0.2.7: add EntityDamageEvent

gradle.properties

@@ -9,6 +9,6 @@ loader_version=0.12.12
 fabric_version=0.45.0+1.18
 
 # Mod Properties
-mod_version=0.2.6
+mod_version=0.2.7
 maven_group=xyz.nucleoid
 archives_base_name=stimuli

src/main/java/xyz/nucleoid/stimuli/event/entity/EntityDamageEvent.java

@@ -0,0 +1,35 @@
+package xyz.nucleoid.stimuli.event.entity;
+
+import net.minecraft.entity.LivingEntity;
+import net.minecraft.entity.damage.DamageSource;
+import net.minecraft.util.ActionResult;
+import xyz.nucleoid.stimuli.event.StimulusEvent;
+
+/**
+ * Called when a {@link LivingEntity} is damaged.
+ *
+ * <p>Upon return:
+ * <ul>
+ * <li>{@link ActionResult#SUCCESS} cancels further processing and damages the entity.
+ * <li>{@link ActionResult#FAIL} cancels further processing and does not damage the entity.
+ * <li>{@link ActionResult#PASS} moves on to the next listener.</ul>
+ * <p>
+ * If all listeners return {@link ActionResult#PASS}, the entity is damaged as per normal behavior.
+ */
+public interface EntityDamageEvent {
+    StimulusEvent<EntityDamageEvent> EVENT = StimulusEvent.create(EntityDamageEvent.class, ctx -> (entity, source, amount) -> {
+        try {
+            for (var listener : ctx.getListeners()) {
+                var result = listener.onDamage(entity, source, amount);
+                if (result != ActionResult.PASS) {
+                    return result;
+                }
+            }
+        } catch (Throwable t) {
+            ctx.handleException(t);
+        }
+        return ActionResult.PASS;
+    });
+
+    ActionResult onDamage(LivingEntity entity, DamageSource source, float amount);
+}

src/main/java/xyz/nucleoid/stimuli/mixin/entity/LivingEntityMixin.java

@@ -14,7 +14,9 @@
 import org.spongepowered.asm.mixin.injection.Inject;
 import org.spongepowered.asm.mixin.injection.Redirect;
 import org.spongepowered.asm.mixin.injection.callback.CallbackInfo;
+import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
 import xyz.nucleoid.stimuli.Stimuli;
+import xyz.nucleoid.stimuli.event.entity.EntityDamageEvent;
 import xyz.nucleoid.stimuli.event.entity.EntityDeathEvent;
 import xyz.nucleoid.stimuli.event.entity.EntityDropItemsEvent;
 
@@ -26,6 +28,22 @@ private LivingEntityMixin(EntityType<?> type, World world) {
         super(type, world);
     }
 
+    @Inject(method = "damage", at = @At("HEAD"), cancellable = true)
+    private void onDamage(DamageSource source, float amount, CallbackInfoReturnable<Boolean> ci) {
+        if (this.world.isClient) {
+            return;
+        }
+
+        var entity = (LivingEntity) (Object) this;
+
+        try (var invokers = Stimuli.select().forEntity(entity)) {
+            var result = invokers.get(EntityDamageEvent.EVENT).onDamage(entity, source, amount);
+            if (result == ActionResult.FAIL) {
+                ci.cancel();
+            }
+        }
+    }
+
     @Inject(method = "onDeath", at = @At("HEAD"), cancellable = true)
     private void callDeathListener(DamageSource source, CallbackInfo ci) {
         if (this.world.isClient) {