dyn_ext_derive 0.1.5

use proc_macro::TokenStream;
use quote::quote;
use syn::{parse_macro_input, DeriveInput, Expr, Lit};

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

    let expanded = quote! {
        impl #impl_generics dyn_ext::AsAny for #name #ty_generics #where_clause {
            fn as_any(&self) -> &dyn std::any::Any {
                self
            }
        }
    };

    TokenStream::from(expanded)
}

#[proc_macro_derive(BoxedClone, attributes(boxed_clone))]
pub fn derive_boxed_clone(input: TokenStream) -> TokenStream {
    let input = parse_macro_input!(input as DeriveInput);
    let name = &input.ident;
    let generics = input.generics;
    let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();

    let mut target: Option<syn::Type> = None;

    for attr in &input.attrs {
        if attr.path().is_ident("boxed_clone") {
            let _ = attr.parse_nested_meta(|meta| {
                if meta.path.is_ident("Target") {
                    let expr: Expr = meta.value()?.parse()?;
                    if let Expr::Lit(expr_lit) = expr {
                        if let Lit::Str(lit_str) = expr_lit.lit {
                            target = Some(lit_str.parse().unwrap());
                        }
                    }
                }
                Ok(())
            });
        }
    }

    let target = target.unwrap_or_else(|| panic!("Target must be defined, add `#[boxed_clone(Target = \"...\")]` bellow `#[derive(BoxedClone)]`"));

    let expanded = quote! {
        impl #impl_generics dyn_ext::BoxedClone for #name #ty_generics #where_clause {
            type Target = #target;

            fn boxed_clone(&self) -> Box<Self::Target> {
                Box::new(self.clone())
            }
        }
    };

    TokenStream::from(expanded)
}