fn main() {
    #[cfg(feature = "debug_server")]
    pack_debug_page().unwrap();

    println!("cargo:rerun-if-changed=web/main.js");
    println!("cargo:rerun-if-changed=web/index.html");
    println!("cargo:rerun-if-changed=web/main.css");
    println!("cargo:rerun-if-changed=web/connected.svg");
}

#[cfg(feature = "debug_server")]
fn pack_debug_page() -> Result<(), Box<dyn std::error::Error>> {
    use flate2::{write::GzEncoder, Compression};
    use std::io::Write;

    use css_minify::optimizations::{Level, Minifier};

    let js = std::fs::read_to_string("web/main.js").unwrap();
    let html = std::fs::read_to_string("web/index.html").unwrap();
    let css = std::fs::read_to_string("web/main.css").unwrap();
    let svg = std::fs::read_to_string("web/connected.svg").unwrap();

    let mut out = Vec::new();
    minify_js::minify(
        &minify_js::Session::new(),
        minify_js::TopLevelMode::Global,
        js.as_bytes(),
        &mut out,
    )
    .unwrap();
    let js = std::str::from_utf8(&out)?;

    let css = Minifier::default().minify(&css, Level::One).unwrap();

    let (start, end) = html
        .split_once("<!--INSERT SVG HERE-->")
        .expect("did not find svg split point in html");

    let html = format!("{start}{svg}{end}");

    let (head, body) = html
        .split_once("<!--INSERT HEAD CONTENT HERE-->")
        .expect("did not find head split point in html");

    let (body_a, body_b) = body
        .split_once("#INSERT VERSION HERE#")
        .expect("did not find version split point in html");

    let version = env!("CARGO_PKG_VERSION");

    let html = minify_html::minify(
        format!("{head}<style>{css}</style><script>{js}</script>{body_a}{version}{body_b}")
            .as_bytes(),
        &minify_html::Cfg::spec_compliant(),
    );

    let mut encoder = GzEncoder::new(
        std::fs::File::create(std::env::var("OUT_DIR").unwrap() + "/minified.html.gz")?,
        Compression::best(),
    );

    encoder.write_all(&html)?;

    Ok(())
}