Add working leaving of a group

Additionally fixed a two bugs:
- one group member will no longer show "1 members"
- deletion of empty groups no longer throws an exception

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

@@ -379,12 +379,27 @@ public final class LocalDB implements EventListener {
 	 */
 	public void setUserAndMergeContacts(User user) {
 		this.user = user;
-		if (contactsChanged)
+		if (contactsChanged) {
+			final var contacts = user.getContacts();
 
 			// Mark chats as disabled if a contact is no longer in this users contact list
-			changedChats = chats.stream()
-				.filter(not(chat -> user.getContacts().contains(chat.getRecipient())))
+			final var changedUserChats = chats.stream()
+				.filter(not(chat -> contacts.contains(chat.getRecipient())))
 				.peek(chat -> { chat.setDisabled(true); logger.log(Level.INFO, String.format("Marked %s as blocked.", chat.getRecipient())); });
+
+			// Also update groups with a different member count
+			final var changedGroupChats = contacts.stream().filter(Group.class::isInstance).flatMap(group -> {
+				final var potentialChat = getChat(group.getID());
+				if (potentialChat.isEmpty()) return Stream.empty();
+				final var chat = potentialChat.get();
+				if (group.getContacts().size() != chat.getRecipient().getContacts().size()) {
+					logger.log(Level.INFO, "Removed one (or more) members from " + group);
+					return Stream.of(chat);
+				} else return Stream.empty();
+			});
+
+			changedChats = Stream.concat(changedUserChats, changedGroupChats);
+		}
 	}
 
 	/**

client/src/main/java/envoy/client/ui/control/GroupSizeLabel.java

@@ -16,5 +16,7 @@ public final class GroupSizeLabel extends Label {
 	 * @param recipient the group whose members to show
 	 * @since Envoy Client v0.3-beta
 	 */
-	public GroupSizeLabel(Group recipient) { super(recipient.getContacts().size() + " members"); }
+	public GroupSizeLabel(Group recipient) {
+		super(recipient.getContacts().size() + " member" + (recipient.getContacts().size() != 1 ? "s" : ""));
+	}
 }

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

@@ -281,7 +281,8 @@ public final class ChatScene implements EventListener, Restorable {
 
 			// Update the top-bar status label if all conditions apply
 			if (currentChat != null && currentChat.getRecipient().equals(chatFound.get().getRecipient()))
-				topBarStatusLabel.setText(chatFound.get().getRecipient().getContacts().size() + " members");
+				topBarStatusLabel.setText(chatFound.get().getRecipient().getContacts().size() + " member"
+						+ (currentChat.getRecipient().getContacts().size() != 1 ? "s" : ""));
 		});
 	}
 
@@ -383,7 +384,8 @@ public final class ChatScene implements EventListener, Restorable {
 				topBarStatusLabel.setVisible(true);
 				recipientProfilePic.setImage(IconUtil.loadIconThemeSensitive("user_icon", 43));
 			} else {
-				topBarStatusLabel.setText(currentChat.getRecipient().getContacts().size() + " members");
+				topBarStatusLabel.setText(currentChat.getRecipient().getContacts().size() + " member"
+						+ (currentChat.getRecipient().getContacts().size() != 1 ? "s" : ""));
 				topBarStatusLabel.getStyleClass().clear();
 				recipientProfilePic.setImage(IconUtil.loadIconThemeSensitive("group_icon", 43));
 			}
@@ -752,7 +754,13 @@ public final class ChatScene implements EventListener, Restorable {
 	 * @since Envoy Client v0.3-beta
 	 */
 	public void disableChat(Contact recipient, boolean refreshChatList) {
-		if (refreshChatList) chatList.refresh();
+		if (refreshChatList) {
+			chatList.refresh();
+
+			// Decrement member count for groups
+			if (recipient instanceof Group)
+				topBarStatusLabel.setText(recipient.getContacts().size() + " member" + (recipient.getContacts().size() != 1 ? "s" : ""));
+		}
 		if (currentChat != null && currentChat.getRecipient().equals(recipient)) {
 			messageTextArea.setDisable(true);
 			voiceButton.setDisable(true);

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

@@ -82,15 +82,19 @@ public final class UserUtil {
 		if (!context.getClient().isOnline() || block == null) return;
 		else {
 			final var alert = new Alert(AlertType.CONFIRMATION);
-			alert.setContentText("Are you sure you want to block " + block.getName() + "?");
+			alert.setContentText("Are you sure you want to " + (block instanceof User ? "block " : "leave group ") + block.getName() + "?");
 			AlertHelper.confirmAction(alert, () -> {
 				context.getClient()
 					.send(block instanceof User ? new UserOperation((User) block, ElementOperation.REMOVE)
 							: new GroupResize(context.getLocalDB().getUser(), (Group) block, ElementOperation.REMOVE));
 				context.getLocalDB().getChat(block.getID()).ifPresent(chat -> chat.setDisabled(true));
+				if (block instanceof User) logger.log(Level.INFO, "A user was blocked.");
+				else {
+					block.getContacts().remove(context.getLocalDB().getUser());
+					logger.log(Level.INFO, "The user left a group.");
+				}
 				final var controller = context.getSceneContext().getController();
 				if (controller instanceof ChatScene) ((ChatScene) controller).disableChat(block, true);
-				logger.log(Level.INFO, "A contact was blocked.");
 			});
 		}
 	}

server/src/main/java/envoy/server/Startup.java

@@ -49,6 +49,7 @@ public final class Startup {
 						new MessageStatusChangeProcessor(),
 						new GroupMessageStatusChangeProcessor(),
 						new UserStatusChangeProcessor(),
+						new GroupResizeProcessor(),
 						new IDGeneratorRequestProcessor(),
 						new UserSearchProcessor(),
 						new UserOperationProcessor(),

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

@@ -51,7 +51,7 @@ public class Message {
 	@Id
 	protected long id;
 
-	@ManyToOne
+	@ManyToOne(cascade = CascadeType.REMOVE)
 	@JoinColumn
 	protected User sender;
 

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

@@ -105,11 +105,6 @@ public final class PersistenceManager {
 			// Remove this contact from the contact list of his contacts
 			for (final var remainingContact : contact.getContacts())
 				remainingContact.getContacts().remove(contact);
-
-			// Delete messages sent or received by this contact
-			entityManager.createQuery("DELETE FROM Message m WHERE (m.sender = :contact OR m.recipient = :contact )")
-				.setParameter("contact", contact)
-				.executeUpdate();
 		});
 		remove(contact);
 	}

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

@@ -1,8 +1,12 @@
 package envoy.server.processors;
 
+import java.time.Instant;
+import java.util.logging.Level;
+
 import envoy.event.GroupResize;
 import envoy.server.data.*;
-import envoy.server.net.*;
+import envoy.server.net.ObjectWriteProxy;
+import envoy.util.EnvoyLog;
 
 /**
  * @author Maximilian Käfer
@@ -11,34 +15,37 @@ import envoy.server.net.*;
 public final class GroupResizeProcessor implements ObjectProcessor<GroupResize> {
 
 	private static final PersistenceManager persistenceManager = PersistenceManager.getInstance();
-	private static final ConnectionManager	connectionManager	= ConnectionManager.getInstance();
 
 	@Override
 	public void process(GroupResize groupResize, long socketID, ObjectWriteProxy writeProxy) {
 
 		// Acquire the group to resize from the database
-		var group = persistenceManager.getGroupByID(groupResize.getGroupID());
+		final var	group	= persistenceManager.getGroupByID(groupResize.getGroupID());
+		final var	sender	= persistenceManager.getUserByID(groupResize.get().getID());
 
 		// Perform the desired operation
 		switch (groupResize.getOperation()) {
 			case ADD:
-				group.getContacts().add(persistenceManager.getUserByID(groupResize.get().getID()));
-				break;
+				persistenceManager.addContactBidirectional(sender, group);
+				writeProxy.writeToOnlineContacts(group.getContacts(), group.toCommon());
+				return;
 			case REMOVE:
-				group.getContacts().remove(persistenceManager.getUserByID(groupResize.get().getID()));
-				break;
+				persistenceManager.removeContactBidirectional(sender, group);
+				sender.setLatestContactDeletion(Instant.now());
+
+				// The group has no more members and hence will be deleted
+				if (group.getContacts().isEmpty()) {
+					EnvoyLog.getLogger(GroupResizeProcessor.class).log(Level.INFO, "Deleting now empty group " + group.getName());
+					persistenceManager.deleteContact(group);
+				} else {
+
+					// Informing the other members
+					writeProxy.writeToOnlineContacts(group.getContacts(), groupResize);
+					group.getContacts().forEach(c -> ((User) c).setLatestContactDeletion(Instant.now()));
 				}
 
-		// Update the group in the database
-		persistenceManager.updateContact(group);
-
-		// Send the updated group to all of its members
-		var commonGroup = group.toCommon();
-		group.getContacts()
-			.stream()
-			.map(Contact::getID)
-			.filter(connectionManager::isOnline)
-			.map(connectionManager::getSocketID)
-			.forEach(memberSocketID -> writeProxy.write(memberSocketID, commonGroup));
+				group.getContacts().remove(persistenceManager.getUserByID(groupResize.get().getID()));
+				return;
+		}
 	}
 }