InvStack.java

package mekanism.common.content.transporter;

import java.util.ArrayList;

import net.minecraft.inventory.IInventory;
import net.minecraft.item.ItemStack;

public final class InvStack
{
	public IInventory inventory;
	public ArrayList<ItemStack> itemStacks;
	public ArrayList<Integer> slotIDs;

	public InvStack(IInventory inv)
	{
		inventory = inv;
		itemStacks = new ArrayList<ItemStack>();
		slotIDs = new ArrayList<Integer>();
	}

	public InvStack(IInventory inv, int id, ItemStack stack)
	{
		inventory = inv;
		itemStacks = new ArrayList<ItemStack>();
		slotIDs = new ArrayList<Integer>();

		appendStack(id, stack);
	}

	public ItemStack getStack()
	{
		int size = 0;

		for(ItemStack stack : itemStacks)
		{
			size += stack.stackSize;
		}

		if(!itemStacks.isEmpty())
		{
			ItemStack ret = itemStacks.get(0).copy();
			ret.stackSize = size;

			return ret;
		}

		return null;
	}

	public void appendStack(int id, ItemStack stack)
	{
		slotIDs.add(id);
		itemStacks.add(stack);
	}

	public void use(int amount)
	{
		for(int i = 0; i < slotIDs.size(); i++)
		{
			ItemStack stack = itemStacks.get(i);

			if(inventory.getStackInSlot(slotIDs.get(i)).stackSize == stack.stackSize && stack.stackSize <= amount)
			{
				inventory.setInventorySlotContents(slotIDs.get(i), null);
				amount -= stack.stackSize;
			}
			else {
				ItemStack ret = stack.copy();
				ret.stackSize = inventory.getStackInSlot(slotIDs.get(i)).stackSize - Math.min(stack.stackSize, amount);
				inventory.setInventorySlotContents(slotIDs.get(i), ret);
				amount -= ret.stackSize;
			}

			if(amount == 0)
			{
				return;
			}
		}
	}

	public void use()
	{
		use(getStack().stackSize);
	}
}