use crate::loom::sync::atomic::Ordering::{Acquire, Relaxed, Release};
use crate::loom::sync::atomic::{AtomicBool, AtomicUsize};
use crate::loom::sync::{Arc, Mutex};
use crate::spawn;
use crate::tests::loom_oneshot as oneshot;
use crate::thread_pool::ThreadPool;

use std::future::Future;

#[test]
fn pool_multi_spawn() {
    loom::model(|| {
        let pool = ThreadPool::new();

        let c1 = Arc::new(AtomicUsize::new(0));

        let (tx, rx) = oneshot::channel();
        let tx1 = Arc::new(Mutex::new(Some(tx)));

        // Spawn a task
        let c2 = c1.clone();
        let tx2 = tx1.clone();
        pool.spawn(async move {
            spawn(async move {
                if 1 == c1.fetch_add(1, Relaxed) {
                    tx1.lock().unwrap().take().unwrap().send(());
                }
            });
        });

        // Spawn a second task
        pool.spawn(async move {
            spawn(async move {
                if 1 == c2.fetch_add(1, Relaxed) {
                    tx2.lock().unwrap().take().unwrap().send(());
                }
            });
        });

        rx.recv();
    });
}

#[test]
fn pool_multi_notify() {
    loom::model(|| {
        let pool = ThreadPool::new();

        let c1 = Arc::new(AtomicUsize::new(0));

        let (done_tx, done_rx) = oneshot::channel();
        let done_tx1 = Arc::new(Mutex::new(Some(done_tx)));

        // Spawn a task
        let c2 = c1.clone();
        let done_tx2 = done_tx1.clone();
        pool.spawn(async move {
            gated().await;
            gated().await;

            if 1 == c1.fetch_add(1, Relaxed) {
                done_tx1.lock().unwrap().take().unwrap().send(());
            }
        });

        // Spawn a second task
        pool.spawn(async move {
            gated().await;
            gated().await;

            if 1 == c2.fetch_add(1, Relaxed) {
                done_tx2.lock().unwrap().take().unwrap().send(());
            }
        });

        done_rx.recv();
    });
}

#[test]
fn pool_shutdown() {
    loom::model(|| {
        let pool = ThreadPool::new();

        pool.spawn(async move {
            gated2(true).await;
        });

        drop(pool);
    });
}

fn gated() -> impl Future<Output = &'static str> {
    gated2(false)
}

fn gated2(thread: bool) -> impl Future<Output = &'static str> {
    use crate::loom::thread;
    use futures_util::future::poll_fn;
    use std::sync::Arc;
    use std::task::Poll;

    let gate = Arc::new(AtomicBool::new(false));
    let mut fired = false;

    poll_fn(move |cx| {
        if !fired {
            let gate = gate.clone();
            let waker = cx.waker().clone();

            if thread {
                thread::spawn(move || {
                    gate.store(true, Release);
                    waker.wake_by_ref();
                });
            } else {
                spawn(async move {
                    gate.store(true, Release);
                    waker.wake_by_ref();
                });
            }

            fired = true;

            return Poll::Pending;
        }

        if gate.load(Acquire) {
            Poll::Ready("hello world")
        } else {
            Poll::Pending
        }
    })
}