Fix item dupe in own inventory

Reduce desync for other actions in own inventory

Closes #182

plugin/src/main/java/com/lishid/openinv/listeners/InventoryListener.java

@@ -16,7 +16,8 @@
 
 package com.lishid.openinv.listeners;
 
-import com.lishid.openinv.IOpenInv;
+import com.lishid.openinv.OpenInv;
+import com.lishid.openinv.internal.ISpecialPlayerInventory;
 import com.lishid.openinv.util.InventoryAccess;
 import com.lishid.openinv.util.Permissions;
 import org.bukkit.GameMode;
@@ -25,11 +26,14 @@ import org.bukkit.entity.Player;
 import org.bukkit.event.EventHandler;
 import org.bukkit.event.EventPriority;
 import org.bukkit.event.Listener;
+import org.bukkit.event.inventory.InventoryAction;
 import org.bukkit.event.inventory.InventoryClickEvent;
 import org.bukkit.event.inventory.InventoryCloseEvent;
 import org.bukkit.event.inventory.InventoryDragEvent;
 import org.bukkit.event.inventory.InventoryInteractEvent;
 import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.ItemStack;
+import org.jetbrains.annotations.NotNull;
 
 /**
  * Listener for inventory-related events to prevent modification of inventories where not allowed.
@@ -38,14 +42,14 @@ import org.bukkit.inventory.Inventory;
  */
 public class InventoryListener implements Listener {
 
-    private final IOpenInv plugin;
+    private final OpenInv plugin;
 
-    public InventoryListener(final IOpenInv plugin) {
+    public InventoryListener(final OpenInv plugin) {
         this.plugin = plugin;
     }
 
     @EventHandler
-    public void onInventoryClose(final InventoryCloseEvent event) {
+    public void onInventoryClose(@NotNull final InventoryCloseEvent event) {
         if (!(event.getPlayer() instanceof Player)) {
             return;
         }
@@ -58,37 +62,92 @@ public class InventoryListener implements Listener {
     }
 
     @EventHandler(priority = EventPriority.LOWEST)
-    public void onInventoryClick(InventoryClickEvent event) {
-        onInventoryInteract(event);
+    public void onInventoryClick(@NotNull final InventoryClickEvent event) {
+        if (handleInventoryInteract(event)) {
+            return;
+        }
+
+        // Only specially handle actions in the player's own inventory.
+        if (!event.getWhoClicked().equals(event.getView().getTopInventory().getHolder())) {
+            return;
+        }
+
+        // Safe cast - has to be a player to be the holder of a special player inventory.
+        Player player = (Player) event.getWhoClicked();
+
+        if (event.getAction() != InventoryAction.MOVE_TO_OTHER_INVENTORY) {
+            // All own-inventory interactions require updates to display properly.
+            // Update in same tick after event completion.
+            this.plugin.getServer().getScheduler().runTask(this.plugin, player::updateInventory);
+            return;
+        }
+
+        // Extra handling for MOVE_TO_OTHER_INVENTORY - apparently Mojang no longer removes the item from the target
+        // inventory prior to adding it to existing stacks.
+        ItemStack currentItem = event.getCurrentItem();
+        if (currentItem == null) {
+            // Other plugin doing some sort of handling (would be NOTHING for null item otherwise), ignore.
+            return;
+        }
+
+        ItemStack clone = currentItem.clone();
+        event.setCurrentItem(null);
+
+        // Complete add action in same tick after event completion.
+        this.plugin.getServer().getScheduler().runTask(this.plugin, () -> {
+            player.getInventory().addItem(clone);
+            player.updateInventory();
+        });
     }
 
     @EventHandler(priority = EventPriority.LOWEST)
-    public void onInventoryDrag(InventoryDragEvent event) {
-        onInventoryInteract(event);
+    public void onInventoryDrag(@NotNull final InventoryDragEvent event) {
+        handleInventoryInteract(event);
     }
 
-    private void onInventoryInteract(InventoryInteractEvent event) {
+    /**
+     * Handle common InventoryInteractEvent functions.
+     *
+     * @param event the InventoryInteractEvent
+     * @return true unless the top inventory is an opened player inventory
+     */
+    private boolean handleInventoryInteract(@NotNull final InventoryInteractEvent event) {
         HumanEntity entity = event.getWhoClicked();
 
+        // Un-cancel spectator interactions.
         if (Permissions.SPECTATE.hasPermission(entity) && entity.getGameMode() == GameMode.SPECTATOR) {
             event.setCancelled(false);
         }
 
         if (event.isCancelled()) {
-            return;
+            return true;
         }
 
-        Inventory inventory = event.getInventory();
+        Inventory inventory = event.getView().getTopInventory();
 
-        if (InventoryAccess.isPlayerInventory(inventory)) {
-            if (!Permissions.EDITINV.hasPermission(entity)) {
-                event.setCancelled(true);
-            }
-        } else if (InventoryAccess.isEnderChest(inventory)) {
+        // Is the inventory a special ender chest?
+        if (InventoryAccess.isEnderChest(inventory)) {
+            // Disallow ender chest interaction for users without edit permission.
             if (!Permissions.EDITENDER.hasPermission(entity)) {
                 event.setCancelled(true);
             }
+            return true;
         }
+
+        ISpecialPlayerInventory playerInventory = InventoryAccess.getPlayerInventory(inventory);
+
+        // Ignore inventories other than special player inventories.
+        if (playerInventory == null) {
+            return true;
+        }
+
+        // Disallow player inventory interaction for users without edit permission.
+        if (!Permissions.EDITINV.hasPermission(entity)) {
+            event.setCancelled(true);
+            return true;
+        }
+
+        return false;
     }
 
 }