From b03d2942e1bef98e13acadde5cbb8856a3f8c74d Mon Sep 17 00:00:00 2001
From: mat <git@matdoes.dev>
Date: Thu, 19 Mar 2026 04:12:20 -0100
Subject: implement speed effect

---
 azalea-entity/src/plugin/effect_events.rs | 58 +++++++++++++++++++++++++++++++
 azalea-entity/src/plugin/mod.rs           |  4 +++
 2 files changed, 62 insertions(+)
 create mode 100644 azalea-entity/src/plugin/effect_events.rs

(limited to 'azalea-entity/src/plugin')

diff --git a/azalea-entity/src/plugin/effect_events.rs b/azalea-entity/src/plugin/effect_events.rs
new file mode 100644
index 00000000..2d37c463
--- /dev/null
+++ b/azalea-entity/src/plugin/effect_events.rs
@@ -0,0 +1,58 @@
+use azalea_registry::builtin::MobEffect;
+use bevy_ecs::{entity::Entity, event::EntityEvent, observer::On, system::Query};
+use tracing::warn;
+
+use crate::{ActiveEffects, Attributes, MobEffectData, effects::attribute_modifier_for_effect};
+
+#[derive(EntityEvent)]
+pub struct AddEffectEvent {
+    pub entity: Entity,
+    pub id: MobEffect,
+    pub data: MobEffectData,
+}
+pub fn handle_add_effect(
+    add_effect: On<AddEffectEvent>,
+    mut query: Query<(&mut ActiveEffects, &mut Attributes)>,
+) {
+    let Ok((mut active_effects, mut attributes)) = query.get_mut(add_effect.entity) else {
+        warn!("got handle_add_effect for an entity without the required components");
+        return;
+    };
+
+    active_effects.insert(add_effect.id, add_effect.data.clone());
+
+    if let Some((attribute, modifier)) = attribute_modifier_for_effect(add_effect.id) {
+        let modifier = modifier.create(add_effect.data.amplifier);
+        if let Some(attribute) = attributes.get_mut(attribute) {
+            attribute.insert(modifier);
+        }
+    }
+}
+
+#[derive(EntityEvent)]
+pub struct RemoveEffectsEvent {
+    pub entity: Entity,
+    pub effects: Vec<MobEffect>,
+}
+pub fn handle_remove_effects(
+    remove_effects: On<RemoveEffectsEvent>,
+    mut query: Query<(&mut ActiveEffects, &mut Attributes)>,
+) {
+    let Ok((mut active_effects, mut attributes)) = query.get_mut(remove_effects.entity) else {
+        warn!("got handle_remove_effects for an entity without the required components");
+        return;
+    };
+
+    for &effect in &remove_effects.effects {
+        active_effects.remove(effect);
+
+        if let Some((attribute, modifier)) = attribute_modifier_for_effect(effect) {
+            // we're just trying to get the id of the modifier, so the amplifier passed here
+            // doesn't matter
+            let modifier = modifier.create(0);
+            if let Some(attribute) = attributes.get_mut(attribute) {
+                attribute.remove(&modifier.id);
+            }
+        }
+    }
+}
diff --git a/azalea-entity/src/plugin/mod.rs b/azalea-entity/src/plugin/mod.rs
index 6035f674..4d97080f 100644
--- a/azalea-entity/src/plugin/mod.rs
+++ b/azalea-entity/src/plugin/mod.rs
@@ -1,4 +1,5 @@
 mod components;
+pub mod effect_events;
 pub mod indexing;
 
 use std::collections::HashSet;
@@ -22,6 +23,7 @@ use crate::{
     FluidOnEyes, LookDirection, Physics, Pose, Position,
     dimensions::{EntityDimensions, calculate_dimensions},
     metadata::{self, Health, Player},
+    plugin::effect_events::{handle_add_effect, handle_remove_effects},
 };
 
 /// A Bevy [`SystemSet`] for various types of entity updates.
@@ -65,6 +67,8 @@ impl Plugin for EntityPlugin {
             ),
         )
         .add_systems(GameTick, (update_in_loaded_chunk, update_fluid_on_eyes))
+        .add_observer(handle_add_effect)
+        .add_observer(handle_remove_effects)
         .init_resource::<EntityUuidIndex>();
     }
 }
-- 
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