CartTransferBase.java

/* 
 * Copyright (c) CovertJaguar, 2014 http://railcraft.info
 * 
 * This code is the property of CovertJaguar
 * and may only be used with explicit written
 * permission unless otherwise specified on the
 * license page at http://railcraft.info/wiki/info:license.
 */
package com.dta.extracarts.othermodcode.railcraft.common.carts;

import cpw.mods.fml.common.Optional;
import mods.railcraft.api.carts.CartTools;
import mods.railcraft.api.carts.IItemTransfer;
import mods.railcraft.api.carts.ILinkageManager;
import mods.railcraft.api.core.items.IStackFilter;
import com.dta.extracarts.othermodcode.railcraft.common.util.inventory.filters.ArrayStackFilter;
import net.minecraft.entity.item.EntityMinecart;
import net.minecraft.entity.item.EntityMinecartContainer;
import net.minecraft.inventory.IInventory;
import net.minecraft.item.ItemStack;
import net.minecraft.world.World;

/**
 * Abstract minecart class that implements the IItemTransfer interface for
 * convenience and as example for others who wish to create carts that
 * implements IItemTransfer. This particular implementation assumes a simple
 * inventory and will attempt to pass along offers and requests to linked carts
 * if it cannot fulfill them itself. <br/> <br/> Classes that extend this
 * class:<br/> EntityCartChest<br/> EntityCartAnchor<br/>
 *
 * @author CovertJaguar <http://www.railcraft.info>
 */
@Optional.Interface(iface = "mods.railcraft.api.carts.IItemTransfer", modid = "RailcraftAPI|carts")
public abstract class CartTransferBase extends EntityMinecartContainer implements IItemTransfer {

	/**
	 * If passThrough == true, this cart will only pass requests along, it wont
	 * attempt to fulfill them.
	 */
	protected boolean passThrough = false;

	public CartTransferBase(World world) {
		super(world);
	}

	public CartTransferBase(World world, double x, double y, double z) {
		super(world, x, y, z);
	}

	@Optional.Method(modid = "RailcraftAPI|carts")
	public ItemStack offerItem(Object source, ItemStack offer) {
		if (!passThrough && getSizeInventory() > 0) {
			offer = moveItemStack(offer, this);
			if (offer == null)
				return null;
		}

		ILinkageManager lm = CartTools.getLinkageManager(worldObj);

		EntityMinecart linkedCart = lm.getLinkedCartA(this);
		if (linkedCart != source && linkedCart instanceof IItemTransfer)
			offer = ((IItemTransfer) linkedCart).offerItem(this, offer);

		if (offer == null)
			return null;

		linkedCart = lm.getLinkedCartB(this);
		if (linkedCart != source && linkedCart instanceof IItemTransfer)
			offer = ((IItemTransfer) linkedCart).offerItem(this, offer);

		return offer;
	}

	@Optional.Method(modid = "RailcraftAPI|carts")
	public ItemStack requestItem(Object source) {
		return requestItem(this, IStackFilter.filters.get("ALL"));
	}

	@Optional.Method(modid = "RailcraftAPI|carts")
	public ItemStack requestItem(Object source, ItemStack request) {
		return requestItem(this, new ArrayStackFilter(request));
	}

	@Optional.Method(modid = "RailcraftAPI|carts")
	public ItemStack requestItem(Object source, IStackFilter request) {
		ItemStack result = null;
		if (!passThrough && getSizeInventory() > 0) {
			result = removeOneItem(this, request);
			if (result != null)
				return result;
		}

		ILinkageManager lm = CartTools.getLinkageManager(worldObj);

		EntityMinecart linkedCart = lm.getLinkedCartA(this);
		if (linkedCart != source && linkedCart instanceof IItemTransfer)
			result = ((IItemTransfer) linkedCart).requestItem(this, request);

		if (result != null)
			return result;

		linkedCart = lm.getLinkedCartB(this);
		if (linkedCart != source && linkedCart instanceof IItemTransfer)
			result = ((IItemTransfer) linkedCart).requestItem(this, request);

		return result;
	}

	/**
	 * Removes and returns a single item from the inventory that matches the
	 * filter.
	 *
	 * @param inv The inventory
	 * @param filter EnumItemType to match against
	 * @return An ItemStack
	 */
	protected ItemStack removeOneItem(IInventory inv, IStackFilter filter) {
		for (int i = 0; i < inv.getSizeInventory(); i++) {
			ItemStack slot = inv.getStackInSlot(i);
			if (slot != null && filter.matches(slot))
				return inv.decrStackSize(i, 1);
		}
		return null;
	}

	protected ItemStack moveItemStack(ItemStack stack, IInventory dest) {
		if (stack == null)
			return null;
		stack = stack.copy();
		if (dest == null)
			return stack;
		boolean movedItem = false;
		do {
			movedItem = false;
			ItemStack destStack = null;
			for (int ii = 0; ii < dest.getSizeInventory(); ii++) {
				destStack = dest.getStackInSlot(ii);
				if (destStack != null && destStack.isItemEqual(stack)) {
					int maxStack = Math.min(destStack.getMaxStackSize(), dest.getInventoryStackLimit());
					int room = maxStack - destStack.stackSize;
					if (room > 0) {
						int move = Math.min(room, stack.stackSize);
						destStack.stackSize += move;
						stack.stackSize -= move;
						if (stack.stackSize <= 0)
							return null;
						movedItem = true;
					}
				}
			}
			if (!movedItem)
				for (int ii = 0; ii < dest.getSizeInventory(); ii++) {
					destStack = dest.getStackInSlot(ii);
					if (destStack == null) {
						if (stack.stackSize > dest.getInventoryStackLimit())
							dest.setInventorySlotContents(ii, stack.splitStack(dest.getInventoryStackLimit()));
						else {
							dest.setInventorySlotContents(ii, stack);
							return null;
						}
						movedItem = true;
					}
				}
		} while (movedItem);
		return stack;
	}

}