1use convert_case::{Case, Casing};
 2use proc_macro::TokenStream;
 3use quote::quote;
 4use syn::{DeriveInput, Lit, Meta, MetaList, MetaNameValue, NestedMeta, parse_macro_input};
 5
 6pub fn derive_into_component(input: TokenStream) -> TokenStream {
 7    let input = parse_macro_input!(input as DeriveInput);
 8    let mut scope_val = None;
 9    let mut description_val = None;
10
11    for attr in &input.attrs {
12        if attr.path.is_ident("component") {
13            if let Ok(Meta::List(MetaList { nested, .. })) = attr.parse_meta() {
14                for item in nested {
15                    if let NestedMeta::Meta(Meta::NameValue(MetaNameValue {
16                        path,
17                        lit: Lit::Str(s),
18                        ..
19                    })) = item
20                    {
21                        let ident = path.get_ident().map(|i| i.to_string()).unwrap_or_default();
22                        if ident == "scope" {
23                            scope_val = Some(s.value());
24                        } else if ident == "description" {
25                            description_val = Some(s.value());
26                        }
27                    }
28                }
29            }
30        }
31    }
32
33    let name = &input.ident;
34
35    let scope_impl = if let Some(s) = scope_val {
36        let scope_str = s.clone();
37        quote! {
38            fn scope() -> Option<component::ComponentScope> {
39                Some(component::ComponentScope::from(#scope_str))
40            }
41        }
42    } else {
43        quote! {
44            fn scope() -> Option<component::ComponentScope> {
45                None
46            }
47        }
48    };
49
50    let description_impl = if let Some(desc) = description_val {
51        quote! {
52            fn description() -> Option<&'static str> {
53                Some(#desc)
54            }
55        }
56    } else {
57        quote! {}
58    };
59
60    let register_component_name = syn::Ident::new(
61        &format!(
62            "__register_component_{}",
63            Casing::to_case(&name.to_string(), Case::Snake)
64        ),
65        name.span(),
66    );
67    let register_preview_name = syn::Ident::new(
68        &format!(
69            "__register_preview_{}",
70            Casing::to_case(&name.to_string(), Case::Snake)
71        ),
72        name.span(),
73    );
74
75    let expanded = quote! {
76        impl component::Component for #name {
77            #scope_impl
78
79            fn name() -> &'static str {
80                stringify!(#name)
81            }
82
83            #description_impl
84        }
85
86        #[linkme::distributed_slice(component::__ALL_COMPONENTS)]
87        fn #register_component_name() {
88            component::register_component::<#name>();
89        }
90
91        #[linkme::distributed_slice(component::__ALL_PREVIEWS)]
92        fn #register_preview_name() {
93            component::register_preview::<#name>();
94        }
95    };
96
97    expanded.into()
98}