From bfcb849fdf37412e0c61fd0b6f843caa6c4668a9 Mon Sep 17 00:00:00 2001
From: HampusM <hampus@hampusmat.com>
Date: Mon, 11 Nov 2024 00:12:44 +0100
Subject: feat(ecs-macros): add support for new component IDs

---
 ecs-macros/src/lib.rs | 123 ++++++++++++++++++++++++++++++++++++++------------
 1 file changed, 94 insertions(+), 29 deletions(-)

diff --git a/ecs-macros/src/lib.rs b/ecs-macros/src/lib.rs
index bc2d5ed..8bfce38 100644
--- a/ecs-macros/src/lib.rs
+++ b/ecs-macros/src/lib.rs
@@ -1,12 +1,12 @@
-use std::env;
 use std::path::PathBuf as FsPathBuf;
 
 use proc_macro::TokenStream;
-use quote::{quote, ToTokens};
+use quote::{format_ident, quote, ToTokens};
 use syn::spanned::Spanned;
 use syn::{
     parse,
     Attribute,
+    GenericParam,
     Generics,
     Ident,
     Item,
@@ -52,45 +52,110 @@ pub fn component_derive(input: TokenStream) -> TokenStream
 
     let ecs_path = find_engine_ecs_crate_path().unwrap_or_else(|| syn_path!(ecs));
 
+    let (id_or_ids, get_id) = if !item.generics().params.is_empty() {
+        let id_lut_ident =
+            format_ident!("{}_ID_LUT", item_ident.to_string().to_uppercase());
+
+        let id_lut = quote! {
+            static #id_lut_ident: LazyLock<Mutex<HashMap<TypeId, Uid>>> =
+                LazyLock::new(|| Mutex::new(HashMap::new()));
+        };
+
+        let generics = item.generics().params.iter().map(|param| match param {
+            GenericParam::Type(type_param) => type_param.ident.clone(),
+            GenericParam::Lifetime(_) => panic!("Lifetime generics are not supported"),
+            GenericParam::Const(_) => panic!("Const generics are not supported"),
+        });
+
+        let get_id = quote! {
+            *#id_lut_ident
+                .try_lock()
+                .unwrap()
+                .entry(TypeId::of::<(#(#generics,)*)>())
+                .or_insert_with(|| Uid::new_unique(UidKind::Component))
+        };
+
+        (id_lut, get_id)
+    } else {
+        let id_lazylock_ident =
+            format_ident!("{}_ID", item_ident.to_string().to_uppercase());
+
+        let id_lazylock = quote! {
+            static #id_lazylock_ident: LazyLock<Uid> = LazyLock::new(|| {
+                Uid::new_unique(UidKind::Component)
+            });
+        };
+
+        let get_id = quote! {
+            *#id_lazylock_ident
+        };
+
+        (id_lazylock, get_id)
+    };
+
+    let mod_ident = format_ident!(
+        "__ecs_priv_component_impl_{}",
+        item_ident.to_string().to_lowercase()
+    );
+
     quote! {
-        impl #impl_generics #ecs_path::component::Component for #item_ident #type_generics
-        #where_clause
-        {
-            type Component = Self;
+        mod #mod_ident {
+            use ::std::any::{Any, TypeId};
+            use ::std::sync::{LazyLock, Mutex};
+            use ::std::collections::HashMap;
 
-            type RefMut<'component> =
-                #ecs_path::system::ComponentRefMut<'component, Self>;
+            use #ecs_path::component::Component;
+            use #ecs_path::system::ComponentRefMut;
+            use #ecs_path::system::ComponentRef;
+            use #ecs_path::uid::{Uid, Kind as UidKind};
+            use #ecs_path::system::Input as SystemInput;
+            use #ecs_path::type_name::TypeName;
 
-            type Ref<'component> =
-                #ecs_path::system::ComponentRef<'component, Self>;
+            use super::*;
 
-            fn id(&self) -> #ecs_path::component::Id
-            {
-                #ecs_path::component::Id::of::<Self>()
-            }
+            #id_or_ids
 
-            fn as_any_mut(&mut self) -> &mut dyn std::any::Any
+            impl #impl_generics Component for #item_ident #type_generics
+            #where_clause
             {
-                self
+                type Component = Self;
+
+                type RefMut<'component> = ComponentRefMut<'component, Self>;
+                type Ref<'component> = ComponentRef<'component, Self>;
+
+                fn id() -> Uid
+                {
+                    #get_id
+                }
+
+                fn self_id(&self) -> Uid
+                {
+                    Self::id()
+                }
+
+                fn as_any_mut(&mut self) -> &mut dyn Any
+                {
+                    self
+                }
+
+                fn as_any(&self) -> &dyn Any
+                {
+                    self
+                }
             }
 
-            fn as_any(&self) -> &dyn std::any::Any
+            impl #impl_generics SystemInput for #item_ident #type_generics
+            #where_clause
             {
-                self
             }
-        }
 
-        impl #impl_generics #ecs_path::system::Input for #item_ident #type_generics
-        #where_clause
-        {
-        }
-
-        impl #impl_generics #ecs_path::type_name::TypeName for #item_ident #type_generics
-        #where_clause
-        {
-            fn type_name(&self) -> &'static str
+            impl #impl_generics TypeName for #item_ident #type_generics
+            #where_clause
             {
-                std::any::type_name::<Self>()
+                fn type_name(&self) -> &'static str
+                {
+                    std::any::type_name::<Self>()
+                }
             }
         }
     }
-- 
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