use tokio_util::sync::CancellationToken;

/// Install a ctrl-c handler that triggers the returned token.
///
/// The first ctrl-c cancels gracefully; a second ctrl-c terminates the process.
pub fn install_ctrl_c() -> CancellationToken {
    let token = CancellationToken::new();
    let trigger = token.clone();
    tokio::spawn(async move {
        if let Err(e) = tokio::signal::ctrl_c().await {
            // Installing the handler failed — ctrl-c won't trigger a graceful
            // shutdown. Say so instead of failing silently; the user can still
            // kill the process, and the second-ctrl-c arm below would only fail
            // the same way, so bail out of the task.
            tracing::warn!("could not install ctrl-c handler: {e}; ctrl-c won't shut down cleanly");
            return;
        }
        tracing::info!("ctrl-c received, shutting down");
        trigger.cancel();

        if tokio::signal::ctrl_c().await.is_ok() {
            tracing::warn!("second ctrl-c — exiting now");
            std::process::exit(130);
        }
    });
    token
}