use std::env;
use std::path::Path;
use std::fs::File;
use std::io::Write;
use std::process::{Command, Stdio};

pub fn main() {
    let cmd = Command::new("git")
        .args(&["describe", "--tags", "--always", "--dirty=-dirty"])
        .stderr(Stdio::inherit())
        .output().unwrap();
    let gitver = String::from_utf8_lossy(&cmd.stdout).to_owned();
    let gitver = gitver.trim();

    let out_dir = env::var("OUT_DIR").unwrap();
    let dest_path = Path::new(&out_dir).join("build_id.rs");
    let mut f = File::create(&dest_path).unwrap();

    f.write_all(b"pub const BUILD_ID : &'static str = \"").unwrap();
    f.write_all(gitver.as_bytes()).unwrap();
    f.write_all(b"\";\n").unwrap();
}