#[path = "../../../os-turkfs-journal/src/ordering.rs"]
mod ordering;
use ordering::{Block, Device, Error, State, Writer};

#[derive(Clone, Copy, Debug, PartialEq, Eq)]
enum Event { Write(u64, u8), Flush }
struct Disk { events: Vec<Event>, fail_at: Option<usize> }
impl Disk {
    fn push(&mut self, event: Event) -> Result<(), ()> {
        let index = self.events.len(); self.events.push(event);
        if self.fail_at == Some(index) { Err(()) } else { Ok(()) }
    }
}
impl Device for Disk {
    fn write(&mut self, lba: u64, bytes: &Block) -> Result<(), ()> { self.push(Event::Write(lba, bytes[0])) }
    fn flush(&mut self) -> Result<(), ()> { self.push(Event::Flush) }
}

#[test]
fn os_turkfs_journal_ordering_positive() {
    let mut disk = Disk {events: Vec::new(), fail_at: None};
    let mut writer = Writer::new();
    writer.execute(&mut disk, &[0x44; 512], &[0x55; 512], &[0x66; 512]).unwrap();
    assert_eq!(disk.events, [Event::Write(120, 0x44), Event::Flush,
        Event::Write(112, 0x55), Event::Flush, Event::Write(113, 0x66), Event::Flush]);
    assert_eq!(writer.state(), State::Published);
    assert!(writer.published());
    assert_eq!(writer.execute(&mut disk, &[0; 512], &[0; 512], &[0; 512]), Err(Error::Order));
    assert_eq!(disk.events.len(), 6);
}

#[test]
fn os_turkfs_journal_ordering_negative() {
    let mut fresh = Writer::new();
    let before = fresh;
    assert_eq!(fresh.publish(), Err(Error::Order));
    assert_eq!(fresh, before);
    for failure in 0..6 {
        let mut disk = Disk {events: Vec::new(), fail_at: Some(failure)};
        let mut writer = Writer::new();
        assert_eq!(writer.execute(&mut disk, &[0x44; 512], &[0x55; 512], &[0x66; 512]), Err(Error::Io));
        assert_eq!(disk.events.len(), failure + 1);
        assert_eq!(writer.state(), State::Failed);
        assert!(!writer.published());
        assert_eq!(writer.publish(), Err(Error::Order));
        assert_eq!(writer.execute(&mut disk, &[0; 512], &[0; 512], &[0; 512]), Err(Error::Order));
        assert_eq!(disk.events.len(), failure + 1);
    }
}