decode(codec, data, len, pcm, frameSize, decodeFec);
+    }
+
+    public void decoderDestroy() throws RemoteException {
+        mOpusCodecService.decoderDestroy(codec);
+    }
+}

app/src/main/java/nodomain/freeyourgadget/gadgetbridge/voice/VoiceHelper.java

@@ -0,0 +1,135 @@
+/*  Copyright (C) 2023 José Rebelo
+
+    This file is part of Gadgetbridge.
+
+    Gadgetbridge is free software: you can redistribute it and/or modify
+    it under the terms of the GNU Affero General Public License as published
+    by the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    Gadgetbridge is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU Affero General Public License for more details.
+
+    You should have received a copy of the GNU Affero General Public License
+    along with this program.  If not, see <http://www.gnu.org/licenses/>. */
+package nodomain.freeyourgadget.gadgetbridge.voice;
+
+import static nodomain.freeyourgadget.gadgetbridge.activities.voice.VoiceHelperSettingsConst.VOICE_HELPER_PACKAGE;
+
+import android.content.ComponentName;
+import android.content.Context;
+import android.content.Intent;
+import android.content.ServiceConnection;
+import android.content.pm.PackageManager;
+import android.os.IBinder;
+import android.os.RemoteException;
+
+import org.slf4j.Logger;
+import org.slf4j.LoggerFactory;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Locale;
+
+import nodomain.freeyourgadget.gadgetbridge.GBApplication;
+import nodomain.freeyourgadget.gadgetbridge.util.Prefs;
+import nodomain.freeyourgadget.voice.IOpusCodecService;
+
+public class VoiceHelper {
+    private static final Logger LOG = LoggerFactory.getLogger(VoiceHelper.class);
+
+    public static final List<String> KNOWN_PACKAGES = new ArrayList<String>() {{
+        add("nodomain.freeyourgadget.voice");
+        add("nodomain.freeyourgadget.voice.debug");
+        add("nodomain.freeyourgadget.voice.nightly");
+    }};
+
+    private final Context mContext;
+    private final Callback mCallback;
+    private final String packageName;
+
+    private ServiceConnection mConnection;
+    private IOpusCodecService mOpusCodecService;
+
+    public VoiceHelper(final Context context, final Callback callback) {
+        this.mContext = context;
+        this.mCallback = callback;
+
+        final List<CharSequence> installedPackages = findInstalledPackages(mContext);
+        if (installedPackages.isEmpty()) {
+            LOG.warn("Voice Helper is not installed");
+            this.packageName = null;
+            return;
+        }
+        final Prefs prefs = GBApplication.getPrefs();
+        this.packageName = prefs.getString(VOICE_HELPER_PACKAGE, installedPackages.get(0).toString());
+    }
+
+    public void connect() {
+        LOG.info("Connecting to Voice Helper");
+
+        mConnection = new ServiceConnection() {
+            public void onServiceConnected(final ComponentName className, final IBinder service) {
+                LOG.info("onServiceConnected {}", className);
+
+                mOpusCodecService = IOpusCodecService.Stub.asInterface(service);
+                mCallback.onVoiceHelperConnection(true);
+            }
+
+            // Called when the connection with the service disconnects unexpectedly.
+            public void onServiceDisconnected(final ComponentName className) {
+                LOG.error("Service has unexpectedly disconnected");
+                mOpusCodecService = null;
+                mCallback.onVoiceHelperConnection(false);
+            }
+        };
+        final Intent intent = new Intent("nodomain.freeyourgadget.voice.OpusCodecService");
+        intent.setPackage(packageName);
+        boolean res = mContext.bindService(intent, mConnection, Context.BIND_AUTO_CREATE);
+        if (res) {
+            LOG.info("Bound to Voice Helper");
+        } else {
+            LOG.warn("Could not bind to Voice Helper");
+        }
+    }
+
+    public void disconnect() {
+        mContext.unbindService(mConnection);
+    }
+
+    public boolean isConnected() {
+        return mOpusCodecService != null;
+    }
+
+    public OpusCodec createOpusCodec() throws RemoteException {
+        return new OpusCodec(mOpusCodecService);
+    }
+
+    public static String getPermission(final String packageName) {
+        return String.format(Locale.ROOT, "%s.VOICE_HELPER", packageName);
+    }
+
+    public static List<CharSequence> findInstalledPackages(final Context context) {
+        final List<CharSequence> installedPackages = new ArrayList<>();
+        for (final String knownPackage : KNOWN_PACKAGES) {
+            if (isPackageInstalled(context, knownPackage)) {
+                installedPackages.add(knownPackage);
+            }
+        }
+        return installedPackages;
+    }
+
+    private static boolean isPackageInstalled(final Context context, final String packageName) {
+        try {
+            return context.getPackageManager().getApplicationInfo(packageName, 0).enabled;
+        } catch (final PackageManager.NameNotFoundException e) {
+            return false;
+        }
+    }
+
+    public interface Callback {
+        void onVoiceHelperConnection(boolean connected);
+    }
+}

app/src/main/res/values/strings.xml

@@ -2429,4 +2429,11 @@
     <string name="wake_up_time">Wake Up</string>
     <string name="pref_sleep_mode_schedule_title">Sleep Mode Schedule</string>
     <string name="pref_sleep_mode_schedule_summary">Send a reminder and enter sleep mode at bedtime. At the scheduled wake-up time, the wake-up alarm will sound.</string>
+    <string name="activity_prefs_voice_helper">Voice Helper options</string>
+    <string name="voice_helper_package">Voice Helper package name</string>
+    <string name="voice_helper_install">Install Voice Helper</string>
+    <string name="voice_helper_permissions_summary">Gadgetbridge needs permission to use the Voice Helper. Tap this button to grant them.</string>
+    <string name="voice_helper_not_installed">Voice Helper is not installed</string>
+    <string name="voice_helper_not_compatible">The installed Voice Helper version is not compatible with Gadgetbridge. Please update the Voice Helper and Gadgetbridge to the latest versions.</string>
+    <string name="voice_helper_install_fail">Failed to open app store to install Voice Helper</string>
 </resources>

app/src/main/res/xml/preferences.xml

@@ -360,6 +360,10 @@
             android:key="pref_discovery_pairing"
             android:title="@string/activity_prefs_discovery_pairing"
             app:iconSpaceReserved="false" />
+        <Preference
+            android:key="pref_voice_helper"
+            android:title="@string/activity_prefs_voice_helper"
+            app:iconSpaceReserved="false" />
     </PreferenceCategory>
 
     <PreferenceScreen

app/src/main/res/xml/voice_helper.xml

@@ -0,0 +1,34 @@
+<?xml version="1.0" encoding="utf-8"?>
+<androidx.preference.PreferenceScreen xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto">
+    <PreferenceCategory
+        android:key="pref_key_header_voice_helper"
+        android:title="@string/activity_prefs_voice_helper"
+        app:iconSpaceReserved="false">
+
+        <ListPreference
+            android:defaultValue="nodomain.freeyourgadget.voice"
+            android:entries="@array/pref_huami2021_empty_array"
+            android:entryValues="@array/pref_huami2021_empty_array"
+            android:icon="@drawable/ic_voice"
+            android:key="voice_helper_package"
+            android:summary="%s"
+            android:title="@string/voice_helper_package" />
+
+        <Preference
+            android:icon="@drawable/ic_warning_gray"
+            android:key="voice_helper_not_installed"
+            android:summary="@string/voice_helper_not_installed" />
+
+        <Preference
+            android:icon="@drawable/ic_voice"
+            android:key="voice_helper_install"
+            android:title="@string/voice_helper_install" />
+
+        <Preference
+            android:icon="@drawable/ic_warning_gray"
+            android:key="voice_helper_permissions"
+            android:summary="@string/voice_helper_permissions_summary"
+            android:title="@string/loyalty_cards_catima_permissions_title" />
+    </PreferenceCategory>
+</androidx.preference.PreferenceScreen>