use std::io::Write;
use std::path::PathBuf;

fn main() -> Result<(), Box<dyn std::error::Error>> {
    // For each hid.bin file in our test/data directory, create one basic test function
    // that attempts to parse that report descriptor
    let datadir: PathBuf = [concat!(env!("CARGO_MANIFEST_DIR"), "/tests/data")]
        .iter()
        .collect();
    let out_dir = std::env::var_os("OUT_DIR").unwrap();
    let dest_path = PathBuf::from(&out_dir).join("test-report-descriptors.rs");
    let mut file = std::fs::File::create(dest_path)?;

    writeln!(file, "use hidreport::*;")?;
    writeln!(file)?;

    if datadir.exists() {
        std::fs::read_dir(datadir)
            .unwrap()
            .flatten()
            .for_each(|rdesc| {
                let filename = rdesc.file_name().into_string().unwrap();
                let funcname = filename.replace([':', '.', '-'], "_");
                let path = rdesc.path();
                writeln!(
                    file,
                    "
    #[test]
    #[allow(non_snake_case)]
    fn test_{funcname}() {{
        let bytes: Vec<u8> = std::fs::read({path:?}).unwrap();
        if !bytes.is_empty() {{
            ReportDescriptor::try_from(&bytes).expect(&format!(\"Failed to parse {filename}\"));
        }}
    }}
    "
                )
                .unwrap();
            });
    }

    Ok(())
}