refactor(config): simplify config reading

!squash me

!squash me

derive_macro/Cargo.lock

@@ -0,0 +1,47 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 4
+
+[[package]]
+name = "derive_macro"
+version = "0.1.0"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "syn",
+]
+
+[[package]]
+name = "proc-macro2"
+version = "1.0.95"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "02b3e5e68a3a1a02aad3ec490a98007cbc13c37cbe84a3cd7b8e406d76e7f778"
+dependencies = [
+ "unicode-ident",
+]
+
+[[package]]
+name = "quote"
+version = "1.0.40"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "1885c039570dc00dcb4ff087a89e185fd56bae234ddc7f056a945bf36467248d"
+dependencies = [
+ "proc-macro2",
+]
+
+[[package]]
+name = "syn"
+version = "2.0.104"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "17b6f705963418cdb9927482fa304bc562ece2fdd4f616084c50b7023b435a40"
+dependencies = [
+ "proc-macro2",
+ "quote",
+ "unicode-ident",
+]
+
+[[package]]
+name = "unicode-ident"
+version = "1.0.18"
+source = "registry+https://github.com/rust-lang/crates.io-index"
+checksum = "5a5f39404a5da50712a4c1eecf25e90dd62b613502b7e925fd4e4d19b5c96512"

derive_macro/Cargo.toml

@@ -0,0 +1,12 @@
+[package]
+name = "derive_macro"
+version = "0.1.0"
+edition = "2024"
+
+[lib]
+crate-type = ["proc-macro"]
+
+[dependencies]
+proc-macro2 = "1.0"
+quote = "1.0"
+syn = { version = "2.0", features = ["full", "extra-traits"] }

derive_macro/src/from_file.rs

@@ -0,0 +1,42 @@
+use proc_macro::TokenStream;
+use quote::quote;
+use syn::{Data, DeriveInput, Fields, Ident};
+
+pub fn impl_from_file(input: DeriveInput) -> TokenStream {
+    let name = &input.ident;
+    let file_name = format!("{name}File");
+    let file_ident = Ident::new(&file_name, name.span());
+
+    let fields = match &input.data {
+        Data::Struct(data) => match &data.fields {
+            Fields::Named(fields) => &fields.named,
+            _ => panic!("Only named fields are supported"),
+        },
+        _ => panic!("Only structs are supported"),
+    };
+
+    let field_idents = fields.iter().map(|f| &f.ident);
+    let field_idents2 = field_idents.clone();
+
+    quote! {
+        impl #name {
+            fn from_file(file: Option<#file_ident>) -> Self 
+            where
+                #file_ident: Default + Clone
+            {
+                let default = #file_ident::default();
+                let file = file.unwrap_or_else(|| default.clone());
+
+                Self {
+                    #(#field_idents: file.#field_idents2.unwrap_or_else(|| default.#field_idents.clone().unwrap())),*
+                }
+            }
+        }
+
+        impl From<Option<#file_ident>> for #name {
+            fn from(value: Option<#file_ident>) -> Self {
+                Self::from_file(value)
+            }
+        }
+    }.into()
+}

derive_macro/src/lib.rs

@@ -0,0 +1,10 @@
+mod from_file;
+
+use proc_macro::TokenStream;
+use syn::{DeriveInput, parse_macro_input};
+
+#[proc_macro_derive(FromFile)]
+pub fn derive_from_file(input: TokenStream) -> TokenStream {
+    let input = parse_macro_input!(input as DeriveInput);
+    from_file::impl_from_file(input)
+}