/*
Additionnal build, doc: https://doc.rust-lang.org/cargo/reference/build-scripts.html

What is build here:
 - Compile the SASS file to CSS file.
*/

use std::{
    env,
    path::Path,
    process::{Command, Output},
};

fn exists_in_path<P>(filename: P) -> bool
where
    P: AsRef<Path>,
{
    for path in env::split_paths(&env::var_os("PATH").unwrap()) {
        if path.join(&filename).is_file() {
            return true;
        }
    }
    false
}

fn main() {
    println!("cargo:rerun-if-changed=style.scss");

    fn run_sass(filename_without_extension: &str) {
        fn run_sass_command(command: &mut Command, name: &str) -> Output {
            command
                .arg("--no-source-map")
                .arg(format!("scss/{}.scss", name))
                .arg(format!("static/{}.css", name))
                .output()
                .expect("Unable to compile SASS file, install SASS, see https://sass-lang.com/")
        }

        let output = if exists_in_path("sass.bat") {
            run_sass_command(
                Command::new("cmd").args(["/C", "sass.bat"]),
                filename_without_extension,
            )
        } else {
            run_sass_command(&mut Command::new("sass"), filename_without_extension)
        };

        if !output.status.success() {
            // SASS will put the error in the file.
            let error =
                std::fs::read_to_string(format!("./static/{}.css", filename_without_extension))
                    .unwrap_or_else(|_| {
                        panic!("unable to read {}.css", filename_without_extension)
                    });
            panic!("{}", error);
        }
    }

    run_sass("style_light");
    run_sass("style_dark");
}