use std::process::Command;

fn main() {
    // Emit git commit hash (short)
    let commit_hash = Command::new("git")
        .args(["rev-parse", "--short", "HEAD"])
        .output()
        .ok()
        .and_then(|o| String::from_utf8(o.stdout).ok())
        .map(|s| s.trim().to_string())
        .unwrap_or_else(|| "unknown".to_string());

    println!("cargo:rustc-env=GIT_COMMIT_HASH={commit_hash}");

    // Emit git tag describing the current commit (e.g. "v1.0.0" or "v1.0.0-3-gabcdef1")
    // `git describe --tags --exact-match` gives the exact tag; fall back to `git describe --tags`.
    let git_tag = Command::new("git")
        .args(["describe", "--tags", "--exact-match"])
        .output()
        .ok()
        .filter(|o| o.status.success())
        .and_then(|o| String::from_utf8(o.stdout).ok())
        .map(|s| s.trim().to_string())
        .or_else(|| {
            Command::new("git")
                .args(["describe", "--tags"])
                .output()
                .ok()
                .filter(|o| o.status.success())
                .and_then(|o| String::from_utf8(o.stdout).ok())
                .map(|s| s.trim().to_string())
        });

    let tag_value = git_tag.unwrap_or_else(|| "untagged".to_string());
    println!("cargo:rustc-env=GIT_TAG={tag_value}");

    // Re-run if HEAD or tag refs change
    println!("cargo:rerun-if-changed=.git/HEAD");
    println!("cargo:rerun-if-changed=.git/refs/tags");
    println!("cargo:rerun-if-changed=.git/packed-refs");
}