use mio::{Events, Poll, PollOpt, Ready, Registration, SetReadiness, Token};
use mio::event::Evented;
use std::time::Duration;

#[test]
fn smoke() {
    let poll = Poll::new().unwrap();
    let mut events = Events::with_capacity(128);

    let (r, set) = Registration::new2();
    r.register(&poll, Token(0), Ready::readable(), PollOpt::edge()).unwrap();

    let n = poll.poll(&mut events, Some(Duration::from_millis(0))).unwrap();
    assert_eq!(n, 0);

    set.set_readiness(Ready::readable()).unwrap();

    let n = poll.poll(&mut events, Some(Duration::from_millis(0))).unwrap();
    assert_eq!(n, 1);

    assert_eq!(events.get(0).unwrap().token(), Token(0));
}

#[test]
fn set_readiness_before_register() {
    use std::sync::{Arc, Barrier};
    use std::thread;

    let poll = Poll::new().unwrap();
    let mut events = Events::with_capacity(128);

    for _ in 0..5_000 {
        let (r, set) = Registration::new2();

        let b1 = Arc::new(Barrier::new(2));
        let b2 = b1.clone();

        let th = thread::spawn(move || {
            // set readiness before register
            set.set_readiness(Ready::readable()).unwrap();

            // run into barrier so both can pass
            b2.wait();
        });

        // wait for readiness
        b1.wait();

        // now register
        poll.register(&r, Token(123), Ready::readable(), PollOpt::edge()).unwrap();

        loop {
            let n = poll.poll(&mut events, None).unwrap();

            if n == 0 {
                continue;
            }

            assert_eq!(n, 1);
            assert_eq!(events.get(0).unwrap().token(), Token(123));
            break;
        }

        th.join().unwrap();
    }
}

#[cfg(any(target_os = "linux", target_os = "macos", target_os = "windows"))]
mod stress {
    use mio::{Events, Poll, PollOpt, Ready, Registration, SetReadiness, Token};
    use mio::event::Evented;
    use std::time::Duration;

    #[test]
    fn single_threaded_poll() {
        use std::sync::Arc;
        use std::sync::atomic::AtomicUsize;
        use std::sync::atomic::Ordering::{Acquire, Release};
        use std::thread;

        const NUM_ATTEMPTS: usize = 30;
        const NUM_ITERS: usize = 500;
        const NUM_THREADS: usize = 4;
        const NUM_REGISTRATIONS: usize = 128;

        for _ in 0..NUM_ATTEMPTS {
            let poll = Poll::new().unwrap();
            let mut events = Events::with_capacity(NUM_REGISTRATIONS);

            let registrations: Vec<_> = (0..NUM_REGISTRATIONS).map(|i| {
                let (r, s) = Registration::new2();
                r.register(&poll, Token(i), Ready::readable(), PollOpt::edge()).unwrap();
                (r, s)
            }).collect();

            let mut ready: Vec<_> = (0..NUM_REGISTRATIONS).map(|_| Ready::empty()).collect();

            let remaining = Arc::new(AtomicUsize::new(NUM_THREADS));

            for _ in 0..NUM_THREADS {
                let remaining = remaining.clone();

                let set_readiness: Vec<SetReadiness> =
                    registrations.iter().map(|r| r.1.clone()).collect();

                thread::spawn(move || {
                    for _ in 0..NUM_ITERS {
                        for i in 0..NUM_REGISTRATIONS {
                            set_readiness[i].set_readiness(Ready::readable()).unwrap();
                            set_readiness[i].set_readiness(Ready::empty()).unwrap();
                            set_readiness[i].set_readiness(Ready::writable()).unwrap();
                            set_readiness[i].set_readiness(Ready::readable() | Ready::writable()).unwrap();
                            set_readiness[i].set_readiness(Ready::empty()).unwrap();
                        }
                    }

                    for i in 0..NUM_REGISTRATIONS {
                        set_readiness[i].set_readiness(Ready::readable()).unwrap();
                    }

                    remaining.fetch_sub(1, Release);
                });
            }

            while remaining.load(Acquire) > 0 {
                // Set interest
                for (i, &(ref r, _)) in registrations.iter().enumerate() {
                    r.reregister(&poll, Token(i), Ready::writable(), PollOpt::edge()).unwrap();
                }

                poll.poll(&mut events, Some(Duration::from_millis(0))).unwrap();

                for event in &events {
                    ready[event.token().0] = event.readiness();
                }

                // Update registration
                // Set interest
                for (i, &(ref r, _)) in registrations.iter().enumerate() {
                    r.reregister(&poll, Token(i), Ready::readable(), PollOpt::edge()).unwrap();
                }
            }

            // Finall polls, repeat until readiness-queue empty
            loop {
                // Might not read all events from custom-event-queue at once, implementation dependend
                poll.poll(&mut events, Some(Duration::from_millis(0))).unwrap();
                if events.is_empty() {
                    // no more events in readiness queue pending
                    break;
                }
                for event in &events {
                    ready[event.token().0] = event.readiness();
                }
            }

            // Everything should be flagged as readable
            for ready in ready {
                assert_eq!(ready, Ready::readable());
            }
        }
    }

    #[test]
    fn multi_threaded_poll() {
        use std::sync::{Arc, Barrier};
        use std::sync::atomic::{AtomicUsize};
        use std::sync::atomic::Ordering::{Relaxed, SeqCst};
        use std::thread;

        const ENTRIES: usize = 10_000;
        const PER_ENTRY: usize = 16;
        const THREADS: usize = 4;
        const NUM: usize = ENTRIES * PER_ENTRY;

        struct Entry {
            #[allow(dead_code)]
            registration: Registration,
            set_readiness: SetReadiness,
            num: AtomicUsize,
        }

        impl Entry {
            fn fire(&self) {
                self.set_readiness.set_readiness(Ready::readable()).unwrap();
            }
        }

        let poll = Arc::new(Poll::new().unwrap());
        let mut entries = vec![];

        // Create entries
        for i in 0..ENTRIES {
            let (registration, set_readiness) = Registration::new2();
            registration.register(&poll, Token(i), Ready::readable(), PollOpt::edge()).unwrap();

            entries.push(Entry {
                registration,
                set_readiness,
                num: AtomicUsize::new(0),
            });
        }

        let total = Arc::new(AtomicUsize::new(0));
        let entries = Arc::new(entries);
        let barrier = Arc::new(Barrier::new(THREADS));

        let mut threads = vec![];

        for th in 0..THREADS {
            let poll = poll.clone();
            let total = total.clone();
            let entries = entries.clone();
            let barrier = barrier.clone();

            threads.push(thread::spawn(move || {
                let mut events = Events::with_capacity(128);

                barrier.wait();

                // Prime all the registrations
                let mut i = th;
                while i < ENTRIES {
                    entries[i].fire();
                    i += THREADS;
                }

                let mut n = 0;


                while total.load(SeqCst) < NUM {
                    // A poll timeout is necessary here because there may be more
                    // than one threads blocked in `poll` when the final wakeup
                    // notification arrives (and only notifies one thread).
                    n += poll.poll(&mut events, Some(Duration::from_millis(100))).unwrap();

                    let mut num_this_tick = 0;

                    for event in &events {
                        let e = &entries[event.token().0];

                        let mut num = e.num.load(Relaxed);

                        loop {
                            if num < PER_ENTRY {
                                let actual = e.num.compare_and_swap(num, num + 1, Relaxed);

                                if actual == num {
                                    num_this_tick += 1;
                                    e.fire();
                                    break;
                                }

                                num = actual;
                            } else {
                                break;
                            }
                        }
                    }

                    total.fetch_add(num_this_tick, SeqCst);
                }

                n
            }));
        }

        let _: Vec<_> = threads.into_iter()
            .map(|th| th.join().unwrap())
            .collect();

        for entry in entries.iter() {
            assert_eq!(PER_ENTRY, entry.num.load(Relaxed));
        }
    }

    #[test]
    fn with_small_events_collection() {
        const N: usize = 8;
        const ITER: usize = 1_000;

        use std::sync::{Arc, Barrier};
        use std::sync::atomic::AtomicBool;
        use std::sync::atomic::Ordering::{Acquire, Release};
        use std::thread;

        let poll = Poll::new().unwrap();
        let mut registrations = vec![];

        let barrier = Arc::new(Barrier::new(N + 1));
        let done = Arc::new(AtomicBool::new(false));

        for i in 0..N {
            let (registration, set_readiness) = Registration::new2();
            poll.register(&registration, Token(i), Ready::readable(), PollOpt::edge()).unwrap();

            registrations.push(registration);

            let barrier = barrier.clone();
            let done = done.clone();

            thread::spawn(move || {
                barrier.wait();

                while !done.load(Acquire) {
                    set_readiness.set_readiness(Ready::readable()).unwrap();
                }

                // Set one last time
                set_readiness.set_readiness(Ready::readable()).unwrap();
            });
        }

        let mut events = Events::with_capacity(4);

        barrier.wait();

        for _ in 0..ITER {
            poll.poll(&mut events, None).unwrap();
        }

        done.store(true, Release);

        let mut final_ready = vec![false; N];


        for _ in 0..5 {
            poll.poll(&mut events, None).unwrap();

            for event in &events {
                final_ready[event.token().0] = true;
            }

            if final_ready.iter().all(|v| *v) {
                return;
            }

            thread::sleep(Duration::from_millis(10));
        }

        panic!("dead lock?");
    }
}

#[test]
fn drop_registration_from_non_main_thread() {
    use std::thread;
    use std::sync::mpsc::channel;

    const THREADS: usize = 8;
    const ITERS: usize = 50_000;

    let poll = Poll::new().unwrap();
    let mut events = Events::with_capacity(1024);
    let mut senders = Vec::with_capacity(THREADS);
    let mut token_index = 0;

    // spawn threads, which will send messages to single receiver
    for _ in 0..THREADS {
        let (tx, rx) = channel::<(Registration, SetReadiness)>();
        senders.push(tx);

        thread::spawn(move || {
            for (registration, set_readiness) in rx {
                let _ = set_readiness.set_readiness(Ready::readable());
                drop(registration);
                drop(set_readiness);
            }
        });
    }

    let mut index: usize = 0;
    for _ in 0..ITERS {
        let (registration, set_readiness) = Registration::new2();
        registration.register(&poll, Token(token_index), Ready::readable(), PollOpt::edge()).unwrap();
        let _ = senders[index].send((registration, set_readiness));

        token_index += 1;
        index += 1;
        if index == THREADS {
            index = 0;

            let (registration, set_readiness) = Registration::new2();
            registration.register(&poll, Token(token_index), Ready::readable(), PollOpt::edge()).unwrap();
            let _ = set_readiness.set_readiness(Ready::readable());
            drop(registration);
            drop(set_readiness);
            token_index += 1;

            thread::park_timeout(Duration::from_millis(0));
            let _ = poll.poll(&mut events, None).unwrap();
        }
    }
}