Add scss colors into rust via build-script, flesh out math evaluation in launcher, Restructure some code

build.rs

@@ -1,7 +1,35 @@
+use regex::Regex;
+use std::path::PathBuf;
+use std::{env, fs};
+
 fn main() {
     glib_build_tools::compile_resources(
         &["resources"],
         "resources/resources.gresource.xml",
         "templates.gresource",
     );
+
+    let colors_path = "style/_colors.scss";
+
+    println!("cargo:rerun-if-changed={colors_path}");
+
+    let scss = fs::read_to_string(colors_path).expect("Failed to read SCSS colors");
+
+    let regex =
+        Regex::new(r"(?m)^\s*\$([a-zA-Z_][a-zA-Z0-9_-]*)\s*:\s*(#[0-9a-fA-F]{3,8})\s*;").unwrap();
+
+    let mut generated = String::from("// Generated by build.rs. Do not edit\n\n");
+
+    for captures in regex.captures_iter(&scss) {
+        let name = captures.get(1).unwrap().as_str();
+        let value = captures.get(2).unwrap().as_str();
+
+        let constant_name = name.replace('-', "_").to_uppercase();
+
+        generated.push_str(&format!("pub const {constant_name}: &str = \"{value}\";\n"));
+    }
+
+    let out_dir = PathBuf::from(env::var("OUT_DIR").unwrap());
+
+    fs::write(out_dir.join("theme.rs"), generated).expect("Failed to generate theme.rs");
 }