Various fixes and improvements

- CustomBlockRegistry no longer throws an exception when breaking a custom block
- Commands registered through CommandManager will now be unregistered when the plugin that registered them is disabled
- InventoryGUI now cancels InventoryDragEvents which are in non-open slots in the GUI
- ItemUtils now has a utility method to clone an inventory (cannot be opened, but supports other operations)

src/redempt/redlib/blockdata/CustomBlockRegistry.java

@@ -217,7 +217,7 @@ public <T extends CustomBlock> void onBreak(DataBlockDestroyEvent e) {
 				Bukkit.getScheduler().scheduleSyncDelayedTask(plugin, () -> {
 					List<Item> drops = new ArrayList<>();
 					drops.add(e.getBlock().getWorld().dropItemNaturally(e.getBlock().getLocation(), item));
-					Event event = (Event) NMSHelper.getClass("BlockDropItemEvent").getInstance(e.getBlock(), state, e.getPlayer(), drops).getObject();
+					Event event = (Event) NMSHelper.getClass("org.bukkit.event.block.BlockDropItemEvent").getInstance(e.getBlock(), state, e.getPlayer(), drops).getObject();
 					Bukkit.getPluginManager().callEvent(event);
 					if (((Cancellable) event).isCancelled()) {
 						drops.get(0).remove();

src/redempt/redlib/commandmanager/Command.java

@@ -6,20 +6,21 @@
 import org.bukkit.command.CommandSender;
 import org.bukkit.command.SimpleCommandMap;
 import org.bukkit.entity.Player;
+import org.bukkit.event.server.PluginDisableEvent;
+import org.bukkit.event.server.TabCompleteEvent;
 import org.bukkit.plugin.Plugin;
 import org.bukkit.plugin.java.JavaPlugin;
+import redempt.redlib.RedLib;
 import redempt.redlib.commandmanager.exceptions.CommandParseException;
 import redempt.redlib.commandmanager.exceptions.MissingHookException;
+import redempt.redlib.misc.EventListener;
 import redempt.redlib.region.MultiRegion;
 
 import java.io.InputStream;
 import java.lang.reflect.Field;
 import java.lang.reflect.InvocationTargetException;
 import java.lang.reflect.Method;
-import java.util.ArrayList;
-import java.util.Arrays;
-import java.util.List;
-import java.util.Objects;
+import java.util.*;
 import java.util.function.BiFunction;
 import java.util.function.Function;
 import java.util.stream.Collectors;
@@ -54,7 +55,7 @@ public class Command {
 		}));
 	}
 
-	private Plugin plugin;
+	protected Plugin plugin;
 	private CommandArgument[] args;
 	private ContextProvider<?>[] contextProviders;
 	private ContextProvider<?>[] asserters;
@@ -313,9 +314,9 @@ private boolean assertAll(CommandSender sender) {
 	public void register(String prefix, Object... listeners) {
 		Field field;
 		try {
-			field = Bukkit.getServer().getClass().getDeclaredField("commandMap");
+			field = Bukkit.getPluginManager().getClass().getDeclaredField("commandMap");
 			field.setAccessible(true);
-			SimpleCommandMap map = (SimpleCommandMap) field.get(Bukkit.getServer());
+			SimpleCommandMap map = (SimpleCommandMap) field.get(Bukkit.getPluginManager());
 			org.bukkit.command.Command cmd = new org.bukkit.command.Command(names[0], help == null ? "None" : help, "", Arrays.stream(names).skip(1).collect(Collectors.toList())) {
 
 				@Override
@@ -330,7 +331,26 @@ public List<String> tabComplete(CommandSender sender, String alias, String[] arg
 				}
 
 			};
+			Class<?> clazz = map.getClass();
+			while (!clazz.getSimpleName().equals("SimpleCommandMap")) {
+				clazz = clazz.getSuperclass();
+			}
+			Field mapField = clazz.getDeclaredField("knownCommands");
+			mapField.setAccessible(true);
+			Map<String, org.bukkit.command.Command> knownCommands = (Map<String, org.bukkit.command.Command>) mapField.get(map);
 			map.register(prefix, cmd);
+			if (plugin == null) {
+				plugin = JavaPlugin.getProvidingPlugin(Class.forName(new Exception().getStackTrace()[1].getClassName()));
+			}
+			new EventListener<>(RedLib.getInstance(), PluginDisableEvent.class, e -> {
+				if (e.getPlugin().equals(plugin)) {
+					try {
+						Arrays.stream(names).forEach(knownCommands::remove);
+					} catch (Exception ex) {
+						ex.printStackTrace();
+					}
+				}
+			});
 			loop:
 			for (Object listener : listeners) {
 				for (Method method : listener.getClass().getDeclaredMethods()) {
@@ -435,9 +455,6 @@ protected List<String> tab(CommandSender sender, String[] args) {
 	}
 
 	protected boolean execute(CommandSender sender, String[] args) {
-		if (plugin != null && !plugin.isEnabled()) {
-			return true;
-		}
 		if (permission != null && !sender.hasPermission(permission)) {
 			sender.sendMessage(msg("noPermission").replace("%permission%", permission));
 			return true;

src/redempt/redlib/commandmanager/CommandCollection.java

@@ -7,6 +7,8 @@
 import java.util.stream.Collectors;
 
 import org.bukkit.command.CommandSender;
+import org.bukkit.plugin.Plugin;
+import org.bukkit.plugin.java.JavaPlugin;
 
 /**
  * Represents a collection of commands which can be mass-registered. Can contain any amount of commands, including 0
@@ -28,7 +30,18 @@ public CommandCollection(List<Command> commands) {
 	 */
 	public void register(String prefix, Object... listeners) {
 		mergeBaseCommands();
-		commands.stream().forEach(c -> c.register(prefix, listeners));
+		Plugin plugin = null;
+		try {
+			Class<?> clazz = Class.forName(new Exception().getStackTrace()[1].getClassName());
+			plugin = JavaPlugin.getProvidingPlugin(clazz);
+		} catch (ClassNotFoundException e) {
+			e.printStackTrace();
+		}
+		Plugin fplugin = plugin;
+		commands.stream().forEach(c -> {
+			c.plugin = fplugin;
+			c.register(prefix, listeners);
+		});
 	}
 
 	private void mergeBaseCommands() {

src/redempt/redlib/inventorygui/InventoryGUI.java

@@ -12,10 +12,7 @@
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.HandlerList;
 import org.bukkit.event.Listener;
-import org.bukkit.event.inventory.ClickType;
-import org.bukkit.event.inventory.InventoryAction;
-import org.bukkit.event.inventory.InventoryClickEvent;
-import org.bukkit.event.inventory.InventoryCloseEvent;
+import org.bukkit.event.inventory.*;
 import org.bukkit.inventory.Inventory;
 import org.bukkit.inventory.ItemStack;
 
@@ -317,6 +314,13 @@ public void clear() {
 		buttons.clear();
 	}
 
+	@EventHandler
+	public void onDrag(InventoryDragEvent e) {
+		if (e.getRawSlots().stream().anyMatch(s -> e.getView().getInventory(s).equals(inventory) && !openSlots.contains(s))) {
+			e.setCancelled(true);
+		}
+	}
+
 	@EventHandler
 	public void onClick(InventoryClickEvent e) {
 		if (!inventory.equals(e.getView().getTopInventory())) {

src/redempt/redlib/itemutils/ItemUtils.java

@@ -5,17 +5,18 @@
 import java.util.List;
 import java.util.UUID;
 
+import org.bukkit.Bukkit;
 import org.bukkit.Material;
 import org.bukkit.NamespacedKey;
 import org.bukkit.attribute.Attribute;
 import org.bukkit.attribute.AttributeModifier;
 import org.bukkit.attribute.AttributeModifier.Operation;
 import org.bukkit.enchantments.Enchantment;
 import org.bukkit.entity.Player;
-import org.bukkit.inventory.EquipmentSlot;
-import org.bukkit.inventory.Inventory;
-import org.bukkit.inventory.ItemFlag;
-import org.bukkit.inventory.ItemStack;
+import org.bukkit.event.inventory.ClickType;
+import org.bukkit.event.inventory.InventoryAction;
+import org.bukkit.event.inventory.InventoryClickEvent;
+import org.bukkit.inventory.*;
 import org.bukkit.inventory.meta.ItemMeta;
 import org.bukkit.persistence.PersistentDataType;
 
@@ -423,4 +424,22 @@ public static boolean compare(ItemStack first, ItemStack second) {
 		return true;
 	}
 
+	/**
+	 * Creates a mock inventory clone of the given inventory. Do not try to open this inventory for players,
+	 * it will throw an error.
+	 * @param inv The inventory to clone
+	 * @return A mock clone inventory
+	 */
+	public static Inventory cloneInventory(Inventory inv) {
+		ItemStack[] contents = new ItemStack[inv.getSize()];
+		for (int i = 0; i < inv.getSize(); i++) {
+			ItemStack item = inv.getItem(i);
+			if (item == null) {
+				continue;
+			}
+			contents[i] = item.clone();
+		}
+		return new MockInventory(contents, inv.getHolder(), inv.getType());
+	}
+
 }