optionally search local muc rooms instead of jabber.network

src/main/java/eu/siacs/conversations/entities/Room.java

@@ -0,0 +1,90 @@
+package eu.siacs.conversations.entities;
+
+import com.google.common.base.Objects;
+import com.google.common.base.Strings;
+import com.google.common.collect.ComparisonChain;
+
+import java.util.Comparator;
+
+import eu.siacs.conversations.services.AvatarService;
+import eu.siacs.conversations.utils.LanguageUtils;
+import eu.siacs.conversations.utils.UIHelper;
+import rocks.xmpp.addr.Jid;
+
+public class Room implements AvatarService.Avatarable, Comparable<Room> {
+
+    public String address;
+    public String name;
+    public String description;
+    public String language;
+    public int nusers;
+
+    public Room(String address, String name, String description, String language, int nusers) {
+        this.address = address;
+        this.name = name;
+        this.description = description;
+        this.language = language;
+        this.nusers = nusers;
+    }
+
+    public Room() {
+
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public String getDescription() {
+        return description;
+    }
+
+    public Jid getRoom() {
+        try {
+            return Jid.of(address);
+        } catch (IllegalArgumentException e) {
+            return null;
+        }
+    }
+
+    public String getLanguage() {
+        return LanguageUtils.convert(language);
+    }
+
+    @Override
+    public int getAvatarBackgroundColor() {
+        Jid room = getRoom();
+        return UIHelper.getColorForName(room != null ? room.asBareJid().toEscapedString() : name);
+    }
+
+    @Override
+    public boolean equals(Object o) {
+        if (this == o) return true;
+        if (o == null || getClass() != o.getClass()) return false;
+        Room room = (Room) o;
+        return Objects.equal(address, room.address) &&
+                Objects.equal(name, room.name) &&
+                Objects.equal(description, room.description);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hashCode(address, name, description);
+    }
+
+
+    public boolean contains(String needle) {
+        return Strings.nullToEmpty(name).contains(needle)
+                || Strings.nullToEmpty(description).contains(needle)
+                || Strings.nullToEmpty(address).contains(needle);
+    }
+
+    @Override
+    public int compareTo(Room o) {
+        return ComparisonChain.start()
+                .compare(o.nusers, nusers)
+                .compare(Strings.nullToEmpty(name), Strings.nullToEmpty(o.name))
+                .compare(Strings.nullToEmpty(address), Strings.nullToEmpty(o.address))
+                .result();
+    }
+}

src/main/java/eu/siacs/conversations/generator/IqGenerator.java

@@ -565,4 +565,18 @@ public class IqGenerator extends AbstractGenerator {
         }
         return packet;
     }
+
+    public IqPacket queryDiscoItems(Jid jid) {
+        IqPacket packet = new IqPacket(IqPacket.TYPE.GET);
+        packet.setTo(jid);
+        packet.addChild("query",Namespace.DISCO_ITEMS);
+        return packet;
+    }
+
+    public IqPacket queryDiscoInfo(Jid jid) {
+        IqPacket packet = new IqPacket(IqPacket.TYPE.GET);
+        packet.setTo(jid);
+        packet.addChild("query",Namespace.DISCO_INFO);
+        return packet;
+    }
 }

src/main/java/eu/siacs/conversations/http/services/MuclumbusService.java

@@ -1,20 +1,15 @@
 package eu.siacs.conversations.http.services;
 
-import com.google.common.base.Objects;
-
 import java.util.Collections;
 import java.util.List;
 import java.util.Set;
 
-import eu.siacs.conversations.services.AvatarService;
+import eu.siacs.conversations.entities.Room;
-import eu.siacs.conversations.utils.LanguageUtils;
-import eu.siacs.conversations.utils.UIHelper;
 import retrofit2.Call;
 import retrofit2.http.Body;
 import retrofit2.http.GET;
 import retrofit2.http.POST;
 import retrofit2.http.Query;
-import rocks.xmpp.addr.Jid;
 
 public interface MuclumbusService {
 
@@ -31,55 +26,6 @@ public interface MuclumbusService {
         public List<Room> items;
     }
 
-    class Room implements AvatarService.Avatarable {
-
-        public String address;
-        public String name;
-        public String description;
-        public String language;
-
-        public String getName() {
-            return name;
-        }
-
-        public String getDescription() {
-            return description;
-        }
-
-        public Jid getRoom() {
-            try {
-                return Jid.of(address);
-            } catch (IllegalArgumentException e) {
-                return null;
-            }
-        }
-
-        public String getLanguage() {
-            return LanguageUtils.convert(language);
-        }
-
-        @Override
-        public int getAvatarBackgroundColor() {
-            Jid room = getRoom();
-            return UIHelper.getColorForName(room != null ? room.asBareJid().toEscapedString() : name);
-        }
-
-        @Override
-        public boolean equals(Object o) {
-            if (this == o) return true;
-            if (o == null || getClass() != o.getClass()) return false;
-            Room room = (Room) o;
-            return Objects.equal(address, room.address) &&
-                    Objects.equal(name, room.name) &&
-                    Objects.equal(description, room.description);
-        }
-
-        @Override
-        public int hashCode() {
-            return Objects.hashCode(address, name, description);
-        }
-    }
-
     class SearchRequest {
 
         public final Set<String> keywords;

src/main/java/eu/siacs/conversations/parser/IqParser.java

@@ -1,6 +1,7 @@
 package eu.siacs.conversations.parser;
 
 import android.support.annotation.NonNull;
+import android.text.TextUtils;
 import android.util.Base64;
 import android.util.Log;
 import android.util.Pair;
@@ -27,12 +28,15 @@ import eu.siacs.conversations.crypto.axolotl.AxolotlService;
 import eu.siacs.conversations.entities.Account;
 import eu.siacs.conversations.entities.Contact;
 import eu.siacs.conversations.entities.Conversation;
+import eu.siacs.conversations.entities.Room;
+import eu.siacs.conversations.services.ChannelDiscoveryService;
 import eu.siacs.conversations.services.XmppConnectionService;
 import eu.siacs.conversations.xml.Namespace;
 import eu.siacs.conversations.xml.Element;
 import eu.siacs.conversations.xmpp.InvalidJid;
 import eu.siacs.conversations.xmpp.OnIqPacketReceived;
 import eu.siacs.conversations.xmpp.OnUpdateBlocklist;
+import eu.siacs.conversations.xmpp.forms.Data;
 import eu.siacs.conversations.xmpp.stanzas.IqPacket;
 import rocks.xmpp.addr.Jid;
 
@@ -417,4 +421,55 @@ public class IqParser extends AbstractParser implements OnIqPacketReceived {
         }
     }
 
+
+    public static List<Jid> items(IqPacket packet) {
+        ArrayList<Jid> items = new ArrayList<>();
+        final Element query = packet.findChild("query", Namespace.DISCO_ITEMS);
+        if (query == null) {
+            return items;
+        }
+        for(Element child : query.getChildren()) {
+            if ("item".equals(child.getName())) {
+                Jid jid = child.getAttributeAsJid("jid");
+                if (jid != null) {
+                    items.add(jid);
+                }
+            }
+        }
+        return items;
+    }
+
+    public static Room parseRoom(IqPacket packet) {
+        final Element query = packet.findChild("query", Namespace.DISCO_INFO);
+        if(query == null) {
+            return null;
+        }
+        final Element x = query.findChild("x");
+        if (x == null) {
+            return null;
+        }
+        final Element identity = query.findChild("identity");
+        Data data = Data.parse(x);
+        String address = packet.getFrom().toEscapedString();
+        String name = identity == null ? null : identity.getAttribute("name");
+        String roomName = data.getValue("muc#roomconfig_roomname");;
+        String description = data.getValue("muc#roominfo_description");
+        String language = data.getValue("muc#roominfo_lang");
+        String occupants = data.getValue("muc#roominfo_occupants");
+        int nusers;
+        try {
+            nusers = occupants == null ? 0 : Integer.parseInt(occupants);
+        } catch (NumberFormatException e) {
+            nusers = 0;
+        }
+
+        return new Room(
+                address,
+                TextUtils.isEmpty(roomName) ? name : roomName,
+                description,
+                language,
+                nusers
+        );
+    }
+
 }

src/main/java/eu/siacs/conversations/services/AvatarService.java

@@ -38,6 +38,7 @@ import eu.siacs.conversations.entities.ListItem;
 import eu.siacs.conversations.entities.Message;
 import eu.siacs.conversations.entities.MucOptions;
 import eu.siacs.conversations.entities.RawBlockable;
+import eu.siacs.conversations.entities.Room;
 import eu.siacs.conversations.http.services.MuclumbusService;
 import eu.siacs.conversations.utils.UIHelper;
 import eu.siacs.conversations.xmpp.OnAdvancedStreamFeaturesLoaded;
@@ -81,14 +82,14 @@ public class AvatarService implements OnAdvancedStreamFeaturesLoaded {
 			return get((ListItem) avatarable, size, cachedOnly);
 		} else if (avatarable instanceof MucOptions.User) {
 			return get((MucOptions.User) avatarable, size, cachedOnly);
-		} else if (avatarable instanceof MuclumbusService.Room) {
+		} else if (avatarable instanceof Room) {
-			return get((MuclumbusService.Room) avatarable, size, cachedOnly);
+			return get((Room) avatarable, size, cachedOnly);
 		}
 		throw new AssertionError("AvatarService does not know how to generate avatar from "+avatarable.getClass().getName());
 
 	}
 
-	private Bitmap get(final MuclumbusService.Room result, final int size, boolean cacheOnly) {
+	private Bitmap get(final Room result, final int size, boolean cacheOnly) {
 		final Jid room = result.getRoom();
 		Conversation conversation = room != null ? mXmppConnectionService.findFirstMuc(room) : null;
 		if (conversation != null) {

src/main/java/eu/siacs/conversations/services/ChannelDiscoveryService.java

@@ -7,14 +7,27 @@ import com.google.common.cache.Cache;
 import com.google.common.cache.CacheBuilder;
 
 import java.io.IOException;
+import java.util.ArrayList;
 import java.util.Collections;
+import java.util.HashMap;
+import java.util.HashSet;
 import java.util.List;
+import java.util.Map;
 import java.util.concurrent.Executors;
 import java.util.concurrent.TimeUnit;
+import java.util.concurrent.atomic.AtomicInteger;
 
 import eu.siacs.conversations.Config;
+import eu.siacs.conversations.entities.Account;
+import eu.siacs.conversations.entities.Room;
 import eu.siacs.conversations.http.HttpConnectionManager;
 import eu.siacs.conversations.http.services.MuclumbusService;
+import eu.siacs.conversations.parser.IqParser;
+import eu.siacs.conversations.utils.LanguageUtils;
+import eu.siacs.conversations.utils.UIHelper;
+import eu.siacs.conversations.xmpp.OnIqPacketReceived;
+import eu.siacs.conversations.xmpp.XmppConnection;
+import eu.siacs.conversations.xmpp.stanzas.IqPacket;
 import okhttp3.OkHttpClient;
 import okhttp3.ResponseBody;
 import retrofit2.Call;
@@ -22,6 +35,7 @@ import retrofit2.Callback;
 import retrofit2.Response;
 import retrofit2.Retrofit;
 import retrofit2.converter.gson.GsonConverterFactory;
+import rocks.xmpp.addr.Jid;
 
 public class ChannelDiscoveryService {
 
@@ -30,7 +44,7 @@ public class ChannelDiscoveryService {
 
     private MuclumbusService muclumbusService;
 
-    private final Cache<String, List<MuclumbusService.Room>> cache;
+    private final Cache<String, List<Room>> cache;
 
     ChannelDiscoveryService(XmppConnectionService service) {
         this.service = service;
@@ -56,21 +70,28 @@ public class ChannelDiscoveryService {
         this.muclumbusService = retrofit.create(MuclumbusService.class);
     }
 
-    void discover(String query, OnChannelSearchResultsFound onChannelSearchResultsFound) {
+    void cleanCache() {
-        final boolean all = query == null || query.trim().isEmpty();
+        cache.invalidateAll();
-        List<MuclumbusService.Room> result = cache.getIfPresent(all ? "" : query);
+    }
+
+    void discover(@NonNull final String query, Method method, OnChannelSearchResultsFound onChannelSearchResultsFound) {
+        List<Room> result = cache.getIfPresent(key(method, query));
         if (result != null) {
             onChannelSearchResultsFound.onChannelSearchResultsFound(result);
             return;
         }
-        if (all) {
+        if (method == Method.LOCAL_SERVER) {
-            discoverChannels(onChannelSearchResultsFound);
+            discoverChannelsLocalServers(query, onChannelSearchResultsFound);
         } else {
-            discoverChannels(query, onChannelSearchResultsFound);
+            if (query.isEmpty()) {
+                discoverChannelsJabberNetwork(onChannelSearchResultsFound);
+            } else {
+                discoverChannelsJabberNetwork(query, onChannelSearchResultsFound);
+            }
         }
     }
 
-    private void discoverChannels(OnChannelSearchResultsFound listener) {
+    private void discoverChannelsJabberNetwork(OnChannelSearchResultsFound listener) {
         Call<MuclumbusService.Rooms> call = muclumbusService.getRooms(1);
         try {
             call.enqueue(new Callback<MuclumbusService.Rooms>() {
@@ -82,7 +103,7 @@ public class ChannelDiscoveryService {
                         logError(response);
                         return;
                     }
-                    cache.put("", body.items);
+                    cache.put(key(Method.JABBER_NETWORK, ""), body.items);
                     listener.onChannelSearchResultsFound(body.items);
                 }
 
@@ -97,7 +118,7 @@ public class ChannelDiscoveryService {
         }
     }
 
-    private void discoverChannels(final String query, OnChannelSearchResultsFound listener) {
+    private void discoverChannelsJabberNetwork(final String query, OnChannelSearchResultsFound listener) {
         MuclumbusService.SearchRequest searchRequest = new MuclumbusService.SearchRequest(query);
         Call<MuclumbusService.SearchResult> searchResultCall = muclumbusService.search(searchRequest);
 
@@ -110,7 +131,7 @@ public class ChannelDiscoveryService {
                     logError(response);
                     return;
                 }
-                cache.put(query, body.result.items);
+                cache.put(key(Method.JABBER_NETWORK, query), body.result.items);
                 listener.onChannelSearchResultsFound(body.result.items);
             }
 
@@ -122,6 +143,102 @@ public class ChannelDiscoveryService {
         });
     }
 
+    private void discoverChannelsLocalServers(final String query, final OnChannelSearchResultsFound listener) {
+        final Map<Jid, Account> localMucService = getLocalMucServices();
+        Log.d(Config.LOGTAG, "checking with " + localMucService.size() + " muc services");
+        if (localMucService.size() == 0) {
+            listener.onChannelSearchResultsFound(Collections.emptyList());
+            return;
+        }
+        if (!query.isEmpty()) {
+            final List<Room> cached = cache.getIfPresent(key(Method.LOCAL_SERVER, ""));
+            if (cached != null) {
+                final List<Room> results = copyMatching(cached, query);
+                cache.put(key(Method.LOCAL_SERVER, query), results);
+                listener.onChannelSearchResultsFound(results);
+            }
+        }
+        final AtomicInteger queriesInFlight = new AtomicInteger();
+        final List<Room> rooms = new ArrayList<>();
+        for (Map.Entry<Jid, Account> entry : localMucService.entrySet()) {
+            IqPacket itemsRequest = service.getIqGenerator().queryDiscoItems(entry.getKey());
+            queriesInFlight.incrementAndGet();
+            service.sendIqPacket(entry.getValue(), itemsRequest, (account, itemsResponse) -> {
+                if (itemsResponse.getType() == IqPacket.TYPE.RESULT) {
+                    final List<Jid> items = IqParser.items(itemsResponse);
+                    for (Jid item : items) {
+                        IqPacket infoRequest = service.getIqGenerator().queryDiscoInfo(item);
+                        queriesInFlight.incrementAndGet();
+                        service.sendIqPacket(account, infoRequest, new OnIqPacketReceived() {
+                            @Override
+                            public void onIqPacketReceived(Account account, IqPacket infoResponse) {
+                                if (infoResponse.getType() == IqPacket.TYPE.RESULT) {
+                                    final Room room = IqParser.parseRoom(infoResponse);
+                                    if (room != null) {
+                                        rooms.add(room);
+                                    }
+                                    if (queriesInFlight.decrementAndGet() <= 0) {
+                                        finishDiscoSearch(rooms, query, listener);
+                                    }
+                                } else {
+                                    queriesInFlight.decrementAndGet();
+                                }
+                            }
+                        });
+                    }
+                }
+                if (queriesInFlight.decrementAndGet() <= 0) {
+                    finishDiscoSearch(rooms, query, listener);
+                }
+            });
+        }
+    }
+
+    private void finishDiscoSearch(List<Room> rooms, String query, OnChannelSearchResultsFound listener) {
+        Collections.sort(rooms);
+        cache.put(key(Method.LOCAL_SERVER, ""), rooms);
+        if (query.isEmpty()) {
+            listener.onChannelSearchResultsFound(rooms);
+        } else {
+            List<Room> results = copyMatching(rooms, query);
+            cache.put(key(Method.LOCAL_SERVER, query), results);
+            listener.onChannelSearchResultsFound(rooms);
+        }
+    }
+
+    private static List<Room> copyMatching(List<Room> haystack, String needle) {
+        ArrayList<Room> result = new ArrayList<>();
+        for (Room room : haystack) {
+            if (room.contains(needle)) {
+                result.add(room);
+            }
+        }
+        return result;
+    }
+
+    private Map<Jid, Account> getLocalMucServices() {
+        final HashMap<Jid, Account> localMucServices = new HashMap<>();
+        for (Account account : service.getAccounts()) {
+            if (account.isEnabled()) {
+                final XmppConnection xmppConnection = account.getXmppConnection();
+                if (xmppConnection == null) {
+                    continue;
+                }
+                for (final String mucService : xmppConnection.getMucServers()) {
+                    Jid jid = Jid.of(mucService);
+                    if (!localMucServices.containsKey(jid)) {
+                        localMucServices.put(jid, account);
+                    }
+                }
+            }
+        }
+        return localMucServices;
+    }
+
+    private static String key(Method method, String query) {
+        return String.format("%s\00%s", method, query);
+    }
+
     private static void logError(final Response response) {
         final ResponseBody errorBody = response.errorBody();
         Log.d(Config.LOGTAG, "code from muclumbus=" + response.code());
@@ -129,13 +246,18 @@ public class ChannelDiscoveryService {
             return;
         }
         try {
-            Log.d(Config.LOGTAG,"error body="+errorBody.string());
+            Log.d(Config.LOGTAG, "error body=" + errorBody.string());
         } catch (IOException e) {
             //ignored
         }
     }
 
     public interface OnChannelSearchResultsFound {
-        void onChannelSearchResultsFound(List<MuclumbusService.Room> results);
+        void onChannelSearchResultsFound(List<Room> results);
+    }
+
+    public enum Method {
+        JABBER_NETWORK,
+        LOCAL_SERVER
     }
 }

src/main/java/eu/siacs/conversations/services/XmppConnectionService.java

@@ -34,6 +34,7 @@ import android.provider.ContactsContract;
 import android.security.KeyChain;
 import android.support.annotation.BoolRes;
 import android.support.annotation.IntegerRes;
+import android.support.annotation.NonNull;
 import android.support.v4.app.RemoteInput;
 import android.support.v4.content.ContextCompat;
 import android.text.TextUtils;
@@ -42,6 +43,8 @@ import android.util.Log;
 import android.util.LruCache;
 import android.util.Pair;
 
+import com.google.common.base.Strings;
+
 import org.conscrypt.Conscrypt;
 import org.openintents.openpgp.IOpenPgpService2;
 import org.openintents.openpgp.util.OpenPgpApi;
@@ -857,8 +860,8 @@ public class XmppConnectionService extends Service {
         mChannelDiscoveryService.initializeMuclumbusService();
     }
 
-    public void discoverChannels(String query, ChannelDiscoveryService.OnChannelSearchResultsFound onChannelSearchResultsFound) {
+    public void discoverChannels(String query, ChannelDiscoveryService.Method method, ChannelDiscoveryService.OnChannelSearchResultsFound onChannelSearchResultsFound) {
-        mChannelDiscoveryService.discover(query, onChannelSearchResultsFound);
+        mChannelDiscoveryService.discover(Strings.nullToEmpty(query).trim(), method, onChannelSearchResultsFound);
     }
 
     public boolean isDataSaverDisabled() {
@@ -2244,6 +2247,7 @@ public class XmppConnectionService extends Service {
             getNotificationService().updateErrorNotification();
             toggleForegroundService();
             syncEnabledAccountSetting();
+            mChannelDiscoveryService.cleanCache();
             return true;
         } else {
             return false;
@@ -3086,9 +3090,7 @@ public class XmppConnectionService extends Service {
     }
 
     public void fetchConferenceConfiguration(final Conversation conversation, final OnConferenceConfigurationFetched callback) {
-        IqPacket request = new IqPacket(IqPacket.TYPE.GET);
+        IqPacket request = mIqGenerator.queryDiscoInfo(conversation.getJid().asBareJid());
-        request.setTo(conversation.getJid().asBareJid());
-        request.query("http://jabber.org/protocol/disco#info");
         sendIqPacket(conversation.getAccount(), request, new OnIqPacketReceived() {
             @Override
             public void onIqPacketReceived(Account account, IqPacket packet) {
@@ -4437,7 +4439,7 @@ public class XmppConnectionService extends Service {
                 request.setTo(jid);
                 final String node = presence.getNode();
                 final String ver = presence.getVer();
-                final Element query = request.query("http://jabber.org/protocol/disco#info");
+                final Element query = request.query(Namespace.DISCO_INFO);
                 if (node != null && ver != null) {
                     query.setAttribute("node", node + "#" + ver);
                 }

src/main/java/eu/siacs/conversations/ui/ChannelDiscoveryActivity.java

@@ -7,6 +7,7 @@ import android.content.SharedPreferences;
 import android.databinding.DataBindingUtil;
 import android.net.Uri;
 import android.os.Bundle;
+import android.preference.PreferenceManager;
 import android.support.v7.widget.Toolbar;
 import android.text.Html;
 import android.view.KeyEvent;
@@ -27,7 +28,7 @@ import eu.siacs.conversations.databinding.ActivityChannelDiscoveryBinding;
 import eu.siacs.conversations.entities.Account;
 import eu.siacs.conversations.entities.Bookmark;
 import eu.siacs.conversations.entities.Conversation;
-import eu.siacs.conversations.http.services.MuclumbusService;
+import eu.siacs.conversations.entities.Room;
 import eu.siacs.conversations.services.ChannelDiscoveryService;
 import eu.siacs.conversations.ui.adapter.ChannelSearchResultAdapter;
 import eu.siacs.conversations.ui.util.PendingItem;
@@ -46,6 +47,8 @@ public class ChannelDiscoveryActivity extends XmppActivity implements MenuItem.O
     private MenuItem mMenuSearchView;
     private EditText mSearchEditText;
 
+    private ChannelDiscoveryService.Method method = ChannelDiscoveryService.Method.LOCAL_SERVER;
+
     private boolean optedIn = false;
 
     @Override
@@ -55,14 +58,15 @@ public class ChannelDiscoveryActivity extends XmppActivity implements MenuItem.O
 
     @Override
     void onBackendConnected() {
-        if (optedIn) {
+        if (optedIn || method == ChannelDiscoveryService.Method.LOCAL_SERVER) {
-            String query;
+            final String query;
             if (mMenuSearchView != null && mMenuSearchView.isActionViewExpanded()) {
                 query = mSearchEditText.getText().toString();
             } else {
                 query = mInitialSearchValue.peek();
             }
-            xmppConnectionService.discoverChannels(query, this);
+            toggleLoadingScreen();
+            xmppConnectionService.discoverChannels(query, this.method, this);
         }
     }
 
@@ -74,29 +78,39 @@ public class ChannelDiscoveryActivity extends XmppActivity implements MenuItem.O
         configureActionBar(getSupportActionBar(), true);
         binding.list.setAdapter(this.adapter);
         this.adapter.setOnChannelSearchResultSelectedListener(this);
-        optedIn = getPreferences().getBoolean(CHANNEL_DISCOVERY_OPT_IN, false);
+        this.optedIn = getPreferences().getBoolean(CHANNEL_DISCOVERY_OPT_IN, false);
 
         final String search = savedInstanceState == null ? null : savedInstanceState.getString("search");
         if (search != null) {
             mInitialSearchValue.push(search);
         }
+    }
 
+    private static ChannelDiscoveryService.Method getMethod(final Context c) {
+        final SharedPreferences p = PreferenceManager.getDefaultSharedPreferences(c);
+        final String m = p.getString("channel_discovery_method", c.getString(R.string.default_channel_discovery));
+        try {
+            return ChannelDiscoveryService.Method.valueOf(m);
+        } catch (IllegalArgumentException e) {
+            return ChannelDiscoveryService.Method.JABBER_NETWORK;
+        }
     }
 
     @Override
     public boolean onCreateOptionsMenu(final Menu menu) {
-        getMenuInflater().inflate(R.menu.muc_users_activity, menu);
+        getMenuInflater().inflate(R.menu.channel_discovery_activity, menu);
+        AccountUtils.showHideMenuItems(menu);
         mMenuSearchView = menu.findItem(R.id.action_search);
         final View mSearchView = mMenuSearchView.getActionView();
         mSearchEditText = mSearchView.findViewById(R.id.search_field);
         mSearchEditText.setHint(R.string.search_channels);
-        String initialSearchValue = mInitialSearchValue.pop();
+        final String initialSearchValue = mInitialSearchValue.pop();
         if (initialSearchValue != null) {
             mMenuSearchView.expandActionView();
             mSearchEditText.append(initialSearchValue);
             mSearchEditText.requestFocus();
-            if (optedIn && xmppConnectionService != null) {
+            if ((optedIn || method == ChannelDiscoveryService.Method.LOCAL_SERVER) && xmppConnectionService != null) {
-                xmppConnectionService.discoverChannels(initialSearchValue, this);
+                xmppConnectionService.discoverChannels(initialSearchValue, this.method, this);
             }
         }
         mSearchEditText.setOnEditorActionListener(this);
@@ -120,8 +134,8 @@ public class ChannelDiscoveryActivity extends XmppActivity implements MenuItem.O
         imm.hideSoftInputFromWindow(mSearchEditText.getWindowToken(), InputMethodManager.HIDE_IMPLICIT_ONLY);
         mSearchEditText.setText("");
         toggleLoadingScreen();
-        if (optedIn) {
+        if (optedIn || method == ChannelDiscoveryService.Method.LOCAL_SERVER) {
-            xmppConnectionService.discoverChannels(null, this);
+            xmppConnectionService.discoverChannels(null, this.method, this);
         }
         return true;
     }
@@ -135,7 +149,8 @@ public class ChannelDiscoveryActivity extends XmppActivity implements MenuItem.O
     @Override
     public void onStart() {
         super.onStart();
-        if (!optedIn) {
+        this.method = getMethod(this);
+        if (!optedIn && method == ChannelDiscoveryService.Method.JABBER_NETWORK) {
             final AlertDialog.Builder builder = new AlertDialog.Builder(this);
             builder.setTitle(R.string.channel_discovery_opt_in_title);
             builder.setMessage(Html.fromHtml(getString(R.string.channel_discover_opt_in_message)));
@@ -160,21 +175,21 @@ public class ChannelDiscoveryActivity extends XmppActivity implements MenuItem.O
         SharedPreferences preferences = getPreferences();
         preferences.edit().putBoolean(CHANNEL_DISCOVERY_OPT_IN, true).apply();
         optedIn = true;
-        xmppConnectionService.discoverChannels(null, this);
+        xmppConnectionService.discoverChannels(null, this.method, this);
     }
 
     @Override
     public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
-        if (optedIn) {
+        if (optedIn || method == ChannelDiscoveryService.Method.LOCAL_SERVER) {
             toggleLoadingScreen();
             SoftKeyboardUtils.hideSoftKeyboard(this);
-            xmppConnectionService.discoverChannels(v.getText().toString(), this);
+            xmppConnectionService.discoverChannels(v.getText().toString(), this.method, this);
         }
         return true;
     }
 
     @Override
-    public void onChannelSearchResultsFound(final List<MuclumbusService.Room> results) {
+    public void onChannelSearchResultsFound(final List<Room> results) {
         runOnUiThread(() -> {
             adapter.submitList(results);
             binding.progressBar.setVisibility(View.GONE);
@@ -188,7 +203,7 @@ public class ChannelDiscoveryActivity extends XmppActivity implements MenuItem.O
     }
 
     @Override
-    public void onChannelSearchResult(final MuclumbusService.Room result) {
+    public void onChannelSearchResult(final Room result) {
         List<String> accounts = AccountUtils.getEnabledAccounts(xmppConnectionService);
         if (accounts.size() == 1) {
             joinChannelSearchResult(accounts.get(0), result);
@@ -206,7 +221,7 @@ public class ChannelDiscoveryActivity extends XmppActivity implements MenuItem.O
 
     @Override
     public boolean onContextItemSelected(MenuItem item) {
-        final MuclumbusService.Room room = adapter.getCurrent();
+        final Room room = adapter.getCurrent();
         if (room != null) {
             switch (item.getItemId()) {
                 case R.id.share_with:
@@ -224,7 +239,7 @@ public class ChannelDiscoveryActivity extends XmppActivity implements MenuItem.O
         return false;
     }
 
-    public void joinChannelSearchResult(String selectedAccount, MuclumbusService.Room result) {
+    public void joinChannelSearchResult(String selectedAccount, Room result) {
         final Jid jid = Config.DOMAIN_LOCK == null ? Jid.of(selectedAccount) : Jid.of(selectedAccount, Config.DOMAIN_LOCK, null);
         final boolean syncAutoJoin = getBooleanPreference("autojoin", R.bool.autojoin);
         final Account account = xmppConnectionService.findAccountByJid(jid);

src/main/java/eu/siacs/conversations/ui/adapter/ChannelSearchResultAdapter.java

@@ -16,26 +16,26 @@ import java.util.Locale;
 
 import eu.siacs.conversations.R;
 import eu.siacs.conversations.databinding.SearchResultItemBinding;
-import eu.siacs.conversations.http.services.MuclumbusService;
+import eu.siacs.conversations.entities.Room;
 import eu.siacs.conversations.ui.XmppActivity;
 import eu.siacs.conversations.ui.util.AvatarWorkerTask;
 import rocks.xmpp.addr.Jid;
 
-public class ChannelSearchResultAdapter extends ListAdapter<MuclumbusService.Room, ChannelSearchResultAdapter.ViewHolder> implements View.OnCreateContextMenuListener {
+public class ChannelSearchResultAdapter extends ListAdapter<Room, ChannelSearchResultAdapter.ViewHolder> implements View.OnCreateContextMenuListener {
 
-    private static final DiffUtil.ItemCallback<MuclumbusService.Room> DIFF = new DiffUtil.ItemCallback<MuclumbusService.Room>() {
+    private static final DiffUtil.ItemCallback<Room> DIFF = new DiffUtil.ItemCallback<Room>() {
         @Override
-        public boolean areItemsTheSame(@NonNull MuclumbusService.Room a, @NonNull MuclumbusService.Room b) {
+        public boolean areItemsTheSame(@NonNull Room a, @NonNull Room b) {
             return a.address != null && a.address.equals(b.address);
         }
 
         @Override
-        public boolean areContentsTheSame(@NonNull MuclumbusService.Room a, @NonNull MuclumbusService.Room b) {
+        public boolean areContentsTheSame(@NonNull Room a, @NonNull Room b) {
             return a.equals(b);
         }
     };
     private OnChannelSearchResultSelected listener;
-    private MuclumbusService.Room current;
+    private Room current;
 
     public ChannelSearchResultAdapter() {
         super(DIFF);
@@ -49,7 +49,7 @@ public class ChannelSearchResultAdapter extends ListAdapter<MuclumbusService.Roo
 
     @Override
     public void onBindViewHolder(@NonNull ViewHolder viewHolder, int position) {
-        final MuclumbusService.Room searchResult = getItem(position);
+        final Room searchResult = getItem(position);
         viewHolder.binding.name.setText(searchResult.getName());
         final String description = searchResult.getDescription();
         final String language = searchResult.getLanguage();
@@ -78,7 +78,7 @@ public class ChannelSearchResultAdapter extends ListAdapter<MuclumbusService.Roo
         this.listener = listener;
     }
 
-    public MuclumbusService.Room getCurrent() {
+    public Room getCurrent() {
         return this.current;
     }
 
@@ -86,15 +86,14 @@ public class ChannelSearchResultAdapter extends ListAdapter<MuclumbusService.Roo
     public void onCreateContextMenu(ContextMenu menu, View v, ContextMenu.ContextMenuInfo menuInfo) {
         final Activity activity = XmppActivity.find(v);
         final Object tag = v.getTag();
-        if (activity != null && tag instanceof MuclumbusService.Room) {
+        if (activity != null && tag instanceof Room) {
             activity.getMenuInflater().inflate(R.menu.channel_item_context, menu);
-            this.current = (MuclumbusService.Room) tag;
+            this.current = (Room) tag;
         }
     }
 
-
     public interface OnChannelSearchResultSelected {
-        void onChannelSearchResult(MuclumbusService.Room result);
+        void onChannelSearchResult(Room result);
     }
 
     public static class ViewHolder extends RecyclerView.ViewHolder {

src/main/java/eu/siacs/conversations/utils/AccountUtils.java

@@ -102,7 +102,11 @@ public class AccountUtils {
     public static void showHideMenuItems(final Menu menu) {
         final MenuItem manageAccounts = menu.findItem(R.id.action_accounts);
         final MenuItem manageAccount = menu.findItem(R.id.action_account);
+        if (manageAccount != null) {
             manageAccount.setVisible(MANAGE_ACCOUNT_ACTIVITY == null);
+        }
+        if (manageAccounts != null) {
             manageAccounts.setVisible(MANAGE_ACCOUNT_ACTIVITY != null);
         }
+    }
 }

src/main/java/eu/siacs/conversations/xml/Namespace.java

@@ -1,6 +1,8 @@
 package eu.siacs.conversations.xml;
 
 public final class Namespace {
+	public static final String DISCO_ITEMS = "http://jabber.org/protocol/disco#items";
+	public static final String DISCO_INFO = "http://jabber.org/protocol/disco#info";
 	public static final String BLOCKING = "urn:xmpp:blocking";
 	public static final String ROSTER = "jabber:iq:roster";
 	public static final String REGISTER = "jabber:iq:register";

src/main/res/menu/channel_discovery_activity.xml

@@ -4,8 +4,18 @@
 
     <item
         android:id="@+id/action_search"
-        app:actionLayout="@layout/actionview_search"
         android:icon="?attr/icon_search"
-        app:showAsAction="collapseActionView|always"
+        android:title="@string/search"
-        android:title="@string/search"/>
+        app:actionLayout="@layout/actionview_search"
+        app:showAsAction="collapseActionView|always" />
+    <item
+        android:id="@+id/action_accounts"
+        android:orderInCategory="90"
+        android:title="@string/action_accounts"
+        app:showAsAction="never"/>
+    <item
+        android:id="@+id/action_settings"
+        android:orderInCategory="100"
+        android:title="@string/action_settings"
+        app:showAsAction="never" />
 </menu>

src/main/res/values/arrays.xml

@@ -124,4 +124,14 @@
 		<item>@string/video_720p</item>
 		<item>@string/video_original</item>
 	</string-array>
+
+	<string-array name="channel_discovery_entries">
+		<item>@string/jabber_network</item>
+		<item>@string/local_server</item>
+	</string-array>
+
+	<string-array name="channel_discover_values">
+		<item>JABBER_NETWORK</item>
+		<item>LOCAL_SERVER</item>
+	</string-array>
 </resources>

src/main/res/values/defaults.xml

@@ -43,4 +43,5 @@
     <bool name="use_share_location_plugin">false</bool>
     <bool name="start_searching">false</bool>
     <string name="video_compression">360</string>
+    <string name="default_channel_discovery">JABBER_NETWORK</string>
 </resources>

src/main/res/values/strings.xml

@@ -879,4 +879,9 @@
     <string name="unable_to_perform_this_action">Unable to perform this action</string>
     <string name="open_join_dialog">Join public channel…</string>
     <string name="sharing_application_not_grant_permission">The sharing application did not grant permission to access this file.</string>
+    <string name="group_chats_and_channels"><![CDATA[Group Chats & Channels]]></string>
+    <string name="jabber_network">jabber.network</string>
+    <string name="local_server">Local server</string>
+    <string name="pref_channel_discovery_summary">Most users should choose ‘jabber.network’ for better suggestions from the entirety of the public XMPP ecosystem.</string>
+    <string name="pref_channel_discovery">Channel discovery method</string>
 </resources>

src/main/res/xml/preferences.xml

@@ -16,6 +16,22 @@
         </PreferenceScreen>
     </PreferenceCategory>
     <PreferenceCategory android:title="@string/pref_privacy">
+        <CheckBoxPreference
+            android:defaultValue="@bool/confirm_messages"
+            android:key="confirm_messages"
+            android:summary="@string/pref_confirm_messages_summary"
+            android:title="@string/pref_confirm_messages" />
+        <CheckBoxPreference
+            android:defaultValue="@bool/chat_states"
+            android:key="chat_states"
+            android:summary="@string/pref_chat_states_summary"
+            android:title="@string/pref_chat_states" />
+
+        <CheckBoxPreference
+            android:defaultValue="@bool/last_activity"
+            android:key="last_activity"
+            android:summary="@string/pref_broadcast_last_activity_summary"
+            android:title="@string/pref_broadcast_last_activity" />
         <ListPreference
             android:defaultValue="@string/omemo_setting_default"
             android:entries="@array/omemo_setting_entries"
@@ -23,39 +39,10 @@
             android:key="omemo"
             android:summary="@string/pref_omemo_setting_summary_default_on"
             android:title="@string/pref_omemo_setting" />
-        <CheckBoxPreference
-            android:defaultValue="@bool/confirm_messages"
-            android:key="confirm_messages"
-            android:summary="@string/pref_confirm_messages_summary"
-            android:title="@string/pref_confirm_messages" />
-
-        <CheckBoxPreference
-            android:defaultValue="@bool/chat_states"
-            android:key="chat_states"
-            android:summary="@string/pref_chat_states_summary"
-            android:title="@string/pref_chat_states" />
-        <CheckBoxPreference
-            android:defaultValue="@bool/last_activity"
-            android:key="last_activity"
-            android:summary="@string/pref_broadcast_last_activity_summary"
-            android:title="@string/pref_broadcast_last_activity" />
     </PreferenceCategory>
     <PreferenceCategory
-        android:title="@string/pref_notification_settings"
+        android:key="notification_category"
-        android:key="notification_category">
+        android:title="@string/pref_notification_settings">
-        <PreferenceScreen
-            android:key="more_notification_settings"
-            android:summary="@string/pref_more_notification_settings_summary"
-            android:title="@string/pref_more_notification_settings">
-            <intent android:action="android.settings.CHANNEL_NOTIFICATION_SETTINGS">
-                <extra
-                    android:name="android.provider.extra.APP_PACKAGE"
-                    android:value="@string/applicationId" />
-                <extra
-                    android:name="android.provider.extra.CHANNEL_ID"
-                    android:value="messages" />
-            </intent>
-        </PreferenceScreen>
         <CheckBoxPreference
             android:defaultValue="@bool/notifications_from_strangers"
             android:key="notifications_from_strangers"
@@ -76,24 +63,17 @@
             android:key="led"
             android:summary="@string/pref_led_summary"
             android:title="@string/pref_led" />
-        <RingtonePreference
+        <ListPreference
-            android:defaultValue="@string/notification_ringtone"
+            android:defaultValue="@integer/grace_period"
-            android:key="notification_ringtone"
+            android:entries="@array/grace_periods"
-            android:ringtoneType="notification"
+            android:entryValues="@array/grace_periods_values"
-            android:summary="@string/pref_sound_summary"
+            android:key="grace_period_length"
-            android:title="@string/pref_sound" />
+            android:summary="@string/pref_notification_grace_period_summary"
+            android:title="@string/pref_notification_grace_period" />
         <PreferenceScreen
             android:key="quiet_hours"
             android:summary="@string/pref_quiet_hours_summary"
             android:title="@string/title_pref_quiet_hours">
-            <intent
-                android:action="android.intent.action.VIEW"
-                android:targetClass="eu.siacs.conversations.ui.SettingsActivity"
-                android:targetPackage="@string/applicationId">
-                <extra
-                    android:name="page"
-                    android:value="quiet_hours" />
-            </intent>
             <CheckBoxPreference
                 android:defaultValue="@bool/enable_quiet_hours"
                 android:key="enable_quiet_hours"
@@ -111,25 +91,43 @@
                 android:negativeButtonText="@string/cancel"
                 android:positiveButtonText="@string/set"
                 android:title="@string/title_pref_quiet_hours_end_time" />
+            <intent
+                android:action="android.intent.action.VIEW"
+                android:targetClass="eu.siacs.conversations.ui.SettingsActivity"
+                android:targetPackage="@string/applicationId">
+                <extra
+                    android:name="page"
+                    android:value="quiet_hours" />
+            </intent>
         </PreferenceScreen>
-        <ListPreference
+        <PreferenceScreen
-            android:defaultValue="@integer/grace_period"
+            android:key="more_notification_settings"
-            android:entries="@array/grace_periods"
+            android:summary="@string/pref_more_notification_settings_summary"
-            android:entryValues="@array/grace_periods_values"
+            android:title="@string/pref_more_notification_settings">
-            android:key="grace_period_length"
+            <intent android:action="android.settings.CHANNEL_NOTIFICATION_SETTINGS">
-            android:summary="@string/pref_notification_grace_period_summary"
+                <extra
-            android:title="@string/pref_notification_grace_period" />
+                    android:name="android.provider.extra.APP_PACKAGE"
+                    android:value="@string/applicationId" />
+                <extra
+                    android:name="android.provider.extra.CHANNEL_ID"
+                    android:value="messages" />
+            </intent>
+        </PreferenceScreen>
+        <RingtonePreference
+            android:defaultValue="@string/notification_ringtone"
+            android:key="notification_ringtone"
+            android:ringtoneType="notification"
+            android:summary="@string/pref_sound_summary"
+            android:title="@string/pref_sound" />
     </PreferenceCategory>
     <PreferenceCategory
         android:key="attachments"
         android:title="@string/pref_attachments">
-        <ListPreference
+        <CheckBoxPreference
-            android:defaultValue="@integer/auto_accept_filesize"
+            android:defaultValue="@bool/use_share_location_plugin"
-            android:entries="@array/filesizes"
+            android:key="use_share_location_plugin"
-            android:entryValues="@array/filesizes_values"
+            android:summary="@string/pref_use_share_location_plugin_summary"
-            android:key="auto_accept_file_size"
+            android:title="@string/pref_use_share_location_plugin" />
-            android:summary="@string/pref_accept_files_summary"
-            android:title="@string/pref_accept_files" />
         <ListPreference
             android:defaultValue="@string/picture_compression"
             android:entries="@array/picture_compression_entries"
@@ -144,13 +142,30 @@
             android:key="video_compression"
             android:summary="@string/pref_video_compression_summary"
             android:title="@string/pref_video_compression" />
-        <CheckBoxPreference
+        <ListPreference
-            android:defaultValue="@bool/use_share_location_plugin"
+            android:defaultValue="@integer/auto_accept_filesize"
-            android:key="use_share_location_plugin"
+            android:entries="@array/filesizes"
-            android:summary="@string/pref_use_share_location_plugin_summary"
+            android:entryValues="@array/filesizes_values"
-            android:title="@string/pref_use_share_location_plugin" />
+            android:key="auto_accept_file_size"
+            android:summary="@string/pref_accept_files_summary"
+            android:title="@string/pref_accept_files" />
     </PreferenceCategory>
     <PreferenceCategory android:title="@string/pref_ui_options">
+        <CheckBoxPreference
+            android:defaultValue="@bool/use_green_background"
+            android:key="use_green_background"
+            android:summary="@string/pref_use_green_background_summary"
+            android:title="@string/pref_use_green_background" />
+        <CheckBoxPreference
+            android:defaultValue="@bool/send_button_status"
+            android:key="send_button_status"
+            android:summary="@string/pref_use_send_button_to_indicate_status_summary"
+            android:title="@string/pref_use_send_button_to_indicate_status" />
+        <CheckBoxPreference
+            android:defaultValue="@bool/show_dynamic_tags"
+            android:key="show_dynamic_tags"
+            android:summary="@string/pref_show_dynamic_tags_summary"
+            android:title="@string/pref_show_dynamic_tags" />
         <ListPreference
             android:defaultValue="@string/theme"
             android:entries="@array/themes"
@@ -158,23 +173,6 @@
             android:key="theme"
             android:summary="@string/pref_theme_options_summary"
             android:title="@string/pref_theme_options" />
-        <CheckBoxPreference
-            android:defaultValue="@bool/use_green_background"
-            android:key="use_green_background"
-            android:summary="@string/pref_use_green_background_summary"
-            android:title="@string/pref_use_green_background" />
-        <ListPreference
-            android:defaultValue="@string/default_font_size"
-            android:entries="@array/font_size_entries"
-            android:entryValues="@array/font_size_entry_values"
-            android:key="font_size"
-            android:summary="@string/pref_font_size_summary"
-            android:title="@string/pref_font_size" />
-        <CheckBoxPreference
-            android:defaultValue="@bool/send_button_status"
-            android:key="send_button_status"
-            android:summary="@string/pref_use_send_button_to_indicate_status_summary"
-            android:title="@string/pref_use_send_button_to_indicate_status" />
         <ListPreference
             android:defaultValue="@string/quick_action"
             android:dialogTitle="@string/choose_quick_action"
@@ -183,27 +181,27 @@
             android:key="quick_action"
             android:summary="@string/pref_quick_action_summary"
             android:title="@string/pref_quick_action" />
-        <CheckBoxPreference
+        <ListPreference
-            android:defaultValue="@bool/show_dynamic_tags"
+            android:defaultValue="@string/default_font_size"
-            android:key="show_dynamic_tags"
+            android:entries="@array/font_size_entries"
-            android:summary="@string/pref_show_dynamic_tags_summary"
+            android:entryValues="@array/font_size_entry_values"
-            android:title="@string/pref_show_dynamic_tags" />
+            android:key="font_size"
+            android:summary="@string/pref_font_size_summary"
+            android:title="@string/pref_font_size" />
     </PreferenceCategory>
     <PreferenceCategory
         android:key="advanced"
         android:title="@string/pref_advanced_options">
+        <CheckBoxPreference
+            android:defaultValue="@bool/never_send"
+            android:key="never_send"
+            android:summary="@string/pref_never_send_crash_summary"
+            android:title="@string/pref_never_send_crash" />
+
         <PreferenceScreen
             android:key="expert"
             android:summary="@string/pref_expert_options_summary"
             android:title="@string/pref_expert_options">
-            <intent
-                android:action="android.intent.action.VIEW"
-                android:targetClass="eu.siacs.conversations.ui.SettingsActivity"
-                android:targetPackage="@string/applicationId">
-                <extra
-                    android:name="page"
-                    android:value="expert" />
-            </intent>
             <PreferenceCategory
                 android:key="security_options"
                 android:title="@string/pref_security_settings">
@@ -212,11 +210,6 @@
                     android:key="btbv"
                     android:summary="@string/pref_blind_trust_before_verification_summary"
                     android:title="@string/pref_blind_trust_before_verification" />
-                <ListPreference
-                    android:defaultValue="@integer/automatic_message_deletion"
-                    android:key="automatic_message_deletion"
-                    android:summary="@string/pref_automatically_delete_messages_description"
-                    android:title="@string/pref_automatically_delete_messages" />
                 <CheckBoxPreference
                     android:defaultValue="@bool/dont_trust_system_cas"
                     android:key="dont_trust_system_cas"
@@ -227,15 +220,20 @@
                     android:key="validate_hostname"
                     android:summary="@string/pref_validate_hostname_summary"
                     android:title="@string/pref_validate_hostname" />
-                <Preference
-                    android:key="remove_trusted_certificates"
-                    android:summary="@string/pref_remove_trusted_certificates_summary"
-                    android:title="@string/pref_remove_trusted_certificates_title" />
                 <CheckBoxPreference
                     android:defaultValue="@bool/allow_message_correction"
                     android:key="allow_message_correction"
                     android:summary="@string/pref_allow_message_correction_summary"
                     android:title="@string/pref_allow_message_correction" />
+                <ListPreference
+                    android:defaultValue="@integer/automatic_message_deletion"
+                    android:key="automatic_message_deletion"
+                    android:summary="@string/pref_automatically_delete_messages_description"
+                    android:title="@string/pref_automatically_delete_messages" />
+                <Preference
+                    android:key="remove_trusted_certificates"
+                    android:summary="@string/pref_remove_trusted_certificates_summary"
+                    android:title="@string/pref_remove_trusted_certificates_title" />
                 <Preference
                     android:key="clean_cache"
                     android:summary="@string/pref_clean_cache_summary"
@@ -312,13 +310,24 @@
                     android:title="@string/pref_treat_vibrate_as_silent" />
             </PreferenceCategory>
             <PreferenceCategory
-                android:key="other_expert_category"
+                android:key="group_chats"
-                android:title="@string/pref_expert_options_other">
+                android:title="@string/group_chats_and_channels">
                 <CheckBoxPreference
                     android:defaultValue="@bool/autojoin"
                     android:key="autojoin"
                     android:summary="@string/pref_autojoin_summary"
                     android:title="@string/pref_autojoin" />
+                <ListPreference
+                    android:defaultValue="@string/default_channel_discovery"
+                    android:entries="@array/channel_discovery_entries"
+                    android:entryValues="@array/channel_discover_values"
+                    android:key="channel_discovery_method"
+                    android:summary="@string/pref_channel_discovery_summary"
+                    android:title="@string/pref_channel_discovery" />
+            </PreferenceCategory>
+            <PreferenceCategory
+                android:key="other_expert_category"
+                android:title="@string/pref_expert_options_other">
                 <CheckBoxPreference
                     android:defaultValue="@bool/indicate_received"
                     android:key="indicate_received"
@@ -334,13 +343,15 @@
                     android:summary="@string/pref_create_backup_summary"
                     android:title="@string/pref_create_backup" />
             </PreferenceCategory>
+            <intent
+                android:action="android.intent.action.VIEW"
+                android:targetClass="eu.siacs.conversations.ui.SettingsActivity"
+                android:targetPackage="@string/applicationId">
+                <extra
+                    android:name="page"
+                    android:value="expert" />
+            </intent>
         </PreferenceScreen>
-
-        <CheckBoxPreference
-            android:defaultValue="@bool/never_send"
-            android:key="never_send"
-            android:summary="@string/pref_never_send_crash_summary"
-            android:title="@string/pref_never_send_crash" />
     </PreferenceCategory>
-    <eu.siacs.conversations.ui.AboutPreference/>
+    <eu.siacs.conversations.ui.AboutPreference />
 </PreferenceScreen>