proc macro ✨

Signed-off-by: Jason Volk <jason@zemos.net>

src/macros/Cargo.toml

@@ -0,0 +1,24 @@
+[package]
+name = "conduit_macros"
+categories.workspace = true
+description.workspace = true
+edition.workspace = true
+keywords.workspace = true
+license.workspace = true
+readme.workspace = true
+repository.workspace = true
+version.workspace = true
+
+[lib]
+name = "conduit_macros"
+path = "mod.rs"
+proc-macro = true
+
+[dependencies]
+syn.workspace = true
+quote.workspace = true
+proc-macro2.workspace = true
+conduit-core.workspace = true
+
+[lints]
+workspace = true

src/macros/admin.rs

@@ -0,0 +1,50 @@
+use conduit_core::utils::string::camel_to_snake_string;
+use proc_macro::{Span, TokenStream};
+use proc_macro2::TokenStream as TokenStream2;
+use quote::quote;
+use syn::{parse_macro_input, AttributeArgs, Fields, Ident, ItemEnum, Variant};
+
+pub(super) fn command_dispatch(args: TokenStream, input_: TokenStream) -> TokenStream {
+	let input = input_.clone();
+	let item = parse_macro_input!(input as ItemEnum);
+	let _args = parse_macro_input!(args as AttributeArgs);
+	let arm = item.variants.iter().map(dispatch_arm);
+	let name = item.ident;
+	let q = quote! {
+		pub(super) async fn process(command: #name, body: Vec<&str>) -> Result<RoomMessageEventContent> {
+			use #name::*;
+			#[allow(non_snake_case)]
+			Ok(match command {
+				#( #arm )*
+			})
+		}
+	};
+
+	[input_, q.into()].into_iter().collect::<TokenStream>()
+}
+
+fn dispatch_arm(v: &Variant) -> TokenStream2 {
+	let name = &v.ident;
+	let target = camel_to_snake_string(&format!("{name}"));
+	let handler = Ident::new(&target, Span::call_site().into());
+	match &v.fields {
+		Fields::Named(fields) => {
+			let field = fields.named.iter().filter_map(|f| f.ident.as_ref());
+			let arg = field.clone();
+			quote! {
+				#name { #( #field ),* } => Box::pin(#handler(body, #( #arg ),*)).await?,
+			}
+		},
+		Fields::Unnamed(fields) => {
+			let field = &fields.unnamed.first().expect("one field");
+			quote! {
+				#name ( #field ) => Box::pin(#handler::process(#field, body)).await?,
+			}
+		},
+		Fields::Unit => {
+			quote! {
+				#name => Box::pin(#handler(body)).await?,
+			}
+		},
+	}
+}

src/macros/mod.rs

@@ -0,0 +1,8 @@
+mod admin;
+
+use proc_macro::TokenStream;
+
+#[proc_macro_attribute]
+pub fn admin_command_dispatch(args: TokenStream, input: TokenStream) -> TokenStream {
+	admin::command_dispatch(args, input)
+}