common/universalelectricity/core/item/ItemElectric.java

package universalelectricity.core.item;

import java.util.List;

import net.minecraft.creativetab.CreativeTabs;
import net.minecraft.entity.player.EntityPlayer;
import net.minecraft.item.Item;
import net.minecraft.item.ItemStack;
import net.minecraft.nbt.NBTBase;
import net.minecraft.nbt.NBTTagCompound;
import net.minecraft.nbt.NBTTagDouble;
import net.minecraft.nbt.NBTTagFloat;
import net.minecraft.world.World;
import universalelectricity.core.electricity.ElectricityDisplay;
import universalelectricity.core.electricity.ElectricityDisplay.ElectricUnit;

/** Extend from this class if your item requires electricity or to be charged. Optionally, you can
 * implement IItemElectric instead.
 *
 * @author Calclavia */
public abstract class ItemElectric extends Item implements IItemElectric
{
    public ItemElectric(int id)
    {
        super(id);
        this.setMaxStackSize(1);
        this.setMaxDamage(100);
        this.setNoRepair();
    }

    @Override
    public void addInformation(ItemStack itemStack, EntityPlayer entityPlayer, List list, boolean par4)
    {
        String color = "";
        float joules = this.getElectricityStored(itemStack);

        if (joules <= this.getMaxElectricityStored(itemStack) / 3)
        {
            color = "\u00a74";
        }
        else if (joules > this.getMaxElectricityStored(itemStack) * 2 / 3)
        {
            color = "\u00a72";
        }
        else
        {
            color = "\u00a76";
        }

        list.add(color + ElectricityDisplay.getDisplayShort(joules, ElectricUnit.JOULES) + "/" + ElectricityDisplay.getDisplayShort(this.getMaxElectricityStored(itemStack), ElectricUnit.JOULES));
    }

    /** Makes sure the item is uncharged when it is crafted and not charged. Change this if you do
     * not want this to happen! */
    @Override
    public void onCreated(ItemStack itemStack, World par2World, EntityPlayer par3EntityPlayer)
    {
        this.setElectricity(itemStack, 0);
    }

    @Override
    public float recharge(ItemStack itemStack, float energy, boolean doReceive)
    {
        float rejectedElectricity = Math.max((this.getElectricityStored(itemStack) + energy) - this.getMaxElectricityStored(itemStack), 0);
        float energyToReceive = energy - rejectedElectricity;

        if (doReceive)
        {
            this.setElectricity(itemStack, this.getElectricityStored(itemStack) + energyToReceive);
        }

        return energyToReceive;
    }

    @Override
    public float discharge(ItemStack itemStack, float energy, boolean doTransfer)
    {
        float energyToTransfer = Math.min(this.getElectricityStored(itemStack), energy);

        if (doTransfer)
        {
            this.setElectricity(itemStack, this.getElectricityStored(itemStack) - energyToTransfer);
        }

        return energyToTransfer;
    }

    @Override
    public float getVoltage(ItemStack itemStack)
    {
        return 0.120f;
    }

    @Override
    public void setElectricity(ItemStack itemStack, float joules)
    {
        // Saves the frequency in the ItemStack
        if (itemStack.getTagCompound() == null)
        {
            itemStack.setTagCompound(new NBTTagCompound());
        }

        float electricityStored = Math.max(Math.min(joules, this.getMaxElectricityStored(itemStack)), 0);
        itemStack.getTagCompound().setFloat("electricity", electricityStored);

        /** Sets the damage as a percentage to render the bar properly. */
        itemStack.setItemDamage((int) (100 - (electricityStored / getMaxElectricityStored(itemStack)) * 100));
    }

    @Override
    public float getTransfer(ItemStack itemStack)
    {
        return this.getMaxElectricityStored(itemStack) - this.getElectricityStored(itemStack);
    }

    /** Gets the energy stored in the item. Energy is stored using item NBT */
    @Override
    public float getElectricityStored(ItemStack itemStack)
    {
        if (itemStack.getTagCompound() == null)
        {
            itemStack.setTagCompound(new NBTTagCompound());
        }
        float energyStored = 0f;
        if (itemStack.getTagCompound().hasKey("electricity"))
        {
            NBTBase obj = itemStack.getTagCompound().getTag("electricity");
            if (obj instanceof NBTTagDouble)
            {
                energyStored = (float) ((NBTTagDouble) obj).data;
            }
            else if (obj instanceof NBTTagFloat)
            {
                energyStored = ((NBTTagFloat) obj).data;
            }
        }

        /** Sets the damage as a percentage to render the bar properly. */
        itemStack.setItemDamage((int) (100 - (energyStored / getMaxElectricityStored(itemStack)) * 100));
        return energyStored;
    }

    @Override
    public void getSubItems(int par1, CreativeTabs par2CreativeTabs, List par3List)
    {
        par3List.add(ElectricItemHelper.getUncharged(new ItemStack(this)));
        par3List.add(ElectricItemHelper.getWithCharge(new ItemStack(this), this.getMaxElectricityStored(new ItemStack(this))));
    }
}