ActuallyAdditions/src/main/java/ellpeck/actuallyadditions/inventory/ContainerDropper.java

package ellpeck.actuallyadditions.inventory;

import ellpeck.actuallyadditions.tile.TileEntityBase;
import ellpeck.actuallyadditions.tile.TileEntityDropper;
import invtweaks.api.container.InventoryContainer;
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;

@InventoryContainer
public class ContainerDropper extends Container{

    private TileEntityDropper dropper;

    public ContainerDropper(InventoryPlayer inventory, TileEntityBase tile){
        this.dropper = (TileEntityDropper)tile;

        for (int i = 0; i < 3; i++){
            for (int j = 0; j < 3; j++){
                this.addSlotToContainer(new Slot(this.dropper, j+i*3, 62+j*18, 21+i*18));
            }
        }

        for (int i = 0; i < 3; i++){
            for (int j = 0; j < 9; j++){
                this.addSlotToContainer(new Slot(inventory, j + i * 9 + 9, 8 + j * 18, 97 + i * 18));
            }
        }
        for (int i = 0; i < 9; i++){
            this.addSlotToContainer(new Slot(inventory, i, 8 + i * 18, 155));
        }
    }

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

    @Override
    public ItemStack transferStackInSlot(EntityPlayer player, int slot){
        final int inventoryStart = 9;
        final int inventoryEnd = inventoryStart+26;
        final int hotbarStart = inventoryEnd+1;
        final int hotbarEnd = hotbarStart+8;

        Slot theSlot = (Slot)this.inventorySlots.get(slot);

        if (theSlot != null && theSlot.getHasStack()){
            ItemStack newStack = theSlot.getStack();
            ItemStack currentStack = newStack.copy();

            //Other Slots in Inventory excluded
            if(slot >= inventoryStart){
                //Shift from Inventory
                if(!this.mergeItemStack(newStack, 0, 9, false)){
                    //
                    if(slot >= inventoryStart && slot <= inventoryEnd){
                        if(!this.mergeItemStack(newStack, hotbarStart, hotbarEnd+1, false)) return null;
                    }
                    else if(slot >= inventoryEnd+1 && slot < hotbarEnd+1 && !this.mergeItemStack(newStack, inventoryStart, inventoryEnd+1, false))
                        return null;
                }
            }
            else if(!this.mergeItemStack(newStack, inventoryStart, hotbarEnd+1, false)) return null;

            if (newStack.stackSize == 0) theSlot.putStack(null);
            else theSlot.onSlotChanged();

            if (newStack.stackSize == currentStack.stackSize) return null;
            theSlot.onPickupFromSlot(player, newStack);

            return currentStack;
        }
        return null;
    }
}