#[path = "../../../os-virtio-indices/src/lib.rs"]
mod virtio_indices;

use virtio_indices::{Error, Queue};

#[test]
fn os_virtqueue_indices_positive_wrap() {
    let mut queue = Queue::<8>::new(8).unwrap();
    for sequence in 1..=u16::MAX {
        let ticket = queue.publish(0).unwrap();
        assert_eq!(ticket.avail_index, sequence);
        assert_eq!(queue.observe_used(sequence, 0), Ok(ticket));
    }
    let old = queue.snapshot();
    let wrapped = queue.publish(0).unwrap();
    assert_eq!(wrapped.avail_index, 0);
    assert!(wrapped.generation > u64::from(u16::MAX));
    assert_eq!(queue.observe_used(old.used_index, 0), Err(Error::StaleObservation));
    assert_eq!(queue.observe_used(0, 0), Ok(wrapped));
    assert_eq!(queue.snapshot().outstanding, 0);
}

#[test]
fn os_virtqueue_indices_negative_and_reset() {
    assert!(matches!(Queue::<8>::new(3), Err(Error::InvalidQueue)));
    let mut full = Queue::<8>::new(8).unwrap();
    for head in 0..8 { full.publish(head).unwrap(); }
    let full_snapshot = full.snapshot();
    assert_eq!(full.publish(0), Err(Error::Full));
    assert_eq!(full.observe_used(9, 0), Err(Error::DeviceJump));
    assert_eq!(full.snapshot(), full_snapshot);
    let mut queue = Queue::<8>::new(8).unwrap();
    let first = queue.publish(2).unwrap();
    let before = queue.snapshot();
    assert_eq!(queue.publish(2), Err(Error::DuplicateHead));
    assert_eq!(queue.publish(8), Err(Error::InvalidHead));
    assert_eq!(queue.observe_used(2, 2), Err(Error::DeviceJump));
    assert_eq!(queue.observe_used(1, 7), Err(Error::UnknownHead));
    assert_eq!(queue.observe_used(1, 8), Err(Error::UnknownHead));
    assert_eq!(queue.observe_reset(1, 0, 0, 0), Err(Error::NotReset));
    assert_eq!(queue.snapshot(), before);
    assert_eq!(queue.observe_used(1, 2), Ok(first));
    assert_eq!(queue.observe_used(1, 2), Err(Error::StaleObservation));
    let second = queue.publish(2).unwrap();
    assert!(second.generation > first.generation);
    queue.observe_reset(0, 0, 0, 0).unwrap();
    assert_eq!(queue.snapshot().outstanding, 0);
    assert!(queue.publish(2).unwrap().generation > second.generation);
}