make error message for 'not encrypted for this device'

src/main/java/eu/siacs/conversations/crypto/axolotl/AxolotlService.java

@@ -1372,16 +1372,23 @@ public class AxolotlService implements OnAdvancedStreamFeaturesLoaded {
 		return session;
 	}
 
-	public XmppAxolotlMessage.XmppAxolotlPlaintextMessage processReceivingPayloadMessage(XmppAxolotlMessage message, boolean postponePreKeyMessageHandling) {
+	public XmppAxolotlMessage.XmppAxolotlPlaintextMessage processReceivingPayloadMessage(XmppAxolotlMessage message, boolean postponePreKeyMessageHandling) throws NotEncryptedForThisDeviceException {
 		XmppAxolotlMessage.XmppAxolotlPlaintextMessage plaintextMessage = null;
 
 		XmppAxolotlSession session = getReceivingSession(message);
+		int ownDeviceId = getOwnDeviceId();
 		try {
-			plaintextMessage = message.decrypt(session, getOwnDeviceId());
+			plaintextMessage = message.decrypt(session, ownDeviceId);
 			Integer preKeyId = session.getPreKeyIdAndReset();
 			if (preKeyId != null) {
 				postPreKeyMessageHandling(session, preKeyId, postponePreKeyMessageHandling);
 			}
+		} catch (NotEncryptedForThisDeviceException e) {
+			if (account.getJid().asBareJid().equals(message.getFrom().asBareJid()) && message.getSenderDeviceId() == ownDeviceId) {
+				Log.w(Config.LOGTAG, getLogprefix(account) + "Reflected omemo message received");
+			} else {
+				throw e;
+			}
 		} catch (CryptoFailedException e) {
 			Log.w(Config.LOGTAG, getLogprefix(account) + "Failed to decrypt message from " + message.getFrom() + ": " + e.getMessage());
 		}

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

@@ -42,6 +42,7 @@ public class Message extends AbstractEntity {
 	public static final int ENCRYPTION_DECRYPTED = 3;
 	public static final int ENCRYPTION_DECRYPTION_FAILED = 4;
 	public static final int ENCRYPTION_AXOLOTL = 5;
+	public static final int ENCRYPTION_AXOLOTL_NOT_FOR_THIS_DEVICE = 6;
 
 	public static final int TYPE_TEXT = 0;
 	public static final int TYPE_IMAGE = 1;
@@ -869,6 +870,9 @@ public class Message extends AbstractEntity {
 		if (encryption == ENCRYPTION_DECRYPTED || encryption == ENCRYPTION_DECRYPTION_FAILED) {
 			return ENCRYPTION_PGP;
 		}
+		if (encryption == ENCRYPTION_AXOLOTL_NOT_FOR_THIS_DEVICE) {
+			return ENCRYPTION_AXOLOTL;
+		}
 		return encryption;
 	}
 }

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

@@ -16,6 +16,7 @@ import java.util.UUID;
 import eu.siacs.conversations.Config;
 import eu.siacs.conversations.R;
 import eu.siacs.conversations.crypto.axolotl.AxolotlService;
+import eu.siacs.conversations.crypto.axolotl.NotEncryptedForThisDeviceException;
 import eu.siacs.conversations.crypto.axolotl.XmppAxolotlMessage;
 import eu.siacs.conversations.entities.Account;
 import eu.siacs.conversations.entities.Bookmark;
@@ -114,7 +115,12 @@ public class MessageParser extends AbstractParser implements OnMessagePacketRece
 			return null;
 		}
 		if (xmppAxolotlMessage.hasPayload()) {
-			final XmppAxolotlMessage.XmppAxolotlPlaintextMessage plaintextMessage = service.processReceivingPayloadMessage(xmppAxolotlMessage, postpone);
+			final XmppAxolotlMessage.XmppAxolotlPlaintextMessage plaintextMessage;
+			try {
+				plaintextMessage = service.processReceivingPayloadMessage(xmppAxolotlMessage, postpone);
+			} catch (NotEncryptedForThisDeviceException e) {
+				return new Message(conversation, "", Message.ENCRYPTION_AXOLOTL_NOT_FOR_THIS_DEVICE, status);
+			}
 			if (plaintextMessage != null) {
 				Message finishedMessage = new Message(conversation, plaintextMessage.getPlaintext(), Message.ENCRYPTION_AXOLOTL, status);
 				finishedMessage.setFingerprint(plaintextMessage.getFingerprint());
@@ -545,6 +551,8 @@ public class MessageParser extends AbstractParser implements OnMessagePacketRece
 
 			if (message.getEncryption() == Message.ENCRYPTION_PGP) {
 				notify = conversation.getAccount().getPgpDecryptionService().decrypt(message, notify);
+			} else if (message.getEncryption() == Message.ENCRYPTION_AXOLOTL_NOT_FOR_THIS_DEVICE) {
+				notify = false;
 			}
 
 			if (query == null) {

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

@@ -1054,6 +1054,10 @@ public class ConversationFragment extends XmppFragment implements EditMessage.Ke
 		}
 		if (m.getType() != Message.TYPE_STATUS) {
 
+			if (m.getEncryption() == Message.ENCRYPTION_AXOLOTL_NOT_FOR_THIS_DEVICE) {
+				return;
+			}
+
 			final boolean treatAsFile = m.getType() != Message.TYPE_TEXT
 					&& m.getType() != Message.TYPE_PRIVATE
 					&& !(t instanceof TransferablePlaceholder);

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

@@ -807,16 +807,12 @@ public class MessageAdapter extends ArrayAdapter<Message> implements CopyTextVie
 				}
 			} else {
 				displayInfoMessage(viewHolder, activity.getString(R.string.install_openkeychain), darkBackground);
-				viewHolder.message_box.setOnClickListener(new OnClickListener() {
-
-					@Override
-					public void onClick(View v) {
-						activity.showInstallPgpDialog();
-					}
-				});
+				viewHolder.message_box.setOnClickListener(v -> activity.showInstallPgpDialog());
 			}
 		} else if (message.getEncryption() == Message.ENCRYPTION_DECRYPTION_FAILED) {
 			displayDecryptionFailed(viewHolder, darkBackground);
+		} else if (message.getEncryption() == Message.ENCRYPTION_AXOLOTL_NOT_FOR_THIS_DEVICE) {
+			displayInfoMessage(viewHolder, activity.getString(R.string.not_encrypted_for_this_device), darkBackground);
 		} else {
 			if (message.isGeoUri()) {
 				displayLocationMessage(viewHolder, message);

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

@@ -241,6 +241,7 @@ public final class CryptoHelper {
 			case Message.ENCRYPTION_OTR:
 				return R.string.encryption_choice_otr;
 			case Message.ENCRYPTION_AXOLOTL:
+			case Message.ENCRYPTION_AXOLOTL_NOT_FOR_THIS_DEVICE:
 				return R.string.encryption_choice_omemo;
 			case Message.ENCRYPTION_NONE:
 				return R.string.encryption_choice_unencrypted;

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

@@ -277,6 +277,8 @@ public class UIHelper {
 			return new Pair<>(context.getString(R.string.pgp_message), true);
 		} else if (message.getEncryption() == Message.ENCRYPTION_DECRYPTION_FAILED) {
 			return new Pair<>(context.getString(R.string.decryption_failed), true);
+		} else if (message.getEncryption() == Message.ENCRYPTION_AXOLOTL_NOT_FOR_THIS_DEVICE) {
+			return new Pair<>(context.getString(R.string.not_encrypted_for_this_device), true);
 		} else if (message.getType() == Message.TYPE_FILE || message.getType() == Message.TYPE_IMAGE) {
 			if (message.getStatus() == Message.STATUS_RECEIVED) {
 				return new Pair<>(context.getString(R.string.received_x_file,