ActionColour.java

package pw.stapleton.ColouredCategories.crt;

import crafttweaker.IAction;
import crafttweaker.api.item.IIngredient;
import crafttweaker.api.minecraft.CraftTweakerMC;
import net.minecraft.item.ItemStack;
import pw.stapleton.ColouredCategories.ColouredCategories;

import java.util.HashMap;
import java.util.Map;

public class ActionColour implements IAction {

    private ItemStack ingredient;
    private int bg;
    private int bs;
    private int be;

    public ActionColour(IIngredient ingredients, String background, String borderStart, String borderEnd) {

        this.ingredient = CraftTweakerMC.getItemStack(ingredients);

        if (background.length() == 6) this.bg = Integer.getInteger("0xf0" + background);
        else if (background.length() == 8) this.bg = Integer.getInteger("0x" + background);
        else throw new IllegalArgumentException("background colour value must be either 6 characters long (RGB) or 8 characters long (ARGB)");

        if (borderStart.length() == 6) this.bs = Integer.getInteger("0xf0" + borderStart);
        else if (borderStart.length() == 8) this.bs = Integer.getInteger("0x" + borderStart);
        else throw new IllegalArgumentException("borderStart colour value must be either 6 characters long (RGB) or 8 characters long (ARGB)");

        if (borderEnd.length() == 6) this.be = Integer.getInteger("0xf0" + borderEnd);
        else if (borderEnd.length() == 8) this.be = Integer.getInteger("0x" + borderEnd);
        else throw new IllegalArgumentException("borderEnd colour value must be either 6 characters long (RGB) or 8 characters long (ARGB)");
    }

    public ActionColour(IIngredient[] ingredients, String background, String borderStart, String borderEnd) {
        for (IIngredient ingredient : ingredients) {
            new ActionColour(ingredient, background, borderStart, borderEnd);
        }
    }

    @Override
    public void apply() {
        Map<String, Integer> values = new HashMap<>();

        values.put("background", this.bg);
        values.put("borderStart", this.bs);
        values.put("borderEnd", this.be);

        ColouredCategories.INGREDIENT_MAP.put(this.ingredient, values);
    }

    @Override
    public String describe() {

        return this.ingredient + " has been added and coloured.";
    }
}

ActionRandom.java

package pw.stapleton.ColouredCategories.crt;

import crafttweaker.IAction;
import crafttweaker.api.item.IIngredient;
import crafttweaker.api.minecraft.CraftTweakerMC;
import net.minecraft.item.ItemStack;
import net.minecraft.util.NonNullList;
import pw.stapleton.ColouredCategories.ColouredCategories;

import java.util.HashMap;
import java.util.Map;
import java.util.Random;

public class ActionRandom implements IAction {

    private final NonNullList<ItemStack> randItemStacks = NonNullList.create();
    private final String[] hexChars = { "0", "1", "2", "3", "4", "5", "6", "7", "8", "9", "A", "B", "C", "D", "E", "F" };
    private String transparency;

    public ActionRandom(IIngredient ingredient, String transparency) {
        randItemStacks.add(CraftTweakerMC.getItemStack(ingredient));
        this.transparency = transparency;
    }

    public ActionRandom(IIngredient[] ingredients, String transparency) {
        for (IIngredient ingredient : ingredients) {
            new ActionRandom(ingredient, transparency);
        }
    }

    public Integer random(String transparency) {

        StringBuilder hexBuild = new StringBuilder("0x");
        Random ran = new Random();

        int loop = 8;

        if (!transparency.isEmpty()) {
            hexBuild.append(transparency);
            loop = 6;
        }

        for (int i = 0; i < loop; i++) {
            int ranI = ran.nextInt(hexChars.length);
            ColouredCategories.Logger.info("Var: ActionRandom#random().ranI, From: ActionRandom#random() = " + ranI);
            ColouredCategories.Logger.info("Var: ActionRandom#random().hexChars[ranI], From: ActionRandom#random(). = " + hexChars[ranI]);
            hexBuild.append(hexChars[ranI]);
        }

        ColouredCategories.Logger.info("Var: ActionRandom#random().hexBuild.toString(), From: ActionRandom#random() = " + hexBuild.toString());
        return Integer.getInteger(hexBuild.toString());
    }

    @Override
    public void apply() {
        for (ItemStack item : randItemStacks) {
            Map<String, Integer> values = new HashMap<>();
            ColouredCategories.Logger.info("Call: ActionRandom#random(), From: ActionRandom#apply(). = " + random(this.transparency));

            values.put("background", random(this.transparency));
            values.put("borderStart", random(this.transparency));
            values.put("borderEnd", random(this.transparency));

            ColouredCategories.INGREDIENT_MAP.put(item, values);
        }
    }

    @Override
    public String describe() {

        return "Randomized tooltip colours on " + randItemStacks.size() + " items.";
    }
}

ColouredCategories.java

package pw.stapleton.ColouredCategories;

import net.minecraft.item.ItemStack;
import net.minecraftforge.client.event.RenderTooltipEvent;
import net.minecraftforge.common.MinecraftForge;
import net.minecraftforge.fml.common.Mod;
import net.minecraftforge.fml.common.event.FMLPreInitializationEvent;
import net.minecraftforge.fml.common.eventhandler.EventPriority;
import net.minecraftforge.fml.common.eventhandler.SubscribeEvent;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import pw.stapleton.ColouredCategories.util.Config;
import pw.stapleton.ColouredCategories.util.Reference;

import java.util.HashMap;
import java.util.Map;

@Mod(modid = Reference.MODID, version = Reference.VERSION, clientSideOnly = true, name = Reference.MOD_NAME, dependencies = Reference.DEPENDENCIES)
public class ColouredCategories {

    public static final Map<ItemStack, Map<String, Integer>> INGREDIENT_MAP = new HashMap<>();

    public static Logger Logger = LogManager.getLogger(Reference.MOD_NAME);

    @Mod.Instance(Reference.MOD_NAME)
    public static ColouredCategories instance;

    @Mod.EventHandler
    public void onPreInit(FMLPreInitializationEvent event) {

        new Config(event.getSuggestedConfigurationFile());
        MinecraftForge.EVENT_BUS.register(this);
    }

    @SubscribeEvent(priority = EventPriority.LOWEST)
    public void onTooltipColour(RenderTooltipEvent.Color event) {
        //Logger.info(INGREDIENT_MAP);

        if (event.getStack().isEmpty()) return;

        if (!INGREDIENT_MAP.containsKey(event.getStack())) return;

        Map<String, Integer> values = INGREDIENT_MAP.get(event.getStack());

        event.setBackground(values.get("background"));
        event.setBorderStart(values.get("borderStart"));
        event.setBorderEnd(values.get("borderEnd"));
    }
}

CraftTweaker.java

package pw.stapleton.ColouredCategories.crt;

import crafttweaker.CraftTweakerAPI;
import crafttweaker.annotations.ZenRegister;
import crafttweaker.api.item.IIngredient;
import stanhebben.zenscript.annotations.ZenClass;
import stanhebben.zenscript.annotations.ZenMethod;

@ZenRegister
@ZenClass("mods.ColouredCategories")
public class CraftTweaker {

    @ZenMethod
    public static void colour(IIngredient ingredients, String background, String borderStart, String borderEnd) {
        CraftTweakerAPI.apply(new ActionColour(ingredients, background, borderStart, borderEnd));
    }

    @ZenMethod
    public static void colour(IIngredient[] ingredients, String background, String borderStart, String borderEnd) {
        CraftTweakerAPI.apply(new ActionColour(ingredients, background, borderStart, borderEnd));
    }

    @ZenMethod
    public static void random(IIngredient ingredient, String transparency) {
        CraftTweakerAPI.apply(new ActionRandom(ingredient, transparency));
    }

    @ZenMethod
    public static void random(IIngredient[] ingredients, String transparency) {
        CraftTweakerAPI.apply(new ActionRandom(ingredients, transparency));
    }
}