PotionRecipes

package io.github.winx64.test;

import java.util.ArrayList;
import java.util.Collections;
import java.util.HashMap;
import java.util.HashSet;
import java.util.List;
import java.util.Map;
import java.util.Set;

import org.bukkit.Material;
import org.bukkit.inventory.ItemStack;

import net.minecraft.server.v1_8_R3.Item;
import net.minecraft.server.v1_8_R3.ItemPotion;
import net.minecraft.server.v1_8_R3.Items;
import net.minecraft.server.v1_8_R3.MobEffect;
import net.minecraft.server.v1_8_R3.PotionBrewer;

/**
 * Utility class to provide the different recipes for each potion in the game.
 *
 * @author WinX64
 *
 */
public final class PotionRecipes {

    private static final Map<Integer, Set<List<Material>>> MAPPED_RECIPES = new HashMap<>();
    private static final Map<Material, String> MODIFIERS = new HashMap<>();

    static {
        Item.REGISTRY.forEach(item -> {
            if (item.l(new net.minecraft.server.v1_8_R3.ItemStack(item))) {
                @SuppressWarnings("deprecation")
                Material material = Material.getMaterial(Item.getId(item));
                MODIFIERS.put(material, item.j(null));
            }
        });

        mapPotions(0, new ArrayList<>());
    }

    private PotionRecipes() {}

    /**
     * Gets every recipe the leads to the specified potion
     *
     * @param potion
     *            The potion
     * @return The recipes for the specified potion
     */
    public static Set<List<Material>> getRecipes(ItemStack potion) {
        return getRecipes(potion.getDurability());
    }

    /**
     * Gets every recipe that leads to the specified potion ID
     *
     * @param potionId
     *            The potion ID
     * @return The recipes for the specified potion ID
     */
    public static Set<List<Material>> getRecipes(int potionId) {
        return Collections.unmodifiableSet(MAPPED_RECIPES.getOrDefault(potionId, Collections.emptySet()));
    }

    /**
     * Gets the first recipe that leads to the specified potion
     *
     * @param potion
     *            The potion
     * @return The first recipe for the specified potion
     */
    public static List<Material> getFirstRecipe(ItemStack potion) {
        Set<List<Material>> recipes = getRecipes(potion);

        return recipes.size() < 1 ? null : Collections.unmodifiableList(recipes.iterator().next());
    }

    /**
     * Gets the first recipe that leads to the specified potion ID
     *
     * @param potionId
     *            The potion ID
     * @return The first recipe for the specified potion ID
     */
    public static List<Material> getFirstRecipe(int potionId) {
        Set<List<Material>> recipes = getRecipes(potionId);

        return recipes.size() < 1 ? null : Collections.unmodifiableList(recipes.iterator().next());
    }

    private static void mapPotions(int potionId, List<Material> craftingChain) {
        MODIFIERS.forEach((key, value) -> {
            int newPotionId = calculateNewPotion(potionId, value);
            if (newPotionId == -1) {
                return;
            }

            MAPPED_RECIPES.putIfAbsent(newPotionId, new HashSet<>());
            MAPPED_RECIPES.get(newPotionId).forEach(existingChain -> {
                if (Collections.indexOfSubList(craftingChain, existingChain) != -1) {
                    return;
                }
            });

            List<Material> newCraftingChain = new ArrayList<Material>(craftingChain);
            newCraftingChain.add(key);
            MAPPED_RECIPES.get(newPotionId).add(newCraftingChain);

            mapPotions(newPotionId, newCraftingChain);
        });
    }

    private static int calculateNewPotion(int potionId, String itemUsed) {
        int newPotionId = PotionBrewer.a(potionId, itemUsed);
        List<MobEffect> effects = Items.POTION.e(potionId);
        List<MobEffect> newEffects = Items.POTION.e(newPotionId);
        if (potionId > 0 && effects == newEffects
                || effects != null && (effects.equals(newEffects) || newEffects == null)) {
            if (!ItemPotion.f(potionId) && ItemPotion.f(newPotionId)) {
                return newPotionId;
            }
        } else if (potionId != newPotionId) {
            return newPotionId;
        }
        return -1;
    }
}