use std::process::Command;

fn run_git_command(args: &[&str]) -> Option<String> {
	Command::new("git")
		.args(args)
		.output()
		.ok()
		.filter(|output| output.status.success())
		.and_then(|output| String::from_utf8(output.stdout).ok())
		.map(|s| s.trim().to_owned())
		.filter(|s| !s.is_empty())
}
fn get_env(env_var: &str) -> Option<String> {
	match std::env::var(env_var) {
		| Ok(val) if !val.is_empty() => Some(val),
		| _ => None,
	}
}
fn main() {
	// built gets the default crate from the workspace. Not sure if this is intended
	// behavior, but it's what we want.
	built::write_built_file().expect("Failed to acquire build-time information");

	// --- Git Information ---
	let mut commit_hash = None;
	let mut commit_hash_short = None;
	let mut remote_url_web = None;

	// Get full commit hash
	if let Some(hash) =
		get_env("GIT_COMMIT_HASH").or_else(|| run_git_command(&["rev-parse", "HEAD"]))
	{
		println!("cargo:rustc-env=GIT_COMMIT_HASH={hash}");
		commit_hash = Some(hash);
	}

	// Get short commit hash
	if let Some(short_hash) = get_env("GIT_COMMIT_HASH_SHORT")
		.or_else(|| run_git_command(&["rev-parse", "--short", "HEAD"]))
	{
		println!("cargo:rustc-env=GIT_COMMIT_HASH_SHORT={short_hash}");
		commit_hash_short = Some(short_hash);
	}

	// Get remote URL and convert to web URL
	if let Some(remote_url_raw) = get_env("GIT_REMOTE_URL")
		.or_else(|| run_git_command(&["config", "--get", "remote.origin.url"]))
	{
		println!("cargo:rustc-env=GIT_REMOTE_URL={remote_url_raw}");
		let web_url = if remote_url_raw.starts_with("https://") {
			remote_url_raw.trim_end_matches(".git").to_owned()
		} else if remote_url_raw.starts_with("git@") {
			remote_url_raw
				.trim_end_matches(".git")
				.replacen(':', "/", 1)
				.replacen("git@", "https://", 1)
		} else if remote_url_raw.starts_with("ssh://") {
			remote_url_raw
				.trim_end_matches(".git")
				.replacen("git@", "", 1)
				.replacen("ssh:", "https:", 1)
		} else {
			// Assume it's already a web URL or unknown format
			remote_url_raw
		};
		println!("cargo:rustc-env=GIT_REMOTE_WEB_URL={web_url}");
		remote_url_web = Some(web_url);
	}

	// Construct remote commit URL
	if let Some(remote_commit_url) = get_env("GIT_REMOTE_COMMIT_URL") {
		println!("cargo:rustc-env=GIT_REMOTE_COMMIT_URL={remote_commit_url}");
	} else if let (Some(base_url), Some(hash)) =
		(&remote_url_web, commit_hash.as_ref().or(commit_hash_short.as_ref()))
	{
		let commit_page = format!("{base_url}/commit/{hash}");
		println!("cargo:rustc-env=GIT_REMOTE_COMMIT_URL={commit_page}");
	}

	// --- Rerun Triggers ---
	// TODO: The git rerun triggers seem to always run
	// Rerun if the git HEAD changes
	println!("cargo:rerun-if-changed=.git/HEAD");
	// Rerun if the ref pointed to by HEAD changes (e.g., new commit on branch)
	if let Some(ref_path) = run_git_command(&["symbolic-ref", "--quiet", "HEAD"]) {
		println!("cargo:rerun-if-changed=.git/{ref_path}");
	}

	println!("cargo:rerun-if-env-changed=GIT_COMMIT_HASH");
	println!("cargo:rerun-if-env-changed=GIT_COMMIT_HASH_SHORT");
	println!("cargo:rerun-if-env-changed=GIT_REMOTE_URL");
	println!("cargo:rerun-if-env-changed=GIT_REMOTE_COMMIT_URL");
}