1 files changed, 87 insertions, 0 deletions
diff --git a/crates/utils/cfg_file/cfg_file_derive/src/lib.rs b/crates/utils/cfg_file/cfg_file_derive/src/lib.rs
new file mode 100644
index 0000000..3a6d0fd
--- /dev/null
+++ b/crates/utils/cfg_file/cfg_file_derive/src/lib.rs
@@ -0,0 +1,87 @@
+extern crate proc_macro;
+
+use proc_macro::TokenStream;
+use quote::quote;
+use syn::parse::ParseStream;
+use syn::{
+    parse_macro_input,
+    DeriveInput,
+    Attribute
+};
+
+#[proc_macro_derive(ConfigFile, attributes(cfg_file))]
+pub fn derive_config_file(input: TokenStream) -> TokenStream {
+    let input = parse_macro_input!(input as DeriveInput);
+    let name = &input.ident;
+
+    // Process 'cfg_file'
+    let path_expr = match find_cfg_file_path(&input.attrs) {
+        Some(path) => {
+            if path.starts_with("./") {
+                let path_str = &path[2..];
+                quote! {
+                    std::env::current_dir()?.join(#path_str)
+                }
+            } else {
+                // Using Absolute Path
+                quote! {
+                    std::path::PathBuf::from(#path)
+                }
+            }
+        }
+        None => {
+            let default_file = to_snake_case(&name.to_string()) + ".json";
+            quote! {
+                std::env::current_dir()?.join(#default_file)
+            }
+        }
+    };
+
+    let expanded = quote! {
+        impl cfg_file::config::ConfigFile for #name {
+            type DataType = #name;
+
+            fn default_path() -> Result<std::path::PathBuf, std::io::Error> {
+                Ok(#path_expr)
+            }
+        }
+    };
+
+    TokenStream::from(expanded)
+}
+
+fn find_cfg_file_path(attrs: &[Attribute]) -> Option<String> {
+    for attr in attrs {
+        if attr.path().is_ident("cfg_file") {
+            let parser = |meta: ParseStream| {
+                let path_meta: syn::MetaNameValue = meta.parse()?;
+                if path_meta.path.is_ident("path") {
+                    if let syn::Expr::Lit(syn::ExprLit { lit: syn::Lit::Str(lit), .. }) = path_meta.value {
+                        return Ok(lit.value());
+                    }
+                }
+                Err(meta.error("expected `path = \"...\"`"))
+            };
+
+            if let Ok(path) = attr.parse_args_with(parser) {
+                return Some(path);
+            }
+        }
+    }
+    None
+}
+
+fn to_snake_case(s: &str) -> String {
+    let mut snake = String::new();
+    for (i, c) in s.chars().enumerate() {
+        if c.is_uppercase() {
+            if i != 0 {
+                snake.push('_');
+            }
+            snake.push(c.to_ascii_lowercase());
+        } else {
+            snake.push(c);
+        }
+    }
+    snake
+}
+\ No newline at end of file