1 files changed, 149 insertions, 0 deletions
diff --git a/crates/system_action/action_macros/src/lib.rs b/crates/system_action/action_macros/src/lib.rs
new file mode 100644
index 0000000..2c2e4a8
--- /dev/null
+++ b/crates/system_action/action_macros/src/lib.rs
@@ -0,0 +1,149 @@
+use proc_macro::TokenStream;
+use quote::quote;
+use syn::{ItemFn, parse_macro_input};
+
+/// A procedural macro for generating structs that implement the Action trait
+///
+/// Usage:
+/// #[action_gen] or #[action_gen(local)]
+/// pub fn my_action(ctx: ActionContext, arg: MyArg) -> Result<MyReturn, TcpTargetError> {
+///     todo!()
+/// }
+#[proc_macro_attribute]
+pub fn action_gen(attr: TokenStream, item: TokenStream) -> TokenStream {
+    let input_fn = parse_macro_input!(item as ItemFn);
+    let is_local = if attr.is_empty() {
+        false
+    } else {
+        let attr_str = attr.to_string();
+        attr_str == "local" || attr_str.contains("local")
+    };
+
+    generate_action_struct(input_fn, is_local).into()
+}
+
+fn generate_action_struct(input_fn: ItemFn, _is_local: bool) -> proc_macro2::TokenStream {
+    let fn_vis = &input_fn.vis;
+    let fn_sig = &input_fn.sig;
+    let fn_name = &fn_sig.ident;
+    let fn_block = &input_fn.block;
+
+    validate_function_signature(fn_sig);
+
+    let (arg_type, return_type) = extract_types(fn_sig);
+
+    let struct_name = quote::format_ident!("{}", convert_to_pascal_case(&fn_name.to_string()));
+
+    let action_name_ident = &fn_name;
+
+    quote! {
+        #[derive(Debug, Clone, Default)]
+        #fn_vis struct #struct_name;
+
+        impl vcs_service::action::Action<#arg_type, #return_type> for #struct_name {
+            fn action_name() -> &'static str {
+                Box::leak(string_proc::snake_case!(stringify!(#action_name_ident)).into_boxed_str())
+            }
+
+            fn is_remote_action() -> bool {
+                !#_is_local
+            }
+
+            async fn process(context: vcs_service::action::ActionContext, args: #arg_type) -> Result<#return_type, tcp_connection::error::TcpTargetError> {
+                #fn_block
+            }
+        }
+
+        #[deprecated = "This function is used by #[action_gen] as a template."]
+        #[doc = " This function is used by #[action_gen] as a template to generate the struct. "]
+        #[doc = " It is forbidden to call it anywhere."]
+        #[doc = " You should use the generated struct to register this function in `ActionPool`"]
+        #[doc = " and call it using the function name."]
+        #fn_vis #fn_sig #fn_block
+    }
+}
+
+fn validate_function_signature(fn_sig: &syn::Signature) {
+    if !fn_sig.asyncness.is_some() {
+        panic!("Expected async function for Action, but found synchronous function");
+    }
+
+    if fn_sig.inputs.len() != 2 {
+        panic!(
+            "Expected exactly 2 arguments for Action function: ctx: ActionContext and arg: T, but found {} arguments",
+            fn_sig.inputs.len()
+        );
+    }
+
+    let return_type = match &fn_sig.output {
+        syn::ReturnType::Type(_, ty) => ty,
+        _ => panic!(
+            "Expected Action function to return Result<T, TcpTargetError>, but found no return type"
+        ),
+    };
+
+    if let syn::Type::Path(type_path) = return_type.as_ref() {
+        if let Some(segment) = type_path.path.segments.last() {
+            if segment.ident != "Result" {
+                panic!(
+                    "Expected Action function to return Result<T, TcpTargetError>, but found different return type"
+                );
+            }
+        }
+    } else {
+        panic!(
+            "Expected Action function to return Result<T, TcpTargetError>, but found no return type"
+        );
+    }
+}
+
+fn convert_to_pascal_case(s: &str) -> String {
+    s.split('_')
+        .map(|word| {
+            let mut chars = word.chars();
+            match chars.next() {
+                None => String::new(),
+                Some(first) => first.to_uppercase().collect::<String>() + chars.as_str(),
+            }
+        })
+        .collect()
+}
+
+fn extract_types(fn_sig: &syn::Signature) -> (proc_macro2::TokenStream, proc_macro2::TokenStream) {
+    let mut inputs = fn_sig.inputs.iter();
+
+    let _ = inputs.next();
+
+    let arg_type = match inputs.next() {
+        Some(syn::FnArg::Typed(pat_type)) => {
+            let ty = &pat_type.ty;
+            quote::quote!(#ty)
+        }
+        _ => {
+            panic!("Expected the second argument to be a typed parameter, but found something else")
+        }
+    };
+
+    let return_type = match &fn_sig.output {
+        syn::ReturnType::Type(_, ty) => {
+            if let syn::Type::Path(type_path) = ty.as_ref() {
+                if let syn::PathArguments::AngleBracketed(args) =
+                    &type_path.path.segments.last().unwrap().arguments
+                {
+                    if let Some(syn::GenericArgument::Type(ty)) = args.args.first() {
+                        quote::quote!(#ty)
+                    } else {
+                        panic!("Expected to extract the success type of Result, but failed");
+                    }
+                } else {
+                    panic!("Expected Result type to have generic parameters, but found none");
+                }
+            } else {
+                panic!("Expected return type to be Result, but found different type");
+            }
+        }
+        _ => panic!("Expected function to have return type, but found none"),
+    };
+
+    (arg_type, return_type)
+}