Custom Potion Mixes

paper-api/src/main/java/io/papermc/paper/potion/PotionMix.java

@@ -0,0 +1,103 @@
+package io.papermc.paper.potion;
+
+import java.util.Objects;
+import java.util.function.Predicate;
+import org.bukkit.Keyed;
+import org.bukkit.NamespacedKey;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.RecipeChoice;
+import org.jetbrains.annotations.Contract;
+import org.jspecify.annotations.NullMarked;
+
+/**
+ * Represents a potion mix made in a Brewing Stand.
+ */
+@NullMarked
+public final class PotionMix implements Keyed {
+
+    private final NamespacedKey key;
+    private final ItemStack result;
+    private final RecipeChoice input;
+    private final RecipeChoice ingredient;
+
+    /**
+     * Creates a new potion mix. Add it to the server with {@link org.bukkit.potion.PotionBrewer#addPotionMix(PotionMix)}.
+     *
+     * @param key a unique key for the mix
+     * @param result the resulting itemstack that will appear in the 3 bottom slots
+     * @param input the input placed into the bottom 3 slots
+     * @param ingredient the ingredient placed into the top slot
+     */
+    public PotionMix(final NamespacedKey key, final ItemStack result, final RecipeChoice input, final RecipeChoice ingredient) {
+        this.key = key;
+        this.result = result;
+        this.input = input;
+        this.ingredient = ingredient;
+    }
+
+    /**
+     * Create a {@link RecipeChoice} based on a Predicate. These RecipeChoices are only
+     * valid for {@link PotionMix}, not anywhere else RecipeChoices may be used.
+     *
+     * @param stackPredicate a predicate for an itemstack.
+     * @return a new RecipeChoice
+     */
+    @Contract(value = "_ -> new", pure = true)
+    public static RecipeChoice createPredicateChoice(final Predicate<? super ItemStack> stackPredicate) {
+        return new PredicateRecipeChoice(stackPredicate);
+    }
+
+    @Override
+    public NamespacedKey getKey() {
+        return this.key;
+    }
+
+    /**
+     * Gets the resulting itemstack after the brew has finished.
+     *
+     * @return the result itemstack
+     */
+    public ItemStack getResult() {
+        return this.result;
+    }
+
+    /**
+     * Gets the input for the bottom 3 slots in the brewing stand.
+     *
+     * @return the bottom 3 slot ingredients
+     */
+    public RecipeChoice getInput() {
+        return this.input;
+    }
+
+    /**
+     * Gets the ingredient in the top slot of the brewing stand.
+     *
+     * @return the top slot input
+     */
+    public RecipeChoice getIngredient() {
+        return this.ingredient;
+    }
+
+    @Override
+    public String toString() {
+        return "PotionMix{" +
+            "result=" + this.result +
+            ", base=" + this.input +
+            ", addition=" + this.ingredient +
+            '}';
+    }
+
+    @Override
+    public boolean equals(final Object o) {
+        if (this == o) return true;
+        if (o == null || this.getClass() != o.getClass()) return false;
+        final PotionMix potionMix = (PotionMix) o;
+        return this.key.equals(potionMix.key) && this.result.equals(potionMix.result) && this.input.equals(potionMix.input) && this.ingredient.equals(potionMix.ingredient);
+    }
+
+    @Override
+    public int hashCode() {
+        return Objects.hash(this.key, this.result, this.input, this.ingredient);
+    }
+}

paper-api/src/main/java/io/papermc/paper/potion/PredicateRecipeChoice.java

@@ -0,0 +1,32 @@
+package io.papermc.paper.potion;
+
+import java.util.function.Predicate;
+import org.bukkit.inventory.ItemStack;
+import org.bukkit.inventory.RecipeChoice;
+import org.jetbrains.annotations.ApiStatus;
+import org.jspecify.annotations.NullMarked;
+
+@ApiStatus.Internal
+@NullMarked
+record PredicateRecipeChoice(Predicate<? super ItemStack> itemStackPredicate) implements RecipeChoice, Cloneable {
+
+    @Override
+    @Deprecated
+    public ItemStack getItemStack() {
+        throw new UnsupportedOperationException("PredicateRecipeChoice does not support this");
+    }
+
+    @Override
+    public RecipeChoice clone() {
+        try {
+            return (PredicateRecipeChoice) super.clone();
+        } catch (final CloneNotSupportedException ex) {
+            throw new AssertionError(ex);
+        }
+    }
+
+    @Override
+    public boolean test(final ItemStack itemStack) {
+        return this.itemStackPredicate.test(itemStack);
+    }
+}

paper-api/src/main/java/org/bukkit/Bukkit.java

@@ -2665,6 +2665,15 @@ public final class Bukkit {
     public static io.papermc.paper.datapack.DatapackManager getDatapackManager() {
         return server.getDatapackManager();
     }
+
+    /**
+     * Gets the potion brewer.
+     *
+     * @return the potion brewer
+     */
+    public static @NotNull org.bukkit.potion.PotionBrewer getPotionBrewer() {
+        return server.getPotionBrewer();
+    }
     // Paper end
 
     @NotNull

paper-api/src/main/java/org/bukkit/Server.java

@@ -2322,5 +2322,12 @@ public interface Server extends PluginMessageRecipient, net.kyori.adventure.audi
      */
     @NotNull
     io.papermc.paper.datapack.DatapackManager getDatapackManager();
+
+    /**
+     * Gets the potion brewer.
+     *
+     * @return the potion brewer
+     */
+    @NotNull org.bukkit.potion.PotionBrewer getPotionBrewer();
     // Paper end
 }

paper-api/src/main/java/org/bukkit/potion/PotionBrewer.java

@@ -4,10 +4,31 @@ import java.util.Collection;
 import org.jetbrains.annotations.NotNull;
 
 /**
- * Represents a brewer that can create {@link PotionEffect}s.
+ * Used to manage custom {@link io.papermc.paper.potion.PotionMix}s.
  */
 public interface PotionBrewer {
 
+    // Paper start
+    /**
+     * Adds a new potion mix recipe.
+     *
+     * @param potionMix the potion mix to add
+     */
+    void addPotionMix(@NotNull io.papermc.paper.potion.PotionMix potionMix);
+
+    /**
+     * Removes a potion mix recipe.
+     *
+     * @param key the key of the mix to remove
+     */
+    void removePotionMix(@NotNull org.bukkit.NamespacedKey key);
+
+    /**
+     * Resets potion mixes to their default, removing all custom ones.
+     */
+    void resetPotionMixes();
+    // Paper end
+
     /**
      * Creates a {@link PotionEffect} from the given {@link PotionEffectType},
      * applying duration modifiers and checks.
@@ -16,9 +37,15 @@ public interface PotionBrewer {
      * @param duration The duration in ticks
      * @param amplifier The amplifier of the effect
      * @return The resulting potion effect
+     * @deprecated use {@link PotionEffectType#createEffect(int, int)} instead.
      */
+    @Deprecated(forRemoval = true, since = "1.20.5") // Paper
     @NotNull
-    public PotionEffect createEffect(@NotNull PotionEffectType potion, int duration, int amplifier);
+    // Paper start - make default
+    default PotionEffect createEffect(@NotNull PotionEffectType potion, int duration, int amplifier) {
+        return potion.createEffect(duration, amplifier);
+    }
+    // Paper end
 
     /**
      * Returns a collection of {@link PotionEffect} that would be applied from
@@ -28,9 +55,13 @@ public interface PotionBrewer {
      * @return The list of effects
      * @deprecated Non-Functional
      */
-    @Deprecated(since = "1.6.2")
+    @Deprecated(since = "1.6.2", forRemoval = true) // Paper
     @NotNull
-    public Collection<PotionEffect> getEffectsFromDamage(int damage);
+    // Paper start - make default
+    default Collection<PotionEffect> getEffectsFromDamage(final int damage) {
+        return new java.util.ArrayList<>();
+    }
+    // Paper end
 
     /**
      * Returns a collection of {@link PotionEffect} that would be applied from
@@ -43,6 +74,6 @@ public interface PotionBrewer {
      * @deprecated Upgraded / extended potions are now their own {@link PotionType} use {@link PotionType#getPotionEffects()} instead
      */
     @NotNull
-    @Deprecated(since = "1.20.2")
+    @Deprecated(since = "1.20.2", forRemoval = true) // Paper
     public Collection<PotionEffect> getEffects(@NotNull PotionType type, boolean upgraded, boolean extended);
 }