client/src/main/java/envoy/client/data/Chat.java

@@ -22,20 +22,21 @@ import envoy.client.net.WriteProxy;
  */
 public class Chat implements Serializable {
 
+	protected transient ObservableList<Message> messages = FXCollections.observableArrayList();
+
+	protected final Contact recipient;
+
 	protected boolean	disabled;
+	protected boolean	underlyingContactDeleted;
 
 	/**
 	 * Stores the last time an {@link envoy.event.IsTyping} event has been sent.
 	 */
 	protected transient long lastWritingEvent;
 
-	protected transient ObservableList<Message> messages = FXCollections.observableArrayList();
-
 	protected int						unreadAmount;
 	protected static IntegerProperty	totalUnreadAmount	= new SimpleIntegerProperty();
 
-	protected final Contact recipient;
-
 	private static final long serialVersionUID = 2L;
 
 	/**

client/src/main/java/envoy/client/data/LocalDB.java

@@ -248,6 +248,10 @@ public final class LocalDB implements EventListener {
 	 */
 	@Event(eventType = EnvoyCloseEvent.class, priority = 500)
 	private synchronized void save() {
+
+		// Stop saving if this account has been deleted
+		if (userFile == null)
+			return;
 		EnvoyLog.getLogger(LocalDB.class).log(Level.FINER, "Saving local database...");
 
 		// Save users
@@ -273,6 +277,29 @@ public final class LocalDB implements EventListener {
 		}
 	}
 
+	/**
+	 * Deletes any local remnant of this user.
+	 *
+	 * @since Envoy Client v0.3-beta
+	 */
+	public void delete() {
+		try {
+
+			// Save ID generator - can be used for other users in that db
+			if (hasIDGenerator())
+				SerializationUtils.write(idGeneratorFile, idGenerator);
+		} catch (final IOException e) {
+			EnvoyLog.getLogger(LocalDB.class).log(Level.SEVERE, "Unable to save local database: ",
+				e);
+		}
+		if (lastLoginFile != null)
+			lastLoginFile.delete();
+		userFile.delete();
+		users.remove(user.getName());
+		userFile = null;
+		onLogout();
+	}
+
 	@Event(priority = 500)
 	private void onMessage(Message msg) {
 		if (msg.getStatus() == MessageStatus.SENT)
@@ -404,6 +431,14 @@ public final class LocalDB implements EventListener {
 		getChat(event.get().getID()).ifPresent(chat -> chat.setDisabled(true));
 	}
 
+	@Event(priority = 500)
+	private void onAccountDeletion(AccountDeletion deletion) {
+		if (user.getID() == deletion.get())
+			logger.log(Level.WARNING,
+				"I have been informed by the server that I have been deleted without even knowing it...");
+		getChat(deletion.get()).ifPresent(chat -> chat.setDisabled(true));
+	}
+
 	/**
 	 * @return a {@code Map<String, User>} of all users stored locally with their user names as keys
 	 * @since Envoy Client v0.2-alpha

client/src/main/java/envoy/client/event/AccountDeletion.java

@@ -0,0 +1,22 @@
+package envoy.client.event;
+
+import envoy.event.Event;
+
+/**
+ * Signifies the deletion of an account.
+ * 
+ * @author Leon Hofmeister
+ * @since Envoy Common v0.3-beta
+ */
+public class AccountDeletion extends Event<Long> {
+
+	private static final long serialVersionUID = 1L;
+
+	/**
+	 * @param value the ID of the contact that was deleted
+	 * @since Envoy Common v0.3-beta
+	 */
+	public AccountDeletion(Long value) {
+		super(value);
+	}
+}

client/src/main/java/envoy/client/ui/controller/ChatScene.java

@@ -6,6 +6,7 @@ import java.io.*;
 import java.nio.file.Files;
 import java.time.LocalDateTime;
 import java.time.format.DateTimeFormatter;
+import java.util.Map;
 import java.util.logging.*;
 
 import javafx.animation.RotateTransition;
@@ -31,12 +32,13 @@ import envoy.data.*;
 import envoy.data.Attachment.AttachmentType;
 import envoy.data.Message.MessageStatus;
 import envoy.event.*;
-import envoy.event.contact.UserOperation;
+import envoy.event.contact.*;
 import envoy.exception.EnvoyException;
 import envoy.util.EnvoyLog;
 
 import envoy.client.data.*;
 import envoy.client.data.audio.AudioRecorder;
+import envoy.client.data.shortcuts.KeyboardMapping;
 import envoy.client.event.*;
 import envoy.client.net.*;
 import envoy.client.ui.*;
@@ -51,7 +53,7 @@ import envoy.client.util.*;
  * @author Kai S. K. Engelbart
  * @since Envoy Client v0.1-beta
  */
-public final class ChatScene implements EventListener, Restorable {
+public final class ChatScene implements EventListener, Restorable, KeyboardMapping {
 
 	@FXML
 	private ListView<Message> messageList;
@@ -346,6 +348,11 @@ public final class ChatScene implements EventListener, Restorable {
 		eventBus.removeListener(this);
 	}
 
+	@Event(eventType = AccountDeletion.class)
+	private void onAccountDeletion() {
+		Platform.runLater(chatList::refresh);
+	}
+
 	@Override
 	public void onRestore() {
 		updateRemainingCharsLabel();
@@ -871,4 +878,25 @@ public final class ChatScene implements EventListener, Restorable {
 			: c -> c.getRecipient().getName().toLowerCase()
 				.contains(contactSearch.getText().toLowerCase()));
 	}
+
+	@Override
+	public Map<KeyCombination, Runnable> getKeyboardShortcuts() {
+		return Map.<KeyCombination, Runnable>of(
+
+			// Delete text before the caret with "Control" + U
+			new KeyCodeCombination(KeyCode.U, KeyCombination.CONTROL_DOWN), () -> {
+				messageTextArea
+					.setText(
+						messageTextArea.getText().substring(messageTextArea.getCaretPosition()));
+				checkPostConditions(false);
+
+				// Delete text after the caret with "Control" + K
+			}, new KeyCodeCombination(KeyCode.K, KeyCombination.CONTROL_DOWN), () -> {
+				messageTextArea
+					.setText(
+						messageTextArea.getText().substring(0, messageTextArea.getCaretPosition()));
+				checkPostConditions(false);
+				messageTextArea.positionCaret(messageTextArea.getText().length());
+			});
+	}
 }

client/src/main/java/envoy/client/ui/controller/GroupCreationTab.java

@@ -14,11 +14,11 @@ import dev.kske.eventbus.*;
 
 import envoy.data.*;
 import envoy.event.GroupCreation;
-import envoy.event.contact.UserOperation;
+import envoy.event.contact.*;
 import envoy.util.Bounds;
 
 import envoy.client.data.*;
-import envoy.client.event.BackEvent;
+import envoy.client.event.*;
 import envoy.client.ui.control.*;
 import envoy.client.ui.listcell.ListCellFactory;
 
@@ -252,4 +252,10 @@ public class GroupCreationTab implements EventListener {
 			}
 		});
 	}
+
+	@Event
+	private void onAccountDeletion(AccountDeletion deletion) {
+		final var deletedID = deletion.get();
+		Platform.runLater(() -> userList.getItems().removeIf(user -> (user.getID() == deletedID)));
+	}
 }

client/src/main/java/envoy/client/ui/settings/UserSettingsPane.java

@@ -13,6 +13,7 @@ import javafx.scene.image.*;
 import javafx.scene.input.InputEvent;
 import javafx.scene.layout.HBox;
 import javafx.stage.FileChooser;
+import javafx.util.Duration;
 
 import dev.kske.eventbus.EventBus;
 
@@ -20,7 +21,7 @@ import envoy.event.*;
 import envoy.util.*;
 
 import envoy.client.ui.control.ProfilePicImageView;
-import envoy.client.util.IconUtil;
+import envoy.client.util.*;
 
 /**
  * @author Leon Hofmeister
@@ -38,6 +39,7 @@ public final class UserSettingsPane extends OnlineOnlySettingsPane {
 	private final PasswordField	newPasswordField		= new PasswordField();
 	private final PasswordField	repeatNewPasswordField	= new PasswordField();
 	private final Button		saveButton				= new Button("Save");
+	private final Button		deleteAccountButton		= new Button("Delete Account (Locally)");
 
 	private static final EventBus	eventBus	= EventBus.getInstance();
 	private static final Logger		logger		= EnvoyLog.getLogger(UserSettingsPane.class);
@@ -112,15 +114,18 @@ public final class UserSettingsPane extends OnlineOnlySettingsPane {
 
 		final PasswordField[]					passwordFields	=
 			{ currentPasswordField, newPasswordField, repeatNewPasswordField };
-		final EventHandler<? super InputEvent>	passwordEntered	= e -> {
+		final EventHandler<? super InputEvent>	passwordEntered	=
+			e -> {
 																		newPassword	=
-																		newPasswordField.getText();
-																	validPassword	= newPassword
-																		.equals(
+																			newPasswordField
+																				.getText();
+																		validPassword =
+																			newPassword.equals(
 																				repeatNewPasswordField
 																					.getText())
 																				&& !newPasswordField
-																			.getText().isBlank();
+																					.getText()
+																					.isBlank();
 																	};
 		newPasswordField.setOnInputMethodTextChanged(passwordEntered);
 		newPasswordField.setOnKeyTyped(passwordEntered);
@@ -140,6 +145,18 @@ public final class UserSettingsPane extends OnlineOnlySettingsPane {
 			.setOnAction(e -> save(currentPasswordField.getText()));
 		saveButton.setAlignment(Pos.BOTTOM_RIGHT);
 		getChildren().add(saveButton);
+
+		// Displaying the delete account button
+		deleteAccountButton.setAlignment(Pos.BASELINE_CENTER);
+		deleteAccountButton.setOnAction(e -> UserUtil.deleteAccount());
+		deleteAccountButton.setText("Delete Account (locally)");
+		deleteAccountButton.setPrefHeight(25);
+		deleteAccountButton.getStyleClass().clear();
+		deleteAccountButton.getStyleClass().add("danger-button");
+		final var tooltip = new Tooltip("Remote deletion is currently unsupported.");
+		tooltip.setShowDelay(Duration.millis(100));
+		deleteAccountButton.setTooltip(tooltip);
+		getChildren().add(deleteAccountButton);
 	}
 
 	/**

client/src/main/java/envoy/client/util/UserUtil.java

@@ -2,7 +2,7 @@ package envoy.client.util;
 
 import java.util.logging.*;
 
-import javafx.scene.control.Alert;
+import javafx.scene.control.*;
 import javafx.scene.control.Alert.AlertType;
 
 import dev.kske.eventbus.EventBus;
@@ -121,4 +121,35 @@ public final class UserUtil {
 			});
 		}
 	}
+
+	/**
+	 * Deletes anything pointing to this user, independent of client or server. Will do nothing if
+	 * the client is currently offline.
+	 *
+	 * @since Envoy Client v0.3-beta
+	 */
+	public static void deleteAccount() {
+
+		// Show the first wall of defense, if not disabled by the user
+		final var outerAlert = new Alert(AlertType.CONFIRMATION);
+		outerAlert.setContentText(
+			"Are you sure you want to delete your account entirely? This action can seriously not be undone.");
+		outerAlert.setTitle("Delete Account?");
+		AlertHelper.confirmAction(outerAlert, () -> {
+
+			// Show the final wall of defense in every case
+			final var lastAlert = new Alert(AlertType.WARNING,
+				"Do you REALLY want to delete your account? Last Warning. Proceed?",
+				ButtonType.CANCEL, ButtonType.OK);
+			lastAlert.setTitle("Delete Account?");
+			lastAlert.showAndWait().filter(ButtonType.OK::equals).ifPresent(b2 -> {
+
+				// Delete the account
+				// TODO: Notify server of account deletion
+				context.getLocalDB().delete();
+				logger.log(Level.INFO, "The user just deleted his account. Goodbye.");
+				ShutdownHelper.exit(true);
+			});
+		});
+	}
 }

client/src/main/resources/css/base.css

@@ -70,6 +70,17 @@
 	-fx-text-fill: gray;
 }
 
+.danger-button {
+	-fx-background-color: red;
+	-fx-text-fill: white;
+	-fx-background-radius: 0.2em;
+}
+
+.danger-button:hover {
+	-fx-scale-x: 1.05;
+	-fx-scale-y: 1.05;
+}
+
 .received-message {
 	-fx-alignment: center-left;
 	-fx-background-radius: 1.3em;

client/src/main/resources/css/light.css

@@ -30,6 +30,10 @@
 	-fx-background-color: black;
 }
 
+.tooltip {
+	-fx-text-fill: black;
+}
+
 #login-input-field {
 	-fx-border-color: black;
 }

server/src/main/java/envoy/server/data/PersistenceManager.java

@@ -121,8 +121,9 @@ public final class PersistenceManager {
 		transaction(() -> {
 
 			// Remove this contact from the contact list of his contacts
-			for (final var remainingContact : contact.getContacts())
+			for (final var remainingContact : contact.contacts)
 				remainingContact.getContacts().remove(contact);
+			contact.contacts.clear();
 		});
 		remove(contact);
 	}

server/src/main/java/envoy/server/net/ConnectionManager.java

@@ -49,8 +49,10 @@ public final class ConnectionManager implements ISocketIdListener {
 			// Notify contacts of this users offline-going
 			final envoy.server.data.User user =
 				PersistenceManager.getInstance().getUserByID(getUserIDBySocketID(socketID));
+			if (user != null) {
 				user.setLastSeen(Instant.now());
 				UserStatusChangeProcessor.updateUserStatus(user, UserStatus.OFFLINE);
+			}
 
 			// Remove the socket
 			sockets.entrySet().removeIf(e -> e.getValue() == socketID);

server/src/main/java/envoy/server/processors/GroupMessageStatusChangeProcessor.java

@@ -38,6 +38,8 @@ public final class GroupMessageStatusChangeProcessor
 		}
 		
 		GroupMessage gmsg = (GroupMessage) persistenceManager.getMessageByID(statusChange.getID());
+		if (gmsg == null)
+			return;
 
 		// Any other status than READ is not supposed to be sent to the server
 		if (statusChange.get() != MessageStatus.READ) {

server/src/main/java/envoy/server/processors/GroupResizeProcessor.java

@@ -24,6 +24,10 @@ public final class GroupResizeProcessor implements ObjectProcessor<GroupResize>
 		final var	group	= persistenceManager.getGroupByID(groupResize.getGroupID());
 		final var	sender	= persistenceManager.getUserByID(groupResize.get().getID());
 
+		// TODO: Inform the sender that this group has already been deleted
+		if (group == null)
+			return;
+
 		// Perform the desired operation
 		switch (groupResize.getOperation()) {
 			case ADD:

server/src/main/java/envoy/server/processors/MessageStatusChangeProcessor.java

@@ -32,6 +32,8 @@ public final class MessageStatusChangeProcessor implements ObjectProcessor<Messa
 		}
 
 		final var msg = persistenceManager.getMessageByID(statusChange.getID());
+		if (msg == null)
+			return;
 		msg.read();
 		persistenceManager.updateMessage(msg);
 

server/src/main/java/envoy/server/processors/UserOperationProcessor.java

@@ -22,9 +22,15 @@ public final class UserOperationProcessor implements ObjectProcessor<UserOperati
 	private static final PersistenceManager	persistenceManager	= PersistenceManager.getInstance();
 
 	@Override
-	public void process(UserOperation evt, long socketId, ObjectWriteProxy writeProxy) {
-		final long	userID		= ConnectionManager.getInstance().getUserIDBySocketID(socketId);
+	public void process(UserOperation evt, long socketID, ObjectWriteProxy writeProxy) {
+		final long	userID		= ConnectionManager.getInstance().getUserIDBySocketID(socketID);
 		final long	contactID	= evt.get().getID();
+		final var	recipient	= persistenceManager.getUserByID(contactID);
+
+		// TODO: Inform the sender if the requested contact has already been deleted
+		if (recipient == null)
+			return;
+
 		final var sender = persistenceManager.getUserByID(userID);
 		switch (evt.getOperationType()) {
 			case ADD:
@@ -45,7 +51,7 @@ public final class UserOperationProcessor implements ObjectProcessor<UserOperati
 				sender.setLatestContactDeletion(Instant.now());
 
 				// Notify the removed contact on next startup(s) of this deletion
-				persistenceManager.getUserByID(contactID).setLatestContactDeletion(Instant.now());
+				recipient.setLatestContactDeletion(Instant.now());
 
 				// Notify the removed contact if online
 				if (connectionManager.isOnline(contactID))