feat: Created a theme validation macro to verify theme configurations before allowing the TUI to start

proc_macros/validate_theme_derive/src/lib.rs

@@ -0,0 +1,41 @@
+use proc_macro::TokenStream;
+use quote::quote;
+use syn::{parse_macro_input, Data, DeriveInput, Fields};
+
+#[proc_macro_derive(ValidateTheme, attributes(validate))]
+pub fn derive_validate_theme(input: TokenStream) -> TokenStream {
+	let input = parse_macro_input!(input as DeriveInput);
+	let struct_name = &input.ident;
+
+	let mut validation_checks = Vec::new();
+
+	if let Data::Struct(data_struct) = &input.data {
+		if let Fields::Named(fields) = &data_struct.fields {
+			for field in &fields.named {
+				let field_name = &field.ident;
+
+				let has_validate_attr = field.attrs.iter().any(|attr| {
+					attr.path().is_ident("validate")
+				});
+
+				if has_validate_attr {
+					validation_checks.push(quote! {
+						if self.#field_name.is_none() {
+							log::error!("{} is missing a color value.", stringify!(#field_name));
+								eprintln!("{} is missing a color value.", stringify!(#field_name));
+								process::exit(1);
+						}
+					})
+				}
+			}
+		}
+	}
+
+	quote! {
+		impl #struct_name {
+			pub fn validate(&self) {
+				#(#validation_checks)*
+			}
+		}
+	}.into()
+}