feat(health): added damage event and vulnerable structs

src/health/event.rs

@@ -0,0 +1,22 @@
+use bevy::prelude::*;
+
+use crate::health::Health;
+
+/// Event that is called on entities when they should recieve damage
+#[derive(EntityEvent)]
+pub struct Damage {
+    entity: Entity,
+    damage: usize
+}
+
+/// Marker-component that marks entity for an automatic damage handling
+#[derive(Component)]
+#[require(Health)]
+pub struct Vulnerable;
+
+/// Damages every vulnerable health components.
+pub(super) fn damage_vulnerable_system(event: On<Damage>, mut health_query: Query<&mut Health,With<Vulnerable>>) {
+    if let Ok(mut health) = health_query.get_mut(event.entity) {
+        health.damage(event.damage);
+    }
+}

src/health/mod.rs

@@ -1,5 +1,9 @@
 use bevy::prelude::*;
 
+use event::damage_vulnerable_system;
+
+pub use event::{Damage,Vulnerable};
+
 pub mod event;
 
 /// Health plugin provides systems to handle health modifications and events
@@ -7,7 +11,7 @@ pub struct HealthPlugin;
 
 impl Plugin for HealthPlugin {
     fn build(&self, app: &mut App) {
-        app.add_systems(PostUpdate,cleanup_killed);
+        app.add_systems(PostUpdate,cleanup_killed).add_observer(damage_vulnerable_system);
     }
 }