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.getHasStack()){
            ItemStack currentStack = theSlot.getStack();
            ItemStack newStack = currentStack.copy();

            if(currentStack.getItem() != null){
                if(slot <= hotbarEnd && slot >= inventoryStart){
                    this.mergeItemStack(newStack, 0, 9, false);
                }

                if(slot <= hotbarEnd && slot >= hotbarStart){
                    this.mergeItemStack(newStack, inventoryStart, inventoryEnd+1, false);
                }

                else if(slot <= inventoryEnd && slot >= inventoryStart){
                    this.mergeItemStack(newStack, hotbarStart, hotbarEnd+1, false);
                }

                else if(slot < inventoryStart){
                    this.mergeItemStack(newStack, inventoryStart, hotbarEnd+1, false);
                }

                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;
    }
}