display propper toast after room has been destroyed

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

@@ -167,6 +167,7 @@ public class MucOptions {
 		RESOURCE_CONSTRAINT,
 		KICKED,
 		SHUTDOWN,
+		DESTROYED,
 		INVALID_NICK,
 		UNKNOWN
 	}

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

@@ -20,6 +20,7 @@ import eu.siacs.conversations.entities.Presence;
 import eu.siacs.conversations.generator.IqGenerator;
 import eu.siacs.conversations.generator.PresenceGenerator;
 import eu.siacs.conversations.services.XmppConnectionService;
+import eu.siacs.conversations.utils.XmppUri;
 import eu.siacs.conversations.xml.Element;
 import eu.siacs.conversations.xml.Namespace;
 import eu.siacs.conversations.xmpp.InvalidJid;
@@ -125,7 +126,15 @@ public class PresenceParser extends AbstractParser implements
 					}
 				}
 			} else if (type.equals("unavailable")) {
-				if (codes.contains(MucOptions.STATUS_CODE_SHUTDOWN) && from.equals(mucOptions.getSelf().getFullJid())) {
+				final boolean fullJidMatches = from.equals(mucOptions.getSelf().getFullJid());
+				if (x.hasChild("destroy") && fullJidMatches) {
+					Element destroy = x.findChild("destroy");
+					final Jid alternate = destroy == null ? null : InvalidJid.getNullForInvalid(destroy.getAttributeAsJid("jid"));
+					mucOptions.setError(MucOptions.Error.DESTROYED);
+					if (alternate != null) {
+						Log.d(Config.LOGTAG, conversation.getAccount().getJid().asBareJid() + ": muc destroyed. alternate location " + alternate);
+					}
+				} else if (codes.contains(MucOptions.STATUS_CODE_SHUTDOWN) && fullJidMatches) {
 					mucOptions.setError(MucOptions.Error.SHUTDOWN);
 				} else if (codes.contains(MucOptions.STATUS_CODE_SELF_PRESENCE)) {
 					if (codes.contains(MucOptions.STATUS_CODE_KICKED)) {
@@ -171,6 +180,23 @@ public class PresenceParser extends AbstractParser implements
 					mucOptions.setError(MucOptions.Error.MEMBERS_ONLY);
 				} else if (error.hasChild("resource-constraint")) {
 					mucOptions.setError(MucOptions.Error.RESOURCE_CONSTRAINT);
+				} else if (error.hasChild("gone")) {
+					final String gone = error.findChildContent("gone");
+					final Jid alternate;
+					if (gone != null) {
+						final XmppUri xmppUri = new XmppUri(gone);
+						if (xmppUri.isJidValid()) {
+							alternate = xmppUri.getJid();
+						} else {
+							alternate = null;
+						}
+					} else {
+						alternate = null;
+					}
+					mucOptions.setError(MucOptions.Error.DESTROYED);
+					if (alternate != null) {
+						Log.d(Config.LOGTAG, conversation.getAccount().getJid().asBareJid() + ": muc destroyed. alternate location " + alternate);
+					}
 				} else {
 					final String text = error.findChildContent("text");
 					if (text != null && text.contains("attribute 'to'")) {

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

@@ -2034,6 +2034,9 @@ public class ConversationFragment extends XmppFragment implements EditMessage.Ke
 				case SHUTDOWN:
 					showSnackbar(R.string.conference_shutdown, R.string.try_again, joinMuc);
 					break;
+				case DESTROYED:
+					showSnackbar(R.string.conference_destroyed, R.string.leave, leaveMuc);
+					break;
 				default:
 					hideSnackbar();
 					break;

src/main/res/values/strings.xml

@@ -721,4 +721,5 @@
     <string name="group_chat_name">Name</string>
     <string name="providing_a_name_is_optional">Providing a name is optional</string>
     <string name="create_dialog_group_chat_name">Group chat name</string>
+    <string name="conference_destroyed">This group chat has been destroyed</string>
 </resources>