use std::env;
use std::fs;
use std::path::Path;

fn main() {
  let hadron_version = env!("CARGO_PKG_VERSION");
  let git_branch = duct::cmd!("git", "rev-parse", "--abbrev-ref", "HEAD")
    .read()
    .unwrap_or("<not on git branch>".to_string());
  let git_sha_abbrev =
    duct::cmd!("git", "log", "-1", "--format=%h").read().unwrap_or("<unknown>".to_string());
  let git_sha = duct::cmd!("git", "log", "-1", "--format=%H")
    .read()
    .unwrap_or("<unknown sha hash>".to_string());

  let vars_file = format!(
    "\
    pub const fn hadron_version() -> &'static str {{
      \"{}\"
    }}

    pub const fn hadron_git_branch() -> &'static str {{
      \"{}\"
    }}

    pub const fn hadron_git_sha_abbrev() -> &'static str {{
      \"{}\"
    }}

    pub const fn hadron_git_sha() -> &'static str {{
      \"{}\"
    }}
  ",
    hadron_version, git_branch, git_sha_abbrev, git_sha
  );

  let out_dir = env::var_os("OUT_DIR").unwrap();
  let dest_path = Path::new(&out_dir).join("hadron_vars.rs");
  fs::write(dest_path, vars_file).unwrap();
}