From 2d3013d1d35a2bcba63cffd9012898defff26f93 Mon Sep 17 00:00:00 2001
From: changyong guo <guo1487@163.com>
Date: Sun, 24 Jun 2018 17:24:10 +0800
Subject: Support swap item between main hand and offhand by press key "F"
 (#4241)

Hi,

I found cuberite don't support to press key "F" to swap items on main hand and offhand, so I implemented this feature.

Best regards
Changyong
---
 CONTRIBUTORS                       |  1 +
 Server/Plugins/APIDump/APIDesc.lua | 10 ++++++++++
 src/ClientHandle.cpp               |  9 ++++++++-
 src/Entities/Entity.h              |  3 +++
 src/Entities/Player.h              |  3 +++
 5 files changed, 25 insertions(+), 1 deletion(-)

diff --git a/CONTRIBUTORS b/CONTRIBUTORS
index 35d8496b4..b888c83cf 100644
--- a/CONTRIBUTORS
+++ b/CONTRIBUTORS
@@ -13,6 +13,7 @@ beeduck
 bibo38
 birkett (Anthony Birkett)
 Bond_009
+changyongGuo
 Cocosushi6
 derouinw
 Diusrex
diff --git a/Server/Plugins/APIDump/APIDesc.lua b/Server/Plugins/APIDump/APIDesc.lua
index eed6bd40f..ee1ed0d04 100644
--- a/Server/Plugins/APIDump/APIDesc.lua
+++ b/Server/Plugins/APIDump/APIDesc.lua
@@ -3317,6 +3317,16 @@ local Hash = cCryptoHash.sha1HexString("DataToHash")
 					},
 					Notes = "Returns the weapon that the entity has equipped. Returns an empty cItem if no weapon equipped or not applicable.",
 				},
+				GetOffHandEquipedItem =
+				{
+					Returns =
+					{
+						{
+							Type = "cItem",
+						},
+					},
+					Notes = "Returns the item that the entity has equipped on off-hand. Returns an empty cItem if no item equipped or not applicable.",
+				},
 				GetGravity =
 				{
 					Returns =
diff --git a/src/ClientHandle.cpp b/src/ClientHandle.cpp
index a895dd3b3..ff649ea4d 100644
--- a/src/ClientHandle.cpp
+++ b/src/ClientHandle.cpp
@@ -1188,7 +1188,14 @@ void cClientHandle::HandleLeftClick(int a_BlockX, int a_BlockY, int a_BlockZ, eB
 
 		case DIG_STATUS_SWAP_ITEM_IN_HAND:
 		{
-			// TODO: Not yet implemented
+
+			cItem EquippedItem = m_Player->GetEquippedItem();
+			cItem OffhandItem = m_Player->GetOffHandEquipedItem();
+
+			cInventory & Intentory = m_Player->GetInventory();
+			Intentory.SetShieldSlot(EquippedItem);
+			Intentory.SetHotbarSlot(Intentory.GetEquippedSlotNum(), OffhandItem);
+
 			return;
 		}
 
diff --git a/src/Entities/Entity.h b/src/Entities/Entity.h
index 9abf75968..7ac12c95b 100644
--- a/src/Entities/Entity.h
+++ b/src/Entities/Entity.h
@@ -351,6 +351,9 @@ public:
 	/** Returns the currently equipped boots; empty item if none */
 	virtual cItem GetEquippedBoots(void) const { return cItem(); }
 
+	/** Returns the currently offhand equipped item; empty item if none */
+	virtual cItem GetOffHandEquipedItem(void) const { return cItem(); }
+
 	/** Applies damage to the armor after the armor blocked the given amount */
 	virtual void ApplyArmorDamage(int DamageBlocked);
 
diff --git a/src/Entities/Player.h b/src/Entities/Player.h
index 32a4b0348..f04f90a2b 100644
--- a/src/Entities/Player.h
+++ b/src/Entities/Player.h
@@ -71,6 +71,9 @@ public:
 	/** Returns the currently equipped boots; empty item if none */
 	virtual cItem GetEquippedBoots(void) const override { return m_Inventory.GetEquippedBoots(); }
 
+	/** Returns the currently offhand equipped item; empty item if none */
+	virtual cItem GetOffHandEquipedItem(void) const override { return m_Inventory.GetShieldSlot(); }
+
 	virtual void ApplyArmorDamage(int DamageBlocked) override;
 
 	// tolua_begin
-- 
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