FluidHandlerItemStackSimple.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.capability.templates;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;

import net.minecraft.item.ItemStack;
import net.minecraft.nbt.NBTTagCompound;
import net.minecraft.util.EnumFacing;
import net.minecraftforge.common.capabilities.Capability;
import net.minecraftforge.common.capabilities.ICapabilityProvider;
import net.minecraftforge.fluids.FluidStack;
import net.minecraftforge.fluids.capability.FluidTankProperties;
import net.minecraftforge.fluids.capability.IFluidHandlerItem;
import net.minecraftforge.fluids.capability.IFluidTankProperties;
import net.minecraftforge.fluids.capability.CapabilityFluidHandler;

/**
 * FluidHandlerItemStackSimple is a template capability provider for ItemStacks.
 * Data is stored directly in the vanilla NBT, in the same way as the old ItemFluidContainer.
 *
 * This implementation only allows item containers to be fully filled or emptied, similar to vanilla buckets.
 */
public class FluidHandlerItemStackSimple implements IFluidHandlerItem, ICapabilityProvider
{
    public static final String FLUID_NBT_KEY = "Fluid";

    @Nonnull
    protected ItemStack container;
    protected int capacity;

    /**
     * @param container  The container itemStack, data is stored on it directly as NBT.
     * @param capacity   The maximum capacity of this fluid tank.
     */
    public FluidHandlerItemStackSimple(@Nonnull ItemStack container, int capacity)
    {
        this.container = container;
        this.capacity = capacity;
    }

    @Nonnull
    @Override
    public ItemStack getContainer()
    {
        return container;
    }

    @Nullable
    public FluidStack getFluid()
    {
        NBTTagCompound tagCompound = container.getTagCompound();
        if (tagCompound == null || !tagCompound.hasKey(FLUID_NBT_KEY))
        {
            return null;
        }
        return FluidStack.loadFluidStackFromNBT(tagCompound.getCompoundTag(FLUID_NBT_KEY));
    }

    protected void setFluid(FluidStack fluid)
    {
        if (!container.hasTagCompound())
        {
            container.setTagCompound(new NBTTagCompound());
        }

        NBTTagCompound fluidTag = new NBTTagCompound();
        fluid.writeToNBT(fluidTag);
        container.getTagCompound().setTag(FLUID_NBT_KEY, fluidTag);
    }

    @Override
    public IFluidTankProperties[] getTankProperties()
    {
        return new IFluidTankProperties[] { new FluidTankProperties(getFluid(), capacity) };
    }

    @Override
    public int fill(FluidStack resource, boolean doFill)
    {
        if (container.getCount() != 1 || resource == null || resource.amount <= 0 || !canFillFluidType(resource))
        {
            return 0;
        }

        FluidStack contained = getFluid();
        if (contained == null)
        {
            int fillAmount = Math.min(capacity, resource.amount);
            if (fillAmount == capacity) {
                if (doFill) {
                    FluidStack filled = resource.copy();
                    filled.amount = fillAmount;
                    setFluid(filled);
                }

                return fillAmount;
            }
        }

        return 0;
    }

    @Override
    public FluidStack drain(FluidStack resource, boolean doDrain)
    {
        if (container.getCount() != 1 || resource == null || resource.amount <= 0 || !resource.isFluidEqual(getFluid()))
        {
            return null;
        }
        return drain(resource.amount, doDrain);
    }

    @Override
    public FluidStack drain(int maxDrain, boolean doDrain)
    {
        if (container.getCount() != 1 || maxDrain <= 0)
        {
            return null;
        }

        FluidStack contained = getFluid();
        if (contained == null || contained.amount <= 0 || !canDrainFluidType(contained))
        {
            return null;
        }

        final int drainAmount = Math.min(contained.amount, maxDrain);
        if (drainAmount == capacity) {
            FluidStack drained = contained.copy();

            if (doDrain) {
                setContainerToEmpty();
            }

            return drained;
        }

        return null;
    }

    public boolean canFillFluidType(FluidStack fluid)
    {
        return true;
    }

    public boolean canDrainFluidType(FluidStack fluid)
    {
        return true;
    }

    /**
     * Override this method for special handling.
     * Can be used to swap out the container's item for a different one with "container.setItem".
     * Can be used to destroy the container with "container.stackSize--"
     */
    protected void setContainerToEmpty()
    {
        container.getTagCompound().removeTag(FLUID_NBT_KEY);
    }

    @Override
    public boolean hasCapability(@Nonnull Capability<?> capability, @Nullable EnumFacing facing)
    {
        return capability == CapabilityFluidHandler.FLUID_HANDLER_ITEM_CAPABILITY;
    }

    @SuppressWarnings("unchecked")
    @Override
    @Nullable
    public <T> T getCapability(@Nonnull Capability<T> capability, @Nullable EnumFacing facing)
    {
        return capability == CapabilityFluidHandler.FLUID_HANDLER_ITEM_CAPABILITY ? (T) this : null;
    }

    /**
     * Destroys the container item when it's emptied.
     */
    public static class Consumable extends FluidHandlerItemStackSimple
    {
        public Consumable(ItemStack container, int capacity)
        {
            super(container, capacity);
        }

        @Override
        protected void setContainerToEmpty()
        {
            super.setContainerToEmpty();
            container.shrink(1);
        }
    }

    /**
     * Swaps the container item for a different one when it's emptied.
     */
    public static class SwapEmpty extends FluidHandlerItemStackSimple
    {
        protected final ItemStack emptyContainer;

        public SwapEmpty(ItemStack container, ItemStack emptyContainer, int capacity)
        {
            super(container, capacity);
            this.emptyContainer = emptyContainer;
        }

        @Override
        protected void setContainerToEmpty()
        {
            super.setContainerToEmpty();
            container = emptyContainer;
        }
    }
}