use once_spin::*;
use std::{
    sync::{
        mpsc::{channel, TryRecvError},
        Arc,
    },
    thread,
};

fn use_barrier(n: usize, barrier: Arc<Barrier>) {
    let (tx, rx) = channel();

    for _ in 0..n - 1 {
        let c = barrier.clone();
        let tx = tx.clone();
        thread::spawn(move || {
            tx.send(c.wait().is_leader()).unwrap();
        });
    }

    assert!(match rx.try_recv() {
        Err(TryRecvError::Empty) => true,
        _ => false,
    });

    let mut leader_found = barrier.wait().is_leader();

    for _ in 0..n - 1 {
        if rx.recv().unwrap() {
            assert!(!leader_found);
            leader_found = true;
        }
    }
    assert!(leader_found);
}

#[test]
fn test_barrier() {
    const N: usize = 10;

    let barrier = Arc::new(Barrier::new(N));

    use_barrier(N, barrier.clone());

    use_barrier(N, barrier.clone());
}