Smelter Container

package neo.projectshadow.inventory;

import neo.projectshadow.tileentity.TileBlacksmithSmelter;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.entity.player.InventoryPlayer;
import net.minecraft.inventory.Container;
import net.minecraft.inventory.Slot;
import net.minecraft.item.ItemStack;
import net.minecraft.tileentity.TileEntityFurnace;

public class ContainerBlacksmithSmelter extends Container {

    private TileBlacksmithSmelter tileEntity;

    public ContainerBlacksmithSmelter(InventoryPlayer playerinv, TileBlacksmithSmelter tileEntity)
    {
        this.tileEntity = tileEntity;

        //Input
            addSlotToContainer(new Slot(tileEntity, TileBlacksmithSmelter.INPUT_INVENTORY_INDEX, 56, 17));

        //Fuel
            addSlotToContainer(new Slot(tileEntity, TileBlacksmithSmelter.FUEL_INVENTORY_INDEX, 56, 53));

        //Output
            addSlotToContainer(new Slot(tileEntity, TileBlacksmithSmelter.OUTPUT_INVENTORY_INDEX, 116, 35));

        //Player Inv
            bindPlayerInventory(playerinv);

    }

    // Populates GUI inventory section to Players current hot bar and inventory
    private void bindPlayerInventory(InventoryPlayer playerInventory)
    {
        // Add the player's inventory slots to the container
        for (int inventoryRowIndex = 0; inventoryRowIndex < 3; ++inventoryRowIndex) {
            for (int inventoryColumnIndex = 0; inventoryColumnIndex < 9; ++inventoryColumnIndex) {
                this.addSlotToContainer(new Slot(playerInventory, inventoryColumnIndex + inventoryRowIndex * 9 + 9, 8 + inventoryColumnIndex * 18, 94 + inventoryRowIndex * 18));
            }
        }

        // Add the player's action bar slots to the container
        for (int actionBarSlotIndex = 0; actionBarSlotIndex < 9; ++actionBarSlotIndex) {
            this.addSlotToContainer(new Slot(playerInventory, actionBarSlotIndex, 8 + actionBarSlotIndex * 18, 152));
        }

    }

    @Override
    public boolean canInteractWith(EntityPlayer player) {
        return tileEntity.isUseableByPlayer(player);
    }

    @Override
    public ItemStack transferStackInSlot(EntityPlayer player, int slotIndex)
    {
        ItemStack itemStack = null;
        Slot slot = (Slot)inventorySlots.get(slotIndex);

        if(slot != null && slot.getHasStack())
        {
            ItemStack slotItemStack = slot.getStack();
            itemStack = slotItemStack.copy();

            // Merges the item into the player inventory
            if(slotIndex < TileBlacksmithSmelter.INVENTORY_SIZE)
            {
                if(!this.mergeItemStack(slotItemStack, TileBlacksmithSmelter.INVENTORY_SIZE, inventorySlots.size(), false)){
                    return null;
                }
            }
            else {
                if (TileEntityFurnace.isItemFuel(slotItemStack)) {
                    if(!this.mergeItemStack(slotItemStack, TileBlacksmithSmelter.FUEL_INVENTORY_INDEX, TileBlacksmithSmelter.OUTPUT_INVENTORY_INDEX, false)) {
                        return null;
                    }
                }
                else if (!this.mergeItemStack(slotItemStack, TileBlacksmithSmelter.INPUT_INVENTORY_INDEX, TileBlacksmithSmelter.OUTPUT_INVENTORY_INDEX, false)){
                    return null;
                }
            }
            if (slotItemStack.stackSize == 0) {
                slot.putStack((ItemStack) null);
            } else {
                slot.onSlotChanged();
            }
        }
        return itemStack;
    }
}