From 04a975d0111bc26dc8ab700708d57db442c350a8 Mon Sep 17 00:00:00 2001
From: "copilot-swe-agent[bot]" <198982749+Copilot@users.noreply.github.com>
Date: Tue, 2 Jun 2026 07:57:13 +0000
Subject: [PATCH] fix: support offhand food useitem fallback

---
 MinecraftClient/Commands/UseItem.cs | 52 +++++++++++++++++++++++------
 docs/guide/usage.md                 | 12 +++++++
 2 files changed, 54 insertions(+), 10 deletions(-)

diff --git a/MinecraftClient/Commands/UseItem.cs b/MinecraftClient/Commands/UseItem.cs
index 40993c7a..70ad0003 100644
--- a/MinecraftClient/Commands/UseItem.cs
+++ b/MinecraftClient/Commands/UseItem.cs
@@ -10,7 +10,7 @@ namespace MinecraftClient.Commands
     class UseItem : Command
     {
         public override string CmdName { get { return "useitem"; } }
-        public override string CmdUsage { get { return "useitem [x] [y] [z]"; } }
+        public override string CmdUsage { get { return "useitem [mainhand|offhand] | useitem [x] [y] [z] [mainhand|offhand]"; } }
         public override string CmdDesc { get { return Translations.cmd_useitem_desc; } }
 
         public override void RegisterCommand(CommandDispatcher<CmdResult> dispatcher)
@@ -23,8 +23,16 @@ namespace MinecraftClient.Commands
 
             dispatcher.Register(l => l.Literal(CmdName)
                 .Executes(r => DoUseItem(r.Source))
+                .Then(l => l.Literal("mainhand")
+                    .Executes(r => DoUseItem(r.Source, Hand.MainHand)))
+                .Then(l => l.Literal("offhand")
+                    .Executes(r => DoUseItem(r.Source, Hand.OffHand)))
                 .Then(l => l.Argument("Location", MccArguments.Location())
-                    .Executes(r => DoUseItemAtLocation(r.Source, MccArguments.GetLocation(r, "Location"))))
+                    .Executes(r => DoUseItemAtLocation(r.Source, MccArguments.GetLocation(r, "Location"), Hand.MainHand))
+                    .Then(l => l.Literal("mainhand")
+                        .Executes(r => DoUseItemAtLocation(r.Source, MccArguments.GetLocation(r, "Location"), Hand.MainHand)))
+                    .Then(l => l.Literal("offhand")
+                        .Executes(r => DoUseItemAtLocation(r.Source, MccArguments.GetLocation(r, "Location"), Hand.OffHand))))
                 .Then(l => l.Literal("_help")
                     .Executes(r => GetUsage(r.Source, string.Empty))
                     .Redirect(dispatcher.GetRoot().GetChild("help").GetChild(CmdName)))
@@ -41,29 +49,53 @@ namespace MinecraftClient.Commands
             });
         }
 
-        private int DoUseItem(CmdResult r)
+        private static bool ShouldUseOffhandFood(McClient handler)
+        {
+            Container? inventory = handler.GetInventory(0);
+            if (inventory is null)
+                return false;
+
+            if (!inventory.Items.TryGetValue(45, out Item? offhandItem)
+                || offhandItem.IsEmpty
+                || !offhandItem.Type.IsFood())
+                return false;
+
+            int mainHandSlot = 36 + handler.GetCurrentSlot();
+            return !inventory.Items.TryGetValue(mainHandSlot, out Item? mainHandItem)
+                || mainHandItem.IsEmpty
+                || !mainHandItem.Type.IsFood();
+        }
+
+        private int DoUseItem(CmdResult r, Hand? requestedHand = null)
         {
             McClient handler = CmdResult.currentHandler!;
             if (!handler.GetInventoryEnabled())
                 return r.SetAndReturn(Status.FailNeedInventory);
 
-            if (handler.GetTerrainEnabled())
+            Hand hand = requestedHand ?? (ShouldUseOffhandFood(handler) ? Hand.OffHand : Hand.MainHand);
+            bool useOffhandFood = !requestedHand.HasValue && hand == Hand.OffHand;
+
+            if (!useOffhandFood && handler.GetTerrainEnabled())
             {
                 const double maxDistance = 4.5;
                 var raycast = RaycastHelper.RaycastBlock(handler, maxDistance, false);
                 if (raycast.Item1 && raycast.Item3.Type != Material.Air)
                 {
-                    handler.PlaceBlock(raycast.Item2, Direction.Up, lookAtBlock: true);
-                    handler.DoAnimation((int)Hand.MainHand);
+                    handler.PlaceBlock(raycast.Item2, Direction.Up, hand, lookAtBlock: true);
+                    handler.DoAnimation((int)hand);
                     return r.SetAndReturn(Status.Done, Translations.cmd_useitem_use);
                 }
             }
 
-            handler.UseItemOnHand();
+            if (hand == Hand.OffHand)
+                handler.UseItemOnLeftHand();
+            else
+                handler.UseItemOnHand();
+
             return r.SetAndReturn(Status.Done, Translations.cmd_useitem_use);
         }
 
-        private int DoUseItemAtLocation(CmdResult r, Location block)
+        private int DoUseItemAtLocation(CmdResult r, Location block, Hand hand)
         {
             McClient handler = CmdResult.currentHandler!;
             if (!handler.GetTerrainEnabled())
@@ -71,8 +103,8 @@ namespace MinecraftClient.Commands
 
             Location current = handler.GetCurrentLocation();
             block = block.ToAbsolute(current).ToFloor();
-            handler.PlaceBlock(block, Direction.Up, lookAtBlock: true);
-            handler.DoAnimation((int)Hand.MainHand);
+            handler.PlaceBlock(block, Direction.Up, hand, lookAtBlock: true);
+            handler.DoAnimation((int)hand);
             return r.SetAndReturn(Status.Done, Translations.cmd_useitem_use);
         }
 
diff --git a/docs/guide/usage.md b/docs/guide/usage.md
index b165ccd5..5d4d0768 100644
--- a/docs/guide/usage.md
+++ b/docs/guide/usage.md
@@ -1157,12 +1157,24 @@ In scripts and remote control, no slash is needed to perform the command, eg. `q
   /useitem
   ```
 
+  Use the item from a specific hand:
+
+  ```
+  /useitem <mainhand|offhand>
+  ```
+
   Use the item on a specific block:
 
   ```
   /useitem <x> <y> <z>
   ```
 
+  Use the item from a specific hand on a specific block:
+
+  ```
+  /useitem <x> <y> <z> <mainhand|offhand>
+  ```
+
 </details>
 
 <details>