Add debug command for helping with issues related to duplicate entities

Plugin/src/main/java/com/gmail/filoghost/holographicdisplays/commands/main/HologramsCommandHandler.java

@@ -31,6 +31,7 @@ import com.gmail.filoghost.holographicdisplays.commands.main.subs.AddlineCommand
 import com.gmail.filoghost.holographicdisplays.commands.main.subs.AlignCommand;
 import com.gmail.filoghost.holographicdisplays.commands.main.subs.CopyCommand;
 import com.gmail.filoghost.holographicdisplays.commands.main.subs.CreateCommand;
+import com.gmail.filoghost.holographicdisplays.commands.main.subs.DebugCommand;
 import com.gmail.filoghost.holographicdisplays.commands.main.subs.DeleteCommand;
 import com.gmail.filoghost.holographicdisplays.commands.main.subs.EditCommand;
 import com.gmail.filoghost.holographicdisplays.commands.main.subs.HelpCommand;
@@ -75,6 +76,7 @@ public class HologramsCommandHandler implements CommandExecutor {
 		registerSubCommand(new ReadimageCommand());
 		registerSubCommand(new InfoCommand());
 		
+		registerSubCommand(new DebugCommand());
 		registerSubCommand(new HelpCommand());
 	}
 	

Plugin/src/main/java/com/gmail/filoghost/holographicdisplays/commands/main/subs/DebugCommand.java

@@ -0,0 +1,132 @@
+/*
+ *  This program is free software: you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation, either version 3 of the License, or
+ *  (at your option) any later version.
+ *  
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ *  GNU General Public License for more details.
+ *  
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+package com.gmail.filoghost.holographicdisplays.commands.main.subs;
+
+import java.util.Arrays;
+import java.util.HashMap;
+import java.util.List;
+import java.util.Map;
+import java.util.Map.Entry;
+
+import org.bukkit.Bukkit;
+import org.bukkit.World;
+import org.bukkit.command.CommandSender;
+import org.bukkit.entity.Entity;
+
+import com.gmail.filoghost.holographicdisplays.HolographicDisplays;
+import com.gmail.filoghost.holographicdisplays.api.Hologram;
+import com.gmail.filoghost.holographicdisplays.commands.Colors;
+import com.gmail.filoghost.holographicdisplays.commands.Strings;
+import com.gmail.filoghost.holographicdisplays.commands.main.HologramSubCommand;
+import com.gmail.filoghost.holographicdisplays.exception.CommandException;
+import com.gmail.filoghost.holographicdisplays.nms.interfaces.entity.NMSEntityBase;
+import com.gmail.filoghost.holographicdisplays.object.NamedHologram;
+import com.gmail.filoghost.holographicdisplays.object.PluginHologram;
+
+public class DebugCommand extends HologramSubCommand {
+
+	public DebugCommand() {
+		super("debug");
+		setPermission(Strings.BASE_PERM + "debug");
+	}
+
+	@Override
+	public String getPossibleArguments() {
+		return "";
+	}
+
+	@Override
+	public int getMinimumArguments() {
+		return 0;
+	}
+
+	@Override
+	public void execute(CommandSender sender, String label, String[] args) throws CommandException {
+		boolean foundAnyHologram = false;
+		
+		for (World world : Bukkit.getWorlds()) {
+			Map<Hologram, HologramDebugInfo> hologramsDebugInfo = new HashMap<>();
+			
+			for (Entity entity : world.getEntities()) {
+				NMSEntityBase nmsEntity = HolographicDisplays.getNMSManager().getNMSEntityBase(entity);
+				
+				if (nmsEntity == null) {
+					continue;
+				}
+				
+				Hologram ownerHologram = nmsEntity.getHologramLine().getParent();
+				HologramDebugInfo hologramDebugInfo = hologramsDebugInfo.computeIfAbsent(ownerHologram, mapKey -> new HologramDebugInfo());
+				
+				if (nmsEntity.isDeadNMS()) {
+					hologramDebugInfo.deadEntities++;
+				} else {
+					hologramDebugInfo.aliveEntities++;
+				}
+			}
+			
+			if (!hologramsDebugInfo.isEmpty()) {
+				foundAnyHologram = true;
+				sender.sendMessage(Colors.PRIMARY + "Holograms in world '" + world.getName() + "':");
+				
+				for (Entry<Hologram, HologramDebugInfo> entry : hologramsDebugInfo.entrySet()) {
+					Hologram hologram = entry.getKey();
+					String displayName = getHologramDisplayName(hologram);
+					HologramDebugInfo debugInfo = entry.getValue();
+					sender.sendMessage(Colors.PRIMARY_SHADOW + "- '" + displayName + "': " + hologram.size() + " lines, "
+							+ debugInfo.getTotalEntities() + " entities (" + debugInfo.aliveEntities + " alive, " + debugInfo.deadEntities + " dead)");
+				}
+			}
+		}
+		
+		if (!foundAnyHologram) {
+			sender.sendMessage(Colors.ERROR + "Couldn't find any loaded hologram (holograms may be in unloaded chunks).");
+		}
+		
+	}
+
+	private String getHologramDisplayName(Hologram hologram) {
+		if (hologram instanceof NamedHologram) {
+			return ((NamedHologram) hologram).getName();
+		} else if (hologram instanceof PluginHologram) {
+			return ((PluginHologram) hologram).getOwner().getName() + "@" + Integer.toHexString(hologram.hashCode());
+		} else {
+			return hologram.toString();
+		}
+	}
+
+	@Override
+	public List<String> getTutorial() {
+		return Arrays.asList("Displays information useful for debugging.");
+	}
+	
+	@Override
+	public SubCommandType getType() {
+		return SubCommandType.HIDDEN;
+	}
+	
+	
+	private static class HologramDebugInfo {
+		
+		private int aliveEntities;
+		private int deadEntities;
+		
+		public int getTotalEntities() {
+			return aliveEntities + deadEntities;
+		}
+		
+	}
+	
+
+}