12 files changed, 167 insertions, 63 deletions

diff --git a/src/Blocks/BlockCauldron.h b/src/Blocks/BlockCauldron.h
index 5b45b2828..d6ef721ad 100644
--- a/src/Blocks/BlockCauldron.h
+++ b/src/Blocks/BlockCauldron.h
@@ -27,17 +27,31 @@ public:
 	virtual bool OnUse(cChunkInterface & a_ChunkInterface, cWorldInterface & a_WorldInterface, cPlayer & a_Player, int a_BlockX, int a_BlockY, int a_BlockZ, eBlockFace a_BlockFace, int a_CursorX, int a_CursorY, int a_CursorZ) override
 	{
 		NIBBLETYPE Meta = a_ChunkInterface.GetBlockMeta({a_BlockX, a_BlockY, a_BlockZ});
-		switch (a_Player.GetEquippedItem().m_ItemType)
+		auto EquippedItem = a_Player.GetEquippedItem();
+		switch (EquippedItem.m_ItemType)
 		{
+			case E_ITEM_BUCKET:
+			{
+				if (Meta == 3)
+				{
+					a_ChunkInterface.SetBlockMeta(a_BlockX, a_BlockY, a_BlockZ, 0);
+					// Give new bucket, filled with fluid when the gamemode is not creative:
+					if (!a_Player.IsGameModeCreative())
+					{
+						a_Player.ReplaceOneEquippedItemTossRest(cItem(E_ITEM_WATER_BUCKET));
+					}
+				}
+				break;
+			}
 			case E_ITEM_WATER_BUCKET:
 			{
 				if (Meta < 3)
 				{
 					a_ChunkInterface.SetBlockMeta(a_BlockX, a_BlockY, a_BlockZ, 3);
+					// Give empty bucket back when the gamemode is not creative:
 					if (!a_Player.IsGameModeCreative())
 					{
-						a_Player.GetInventory().RemoveOneEquippedItem();
-						a_Player.GetInventory().AddItem(cItem(E_ITEM_BUCKET));
+						a_Player.ReplaceOneEquippedItemTossRest(cItem(E_ITEM_BUCKET));
 					}
 				}
 				break;
@@ -47,11 +61,27 @@ public:
 				if (Meta > 0)
 				{
 					a_ChunkInterface.SetBlockMeta(a_BlockX, a_BlockY, a_BlockZ, --Meta);
-					a_Player.GetInventory().RemoveOneEquippedItem();
-					a_Player.GetInventory().AddItem(cItem(E_ITEM_POTION));
+					// Give new potion when the gamemode is not creative:
+					if (!a_Player.IsGameModeCreative())
+					{
+						a_Player.ReplaceOneEquippedItemTossRest(cItem(E_ITEM_POTION));
+					}
 				}
 				break;
 			}
+			case E_ITEM_POTION:
+			{
+				// Refill cauldron with water bottles.
+				if ((Meta < 3) && (EquippedItem.m_ItemDamage == 0))
+				{
+					a_ChunkInterface.SetBlockMeta(Vector3i(a_BlockX, a_BlockY, a_BlockZ), ++Meta);
+					// Give empty bottle when the gamemode is not creative:
+					if (!a_Player.IsGameModeCreative())
+					{
+						a_Player.ReplaceOneEquippedItemTossRest(cItem(E_ITEM_GLASS_BOTTLE));
+					}
+				}
+			}
 		}
 		return true;
 	}
diff --git a/src/ClientHandle.cpp b/src/ClientHandle.cpp
index ef121cf12..9a92a3005 100644
--- a/src/ClientHandle.cpp
+++ b/src/ClientHandle.cpp
@@ -1211,9 +1211,9 @@ void cClientHandle::HandleLeftClick(int a_BlockX, int a_BlockY, int a_BlockZ, eB
 			cItem EquippedItem = m_Player->GetEquippedItem();
 			cItem OffhandItem = m_Player->GetOffHandEquipedItem();
 
-			cInventory & Intentory = m_Player->GetInventory();
-			Intentory.SetShieldSlot(EquippedItem);
-			Intentory.SetHotbarSlot(Intentory.GetEquippedSlotNum(), OffhandItem);
+			cInventory & Inventory = m_Player->GetInventory();
+			Inventory.SetShieldSlot(EquippedItem);
+			Inventory.SetEquippedItem(OffhandItem);
 
 			return;
 		}
diff --git a/src/Entities/Player.cpp b/src/Entities/Player.cpp
index b5d7f7c83..02cb7378d 100644
--- a/src/Entities/Player.cpp
+++ b/src/Entities/Player.cpp
@@ -1959,6 +1959,25 @@ void cPlayer::TossEquippedItem(char a_Amount)
 
 
 
+void cPlayer::ReplaceOneEquippedItemTossRest(const cItem & a_Item)
+{
+	auto PlacedCount = GetInventory().ReplaceOneEquippedItem(a_Item);
+	char ItemCountToToss = a_Item.m_ItemCount - static_cast<char>(PlacedCount);
+
+	if (ItemCountToToss == 0)
+	{
+		return;
+	}
+
+	cItem Pickup = a_Item;
+	Pickup.m_ItemCount = ItemCountToToss;
+	TossPickup(Pickup);
+}
+
+
+
+
+
 void cPlayer::TossHeldItem(char a_Amount)
 {
 	cItems Drops;
diff --git a/src/Entities/Player.h b/src/Entities/Player.h
index fafdd04eb..3ba87f748 100644
--- a/src/Entities/Player.h
+++ b/src/Entities/Player.h
@@ -313,6 +313,13 @@ public:
 	/** tosses the item in the selected hotbar slot */
 	void TossEquippedItem(char a_Amount = 1);
 
+	/** Removes one item from the the current equipped item stack, and attempts to add the specified item stack
+	back to the same slot. If it is not possible to place the item in the same slot, tries to place the specified
+	item elsewhere in the inventory. If this is not possible, then any remaining items are tossed. If the currently
+	equipped slot is empty, its contents are simply set to the given Item.
+	*/
+	void ReplaceOneEquippedItemTossRest(const cItem &);
+
 	/** tosses the item held in hand (when in UI windows) */
 	void TossHeldItem(char a_Amount = 1);
 
diff --git a/src/Inventory.cpp b/src/Inventory.cpp
index d8b67835e..42c243f17 100644
--- a/src/Inventory.cpp
+++ b/src/Inventory.cpp
@@ -121,35 +121,38 @@ int cInventory::AddItem(const cItem & a_Item, bool a_AllowNewStacks)
 		}
 	}
 
-	for (int SlotIdx = 0; SlotIdx < m_InventorySlots.GetNumSlots(); ++SlotIdx)
+	// Add to existing stacks in the hotbar.
+	res += m_HotbarSlots.AddItem(ToAdd, false);
+	ToAdd.m_ItemCount = static_cast<char>(a_Item.m_ItemCount - res);
+	if (ToAdd.m_ItemCount == 0)
 	{
-		auto & Slot = m_InventorySlots.GetSlot(SlotIdx);
-		if (Slot.IsEqual(a_Item))
-		{
-			cItemHandler Handler(Slot.m_ItemType);
-			int AmountToAdd = std::min(static_cast<char>(Handler.GetMaxStackSize() - Slot.m_ItemCount), ToAdd.m_ItemCount);
-			res += AmountToAdd;
+		return res;
+	}
 
-			cItem SlotAdjusted(Slot);
-			SlotAdjusted.m_ItemCount += AmountToAdd;
-			m_InventorySlots.SetSlot(SlotIdx, SlotAdjusted);
+	// Add to existing stacks in main inventory.
+	res += m_InventorySlots.AddItem(ToAdd, false);
+	ToAdd.m_ItemCount = static_cast<char>(a_Item.m_ItemCount - res);
+	if (ToAdd.m_ItemCount == 0)
+	{
+		return res;
+	}
 
-			ToAdd.m_ItemCount -= AmountToAdd;
-			if (ToAdd.m_ItemCount == 0)
-			{
-				return res;
-			}
-		}
+	// All existing stacks are now filled.
+	if (!a_AllowNewStacks)
+	{
+		return res;
 	}
 
-	res += m_HotbarSlots.AddItem(ToAdd, a_AllowNewStacks);
+	// Try adding new stacks to the hotbar.
+	res += m_HotbarSlots.AddItem(ToAdd, true);
 	ToAdd.m_ItemCount = static_cast<char>(a_Item.m_ItemCount - res);
 	if (ToAdd.m_ItemCount == 0)
 	{
 		return res;
 	}
 
-	res += m_InventorySlots.AddItem(ToAdd, a_AllowNewStacks);
+	// Try adding new stacks to the main inventory.
+	res += m_InventorySlots.AddItem(ToAdd, true);
 	return res;
 }
 
@@ -219,6 +222,50 @@ bool cInventory::RemoveOneEquippedItem(void)
 
 
 
+int cInventory::ReplaceOneEquippedItem(const cItem & a_Item, bool a_TryOtherSlots)
+{
+	// Ignore whether there was an item in the slot to remove.
+	RemoveOneEquippedItem();
+
+	auto EquippedItem = GetEquippedItem();
+	if (EquippedItem.IsEmpty())
+	{
+		SetEquippedItem(a_Item);
+		return a_Item.m_ItemCount;
+	}
+
+	// Handle case when equipped item is the same as the replacement item.
+	cItem ItemsToAdd = a_Item;
+	if (EquippedItem.IsEqual(ItemsToAdd))
+	{
+		cItemHandler Handler(ItemsToAdd.m_ItemType);
+		auto AmountToAdd = std::min(static_cast<char>(Handler.GetMaxStackSize() - EquippedItem.m_ItemCount), ItemsToAdd.m_ItemCount);
+
+		EquippedItem.m_ItemCount += AmountToAdd;
+		SetEquippedItem(EquippedItem);
+		ItemsToAdd.m_ItemCount -= AmountToAdd;
+	}
+
+	auto ItemsAdded = a_Item.m_ItemCount - ItemsToAdd.m_ItemCount;
+
+	if (ItemsToAdd.m_ItemCount == 0)
+	{
+		return ItemsAdded;
+	}
+
+	if (!a_TryOtherSlots)
+	{
+		return ItemsAdded;
+	}
+
+	// Try the rest of the inventory.
+	return AddItem(ItemsToAdd) + ItemsAdded;
+}
+
+
+
+
+
 int cInventory::HowManyItems(const cItem & a_Item)
 {
 	return
@@ -300,6 +347,15 @@ void cInventory::SetShieldSlot(const cItem & a_Item)
 
 
 
+void cInventory::SetEquippedItem(const cItem & a_Item)
+{
+	SetHotbarSlot(GetEquippedSlotNum(), a_Item);
+}
+
+
+
+
+
 void cInventory::SendEquippedSlot()
 {
 	int EquippedSlotNum = cInventory::invArmorCount + cInventory::invInventoryCount + GetEquippedSlotNum();
diff --git a/src/Inventory.h b/src/Inventory.h
index b91b16c8b..7436d7528 100644
--- a/src/Inventory.h
+++ b/src/Inventory.h
@@ -71,6 +71,7 @@ public:
 	/** Adds as many items out of a_ItemStack as can fit.
 	If a_AllowNewStacks is set to false, only existing stacks can be topped up;
 	if a_AllowNewStacks is set to true, empty slots can be used for the rest.
+	Fills existing stacks first and fills the hotbar before the main inventory.
 	Returns the number of items that fit.
 	*/
 	int AddItem(const cItem & a_ItemStack, bool a_AllowNewStacks = true);
@@ -90,6 +91,13 @@ public:
 	/** Removes one item out of the currently equipped item stack, returns true if successful, false if empty-handed */
 	bool RemoveOneEquippedItem(void);
 
+	/** Removes one item from the the current equipped item stack, and attempts to add the specified item stack
+	back to the same slot. If it is not possible to place the item in the same slot, optionally (default true) tries to
+	place the specified item elsewhere in the inventory. Returns the number of items successfully added. If the
+	currently equipped slot is empty, its contents are simply set to the given Item.
+	*/
+	int ReplaceOneEquippedItem(const cItem & a_Item, bool a_TryOtherSlots = true);
+
 	/** Returns the number of items of type a_Item that are stored */
 	int HowManyItems(const cItem & a_Item);
 
@@ -143,6 +151,8 @@ public:
 	void          SetHotbarSlot(int a_HotBarSlotNum, const cItem & a_Item);
 	/** Sets current item in shield slot */
 	void          SetShieldSlot(const cItem & a_Item);
+	/** Sets current item in the equipped hotbar slot */
+	void          SetEquippedItem(const cItem & a_Item);
 	/** Sets equiped item to the a_SlotNum slot number */
 	void          SetEquippedSlotNum(int a_SlotNum);
 	/** Returns slot number of equiped item */
diff --git a/src/Items/ItemArmor.h b/src/Items/ItemArmor.h
index 906993a5b..d218c22b3 100644
--- a/src/Items/ItemArmor.h
+++ b/src/Items/ItemArmor.h
@@ -61,7 +61,7 @@ public:
 		{
 			Item.Empty();
 		}
-		a_Player->GetInventory().SetHotbarSlot(a_Player->GetInventory().GetEquippedSlotNum(), Item);
+		a_Player->GetInventory().SetEquippedItem(Item);
 		return true;
 	}
 
diff --git a/src/Items/ItemBottle.h b/src/Items/ItemBottle.h
index b261937e5..18767dcde 100644
--- a/src/Items/ItemBottle.h
+++ b/src/Items/ItemBottle.h
@@ -83,8 +83,11 @@ public:
 			return false;  // Nothing in range.
 		}
 
-		a_Player->GetInventory().RemoveOneEquippedItem();
-		a_Player->GetInventory().AddItem(cItem(E_ITEM_POTION));
+		// Give back a filled water bottle if gamemode is not creative:
+		if (!a_Player->IsGameModeCreative())
+		{
+			a_Player->ReplaceOneEquippedItemTossRest(cItem(E_ITEM_POTION));
+		}
 		return true;
 	}
 } ;
diff --git a/src/Items/ItemBucket.h b/src/Items/ItemBucket.h
index 7a91149d1..8affff6ca 100644
--- a/src/Items/ItemBucket.h
+++ b/src/Items/ItemBucket.h
@@ -70,15 +70,15 @@ public:
 		}
 
 		BLOCKTYPE Block = a_World->GetBlock(BlockPos.x, BlockPos.y, BlockPos.z);
-		ENUM_ITEM_ID NewItem;
+		ENUM_ITEM_ID NewItemType;
 
 		if (IsBlockWater(Block))
 		{
-			NewItem = E_ITEM_WATER_BUCKET;
+			NewItemType = E_ITEM_WATER_BUCKET;
 		}
 		else if (IsBlockLava(Block))
 		{
-			NewItem = E_ITEM_LAVA_BUCKET;
+			NewItemType = E_ITEM_LAVA_BUCKET;
 		}
 		else
 		{
@@ -101,18 +101,7 @@ public:
 		// Give new bucket, filled with fluid when the gamemode is not creative:
 		if (!a_Player->IsGameModeCreative())
 		{
-			// Remove the bucket from the inventory
-			if (!a_Player->GetInventory().RemoveOneEquippedItem())
-			{
-				LOG("Clicked with an empty bucket, but cannot remove one from the inventory? WTF?");
-				ASSERT(!"Inventory bucket mismatch");
-				return true;
-			}
-			if (a_Player->GetInventory().AddItem(cItem(NewItem)) != 1)
-			{
-				// The bucket didn't fit, toss it as a pickup:
-				a_Player->TossPickup(cItem(NewItem));
-			}
+			a_Player->ReplaceOneEquippedItemTossRest(cItem(NewItemType));
 		}
 
 		return true;
@@ -154,19 +143,10 @@ public:
 			return false;
 		}
 
+		// Give back an empty bucket if the gamemode is not creative:
 		if (!a_Player->IsGameModeCreative())
 		{
-			// Remove fluid bucket, add empty bucket:
-			if (!a_Player->GetInventory().RemoveOneEquippedItem())
-			{
-				LOG("Clicked with a full bucket, but cannot remove one from the inventory? WTF?");
-				ASSERT(!"Inventory bucket mismatch");
-				return false;
-			}
-			if (!a_Player->GetInventory().AddItem(cItem(E_ITEM_BUCKET)))
-			{
-				return false;
-			}
+			a_Player->ReplaceOneEquippedItemTossRest(cItem(E_ITEM_BUCKET));
 		}
 
 		// Wash away anything that was there prior to placing:
diff --git a/src/Items/ItemPotion.h b/src/Items/ItemPotion.h
index 470a7c67f..86330d1c0 100644
--- a/src/Items/ItemPotion.h
+++ b/src/Items/ItemPotion.h
@@ -77,8 +77,7 @@ public:
 
 		if (!a_Player->IsGameModeCreative())
 		{
-			a_Player->GetInventory().RemoveOneEquippedItem();
-			a_Player->GetInventory().AddItem(cItem(E_ITEM_GLASS_BOTTLE));
+			a_Player->ReplaceOneEquippedItemTossRest(cItem(E_ITEM_GLASS_BOTTLE));
 		}
 		return true;
 	}
diff --git a/src/Mobs/Cow.cpp b/src/Mobs/Cow.cpp
index a7fb0d476..559b6caea 100644
--- a/src/Mobs/Cow.cpp
+++ b/src/Mobs/Cow.cpp
@@ -44,10 +44,10 @@ void cCow::OnRightClicked(cPlayer & a_Player)
 	short HeldItem = a_Player.GetEquippedItem().m_ItemType;
 	if (HeldItem == E_ITEM_BUCKET)
 	{
+		// Milk the cow.
 		if (!a_Player.IsGameModeCreative())
 		{
-			a_Player.GetInventory().RemoveOneEquippedItem();
-			a_Player.GetInventory().AddItem(cItem(E_ITEM_MILK));
+			a_Player.ReplaceOneEquippedItemTossRest(cItem(E_ITEM_MILK));
 		}
 	}
 }
diff --git a/src/Mobs/Mooshroom.cpp b/src/Mobs/Mooshroom.cpp
index 31a1b8978..135a8ba90 100644
--- a/src/Mobs/Mooshroom.cpp
+++ b/src/Mobs/Mooshroom.cpp
@@ -43,18 +43,18 @@ void cMooshroom::OnRightClicked(cPlayer & a_Player)
 	{
 		case E_ITEM_BUCKET:
 		{
+			// Milk the cow.
 			if (!a_Player.IsGameModeCreative())
 			{
-				a_Player.GetInventory().RemoveOneEquippedItem();
-				a_Player.GetInventory().AddItem(cItem(E_ITEM_MILK));
+				a_Player.ReplaceOneEquippedItemTossRest(cItem(E_ITEM_MILK));
 			}
 		} break;
 		case E_ITEM_BOWL:
 		{
+			// Soup the cow.
 			if (!a_Player.IsGameModeCreative())
 			{
-				a_Player.GetInventory().RemoveOneEquippedItem();
-				a_Player.GetInventory().AddItem(cItem(E_ITEM_MUSHROOM_SOUP));
+				a_Player.ReplaceOneEquippedItemTossRest(cItem(E_ITEM_MUSHROOM_SOUP));
 			}
 		} break;
 		case E_ITEM_SHEARS: