Add new event

src/main/java/net/citizensnpcs/api/ai/goals/WanderGoal.java

@@ -52,7 +52,6 @@ private WanderGoal(NPC npc, int xrange, int yrange, Supplier<PhTreeSolid<Boolean
     private Location findRandomPosition() {
         Location found = MinecraftBlockExaminer.findRandomValidLocation(npc.getEntity().getLocation(NPC_LOCATION),
                 xrange, yrange, new Function<Block, Boolean>() {
-
                     @Override
                     public Boolean apply(Block block) {
                         if ((block.getRelative(BlockFace.UP).isLiquid() || block.getRelative(0, 2, 0).isLiquid())

src/main/java/net/citizensnpcs/api/event/NPCLookCloseChangeTargetEvent.java

@@ -0,0 +1,40 @@
+package net.citizensnpcs.api.event;
+
+import org.bukkit.entity.Player;
+import org.bukkit.event.HandlerList;
+
+import net.citizensnpcs.api.npc.NPC;
+
+public class NPCLookCloseChangeTargetEvent extends NPCEvent {
+    private Player next;
+    private final Player old;
+
+    public NPCLookCloseChangeTargetEvent(NPC npc, Player old, Player next) {
+        super(npc);
+        this.old = old;
+        this.next = next;
+    }
+
+    @Override
+    public HandlerList getHandlers() {
+        return handlers;
+    }
+
+    public Player getNewTarget() {
+        return next;
+    }
+
+    public Player getPreviousTarget() {
+        return old;
+    }
+
+    public void setNewTarget(Player target) {
+        this.next = target;
+    }
+
+    public static HandlerList getHandlerList() {
+        return handlers;
+    }
+
+    private static final HandlerList handlers = new HandlerList();
+}

src/main/java/net/citizensnpcs/api/gui/InventoryMenu.java

@@ -2,18 +2,27 @@
 
 import java.lang.invoke.MethodHandle;
 import java.lang.reflect.Constructor;
+import java.util.Collection;
 import java.util.Map;
 import java.util.WeakHashMap;
 
 import org.bukkit.Bukkit;
+import org.bukkit.entity.Player;
+import org.bukkit.event.EventHandler;
+import org.bukkit.event.inventory.InventoryClickEvent;
+import org.bukkit.event.inventory.InventoryCloseEvent;
 import org.bukkit.event.inventory.InventoryType;
 import org.bukkit.inventory.Inventory;
+import org.bukkit.inventory.InventoryView;
+
+import com.google.common.collect.Lists;
 
 public class InventoryMenu {
     private final MenuContext currentContext;
     private InventoryMenuPage page;
     private final InventoryMenuPattern[] patterns;
     private final InventoryMenuTransition[] transitions;
+    private final Collection<InventoryView> views = Lists.newArrayList();
 
     public InventoryMenu(InventoryMenuInfo info) {
         int[] dim = info.menuAnnotation.dimensions();
@@ -56,10 +65,33 @@ public InventoryMenu(InventoryMenuInfo info) {
         }
     }
 
+    @EventHandler(ignoreCancelled = true)
+    public void onInventoryClick(InventoryClickEvent event) {
+        if (!event.getInventory().equals(currentContext.getInventory()))
+            return;
+        InventoryMenuSlot slot = currentContext.getSlot(event.getSlot());
+        page.onClick(slot, event);
+        slot.onClick(event);
+        // TODO: check for transitions
+    }
+
+    @EventHandler(ignoreCancelled = true)
+    public void onInventoryClose(InventoryCloseEvent event) {
+        if (!event.getInventory().equals(currentContext.getInventory()))
+            return;
+        page.onClose(event.getPlayer());
+        // TODO: transition upwards if required
+    }
+
     private int posToIndex(int[] dim, int[] pos) {
         return pos[0] * dim[1] + pos[1];
     }
 
+    public void present(Player player) {
+        InventoryView view = player.openInventory(currentContext.getInventory());
+        views.add(view);
+    }
+
     private static class Bindable<T> {
         MethodHandle bind;
         T data;

src/main/java/net/citizensnpcs/api/gui/InventoryMenuPage.java

@@ -1,5 +1,12 @@
 package net.citizensnpcs.api.gui;
 
+import org.bukkit.entity.HumanEntity;
+import org.bukkit.event.inventory.InventoryClickEvent;
+
 public abstract class InventoryMenuPage {
     public abstract void create(MenuContext ctx);
+
+    public abstract void onClick(InventoryMenuSlot slot, InventoryClickEvent event);
+
+    public abstract void onClose(HumanEntity player);
 }

src/main/java/net/citizensnpcs/api/gui/InventoryMenuSlot.java

@@ -6,6 +6,7 @@
 import java.util.Set;
 
 import org.bukkit.event.inventory.ClickType;
+import org.bukkit.event.inventory.InventoryClickEvent;
 import org.bukkit.inventory.Inventory;
 import org.bukkit.inventory.ItemStack;
 
@@ -56,6 +57,10 @@ public void initialise(MenuSlot data) {
         setClickFilter(Arrays.asList(data.filter()));
     }
 
+    public void onClick(InventoryClickEvent event) {
+        // TODO
+    }
+
     public void setClickFilter(Collection<ClickType> filter) {
         this.clickFilter = EnumSet.copyOf(filter);
     }