Implement ghost-click

src/dev/w1zzrd/invtweaks/InvTweaksPlugin.java

@@ -133,6 +133,7 @@ public final class InvTweaksPlugin extends JavaPlugin {
     private void initEvents() {
         final PluginManager pluginManager = getServer().getPluginManager();
 
+        pluginManager.registerEvents(new GhostClickListener(), this);
         pluginManager.registerEvents(new StackReplaceListener(this), this);
         pluginManager.registerEvents(new SortListener(), this);
         pluginManager.registerEvents(new MagnetismListener(magnetCommandExecutor), this);

src/dev/w1zzrd/invtweaks/listener/GhostClickListener.java

@@ -0,0 +1,101 @@
+package dev.w1zzrd.invtweaks.listener;
+
+import dev.w1zzrd.invtweaks.InvTweaksPlugin;
+import net.minecraft.core.BlockPosition;
+import net.minecraft.core.EnumDirection;
+import net.minecraft.world.EnumHand;
+import net.minecraft.world.phys.MovingObjectPositionBlock;
+import net.minecraft.world.phys.Vec3D;
+import org.bukkit.Bukkit;
+import org.bukkit.Material;
+import org.bukkit.block.Block;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.EventPriority;
+import org.bukkit.event.Listener;
+import org.bukkit.event.player.PlayerInteractEntityEvent;
+import org.bukkit.inventory.EquipmentSlot;
+
+import java.lang.reflect.Field;
+import java.lang.reflect.InvocationTargetException;
+import java.lang.reflect.Method;
+
+public class GhostClickListener implements Listener {
+    @EventHandler(priority = EventPriority.LOWEST)
+    public void onEntityClick(final PlayerInteractEntityEvent clickEvent) {
+
+        if (clickEvent.getPlayer().getInventory().getItemInMainHand().getType() == Material.AIR &&
+                clickEvent.getPlayer().getInventory().getItemInOffHand().getType() == Material.AIR &&
+                clickEvent.getHand() == EquipmentSlot.HAND) {
+            final Block b = clickEvent.getPlayer().getTargetBlockExact(6);
+            if (b != null) {
+                try {
+                    final Method getNMS = findDeclaredMethod(b.getClass(), "getNMS");
+                    if (getNMS == null) {
+                        Bukkit.getLogger().warning(InvTweaksPlugin.LOG_PLUGIN_NAME + " Cannot find NMS getter for blocks: ghost click will not function!");
+                        return;
+                    }
+                    getNMS.setAccessible(true);
+
+                    final Object nmsBlock = getNMS.invoke(b);
+
+                    final Method interact = findDeclaredMethod(nmsBlock.getClass(), "interact");
+                    if (interact == null) {
+                        Bukkit.getLogger().warning(InvTweaksPlugin.LOG_PLUGIN_NAME + " Cannot find interact method for blocks: ghost click will not function!");
+                        return;
+                    }
+                    interact.setAccessible(true);
+
+                    final Field world = findDeclaredField(b.getClass(), "world");
+                    if (world == null) {
+                        Bukkit.getLogger().warning(InvTweaksPlugin.LOG_PLUGIN_NAME + " Cannot find world field for blocks: ghost click will not function!");
+                        return;
+                    }
+                    world.setAccessible(true);
+
+                    final Field entity = findDeclaredField(clickEvent.getPlayer().getClass(), "entity");
+                    if (entity == null) {
+                        Bukkit.getLogger().warning(InvTweaksPlugin.LOG_PLUGIN_NAME + " Cannot find entity field for players: ghost click will not function!");
+                        return;
+                    }
+                    entity.setAccessible(true);
+
+                    final BlockPosition pos = new BlockPosition(b.getX(), b.getY(), b.getZ());
+
+                    interact.invoke(
+                            nmsBlock,
+                            world.get(b),
+                            entity.get(clickEvent.getPlayer()),
+                            EnumHand.a,
+                            MovingObjectPositionBlock.a(
+                                    new Vec3D(clickEvent.getPlayer().getLocation().getX(), clickEvent.getPlayer().getLocation().getY(), clickEvent.getPlayer().getLocation().getZ()),
+                                    EnumDirection.e,
+                                    pos
+                            )
+                    );
+                } catch (IllegalAccessException | InvocationTargetException e) {
+                    e.printStackTrace();
+                }
+            }
+        }
+    }
+
+    private static Method findDeclaredMethod(Class<?> start, final String name) {
+        do {
+            for (final Method check : start.getDeclaredMethods())
+                if (check.getName().equals(name))
+                    return check;
+            start = start.getSuperclass();
+        } while(start != null);
+        return null;
+    }
+
+    private static Field findDeclaredField(Class<?> start, final String name) {
+        do {
+            for (final Field check : start.getDeclaredFields())
+                if (check.getName().equals(name))
+                    return check;
+            start = start.getSuperclass();
+        } while(start != null);
+        return null;
+    }
+}