From 6a4e4a345d650c8aa7eb4320f544f0d8c465ae2a Mon Sep 17 00:00:00 2001
From: Wlowscha <54003515+Wlowscha@users.noreply.github.com>
Date: Tue, 10 Jun 2025 21:56:57 +0200
Subject: [PATCH] Added some utility functions to check if an item fits a list
 of items/categories, or to filter out which held items fit

---
 src/enums/held-item-id.ts              | 15 +++++++++++++--
 src/field/pokemon-held-item-manager.ts |  9 +++++++--
 2 files changed, 20 insertions(+), 4 deletions(-)

diff --git a/src/enums/held-item-id.ts b/src/enums/held-item-id.ts
index a31f0c9d4f6..7da668d21b2 100644
--- a/src/enums/held-item-id.ts
+++ b/src/enums/held-item-id.ts
@@ -121,10 +121,21 @@ export const HeldItemCategoryId = {
 
 export type HeldItemCategoryId = (typeof HeldItemCategoryId)[keyof typeof HeldItemCategoryId];
 
+const ITEM_CATEGORY_MASK = 0xFF00
+
 function getHeldItemCategory(itemId: HeldItemId): HeldItemCategoryId {
-  return itemId & 0xFF00;
+  return itemId & ITEM_CATEGORY_MASK;
 }
 
 export function isItemInCategory(itemId: HeldItemId, category: HeldItemCategoryId): boolean {
   return getHeldItemCategory(itemId) === category;
-}
\ No newline at end of file
+}
+
+export function isItemInRequested(
+  itemId: HeldItemId,
+  requestedItems: (HeldItemCategoryId | HeldItemId)[]
+): boolean {
+  return requestedItems.some(entry => {
+    itemId === entry || (itemId & ITEM_CATEGORY_MASK) === entry
+  });
+}
diff --git a/src/field/pokemon-held-item-manager.ts b/src/field/pokemon-held-item-manager.ts
index f71d3d73a90..6c66c219369 100644
--- a/src/field/pokemon-held-item-manager.ts
+++ b/src/field/pokemon-held-item-manager.ts
@@ -1,6 +1,6 @@
 import { allHeldItems } from "#app/items/all-held-items";
-import type { HeldItemId } from "#app/enums/held-item-id";
-import type { FormChangeItem } from "#app/data/pokemon-forms";
+import { isItemInRequested, type HeldItemCategoryId, type HeldItemId } from "#app/enums/held-item-id";
+import type { FormChangeItem } from "#enums/form-change-item";
 import type { BASE_STAT_TOTAL_DATA } from "#app/items/held-items/base-stat-total";
 import type { BASE_STAT_FLAT_DATA } from "#app/items/held-items/base-stat-flat";
 
@@ -102,6 +102,11 @@ export class PokemonItemManager {
     }
   }
 
+  filterRequestedItems(requestedItems: (HeldItemCategoryId | HeldItemId)[], transferableOnly = true, exclude = false) {
+    const currentItems = transferableOnly ? this.getTransferableHeldItems() : this.getHeldItems();
+    return currentItems.filter(it => !exclude && isItemInRequested(it, requestedItems));
+  }
+
   addFormChangeItem(id: FormChangeItem) {
     if (!(id in this.formChangeItems)) {
       this.formChangeItems[id] = { active: false };