Fire an advancement trigger when reading a book

Fabric/src/main/java/vazkii/patchouli/fabric/common/FabricModInitializer.java

@@ -12,6 +12,7 @@
 import net.minecraft.world.item.CreativeModeTab;
 import net.minecraft.world.item.CreativeModeTabs;
 
+import vazkii.patchouli.common.advancement.PatchouliCriteriaTriggers;
 import vazkii.patchouli.common.base.PatchouliSounds;
 import vazkii.patchouli.common.book.BookRegistry;
 import vazkii.patchouli.common.command.OpenBookCommand;
@@ -26,6 +27,7 @@ public void onInitialize() {
 		PatchouliSounds.submitRegistrations((id, e) -> Registry.register(BuiltInRegistries.SOUND_EVENT, id, e));
 		PatchouliItems.submitItemRegistrations((id, e) -> Registry.register(BuiltInRegistries.ITEM, id, e));
 		PatchouliItems.submitRecipeSerializerRegistrations((id, e) -> Registry.register(BuiltInRegistries.RECIPE_SERIALIZER, id, e));
+		PatchouliCriteriaTriggers.submitTriggerRegistrations((id, e) -> Registry.register(BuiltInRegistries.TRIGGER_TYPES, id, e));
 		FiberPatchouliConfig.setup();
 		CommandRegistrationCallback.EVENT.register((disp, buildCtx, selection) -> OpenBookCommand.register(disp));
 		UseBlockCallback.EVENT.register(LecternEventHandler::rightClick);

NeoForge/src/main/java/vazkii/patchouli/neoforge/common/NeoForgeModInitializer.java

@@ -16,6 +16,7 @@
 import net.neoforged.neoforge.registries.RegisterEvent;
 
 import vazkii.patchouli.api.PatchouliAPI;
+import vazkii.patchouli.common.advancement.PatchouliCriteriaTriggers;
 import vazkii.patchouli.common.base.PatchouliSounds;
 import vazkii.patchouli.common.book.BookRegistry;
 import vazkii.patchouli.common.command.OpenBookCommand;
@@ -45,6 +46,7 @@ public static void register(RegisterEvent evt) {
 		evt.register(Registries.RECIPE_SERIALIZER, rh -> {
 			PatchouliItems.submitRecipeSerializerRegistrations(rh::register);
 		});
+		evt.register(Registries.TRIGGER_TYPE, rh -> PatchouliCriteriaTriggers.submitTriggerRegistrations(rh::register));
 	}
 
 	@SubscribeEvent

Xplat/src/main/java/vazkii/patchouli/common/advancement/BookOpenTrigger.java

@@ -0,0 +1,52 @@
+package vazkii.patchouli.common.advancement;
+
+import com.mojang.serialization.Codec;
+import com.mojang.serialization.codecs.RecordCodecBuilder;
+
+import net.minecraft.advancements.critereon.*;
+import net.minecraft.resources.ResourceLocation;
+import net.minecraft.server.level.ServerPlayer;
+import net.minecraft.util.ExtraCodecs;
+
+import vazkii.patchouli.api.PatchouliAPI;
+
+import org.jetbrains.annotations.NotNull;
+import org.jetbrains.annotations.Nullable;
+
+import java.util.Optional;
+
+/**
+ * An advancement trigger for opening Patchouli books.
+ */
+public class BookOpenTrigger extends SimpleCriterionTrigger<BookOpenTrigger.TriggerInstance> {
+	public static final ResourceLocation ID = new ResourceLocation(PatchouliAPI.MOD_ID, "open_book");
+	public static final BookOpenTrigger INSTANCE = new BookOpenTrigger();
+
+	@NotNull
+	@Override
+	public Codec<TriggerInstance> codec() {
+		return BookOpenTrigger.TriggerInstance.CODEC;
+	}
+
+	public void trigger(@NotNull ServerPlayer player, @NotNull ResourceLocation book) {
+		trigger(player, instance -> instance.matches(book, null, 0));
+	}
+
+	public void trigger(@NotNull ServerPlayer player, @NotNull ResourceLocation book, @Nullable ResourceLocation entry, int page) {
+		trigger(player, instance -> instance.matches(book, entry, page));
+	}
+
+	public record TriggerInstance(Optional<ContextAwarePredicate> player, ResourceLocation book, Optional<ResourceLocation> entry, MinMaxBounds.Ints page) implements SimpleInstance {
+
+		public static Codec<BookOpenTrigger.TriggerInstance> CODEC = RecordCodecBuilder.create(instance -> instance.group(
+				ExtraCodecs.strictOptionalField(EntityPredicate.ADVANCEMENT_CODEC, "player").forGetter(TriggerInstance::player),
+				ResourceLocation.CODEC.fieldOf("book").forGetter(TriggerInstance::book),
+				ExtraCodecs.strictOptionalField(ResourceLocation.CODEC, "entry").forGetter(TriggerInstance::entry),
+				ExtraCodecs.strictOptionalField(MinMaxBounds.Ints.CODEC, "page", MinMaxBounds.Ints.ANY).forGetter(TriggerInstance::page)
+		).apply(instance, TriggerInstance::new));
+
+		public boolean matches(@NotNull ResourceLocation book, @Nullable ResourceLocation entry, int page) {
+			return this.book.equals(book) && (this.entry.isEmpty() || this.entry.get().equals(entry)) && this.page.matches(page);
+		}
+	}
+}

Xplat/src/main/java/vazkii/patchouli/common/advancement/PatchouliCriteriaTriggers.java

@@ -0,0 +1,14 @@
+package vazkii.patchouli.common.advancement;
+
+import net.minecraft.advancements.CriterionTrigger;
+import net.minecraft.resources.ResourceLocation;
+
+import java.util.function.BiConsumer;
+
+public class PatchouliCriteriaTriggers {
+	public static final BookOpenTrigger BOOK_OPEN = new BookOpenTrigger();
+
+	public static void submitTriggerRegistrations(BiConsumer<ResourceLocation, CriterionTrigger<?>> consumer) {
+		consumer.accept(BookOpenTrigger.ID, BOOK_OPEN);
+	}
+}

Xplat/src/main/java/vazkii/patchouli/common/base/PatchouliAPIImpl.java

@@ -28,6 +28,7 @@
 import vazkii.patchouli.client.book.template.BookTemplate;
 import vazkii.patchouli.client.book.text.BookTextParser;
 import vazkii.patchouli.client.handler.MultiblockVisualizationHandler;
+import vazkii.patchouli.common.advancement.BookOpenTrigger;
 import vazkii.patchouli.common.book.Book;
 import vazkii.patchouli.common.book.BookRegistry;
 import vazkii.patchouli.common.item.ItemModBook;
@@ -80,11 +81,13 @@ public boolean getConfigFlag(String flag) {
 
 	@Override
 	public void openBookGUI(ServerPlayer player, ResourceLocation book) {
+		BookOpenTrigger.INSTANCE.trigger(player, book);
 		IXplatAbstractions.INSTANCE.sendOpenBookGui(player, book, null, 0);
 	}
 
 	@Override
 	public void openBookEntry(ServerPlayer player, ResourceLocation book, ResourceLocation entry, int page) {
+		BookOpenTrigger.INSTANCE.trigger(player, book, entry, page);
 		IXplatAbstractions.INSTANCE.sendOpenBookGui(player, book, entry, page);
 	}