path: root/src/Items/ItemHandler.h

#pragma once

#include "../Defines.h"
#include "../Item.h"





// fwd:
class cChunk;
class cWorld;
class cPlayer;
class cBlockPluginInterface;





class cItemHandler
{
public:

	friend class cItem;

	/** Actions that may cause durability of an item may be lost, where the
	magnitude of the loss depends on the specific item used to perform the
	action */
	enum eDurabilityLostAction
	{
		dlaAttackEntity,
		dlaBreakBlock,
		dlaBreakBlockInstant,
	};

	constexpr cItemHandler(int a_ItemType) : m_ItemType(a_ItemType)
	{
	}


	/** Called when the player tries to place the item (right mouse button, IsPlaceable() == true).
	a_ClickedBlockPos is the (neighbor) block that has been clicked to place this item.
	a_ClickedBlockFace is the face of the neighbor that has been clicked to place this item.
	a_CursorPos is the position of the player's cursor within a_ClickedBlockFace.
	The default handler uses GetBlocksToPlace() and places the returned blocks.
	Override if the item needs advanced processing, such as spawning a mob based on the blocks being placed.
	If the block placement is refused inside this call, it will automatically revert the client-side changes. */
	void OnPlayerPlace(cPlayer & a_Player, const cItem & a_HeldItem, Vector3i a_ClickedBlockPosition, eBlockFace a_ClickedBlockFace, Vector3i a_CursorPosition) const;

	/** Called when the player tries to use the item (right mouse button).
	Descendants can return false to abort the usage (default behavior). */
	virtual bool OnItemUse(
		cWorld * a_World,
		cPlayer * a_Player,
		cBlockPluginInterface & a_PluginInterface,
		const cItem & a_HeldItem,
		const Vector3i a_ClickedBlockPos,
		eBlockFace a_ClickedBlockFace
	) const;

	/** Called when the client sends the SHOOT status in the lclk packet (releasing the bow). */
	virtual void OnItemShoot(cPlayer *, const Vector3i a_BlockPos, eBlockFace a_BlockFace) const
	{
		UNUSED(a_BlockPos);
		UNUSED(a_BlockFace);
	}

	/** Called every tick while the item is on the player's inventory (used by maps, for example) - For now, called only for equipped items */
	virtual void OnUpdate(cWorld * a_World, cPlayer * a_Player, const cItem & a_Item) const
	{
		UNUSED(a_World);
		UNUSED(a_Player);
		UNUSED(a_Item);
	}

	/** Called while the player digs a block using this item */
	virtual bool OnDiggingBlock(
		cWorld * a_World, cPlayer * a_Player, const cItem & a_HeldItem,
		const Vector3i a_ClickedBlockPos,
		eBlockFace a_ClickedBlockFace
	) const;

	/** Called when a player attacks an entity with this item in hand. */
	virtual void OnEntityAttack(cPlayer * a_Attacker, cEntity * a_AttackedEntity) const;

	/** Called after the player has eaten this item. */
	virtual void OnFoodEaten(cWorld *a_World, cPlayer *a_Player, cItem *a_Item) const;

	/** Get the durability lost which the item will get, when a specified action
	was performed. This is only relevant for uses where the damage taken may
	depend on the item used. */
	virtual short GetDurabilityLossByAction(eDurabilityLostAction a_Action) const;

	/** Returns the maximum stack size for a given item */
	virtual char GetMaxStackSize(void) const;

	struct FoodInfo
	{
		int    FoodLevel;
		double Saturation;

		constexpr FoodInfo(int a_FoodLevel, double a_Saturation) :
			FoodLevel(a_FoodLevel),
			Saturation(a_Saturation)
		{
		}
	} ;

	/** Returns the FoodInfo for this item. (FoodRecovery and Saturation) */
	virtual FoodInfo GetFoodInfo(const cItem * a_Item) const;

	/** Lets the player eat a selected item. Returns true if the player ate the item */
	virtual bool EatItem(cPlayer * a_Player, cItem * a_Item) const;

	/** Indicates if this item is food */
	virtual bool IsFood(void) const;

	/** Indicates if this item is drinkable */
	virtual bool IsDrinkable(short a_ItemDamage) const;

	/** Blocks simply get placed */
	virtual bool IsPlaceable(void) const;

	/** Can the anvil repair this item, when a_Item is the second input? */
	virtual bool CanRepairWithRawMaterial(short a_ItemType) const;

	/** Returns whether this tool / item can harvest a specific block (e.g. iron pickaxe can harvest diamond ore, but wooden one can't).
	Defaults to false unless overridden. */
	virtual bool CanHarvestBlock(BLOCKTYPE a_BlockType) const;

	/** Returns the strength to break a specific block.
	Defaults to 1 unless overriden. */
	virtual float GetBlockBreakingStrength(BLOCKTYPE a_Block) const;


protected:

	static const cItemHandler & For(int a_ItemType);

	~cItemHandler() = default;

	const int m_ItemType;

	/** Performs the actual placement of this placeable item.
	The descendant handler should call a_Player.PlaceBlock(s) supplying correct values for the newly placed block.
	The default handler uses the stored block type and meta copied from the lowest 4 bits of the player's equipped item's damage value.
	Handlers return what a_Player.PlaceBlock(s) returns, indicating whether the placement was successful. */
	virtual bool CommitPlacement(cPlayer & a_Player, const cItem & a_HeldItem, Vector3i a_PlacePosition, eBlockFace a_ClickedBlockFace, Vector3i a_CursorPosition) const;
};