From a41cf4879e94e0b8960457df695cb1f662373f63 Mon Sep 17 00:00:00 2001
From: 2ndbeam <2ndbeam@disroot.org>
Date: Tue, 21 Apr 2026 17:08:33 +0300
Subject: [PATCH] feat: Dummy enemy and attack hit detection

---
 src/ai/dummy.rs      | 32 +++++++++++++++++++++++++++
 src/ai/mod.rs        |  6 ++++++
 src/combat/attack.rs | 51 ++++++++++++++++++++++++++++++++++++++++----
 src/combat/mod.rs    | 46 +++++++++++++++++++++++++++++++++++++--
 src/lib.rs           | 14 ++++++------
 src/player/mod.rs    |  3 ++-
 src/plugin.rs        |  2 +-
 7 files changed, 140 insertions(+), 14 deletions(-)
 create mode 100644 src/ai/dummy.rs
 create mode 100644 src/ai/mod.rs

diff --git a/src/ai/dummy.rs b/src/ai/dummy.rs
new file mode 100644
index 0000000..dd172a5
--- /dev/null
+++ b/src/ai/dummy.rs
@@ -0,0 +1,32 @@
+//! Dummy enemy module that does nothing
+
+use super::*;
+
+use crate::{GROUP_ATTACK, GROUP_ENEMY, GROUP_FRIENDLY, GROUP_INTERACTIVE, GROUP_STATIC, combat::Health, meters};
+
+/// Dummy enemy. Has [Health] component and no AI logic
+#[derive(Component, Clone, Copy, PartialEq, Eq, Debug, Default, Reflect)]
+#[reflect(Component, Clone, PartialEq, Debug, Default)]
+#[require(Health)]
+pub struct Dummy;
+
+impl Dummy {
+    /// Constructs [Dummy] bundle without sprite
+    pub fn bundle(position: Vec2, health: f32) -> impl Bundle {
+        (
+            // Basic
+            Dummy,
+            Health::new(health),
+
+            // World
+            Transform::from_xyz(position.x, position.y, 0.),
+
+            // Collision
+            Collider::cuboid(meters(0.5), meters(0.5)),
+            CollisionGroups::new(
+                GROUP_ENEMY,
+                GROUP_STATIC | GROUP_INTERACTIVE | GROUP_FRIENDLY | GROUP_ATTACK,
+            ),
+        )
+    }
+}
diff --git a/src/ai/mod.rs b/src/ai/mod.rs
new file mode 100644
index 0000000..535002d
--- /dev/null
+++ b/src/ai/mod.rs
@@ -0,0 +1,6 @@
+//! Enemy AI module
+
+use bevy::prelude::*;
+use bevy_rapier2d::prelude::*;
+
+pub mod dummy;
diff --git a/src/combat/attack.rs b/src/combat/attack.rs
index 95ead23..9146905 100644
--- a/src/combat/attack.rs
+++ b/src/combat/attack.rs
@@ -5,7 +5,7 @@ use std::time::Duration;
 use bevy::prelude::*;
 use bevy_rapier2d::prelude::*;
 
-use crate::{GROUP_ATTACK, GROUP_INTERACTIVE, GROUP_STATIC};
+use crate::{GROUP_ATTACK, GROUP_INTERACTIVE, GROUP_STATIC, combat::Health};
 
 /// Contains logic for attack-related calculations
 #[derive(Component, Clone, Debug, Reflect)]
@@ -27,6 +27,7 @@ pub struct AttackAreaOrigin;
 
 impl AttackArea {
     /// Constructs new attack area
+    #[inline(always)]
     pub fn new(accuracy: f32, damage: f32, duration: Duration, half_area: Vec2) -> Self {
         let max_distance = ((half_area.x * 2.).powi(2) + half_area.y.powi(2)).sqrt();
         Self {
@@ -58,6 +59,9 @@ impl AttackArea {
                 GROUP_STATIC | GROUP_INTERACTIVE | affinity,
             ),
             Collider::cuboid(half_area.x, half_area.y),
+            ActiveCollisionTypes::all(),
+            Sleeping::disabled(),
+            ActiveEvents::COLLISION_EVENTS,
 
             // AttackAreaOrigin
             Children::spawn((
@@ -70,11 +74,19 @@ impl AttackArea {
     }
 
     /// Updates timer and returns true if attack has ended
+    #[inline(always)]
     pub fn tick(&mut self, dt: Duration) -> bool {
         self.timer.tick(dt).is_finished()
     }
 
+    /// Calls [Timer::almost_finish]
+    #[inline(always)]
+    pub fn almost_finish(&mut self) {
+        self.timer.almost_finish();
+    }
+
     /// Returns damage for given distance to origin
+    #[inline(always)]
     pub fn damage(&self, distance_to_origin: f32) -> f32 {
         let distance_ratio = 1. - distance_to_origin.min(self.max_distance) / self.max_distance;
         let total_multiplier = self.accuracy * distance_ratio;
@@ -82,11 +94,42 @@ impl AttackArea {
     }
 }
 
-/// System that updates AttackArea timers and despawns those who timed out
-pub fn update_attack_areas(mut commands: Commands, time: Res<Time>, areas: Query<(Entity, &mut AttackArea)>) {
-    for (area_id, mut area) in areas {
+fn apply_attack(
+    commands: &mut Commands,
+    areas: &mut Query<(Entity, &mut AttackArea)>,
+    healths: &mut Query<&mut Health>,
+    first: &Entity,
+    second: &Entity,
+) -> bool {
+    if let Ok((area_id, mut area)) = areas.get_mut(*first) &&
+        let Ok(mut health) = healths.get_mut(*second) {
+        health.apply(area.damage(0.), commands.entity(*second));
+        info!("{area_id} hit {second}, health: {}", health.to_string());
+        area.almost_finish();
+        return true;
+    }
+    false
+}
+
+/// System that applies attacks and despawns timed out [AttackArea]s
+pub fn update_attack_areas(
+    mut commands: Commands,
+    time: Res<Time>,
+    mut areas: Query<(Entity, &mut AttackArea)>,
+    mut healths: Query<&mut Health>,
+    mut collision_events: MessageReader<CollisionEvent>,
+) {
+    for (area_id, mut area) in areas.iter_mut() {
         if area.tick(time.delta()) {
             commands.entity(area_id).despawn();
         }
     }
+
+    for event in collision_events.read() {
+        if let CollisionEvent::Started(first, second, _) = event {
+            if !apply_attack(&mut commands, &mut areas, &mut healths, first, second) {
+                apply_attack(&mut commands, &mut areas, &mut healths, second, first);
+            }
+        }
+    }
 }
diff --git a/src/combat/mod.rs b/src/combat/mod.rs
index e425307..a0bc13d 100644
--- a/src/combat/mod.rs
+++ b/src/combat/mod.rs
@@ -1,5 +1,7 @@
 //! This module contains core concepts of the combat system
 
+use std::fmt::Display;
+
 use bevy::prelude::*;
 
 pub mod attack;
@@ -9,17 +11,57 @@ pub mod attack;
 #[reflect(Component, Clone, PartialEq, Debug, Default)]
 pub struct Health {
     /// Current health value
-    pub current: f32,
+    current: f32,
     /// Maximum health value
-    pub max: f32,
+    max: f32,
+}
+
+/// Event that occurs when entity health reaches zero
+#[derive(EntityEvent, Clone, Copy, PartialEq, Eq, Debug, Reflect)]
+#[reflect(Event, Clone, PartialEq, Debug)]
+pub struct HealthDepletedEvent {
+    /// Event target
+    #[event_target] pub entity: Entity,
 }
 
 impl Health {
     /// Constructs new health component
+    #[inline(always)]
     pub fn new(max: f32) -> Self {
         Self {
             current: max,
             max,
         }
     }
+
+    /// Returns current health
+    #[inline(always)]
+    pub fn get_current(&self) -> f32 {
+        self.current
+    }
+
+    /// Returns max health
+    #[inline(always)]
+    pub fn get_max(&self) -> f32 {
+        self.max
+    }
+
+    /// Applies health change and invokes [HealthDepletedEvent] if needed
+    pub fn apply(&mut self, amount: f32, mut commands: EntityCommands) {
+        self.current = (self.current - amount).min(self.max);
+        if self.current <= 0. {
+            commands.trigger(|entity| HealthDepletedEvent { entity } );
+        }
+    }
+}
+
+impl Display for Health {
+    fn fmt(&self, f: &mut std::fmt::Formatter<'_>) -> std::fmt::Result {
+        f.write_str(format!("{:.2}/{:.2}", self.current, self.max).as_str())
+    }
+}
+
+/// Standard event observer that despawns entity whose health was depleted
+pub fn despawn_on_health_depleted(event: On<HealthDepletedEvent>, mut commands: Commands) {
+    commands.entity(event.entity).despawn();
 }
diff --git a/src/lib.rs b/src/lib.rs
index 6d956d0..2ed0e5e 100644
--- a/src/lib.rs
+++ b/src/lib.rs
@@ -5,6 +5,7 @@
 #[cfg(test)]
 mod tests;
 
+pub mod ai;
 pub mod anim;
 pub mod combat;
 pub mod graph;
@@ -18,7 +19,7 @@ use std::{collections::HashMap, time::Duration};
 use bevy::prelude::*;
 use bevy_rapier2d::prelude::*;
 
-use crate::{anim::sprite::{AnimatedSprite, AnimationData}, player::Player, timer::BpmTimer};
+use crate::{ai::dummy::Dummy, anim::sprite::{AnimatedSprite, AnimationData}, player::Player, timer::BpmTimer};
 
 const PIXELS_PER_METER: f32 = 16.;
 
@@ -42,11 +43,11 @@ pub fn setup(mut commands: Commands, asset_server: Res<AssetServer>) {
     commands.spawn(Player::bundle(&asset_server, Vec2::ZERO));
 }
 
-/// Test function to setup [AnimatedSprite]
-pub fn setup_animated_sprite(
+/// Test function to setup [Dummy] with [AnimatedSprite]
+pub fn setup_animated_sprite_dummy(
     mut commands: Commands,
     asset_server: Res<AssetServer>,
-    mut layouts: ResMut<Assets<TextureAtlasLayout>>
+    mut layouts: ResMut<Assets<TextureAtlasLayout>>,
 ) {
     let image = asset_server.load("sprites/animated_placeholder.png");
 
@@ -58,9 +59,10 @@ pub fn setup_animated_sprite(
     data.insert("default".into(), AnimationData::new(image.clone(), layout.clone(), 5.));
 
     let id = commands.spawn((
+        Dummy::bundle(vec2(meters(4.), 0.), 10.),
         AnimatedSprite::new(data, Duration::from_millis(500)),
-        Sprite::from_atlas_image(image, TextureAtlas { layout: layout, index: 0 }),
-    )).id();
+    )).observe(combat::despawn_on_health_depleted)
+        .id();
 
     commands.run_system_cached_with(|
         In(entity_id): In<Entity>,
diff --git a/src/player/mod.rs b/src/player/mod.rs
index 803a083..607c97d 100644
--- a/src/player/mod.rs
+++ b/src/player/mod.rs
@@ -6,7 +6,7 @@ use leafwing_input_manager::prelude::*;
 use seldom_state::prelude::*;
 
 use crate::{
-    GROUP_ATTACK, GROUP_ENEMY, GROUP_FRIENDLY, GROUP_INTERACTIVE, GROUP_STATIC, graph::action::ActionGraph, input::{
+    GROUP_ATTACK, GROUP_ENEMY, GROUP_FRIENDLY, GROUP_INTERACTIVE, GROUP_STATIC, combat::Health, graph::action::ActionGraph, input::{
         DefaultInputMap,
         PlayerInput,
     }, meters, player::weapon::{AttackType, Weapon}
@@ -45,6 +45,7 @@ impl Player {
             // Basic
             Name::new("Player"),
             Player::default(),
+            Health::new(100.),
             
             // Visible
             Sprite::from_image(image),
diff --git a/src/plugin.rs b/src/plugin.rs
index ed6a08b..ca75d87 100644
--- a/src/plugin.rs
+++ b/src/plugin.rs
@@ -26,7 +26,7 @@ impl Plugin for GamePlugin {
         .insert_resource(BpmTimer::new(120.))
         .add_systems(Startup, (
             setup,
-            setup_animated_sprite,
+            setup_animated_sprite_dummy,
         ))
         .add_systems(Update, (
             anim::sprite::update_animated_sprites,