Optimize permutations (#761)

Co-authored-by: Martin Robertz <[email protected]>

src/main/java/codechicken/nei/api/ShortcutInputHandler.java

@@ -42,6 +42,31 @@ import codechicken.nei.util.NEIMouseUtils;
 
 public abstract class ShortcutInputHandler {
 
+    private static class HotkeysCache {
+
+        public int mousex;
+        public int mousey;
+        public ItemStack stack;
+        public int groupId;
+        public Map<String, String> hotkeys = new HashMap<>();
+
+        public boolean matches(int mousex, int mousey, ItemStack stack, int groupId) {
+            return Math.abs(this.mousex - mousex) < 16 && Math.abs(this.mousey - mousey) < 16
+                    && (this.stack == null ? stack == null && this.groupId == groupId
+                            : stack != null && NEIClientUtils.areStacksSameTypeWithNBT(stack, this.stack));
+        }
+
+        public void update(int mousex, int mousey, ItemStack stack, int groupId, Map<String, String> hotkeys) {
+            this.mousex = mousex;
+            this.mousey = mousey;
+            this.stack = stack != null ? stack.copy() : null;
+            this.groupId = groupId;
+            this.hotkeys = hotkeys;
+        }
+    }
+
+    private static HotkeysCache hotkeysCache = new HotkeysCache();
+
     public static boolean handleKeyEvent(ItemStack stackover) {
 
         if (!NEIClientConfig.isLoaded()) {
@@ -391,8 +416,13 @@ public abstract class ShortcutInputHandler {
     }
 
     public static Map<String, String> handleHotkeys(int mousex, int mousey, ItemStack stack) {
-        final GuiContainer gui = NEIClientUtils.getGuiContainer();
         final int groupId = ItemPanels.bookmarkPanel.getHoveredGroupId(true);
+
+        if (hotkeysCache.matches(mousex, mousey, stack, groupId)) {
+            return hotkeysCache.hotkeys;
+        }
+
+        final GuiContainer gui = NEIClientUtils.getGuiContainer();
         final Map<String, String> hotkeys = new HashMap<>();
 
         if (groupId != -1) {
@@ -419,9 +449,13 @@ public abstract class ShortcutInputHandler {
                         NEIClientConfig.getKeyName("gui.craft_items", NEIClientUtils.SHIFT_HASH),
                         NEIClientUtils.translate("bookmark.group.craft_all"));
             }
+
+            hotkeysCache.update(mousex, mousey, stack, groupId, hotkeys);
+            return hotkeys;
         }
 
         if (stack == null) {
+            hotkeysCache.update(mousex, mousey, stack, groupId, hotkeys);
             return hotkeys;
         }
 
@@ -582,6 +616,8 @@ public abstract class ShortcutInputHandler {
 
         }
 
+        hotkeysCache.update(mousex, mousey, stack, groupId, hotkeys);
+
         return hotkeys;
     }