From e229b104593d3afede47cc07e9917a42d6d13e60 Mon Sep 17 00:00:00 2001
From: HampusM <hampus@hampusmat.com>
Date: Fri, 15 Aug 2025 13:38:27 +0200
Subject: refactor(ecs): store local components as system entity components

---
 ecs/src/component/local.rs | 67 +++++++++++++++++++++++++++++++++++-----------
 1 file changed, 51 insertions(+), 16 deletions(-)

(limited to 'ecs/src/component/local.rs')

diff --git a/ecs/src/component/local.rs b/ecs/src/component/local.rs
index 0f6f641..6b2463f 100644
--- a/ecs/src/component/local.rs
+++ b/ecs/src/component/local.rs
@@ -1,7 +1,17 @@
+use std::any::type_name;
 use std::ops::{Deref, DerefMut};
 
-use crate::component::{Component, HandleMut as ComponentHandleMut};
-use crate::system::{Param as SystemParam, System};
+use ecs_macros::Component;
+
+use crate::component::{
+    Component,
+    HandleMut as ComponentHandleMut,
+    IntoParts as _,
+    Parts as ComponentParts,
+};
+use crate::pair::Pair;
+use crate::system::initializable::Param as InitializableParam;
+use crate::system::{Metadata as SystemMetadata, Param as SystemParam};
 use crate::World;
 
 /// Holds a component which is local to a single system.
@@ -17,27 +27,44 @@ where
 {
     type Input = LocalComponent;
 
-    fn initialize<SystemImpl>(
-        system: &mut impl System<'world, SystemImpl>,
-        input: Self::Input,
-    )
+    fn new(world: &'world World, system_metadata: &SystemMetadata) -> Self
     {
-        system.set_local_component(input);
-    }
+        let Some(system_ent) = world.get_entity(system_metadata.ent_id) else {
+            panic!(
+                "System entity with ID {} does not exist",
+                system_metadata.ent_id
+            );
+        };
 
-    fn new<SystemImpl>(
-        system: &'world impl System<'world, SystemImpl>,
-        _world: &'world World,
-    ) -> Self
-    {
-        let local_component = system
-            .get_local_component_mut::<LocalComponent>()
-            .expect("Local component is uninitialized");
+        let Some(local_component) = system_ent.get_with_id_mut::<LocalComponent>(
+            Pair::new::<IsLocalComponent>(LocalComponent::id()).id(),
+        ) else {
+            panic!(
+                "Local component {} of system with ID {} is uninitialized",
+                type_name::<LocalComponent>(),
+                system_metadata.ent_id
+            );
+        };
 
         Self { local_component }
     }
 }
 
+impl<'world, LocalComponent, SystemT> InitializableParam<'world, SystemT>
+    for Local<'world, LocalComponent>
+where
+    LocalComponent: Component,
+    SystemT: SystemWithLocalComponents,
+    Self: SystemParam<'world, Input = LocalComponent>,
+{
+    fn initialize(system: &mut SystemT, input: Self::Input)
+    {
+        system.add_local_component(
+            Pair::new_with_comp_target::<IsLocalComponent>(input).into_parts(),
+        );
+    }
+}
+
 impl<LocalComponent> Deref for Local<'_, LocalComponent>
 where
     LocalComponent: Component,
@@ -59,3 +86,11 @@ where
         &mut self.local_component
     }
 }
+
+pub trait SystemWithLocalComponents
+{
+    fn add_local_component(&mut self, component_parts: ComponentParts);
+}
+
+#[derive(Component)]
+struct IsLocalComponent;
-- 
cgit v1.2.3-18-g5258