//! Verify that tasks get polled by the virtualdom properly, and that we escape wait_for_work safely

use std::{sync::atomic::AtomicUsize, time::Duration};

use dioxus::prelude::*;

async fn run_vdom(app: fn() -> Element) {
    let mut dom = VirtualDom::new(app);

    dom.rebuild(&mut dioxus_core::NoOpMutations);

    tokio::select! {
        _ = dom.wait_for_work() => {}
        _ = tokio::time::sleep(Duration::from_millis(500)) => {}
    };
}

#[tokio::test]
async fn running_async() {
    static POLL_COUNT: AtomicUsize = AtomicUsize::new(0);

    fn app() -> Element {
        use_hook(|| {
            spawn(async {
                for x in 0..10 {
                    tokio::time::sleep(Duration::from_micros(50)).await;
                    POLL_COUNT.fetch_add(x, std::sync::atomic::Ordering::Relaxed);
                }
            });

            spawn(async {
                for x in 0..10 {
                    tokio::time::sleep(Duration::from_micros(25)).await;
                    POLL_COUNT.fetch_add(x * 2, std::sync::atomic::Ordering::Relaxed);
                }
            });
        });

        rsx!({})
    }

    run_vdom(app).await;

    // By the time the tasks are finished, we should've accumulated ticks from two tasks
    // Be warned that by setting the delay to too short, tokio might not schedule in the tasks
    assert_eq!(
        POLL_COUNT.fetch_add(0, std::sync::atomic::Ordering::Relaxed),
        135
    );
}

/// Prove that yield_now doesn't cause a deadlock
#[tokio::test]
async fn yield_now_works() {
    thread_local! {
        static SEQUENCE: std::cell::RefCell<Vec<usize>> = std::cell::RefCell::new(Vec::new());
    }

    fn app() -> Element {
        // these two tasks should yield to eachother
        use_hook(|| {
            spawn(async move {
                for _ in 0..10 {
                    tokio::task::yield_now().await;
                    SEQUENCE.with(|s| s.borrow_mut().push(1));
                }
            })
        });

        use_hook(|| {
            spawn(async move {
                for _ in 0..10 {
                    tokio::task::yield_now().await;
                    SEQUENCE.with(|s| s.borrow_mut().push(2));
                }
            })
        });

        rsx!({})
    }

    run_vdom(app).await;

    SEQUENCE.with(|s| assert_eq!(s.borrow().len(), 20));
}

/// Ensure that calling wait_for_flush waits for dioxus to finish its syncrhonous work
#[tokio::test]
async fn flushing() {
    thread_local! {
        static SEQUENCE: std::cell::RefCell<Vec<usize>> = std::cell::RefCell::new(Vec::new());
        static BROADCAST: (tokio::sync::broadcast::Sender<()>, tokio::sync::broadcast::Receiver<()>) = tokio::sync::broadcast::channel(1);
    }

    fn app() -> Element {
        if generation() > 0 {
            println!("App");
            SEQUENCE.with(|s| s.borrow_mut().push(0));
        }
        use_hook(|| {
            spawn(async move {
                needs_update();
            });
        });
        use_hook(|| {
            spawn(async move {
                for _ in 0..10 {
                    BROADCAST.with(|b| b.1.resubscribe()).recv().await.unwrap();
                    println!("Task 1 recved");
                    flush_sync().await;
                    println!("Task 1");
                    SEQUENCE.with(|s| s.borrow_mut().push(1));
                }
            })
        });

        use_hook(|| {
            spawn(async move {
                for _ in 0..10 {
                    BROADCAST.with(|b| b.1.resubscribe()).recv().await.unwrap();
                    println!("Task 2 recved");
                    flush_sync().await;
                    println!("Task 2");
                    SEQUENCE.with(|s| s.borrow_mut().push(2));
                }
            })
        });

        rsx! {}
    }

    let mut dom = VirtualDom::new(app);

    dom.rebuild(&mut dioxus_core::NoOpMutations);

    let fut = async {
        // Trigger the flush by waiting for work
        for _ in 0..30 {
            BROADCAST.with(|b| b.0.send(()).unwrap());
            dom.mark_dirty(ScopeId(0));
            tokio::select! {
                _ = dom.wait_for_work() => {}
                _ = tokio::time::sleep(Duration::from_millis(10)) => {}
            }
            dom.render_immediate(&mut dioxus_core::NoOpMutations);
            println!("Flushed");
        }
    };

    tokio::select! {
        _ = fut => {}
        _ = tokio::time::sleep(Duration::from_millis(500)) => {
            println!("Aborting due to timeout");
        }
    };

    SEQUENCE.with(|s| {
        let s = s.borrow();
        println!("{:?}", s);
        assert_eq!(s.len(), 30);
        // We need to check if every three elements look like [0, 1, 2] or [0, 2, 1]
        let mut has_seen_1 = false;
        for (i, &x) in s.iter().enumerate() {
            let stage = i % 3;
            if stage == 0 {
                assert_eq!(x, 0);
            } else if stage == 1 {
                assert!(x == 1 || x == 2);
                has_seen_1 = x == 1;
            } else if stage == 2 {
                if has_seen_1 {
                    assert_eq!(x, 2);
                } else {
                    assert_eq!(x, 1);
                }
            }
        }
    });
}