use quote::quote;
use syn::{parse_macro_input, DeriveInput};

#[proc_macro_derive(RenderGraphLabel)]
pub fn derive_render_graph_label(input: proc_macro::TokenStream) -> proc_macro::TokenStream {
    let input = parse_macro_input!(input as DeriveInput);
    let (impl_generics, ty_generics, where_clause) = input.generics.split_for_impl();

    let type_ident = &input.ident;

    proc_macro::TokenStream::from(quote! {
        impl #impl_generics crate::render::graph::RenderGraphLabel for #type_ident #ty_generics #where_clause {
            fn rc_clone(&self) -> std::rc::Rc<dyn crate::render::graph::RenderGraphLabel> {
                std::rc::Rc::new(self.clone())
            }

            /* fn as_dyn(&self) -> &dyn crate::render::graph::RenderGraphLabel {
                &self
            }

            fn as_partial_eq(&self) -> &dyn PartialEq<dyn crate::render::graph::RenderGraphLabel> {
                self
            } */
            
            fn as_label_hash(&self) -> u64 {
                let tyid = ::std::any::TypeId::of::<Self>();

                let mut s = ::std::hash::DefaultHasher::new();
                ::std::hash::Hash::hash(&tyid, &mut s);
                ::std::hash::Hash::hash(self, &mut s);
                ::std::hash::Hasher::finish(&s)
            }
        }
    })
}