use tokio::sync::watch;

use super::signals::Signals;

pub struct Shutdown {
    rx: watch::Receiver<bool>,
}

pub fn install() -> Shutdown {
    let (tx, rx) = watch::channel(false);
    tokio::spawn(async move {
        let Some(mut signals) = Signals::new() else {
            tracing::error!("installing shutdown signal handlers failed");
            std::future::pending::<()>().await;
            return;
        };
        let first = signals.next().await;
        tracing::info!(
            signal = first,
            "shutdown signal received; draining in-flight work"
        );
        let _ = tx.send(true);
        let second = signals.next().await;
        tracing::warn!(
            signal = second,
            "second shutdown signal received; exiting immediately"
        );
        std::process::exit(1);
    });
    Shutdown { rx }
}

impl Shutdown {
    pub async fn wait(mut self) {
        let _ = self.rx.wait_for(|requested| *requested).await;
    }
}