Avida-ED assets not injected

fn main() {
    use std::{fs, path::Path};

    let webroot = Path::new("webroot");
    if !webroot.exists() {
        fs::create_dir_all(webroot).expect("create fallback webroot");
        fs::write(
            webroot.join("index.html"),
            "<!doctype html><title>Avida-ED assets not injected</title><p>Run make fetch-v4 build-linux.</p>\n",
        )
        .expect("write fallback webroot index");
    }

    println!("cargo:rerun-if-changed=webroot");
    print_rerun_files(webroot);
    println!("cargo:rerun-if-env-changed=AVIDA_ED_DEFAULT_PATH");
    let default_path = std::env::var("AVIDA_ED_DEFAULT_PATH")
        .unwrap_or_else(|_| "/index.html".to_string());
    println!("cargo:rustc-env=AVIDA_ED_DEFAULT_PATH={default_path}");
}

fn print_rerun_files(path: &std::path::Path) {
    let Ok(entries) = std::fs::read_dir(path) else {
        return;
    };
    for entry in entries.flatten() {
        let path = entry.path();
        if path.is_dir() {
            print_rerun_files(&path);
        } else {
            println!("cargo:rerun-if-changed={}", path.display());
        }
    }
}