Remove empty cauldron contents

Empty in most places was used as a wildcard, recipes normally just checked levels instead. Easier to just make nullable for wildcard and use water elsewhere
Fixes an error where cauldrons placed from vanilla show as empty

src/main/java/knightminer/inspirations/library/recipe/cauldron/CauldronContentTypes.java

@@ -7,22 +7,22 @@
 import io.netty.handler.codec.DecoderException;
 import knightminer.inspirations.Inspirations;
 import knightminer.inspirations.library.recipe.cauldron.contents.CauldronContentType;
-import knightminer.inspirations.library.recipe.cauldron.contents.EmptyCauldronContents;
-import knightminer.inspirations.library.recipe.cauldron.contents.EmptyContentType;
 import knightminer.inspirations.library.recipe.cauldron.contents.ICauldronContents;
 import knightminer.inspirations.recipes.recipe.cauldron.contents.ColorContentType;
 import knightminer.inspirations.recipes.recipe.cauldron.contents.CustomContentType;
 import knightminer.inspirations.recipes.recipe.cauldron.contents.DyeContentType;
 import knightminer.inspirations.recipes.recipe.cauldron.contents.FluidContentType;
 import knightminer.inspirations.recipes.recipe.cauldron.contents.PotionContentType;
 import net.minecraft.fluid.Fluid;
+import net.minecraft.fluid.Fluids;
 import net.minecraft.item.DyeColor;
 import net.minecraft.nbt.CompoundNBT;
 import net.minecraft.network.PacketBuffer;
 import net.minecraft.potion.Potion;
 import net.minecraft.util.JSONUtils;
 import net.minecraft.util.ResourceLocation;
 import net.minecraftforge.common.util.Constants.NBT;
+import net.minecraftforge.common.util.Lazy;
 
 import javax.annotation.Nullable;
 
@@ -36,8 +36,8 @@ public class CauldronContentTypes {
 
   /* Public constants */
 
-  /** Generic water type */
-  public static final EmptyContentType EMPTY = register("empty", new EmptyContentType());
+  /** Contains a specific fluid */
+  public static final CauldronContentType<Fluid> FLUID = register("fluid", new FluidContentType());
 
   /** Contains an arbitrary color */
   public static final CauldronContentType<Integer> COLOR = register("color", new ColorContentType());
@@ -48,12 +48,12 @@ public class CauldronContentTypes {
   /** Contains a specific color */
   public static final CauldronContentType<Potion> POTION = register("potion", new PotionContentType());
 
-  /** Contains a specific fluid */
-  public static final CauldronContentType<Fluid> FLUID = register("fluid", new FluidContentType());
-
   /** Contains a specific fluid */
   public static final CauldronContentType<ResourceLocation> CUSTOM = register("custom", new CustomContentType());
 
+  /** Default cauldron content type, return when reading if type invalid */
+  public static final Lazy<ICauldronContents> DEFAULT = Lazy.of(() -> FLUID.of(Fluids.WATER));
+
   /**
    * Registers a new content type
    * @param name  Name
@@ -157,7 +157,7 @@ public static ICauldronContents read(CompoundNBT nbt) {
         }
       }
     }
-    return EmptyCauldronContents.INSTANCE;
+    return CauldronContentTypes.DEFAULT.get();
   }
 
   /**

src/main/java/knightminer/inspirations/library/recipe/cauldron/inventory/ICauldronState.java

@@ -11,7 +11,7 @@
 public interface ICauldronState extends IEmptyInventory {
   /**
    * Gets the contents of the cauldron.
-   * Should return {@link knightminer.inspirations.library.recipe.cauldron.contents.EmptyCauldronContents#INSTANCE} if {@link #getLevel()} returns 0. Should never return empty otherwise.
+   * If {@link #getLevel()} returns 0, value is indeterminate.
    * @return  Cauldron contents
    */
   ICauldronContents getContents();

src/main/java/knightminer/inspirations/library/recipe/cauldron/recipe/AbstractCauldronRecipe.java

@@ -2,7 +2,7 @@
 
 import com.google.gson.JsonObject;
 import com.google.gson.JsonSyntaxException;
-import knightminer.inspirations.library.recipe.cauldron.contents.EmptyCauldronContents;
+import knightminer.inspirations.library.recipe.cauldron.CauldronContentTypes;
 import knightminer.inspirations.library.recipe.cauldron.contents.ICauldronContents;
 import knightminer.inspirations.library.recipe.cauldron.ingredient.ICauldronIngredient;
 import knightminer.inspirations.library.recipe.cauldron.inventory.ICauldronState;
@@ -12,6 +12,7 @@
 import net.minecraft.util.JSONUtils;
 import net.minecraftforge.fluids.FluidStack;
 
+import javax.annotation.Nullable;
 import java.util.Collections;
 import java.util.List;
 import java.util.stream.Collectors;
@@ -24,6 +25,7 @@ public abstract class AbstractCauldronRecipe implements ICauldronRecipeDisplay {
   protected final ICauldronIngredient ingredient;
   protected final LevelPredicate level;
   protected final TemperaturePredicate temperature;
+  @Nullable
   protected final ICauldronContents outputContents;
 
   // values for JEI display
@@ -38,7 +40,7 @@ public abstract class AbstractCauldronRecipe implements ICauldronRecipeDisplay {
    * @param temperature  Predicate for required cauldron temperature
    * @param output       Output stack, use empty for no output
    */
-  public AbstractCauldronRecipe(ICauldronIngredient ingredient, LevelPredicate level, TemperaturePredicate temperature, ICauldronContents output) {
+  public AbstractCauldronRecipe(ICauldronIngredient ingredient, LevelPredicate level, TemperaturePredicate temperature, @Nullable ICauldronContents output) {
     this.ingredient = ingredient;
     this.level = level;
     this.temperature = temperature;
@@ -85,10 +87,11 @@ public TemperaturePredicate getTemperature() {
 
   @Override
   public ICauldronContents getContentOutput() {
-    if (outputContents == EmptyCauldronContents.INSTANCE) {
+    // if output is null, display first input
+    if (outputContents == null) {
       if (displayContents == null) {
         List<ICauldronContents> inputs = getContentInputs();
-        displayContents = inputs.isEmpty() ? EmptyCauldronContents.INSTANCE : inputs.get(0);
+        displayContents = inputs.isEmpty() ? CauldronContentTypes.DEFAULT.get() : inputs.get(0);
       }
       return displayContents;
     }

src/main/java/knightminer/inspirations/library/recipe/cauldron/recipe/CauldronRecipe.java

@@ -5,7 +5,6 @@
 import knightminer.inspirations.library.recipe.RecipeSerializers;
 import knightminer.inspirations.library.recipe.cauldron.CauldronContentTypes;
 import knightminer.inspirations.library.recipe.cauldron.CauldronIngredients;
-import knightminer.inspirations.library.recipe.cauldron.contents.EmptyCauldronContents;
 import knightminer.inspirations.library.recipe.cauldron.contents.ICauldronContents;
 import knightminer.inspirations.library.recipe.cauldron.ingredient.ICauldronIngredient;
 import knightminer.inspirations.library.recipe.cauldron.ingredient.SizedIngredient;
@@ -54,12 +53,12 @@ public class CauldronRecipe extends AbstractCauldronRecipe implements ICauldronR
    * @param temperature  Predicate for required cauldron temperature
    * @param output       Output stack, use empty for no output
    * @param copyNBT      If true, copies the input NBT to the output
-   * @param newContents  Output contents, use {@link EmptyCauldronContents#INSTANCE} to keep old contents
+   * @param newContents  Output contents, use {@code null} to keep old contents
    * @param levelUpdate  Level updater
    * @param container    Container output. If null, fetches container from the item. If empty, no container
    */
   public CauldronRecipe(ResourceLocation id, String group, SizedIngredient input, ICauldronIngredient contents, LevelPredicate level, TemperaturePredicate temperature,
-                        ItemStack output, boolean copyNBT, ICauldronContents newContents, LevelUpdate levelUpdate, @Nullable ItemStack container, SoundEvent sound) {
+                        ItemStack output, boolean copyNBT, @Nullable ICauldronContents newContents, LevelUpdate levelUpdate, @Nullable ItemStack container, SoundEvent sound) {
     super(contents, level, temperature, newContents);
     this.id = id;
     this.group = group;
@@ -77,7 +76,7 @@ public CauldronRecipe(ResourceLocation id, String group, SizedIngredient input,
   @Override
   public boolean matches(ICauldronInventory inv, World worldIn) {
     // if this cauldron only supports simple recipes, block if the result is not simple
-    if (inv.isSimple() && !outputContents.isSimple()) {
+    if (inv.isSimple() && outputContents != null && !outputContents.isSimple()) {
       return false;
     }
     // check common matches logic
@@ -93,7 +92,7 @@ public boolean matches(ICauldronInventory inv, World worldIn) {
   public void handleRecipe(IModifyableCauldronInventory inventory) {
     // update level
     // only update contents if the level is not empty and we have new contents
-    if (!inventory.updateLevel(levelUpdate) && outputContents != EmptyCauldronContents.INSTANCE) {
+    if (!inventory.updateLevel(levelUpdate) && outputContents != null) {
       inventory.setContents(outputContents);
     }
 
@@ -207,7 +206,7 @@ public CauldronRecipe read(ResourceLocation id, JsonObject json) {
         output = CraftingHelper.getItemStack(JSONUtils.getJsonObject(outputJson, "item"), true);
         copyNBT = JSONUtils.getBoolean(outputJson, "copy_nbt", false);
       }
-      ICauldronContents newContents = EmptyCauldronContents.INSTANCE;
+      ICauldronContents newContents = null;
       if (outputJson.has("contents")) {
         newContents = CauldronContentTypes.read(JSONUtils.getJsonObject(outputJson, "contents"));
       }
@@ -246,7 +245,12 @@ public void write(PacketBuffer buffer, CauldronRecipe recipe) {
       buffer.writeEnumValue(recipe.temperature);
       buffer.writeItemStack(recipe.output);
       buffer.writeBoolean(recipe.copyNBT);
-      CauldronContentTypes.write(recipe.outputContents, buffer);
+      if (recipe.outputContents != null) {
+        buffer.writeBoolean(true);
+        CauldronContentTypes.write(recipe.outputContents, buffer);
+      } else {
+        buffer.writeBoolean(false);
+      }
       recipe.levelUpdate.write(buffer);
       if (recipe.container == null) {
         buffer.writeBoolean(false);
@@ -267,7 +271,10 @@ public CauldronRecipe read(ResourceLocation id, PacketBuffer buffer) {
       TemperaturePredicate boiling = buffer.readEnumValue(TemperaturePredicate.class);
       ItemStack output = buffer.readItemStack();
       boolean copyNBT = buffer.readBoolean();
-      ICauldronContents newContents = CauldronContentTypes.read(buffer);
+      ICauldronContents newContents = null;
+      if (buffer.readBoolean()) {
+        newContents = CauldronContentTypes.read(buffer);
+      }
       LevelUpdate levelUpdate = LevelUpdate.read(buffer);
       ItemStack container = null;
       if (buffer.readBoolean()) {

src/main/java/knightminer/inspirations/library/recipe/cauldron/recipe/CauldronRecipeBuilder.java

@@ -4,7 +4,6 @@
 import knightminer.inspirations.library.recipe.RecipeSerializers;
 import knightminer.inspirations.library.recipe.cauldron.CauldronContentTypes;
 import knightminer.inspirations.library.recipe.cauldron.CauldronIngredients;
-import knightminer.inspirations.library.recipe.cauldron.contents.EmptyCauldronContents;
 import knightminer.inspirations.library.recipe.cauldron.contents.ICauldronContents;
 import knightminer.inspirations.library.recipe.cauldron.ingredient.ICauldronIngredient;
 import knightminer.inspirations.library.recipe.cauldron.ingredient.SizedIngredient;
@@ -38,7 +37,8 @@ public class CauldronRecipeBuilder extends AbstractRecipeBuilder<CauldronRecipeB
   private TemperaturePredicate temperature = TemperaturePredicate.ANY;
   private ItemStack output = ItemStack.EMPTY;
   private boolean copyNBT = false;
-  private ICauldronContents newContents = EmptyCauldronContents.INSTANCE;
+  @Nullable
+  private ICauldronContents newContents = null;
   private LevelUpdate levelUpdate = LevelUpdate.IDENTITY;
   @Nullable
   private ItemStack container = null;
@@ -252,7 +252,7 @@ public void build(Consumer<IFinishedRecipe> consumer) {
       build(consumer, Objects.requireNonNull(output.getItem().getRegistryName()));
       return;
     }
-    if (newContents != EmptyCauldronContents.INSTANCE) {
+    if (newContents != null) {
       ResourceLocation name = nameFromContents(newContents);
       if (name != null) {
         build(consumer, name);
@@ -298,6 +298,7 @@ private static class Result implements IFinishedRecipe {
     private final TemperaturePredicate temperature;
     private final ItemStack output;
     private final boolean copyNBT;
+    @Nullable
     private final ICauldronContents newContents;
     private final LevelUpdate levelUpdate;
     @Nullable
@@ -307,7 +308,7 @@ private static class Result implements IFinishedRecipe {
     private final Advancement.Builder advancementBuilder;
     private final ResourceLocation advancementId;
 
-    private Result(ResourceLocation id, String group, SizedIngredient input, ICauldronIngredient contents, LevelPredicate level, TemperaturePredicate temperature, ItemStack output, boolean copyNBT, ICauldronContents newContents, LevelUpdate levelUpdate, @Nullable ItemStack container, @Nullable SoundEvent sound, Builder advancementBuilder, ResourceLocation advancementId) {
+    private Result(ResourceLocation id, String group, SizedIngredient input, ICauldronIngredient contents, LevelPredicate level, TemperaturePredicate temperature, ItemStack output, boolean copyNBT, @Nullable ICauldronContents newContents, LevelUpdate levelUpdate, @Nullable ItemStack container, @Nullable SoundEvent sound, Builder advancementBuilder, ResourceLocation advancementId) {
       this.id = id;
       this.group = group;
       this.input = input;
@@ -373,7 +374,7 @@ public void serialize(JsonObject json) {
           outputJson.add("container", toJson(container));
         }
       }
-      if (newContents != EmptyCauldronContents.INSTANCE) {
+      if (newContents != null) {
         outputJson.add("contents", CauldronContentTypes.toJson(newContents));
       }
       if (levelUpdate != LevelUpdate.IDENTITY) {

src/main/java/knightminer/inspirations/library/recipe/cauldron/recipe/CauldronTransform.java

@@ -167,7 +167,7 @@ public void write(PacketBuffer buffer, CauldronTransform recipe) {
       CauldronIngredients.write(recipe.ingredient, buffer);
       buffer.writeEnumValue(recipe.temperature);
       recipe.level.write(buffer);
-      CauldronContentTypes.write(recipe.outputContents, buffer);
+      CauldronContentTypes.write(recipe.outputContents == null ? CauldronContentTypes.DEFAULT.get() : recipe.outputContents, buffer);
       buffer.writeVarInt(recipe.time);
       buffer.writeResourceLocation(Objects.requireNonNull(recipe.sound.getRegistryName()));
     }

src/main/java/knightminer/inspirations/library/recipe/cauldron/special/DyeableCauldronRecipe.java

@@ -173,7 +173,7 @@ protected Stream<DisplayCauldronRecipe> getDisplayRecipes(ItemStack stack) {
       List<ItemStack> inputs = Arrays.stream(DyeColor.values()).map(color -> Util.setColor(stack.copy(), color.getColorValue())).collect(Collectors.toList());
       return Stream.of(DisplayCauldronRecipe.builder(1, 0)
                                             .setItemInputs(inputs)
-                                            .setContentInputs(DisplayCauldronRecipe.WATER_CONTENTS.getValue())
+                                            .setContentInputs(DisplayCauldronRecipe.WATER_CONTENTS.get())
                                             .setItemOutput(Util.clearColor(stack.copy()))
                                             .build());
     }