use std::env;
use std::fs::File;
use std::io::Write;
use std::path::Path;
use std::process::Command;

fn get_git_version() -> Result<(u32, String), std::io::Error> {
    let output = Command::new("git")
        .args(["rev-list", "--count", "HEAD"])
        .output()?;

    let output = output.stdout;
    let version_code = String::from_utf8(output).expect("Failed to read git count stdout");
    let version_code: u32 = version_code
        .trim()
        .parse()
        .map_err(|_| std::io::Error::new(std::io::ErrorKind::Other, "Failed to parse git count"))?;
    let version_code = 10000 + 200 + version_code; // For historical reasons

    let version_name = String::from_utf8(
        Command::new("git")
            .args(["describe", "--tags", "--always"])
            .output()?
            .stdout,
    )
    .map_err(|_| {
        std::io::Error::new(
            std::io::ErrorKind::Other,
            "Failed to read git describe stdout",
        )
    })?;
    let version_name = version_name.trim_start_matches('v').to_string();
    Ok((version_code, version_name))
}

fn main() {
    let (code, name) = match get_git_version() {
        Ok((code, name)) => (code, name),
        Err(_) => {
            // show warning if git is not installed
            println!("cargo:warning=Failed to get git version, using 0.0.0");
            (0, "0.0.0".to_string())
        }
    };
    let out_dir = env::var("OUT_DIR").expect("Failed to get $OUT_DIR");
    let out_dir = Path::new(&out_dir);
    File::create(Path::new(out_dir).join("VERSION_CODE"))
        .expect("Failed to create VERSION_CODE")
        .write_all(code.to_string().as_bytes())
        .expect("Failed to write VERSION_CODE");

    File::create(Path::new(out_dir).join("VERSION_NAME"))
        .expect("Failed to create VERSION_NAME")
        .write_all(name.trim().as_bytes())
        .expect("Failed to write VERSION_NAME");
}