ForgePatch/src/main/java/net/minecraftforge/fluids/DispenseFluidContainer.java

/*
 * Minecraft Forge
 * Copyright (c) 2016.
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation version 2.1
 * of the License.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA
 */

package net.minecraftforge.fluids;

import net.minecraft.block.BlockDispenser;
import net.minecraft.dispenser.BehaviorDefaultDispenseItem;
import net.minecraft.dispenser.IBlockSource;
import net.minecraft.item.ItemStack;
import net.minecraft.tileentity.TileEntityDispenser;
import net.minecraft.util.EnumFacing;
import net.minecraft.util.math.BlockPos;
import net.minecraft.world.World;
import net.minecraftforge.fluids.capability.IFluidHandler;

import javax.annotation.Nonnull;

/**
 * Fills or drains a fluid container item using a Dispenser.
 */
public class DispenseFluidContainer extends BehaviorDefaultDispenseItem
{
    private static final DispenseFluidContainer INSTANCE = new DispenseFluidContainer();

    public static DispenseFluidContainer getInstance()
    {
        return INSTANCE;
    }

    private DispenseFluidContainer() {}

    private final BehaviorDefaultDispenseItem dispenseBehavior = new BehaviorDefaultDispenseItem();

    public ItemStack dispenseStack(IBlockSource source, ItemStack stack)
    {
        if (FluidUtil.getFluidContained(stack) != null)
        {
            return dumpContainer(source, stack);
        }
        else
        {
            return fillContainer(source, stack);
        }
    }

    /**
     * Picks up fluid in front of a Dispenser and fills a container with it.
     */
    @Nonnull
    private ItemStack fillContainer(IBlockSource source, @Nonnull ItemStack stack)
    {
        World world = source.getWorld();
        EnumFacing dispenserFacing = source.getBlockState().getValue(BlockDispenser.FACING);
        BlockPos blockpos = source.getBlockPos().offset(dispenserFacing);

        ItemStack result = FluidUtil.tryPickUpFluid(stack, null, world, blockpos, dispenserFacing.getOpposite());
        if (result == null)
        {
            return super.dispenseStack(source, stack);
        }

        if (stack.func_190916_E() == 1)
        {
            stack.deserializeNBT(result.serializeNBT());
        }
        else if (((TileEntityDispenser)source.getBlockTileEntity()).addItemStack(result) < 0)
        {
            this.dispenseBehavior.dispense(source, result);
        }

        stack.func_190918_g(1);
        return stack;
    }

    /**
     * Drains a filled container and places the fluid in front of the Dispenser.
     */
    private ItemStack dumpContainer(IBlockSource source, ItemStack stack)
    {
        ItemStack dispensedStack = stack.copy();
        dispensedStack.func_190920_e(1);
        IFluidHandler fluidHandler = FluidUtil.getFluidHandler(dispensedStack);
        if (fluidHandler == null)
        {
            return super.dispenseStack(source, stack);
        }

        FluidStack fluidStack = fluidHandler.drain(Fluid.BUCKET_VOLUME, false);
        EnumFacing dispenserFacing = source.getBlockState().getValue(BlockDispenser.FACING);
        BlockPos blockpos = source.getBlockPos().offset(dispenserFacing);

        if (fluidStack != null && fluidStack.amount == Fluid.BUCKET_VOLUME && FluidUtil.tryPlaceFluid(null, source.getWorld(), fluidStack, blockpos))
        {
            fluidHandler.drain(Fluid.BUCKET_VOLUME, true);

            if (stack.func_190916_E() == 1)
            {
                stack.deserializeNBT(dispensedStack.serializeNBT());
            }
            else if (((TileEntityDispenser)source.getBlockTileEntity()).addItemStack(dispensedStack) < 0)
            {
                this.dispenseBehavior.dispense(source, dispensedStack);
            }

            return stack;
        }
        else
        {
            return this.dispenseBehavior.dispense(source, stack);
        }
    }
}