ActuallyAdditions/src/main/java/de/ellpeck/actuallyadditions/mod/util/AwfulUtil.java

/*
 * This file ("AwfulUtil.java") is part of the Actually Additions mod for Minecraft.
 * It is created and owned by Ellpeck and distributed
 * under the Actually Additions License to be found at
 * http://ellpeck.de/actaddlicense
 * View the source code at https://github.com/Ellpeck/ActuallyAdditions
 *
 * © 2015-2017 Ellpeck
 */

package de.ellpeck.actuallyadditions.mod.util;

import com.google.common.collect.Lists;
import net.minecraft.item.ItemStack;
import net.minecraft.util.math.MathHelper;
import net.minecraft.world.storage.loot.LootContext;
import net.minecraft.world.storage.loot.LootTable;
import net.minecraftforge.items.IItemHandlerModifiable;

import java.util.Collections;
import java.util.Iterator;
import java.util.List;
import java.util.Random;

//This is stuff copied from somewhere in vanilla and changed so that it works properly
//It's unpolished and vanilla-y, so don't look at it! O_O
public final class AwfulUtil{

    public static void fillInventory(LootTable table, IItemHandlerModifiable inventory, Random rand, LootContext context){
        List<ItemStack> list = table.generateLootForPools(rand, context);
        List<Integer> list1 = getEmptySlotsRandomized(inventory, rand);
        shuffleItems(list, list1.size(), rand);

        for(ItemStack itemstack : list){
            if(itemstack.isEmpty()){
                inventory.setStackInSlot(list1.remove(list1.size()-1), ItemStack.EMPTY);
            }
            else{
                inventory.setStackInSlot(list1.remove(list1.size()-1), itemstack);
            }
        }
    }

    private static void shuffleItems(List<ItemStack> stacks, int someInt, Random rand){
        List<ItemStack> list = Lists.newArrayList();
        Iterator<ItemStack> iterator = stacks.iterator();

        while(iterator.hasNext()){
            ItemStack itemstack = iterator.next();

            if(itemstack.isEmpty()){
                iterator.remove();
            }
            else if(itemstack.getCount() > 1){
                list.add(itemstack);
                iterator.remove();
            }
        }

        someInt = someInt-stacks.size();

        while(someInt > 0 && ((List)list).size() > 0){
            ItemStack itemstack2 = list.remove(MathHelper.getInt(rand, 0, list.size()-1));
            int i = MathHelper.getInt(rand, 1, itemstack2.getCount()/2);
            ItemStack itemstack1 = itemstack2.splitStack(i);

            if(itemstack2.getCount() > 1 && rand.nextBoolean()){
                list.add(itemstack2);
            }
            else{
                stacks.add(itemstack2);
            }

            if(itemstack1.getCount() > 1 && rand.nextBoolean()){
                list.add(itemstack1);
            }
            else{
                stacks.add(itemstack1);
            }
        }

        stacks.addAll(list);
        Collections.shuffle(stacks, rand);
    }

    private static List<Integer> getEmptySlotsRandomized(IItemHandlerModifiable inventory, Random rand){
        List<Integer> list = Lists.newArrayList();

        for(int i = 0; i < inventory.getSlots(); ++i){
            if(inventory.getStackInSlot(i).isEmpty()){
                list.add(i);
            }
        }

        Collections.shuffle(list, rand);
        return list;
    }
}