Disallow joining same chatroom

src/main/java/eu/m724/tweaks/chat/ChatCommands.java

@@ -40,6 +40,12 @@ public class ChatCommands implements CommandExecutor {
                 player.spigot().sendMessage(chatRoom.getInfoComponent());
             } else { // join room
                 String id = args[0];
+
+                if (id.equals(chatRoom.id)) {
+                    sender.spigot().sendMessage(Language.getComponent("chatAlreadyHere", ChatColor.GRAY));
+                    return true;
+                }
+
                 String password = null;
                 if (args.length > 1) {
                     password = Arrays.stream(args).skip(1).collect(Collectors.joining(" "));

src/main/java/eu/m724/tweaks/chat/ChatManager.java

@@ -86,6 +86,9 @@ public class ChatManager {
      */
     public void setPlayerChatRoom(ChatRoom chatRoom, Player player) {
         ChatRoom oldRoom = getPlayerChatRoom(player);
+
+        if (chatRoom.equals(oldRoom)) return; // no change if changing to the same room
+
         oldRoom.players.remove(player);
 
         player.getPersistentDataContainer().set(chatRoomKey, PersistentDataType.STRING, chatRoom.id);

src/main/resources/strings.properties

@@ -18,6 +18,7 @@ updatesClickToOpen = Click to open on SpigotMC "%s"
 chatPasswordProtected = This room is password protected
 chatWrongPassword = Wrong password
 chatNoSuchRoom = No room named %s
+chatAlreadyHere = You're already in this room
 # Room name is added at end
 chatJoined = Joined chat room:
 chatPlayers = %d other players are here