item: add C_Item.IsConsumableItem (+ global IsConsumableItem)

Returns true if an item is a consumable: item class Consumable (0), or
inventory type INVTYPE_AMMO (24) / INVTYPE_THROWN (25). Registered as both
the namespaced C_Item form and the bare global, like IsUsableItem.

Definition established by decoding 3.3.5's Script_IsConsumableItem
(0x005173E0) then verifying the surviving contract on a modern client:
3.3.5 walked the item's on-use spells and returned true for any with a
real effect (which would include on-use trinkets), but that heuristic did
NOT survive -- an on-use trinket with a numeric Use: effect (Talisman of
Ephemeral Power) returns false on modern. It's a plain class/ammo check.
Verified in-game on our client, matching modern exactly: potion / bandage
/ Faintly Glowing Skull (all class 0) and Rough Arrow (Ammo) -> true;
Hearthstone, Talisman, plain armor -> false.

itemID / "item:NNN" / link input (names -> false, no vanilla name->ID
map); uncached -> false with no async load, same contract as
C_Item.IsEquippableItem. Documented in API.md (+ TOC) and the README
Item-row index.

Author: brues-code

README.md

@@ -41,7 +41,7 @@ Full per-function reference: **[docs/API.md](docs/API.md)**.
 | [Hooks](docs/API.md#hooks) | `hooksecurefunc` |
 | [Input](docs/API.md#input) | `GetMouseButtonClicked`, `IsLeftAltKeyDown`, `IsLeftControlKeyDown`, `IsLeftShiftKeyDown`, `IsModifierKeyDown`, `IsMouseButtonDown`, `IsRightAltKeyDown`, `IsRightControlKeyDown`, `IsRightShiftKeyDown` |
 | [Instance](docs/API.md#instance) | `GetInstanceInfo` |
-| [Item](docs/API.md#item) | `C_Item.DoesItemExist`, `C_Item.DoesItemExistByID`, `C_Item.EquipItemByName`, `C_Item.GetCurrentItemLevel`, `C_Item.GetDetailedItemLevelInfo`, `C_Item.GetEnchantInfo`, `C_Item.GetItemCount`, `C_Item.GetItemFamily`, `C_Item.GetItemGUID`, `C_Item.GetItemIcon`, `C_Item.GetItemIconByID`, `C_Item.GetItemID`, `C_Item.GetItemInfoInstant`, `C_Item.GetItemInventorySlotInfo`, `C_Item.GetItemInventorySlotKey`, `C_Item.GetItemInventoryType`, `C_Item.GetItemInventoryTypeByID`, `C_Item.GetItemLink`, `C_Item.GetItemLocation`, `C_Item.GetItemMaxStackSize`, `C_Item.GetItemMaxStackSizeByID`, `C_Item.GetItemName`, `C_Item.GetItemNameByID`, `C_Item.GetItemQuality`, `C_Item.GetItemQualityByID`, `C_Item.GetItemSellPrice`, `C_Item.GetItemSellPriceByID`, `C_Item.GetItemSetID`, `C_Item.GetItemSetIDByID`, `C_Item.GetItemSetInfo`, `C_Item.GetItemSpell`, `C_Item.GetItemStatDelta`, `C_Item.GetItemStats`, `C_Item.GetItemSubClassInfo`, `C_Item.GetItemUniqueness`, `C_Item.GetItemUniquenessByID`, `C_Item.GetStackCount`, `C_Item.GetWeaponEnchantInfo`, `C_Item.IsBound`, `C_Item.IsEquippableItem`, `C_Item.IsEquippedItem`, `C_Item.IsItemDataCached`, `C_Item.IsItemDataCachedByID`, `C_Item.IsItemGUIDInInventory`, `C_Item.IsItemInRange`, `C_Item.IsItemOpenable`, `C_Item.IsLocked`, `C_Item.LockItem`, `C_Item.LockItemByGUID`, `C_Item.UnlockAllItems`, `C_Item.UnlockItem`, `C_Item.RequestLoadItemData`, `C_Item.RequestLoadItemDataByID`, `C_Item.UseAtCursor`, `C_Item.UseAtUnit`, `C_Item.UseItemByName`, `GetAuctionItemID`, `GetAuctionSellItemID`, `GetAverageItemLevel`, `GetCraftReagentItemID`, `GetInboxItemID`, `GetInventoryItemDurability`, `GetInventoryItemID`, `GetInventoryItemsForSlot`, `GetInventoryItemRepairCost`, `GetItemIcon`, `GetLootRollItemID`, `GetLootSlotItemID`, `GetMerchantItemID`, `GetQuestItemID`, `GetQuestLogItemID`, `GetTradePlayerItemID`, `GetTradeSkillItemID`, `GetTradeSkillReagentItemID`, `GetTradeTargetItemID`, `OffhandHasWeapon` |
+| [Item](docs/API.md#item) | `C_Item.DoesItemExist`, `C_Item.DoesItemExistByID`, `C_Item.EquipItemByName`, `C_Item.GetCurrentItemLevel`, `C_Item.GetDetailedItemLevelInfo`, `C_Item.GetEnchantInfo`, `C_Item.GetItemCount`, `C_Item.GetItemFamily`, `C_Item.GetItemGUID`, `C_Item.GetItemIcon`, `C_Item.GetItemIconByID`, `C_Item.GetItemID`, `C_Item.GetItemInfoInstant`, `C_Item.GetItemInventorySlotInfo`, `C_Item.GetItemInventorySlotKey`, `C_Item.GetItemInventoryType`, `C_Item.GetItemInventoryTypeByID`, `C_Item.GetItemLink`, `C_Item.GetItemLocation`, `C_Item.GetItemMaxStackSize`, `C_Item.GetItemMaxStackSizeByID`, `C_Item.GetItemName`, `C_Item.GetItemNameByID`, `C_Item.GetItemQuality`, `C_Item.GetItemQualityByID`, `C_Item.GetItemSellPrice`, `C_Item.GetItemSellPriceByID`, `C_Item.GetItemSetID`, `C_Item.GetItemSetIDByID`, `C_Item.GetItemSetInfo`, `C_Item.GetItemSpell`, `C_Item.GetItemStatDelta`, `C_Item.GetItemStats`, `C_Item.GetItemSubClassInfo`, `C_Item.GetItemUniqueness`, `C_Item.GetItemUniquenessByID`, `C_Item.GetStackCount`, `C_Item.GetWeaponEnchantInfo`, `C_Item.IsBound`, `C_Item.IsConsumableItem`, `C_Item.IsEquippableItem`, `C_Item.IsEquippedItem`, `C_Item.IsItemDataCached`, `C_Item.IsItemDataCachedByID`, `C_Item.IsItemGUIDInInventory`, `C_Item.IsItemInRange`, `C_Item.IsItemOpenable`, `C_Item.IsLocked`, `C_Item.LockItem`, `C_Item.LockItemByGUID`, `C_Item.UnlockAllItems`, `C_Item.UnlockItem`, `C_Item.RequestLoadItemData`, `C_Item.RequestLoadItemDataByID`, `C_Item.UseAtCursor`, `C_Item.UseAtUnit`, `C_Item.UseItemByName`, `GetAuctionItemID`, `GetAuctionSellItemID`, `GetAverageItemLevel`, `GetCraftReagentItemID`, `GetInboxItemID`, `GetInventoryItemDurability`, `GetInventoryItemID`, `GetInventoryItemsForSlot`, `GetInventoryItemRepairCost`, `GetItemIcon`, `GetLootRollItemID`, `GetLootSlotItemID`, `GetMerchantItemID`, `GetQuestItemID`, `GetQuestLogItemID`, `GetTradePlayerItemID`, `GetTradeSkillItemID`, `GetTradeSkillReagentItemID`, `GetTradeTargetItemID`, `OffhandHasWeapon` |
 | [Loot](docs/API.md#loot) | `C_Loot.GetNearbyLootableUnits`, `C_Loot.GetLastScanResults`, `C_Loot.IsScanInProgress`, `C_Loot.LootUnit`, `C_Loot.LootUnitItem`, `C_Loot.ScanNearbyLoot` |
 | [LootHistory](docs/API.md#loothistory) | `C_LootHistory.GetNumItems`, `C_LootHistory.GetItem`, `C_LootHistory.GetPlayerInfo`, `C_LootHistory.Clear` |
 | [LossOfControl](docs/API.md#lossofcontrol) | `C_LossOfControl.GetActiveLossOfControlData`, `C_LossOfControl.GetActiveLossOfControlDataCount` |

docs/API.md

@@ -227,6 +227,7 @@ build instructions.
   - [`C_Item.GetItemUniqueness(itemLocation)` / `C_Item.GetItemUniquenessByID(item)`](#c_itemgetitemuniquenessitemlocation--c_itemgetitemuniquenessbyiditem)
   - [`C_Item.GetStackCount(itemLocation)`](#c_itemgetstackcountitemlocation)
   - [`C_Item.IsBound(itemLocation)`](#c_itemisbounditemlocation)
+  - [`IsConsumableItem(item)` / `C_Item.IsConsumableItem(item)`](#isconsumableitemitem--c_itemisconsumableitemitem)
   - [`C_Item.IsEquippableItem(item)`](#c_itemisequippableitemitem)
   - [`IsUsableItem(item)` / `C_Item.IsUsableItem(item)`](#isusableitemitem--c_itemisusableitemitem)
   - [`C_Item.IsEquippedItem(item)`](#c_itemisequippeditemitem)
@@ -5315,6 +5316,36 @@ if C_Item.IsBound({bagID = 0, slotIndex = 1}) then ... end
 if C_Item.IsBound(itemGUID) then ... end
 ```
 
+### `IsConsumableItem(item)` / `C_Item.IsConsumableItem(item)`
+
+Returns `true` if the item is a consumable, `false` otherwise. An item
+counts as consumable when its **class is `Consumable` (0)** *or* its
+**inventory type is `INVTYPE_AMMO` (24) or `INVTYPE_THROWN` (25)** — ammo
+and thrown weapons being consumed in use. Registered as both the bare
+global and the namespaced `C_Item` form, like `IsUsableItem`.
+
+`item` is an itemID number or `"item:N..."` link. Item names aren't
+accepted (vanilla has no name→ID resolver). Returns `false` for uncached
+items (no async load fired) — same cache contract as
+`C_Item.IsEquippableItem`.
+
+```lua
+IsConsumableItem(118)              -- Minor Healing Potion → true  (class Consumable)
+C_Item.IsConsumableItem(1251)     -- Linen Bandage → true          (class Consumable)
+C_Item.IsConsumableItem(2512)     -- Rough Arrow → true            (INVTYPE_AMMO)
+C_Item.IsConsumableItem(6948)     -- Hearthstone → false
+C_Item.IsConsumableItem(18820)    -- Talisman of Ephemeral Power → false (on-use trinket)
+```
+
+This is a class/ammo check, **not** a "has a usable effect" check.
+3.3.5's `IsConsumableItem` walked the item's on-use spells and returned
+true for any with a real effect (which would include on-use trinkets),
+but that heuristic didn't survive into the modern client: verified in-game
+that an on-use trinket with a numeric `Use:` effect (Talisman of Ephemeral
+Power) returns `false`, while class-`Consumable` items (potions, bandages,
+the class-0 "Faintly Glowing Skull") and ammo return `true`. We match the
+modern contract.
+
 ### `C_Item.IsEquippableItem(item)`
 
 Returns `true` if `item` can be equipped in any character-pane slot,

src/item/Consumable.cpp

@@ -0,0 +1,95 @@
+// This file is part of ClassicAPI.
+//
+// ClassicAPI is free software: you can redistribute it and/or modify it under the terms
+// of the GNU General Public License as published by the Free Software Foundation, either
+// version 3 of the License, or (at your option) any later version.
+//
+// ClassicAPI is distributed in the hope that it will be useful, but WITHOUT ANY
+// WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR
+// PURPOSE. See the GNU General Public License for more details.
+//
+// You should have received a copy of the GNU General Public License along with
+// ClassicAPI. If not, see <https://www.gnu.org/licenses/>.
+
+// `C_Item.IsConsumableItem(item)` — true iff the item is a consumable:
+// item class `Consumable` (0), or an inventory type of `INVTYPE_AMMO`
+// (24) / `INVTYPE_THROWN` (25) — ammo and thrown weapons being consumed
+// in use. `item` is an itemID, `"item:NNN"` string, or item link (names
+// aren't resolvable in vanilla → false).
+//
+// Definition established by decoding 3.3.5's `Script_IsConsumableItem`
+// (`0x005173E0`) and then verifying the surviving contract against a
+// modern client with `/dump`: it is NOT 3.3.5's on-use-spell-effect walk
+// (an on-use trinket like Talisman of Ephemeral Power returns *false*),
+// but a plain class-or-ammo/thrown check. Confirmed true: Minor Healing
+// Potion / Linen Bandage / Faintly Glowing Skull (all class 0), Rough
+// Arrow (Ammo). Confirmed false: Hearthstone (class Misc, valueless
+// teleport), on-use trinkets, plain armor.
+//
+// Cache-miss handling mirrors `C_Item.IsEquippableItem`: returns false
+// without firing a load (sync call, matches modern semantics). Callers
+// that want auto-warm behavior should run `C_Item.RequestLoadItemDataByID`
+// first and re-check on `ITEM_DATA_LOAD_RESULT`.
+
+#include "Game.h"
+#include "Offsets.h"
+#include "item/Arg.h"
+
+#include <cstdint>
+
+namespace Item::Consumable {
+
+namespace {
+
+using GetItemRecord_t = const uint8_t *(__thiscall *)(void *cache, uint32_t itemID,
+                                                      const uint64_t *guid, void *callback,
+                                                      void *userData, int unused);
+
+const uint8_t *PeekItemRecord(uint32_t itemID) {
+    auto fn = reinterpret_cast<GetItemRecord_t>(Offsets::FUN_DBCACHE_ITEMSTATS_GET_RECORD);
+    auto *cache = reinterpret_cast<void *>(Offsets::VAR_ITEMDB_CACHE);
+    const uint64_t zeroGuid = 0;
+    return fn(cache, itemID, &zeroGuid, nullptr, nullptr, 0);
+}
+
+constexpr uint32_t kItemClassConsumable = 0;
+constexpr uint32_t kInvTypeAmmo = 24;   // INVTYPE_AMMO
+constexpr uint32_t kInvTypeThrown = 25; // INVTYPE_THROWN
+
+int __fastcall Script_C_Item_IsConsumableItem(void *L) {
+    const int itemID = Item::Arg::ResolveItemID(L, 1);
+    if (itemID <= 0) {
+        Game::Lua::PushBoolean(L, 0);
+        return 1;
+    }
+    const uint8_t *record = PeekItemRecord(static_cast<uint32_t>(itemID));
+    if (record == nullptr) {
+        Game::Lua::PushBoolean(L, 0);
+        return 1;
+    }
+    const uint32_t classID = *reinterpret_cast<const uint32_t *>(
+        record + Offsets::OFF_ITEMSTATS_CLASS);
+    const uint32_t invType = *reinterpret_cast<const uint32_t *>(
+        record + Offsets::OFF_ITEMSTATS_INVENTORY_TYPE);
+
+    const bool consumable = classID == kItemClassConsumable ||
+                            invType == kInvTypeAmmo || invType == kInvTypeThrown;
+    Game::Lua::PushBoolean(L, consumable);
+    return 1;
+}
+
+void RegisterLuaFunctions() {
+    // Modern exposes both the namespaced `C_Item.IsConsumableItem` and the
+    // bare global `IsConsumableItem` (the older, still-live form); register
+    // both against the same handler, like `IsUsableItem`.
+    Game::Lua::RegisterTableFunction("C_Item", "IsConsumableItem",
+                                     &Script_C_Item_IsConsumableItem);
+    Game::Lua::RegisterGlobalFunction("IsConsumableItem",
+                                      &Script_C_Item_IsConsumableItem);
+}
+
+const Game::ModuleAutoRegister _autoreg{&RegisterLuaFunctions};
+
+} // namespace
+
+} // namespace Item::Consumable