use arc_swap::ArcSwapOption;
use crossbeam_queue::ArrayQueue;
use never::Never;
use std::sync::{
    atomic::{AtomicUsize, Ordering as AtomicOrdering},
    Arc,
};
use tracing::info;

use crate::common::VariantName;

use callbag::{take, Message, Source};

#[cfg(not(all(target_arch = "wasm32", target_os = "wasi")))]
use {
    async_executors::{Timer, TimerExt},
    async_nursery::{NurseExt, Nursery},
    std::{
        sync::{atomic::AtomicBool, RwLock},
        time::Duration,
    },
    tracing_futures::Instrument,
};

#[cfg(all(target_arch = "wasm32", not(target_os = "wasi")))]
use wasm_bindgen_test::wasm_bindgen_test;
#[cfg(all(
    all(target_arch = "wasm32", not(target_os = "wasi")),
    feature = "browser",
))]
use wasm_bindgen_test::wasm_bindgen_test_configure;

pub mod common;

#[cfg(all(
    all(target_arch = "wasm32", not(target_os = "wasi")),
    feature = "browser",
))]
wasm_bindgen_test_configure!(run_in_browser);

/// See <https://github.com/staltz/callbag-take/blob/6ae7755ea5f014306704450a40eb72ffdb21d308/test.js#L4-L103>
#[cfg(not(all(target_arch = "wasm32", target_os = "wasi")))]
#[tracing::instrument]
#[test_log::test(async_std::test)]
#[cfg_attr(
    all(
        all(target_arch = "wasm32", not(target_os = "wasi")),
        feature = "browser",
    ),
    wasm_bindgen_test
)]
async fn it_takes_from_a_pullable_source() {
    let (nursery, nursery_out) = Nursery::new(async_executors::AsyncStd);
    let nursery = nursery.in_current_span();

    let upwards_expected = ["Handshake", "Pull", "Pull", "Pull", "Terminate"];
    let upwards_expected = {
        let q = ArrayQueue::new(upwards_expected.len());
        for v in upwards_expected {
            q.push(v).ok();
        }
        Arc::new(q)
    };
    let downwards_expected_types = ["Handshake", "Data", "Data", "Data", "Terminate"];
    let downwards_expected_types = {
        let q = ArrayQueue::new(downwards_expected_types.len());
        for v in downwards_expected_types {
            q.push(v).ok();
        }
        Arc::new(q)
    };
    let downwards_expected = [10, 20, 30];
    let downwards_expected = {
        let q = ArrayQueue::new(downwards_expected.len());
        for v in downwards_expected {
            q.push(v).ok();
        }
        Arc::new(q)
    };

    let make_source = {
        let nursery = nursery.clone();
        move || {
            let sink_ref = Arc::new(ArcSwapOption::from(None));
            let sent = Arc::new(AtomicUsize::new(0));
            let source_ref: Arc<RwLock<Option<Arc<Source<_>>>>> = Arc::new(RwLock::new(None));
            let source = Arc::new(
                {
                    let source_ref = Arc::clone(&source_ref);
                    move |message: Message<Never, _>| {
                        info!("up: {message:?}");
                        {
                            let e = upwards_expected.pop().unwrap();
                            assert_eq!(message.variant_name(), e, "upwards type is expected: {e}");
                        }

                        if let Message::Handshake(sink) = message {
                            sink_ref.store(Some(sink));
                            let sink_ref = sink_ref.load();
                            let sink_ref = sink_ref.as_ref().unwrap();
                            let source = {
                                let source_ref = &mut *source_ref.write().unwrap();
                                source_ref.take().unwrap()
                            };
                            sink_ref(Message::Handshake(source));
                            return;
                        } else if let Message::Pull = message {
                        } else {
                            return;
                        }

                        if sent.load(AtomicOrdering::Acquire) == 0 {
                            sent.fetch_add(1, AtomicOrdering::AcqRel);
                            nursery
                                .nurse({
                                    let sink_ref = Arc::clone(&sink_ref);
                                    async move {
                                        let sink_ref = sink_ref.load();
                                        let sink_ref = sink_ref.as_ref().unwrap();
                                        sink_ref(Message::Data(10));
                                    }
                                })
                                .unwrap();
                            return;
                        }
                        if sent.load(AtomicOrdering::Acquire) == 1 {
                            sent.fetch_add(1, AtomicOrdering::AcqRel);
                            nursery
                                .nurse({
                                    let sink_ref = Arc::clone(&sink_ref);
                                    async move {
                                        let sink_ref = sink_ref.load();
                                        let sink_ref = sink_ref.as_ref().unwrap();
                                        sink_ref(Message::Data(20));
                                    }
                                })
                                .unwrap();
                            return;
                        }
                        if sent.load(AtomicOrdering::Acquire) == 2 {
                            sent.fetch_add(1, AtomicOrdering::AcqRel);
                            nursery
                                .nurse({
                                    let sink_ref = Arc::clone(&sink_ref);
                                    async move {
                                        let sink_ref = sink_ref.load();
                                        let sink_ref = sink_ref.as_ref().unwrap();
                                        sink_ref(Message::Data(30));
                                    }
                                })
                                .unwrap();
                            return;
                        }
                        if sent.load(AtomicOrdering::Acquire) == 3 {
                            sent.fetch_add(1, AtomicOrdering::AcqRel);
                            nursery
                                .nurse({
                                    let sink_ref = Arc::clone(&sink_ref);
                                    async move {
                                        let sink_ref = sink_ref.load();
                                        let sink_ref = sink_ref.as_ref().unwrap();
                                        sink_ref(Message::Data(40));
                                    }
                                })
                                .unwrap();
                            return;
                        }
                        if sent.load(AtomicOrdering::Acquire) == 4 {
                            sent.fetch_add(1, AtomicOrdering::AcqRel);
                            nursery
                                .nurse({
                                    let sink_ref = Arc::clone(&sink_ref);
                                    async move {
                                        let sink_ref = sink_ref.load();
                                        let sink_ref = sink_ref.as_ref().unwrap();
                                        sink_ref(Message::Data(50));
                                    }
                                })
                                .unwrap();
                            return;
                        }
                        if sent.load(AtomicOrdering::Acquire) == 5 {
                            sent.fetch_add(1, AtomicOrdering::AcqRel);
                            let sink_ref = sink_ref.load();
                            let sink_ref = sink_ref.as_ref().unwrap();
                            sink_ref(Message::Terminate);
                        }
                    }
                }
                .into(),
            );
            {
                let mut source_ref = source_ref.write().unwrap();
                *source_ref = Some(Arc::clone(&source));
            }
            source
        }
    };

    let make_sink = move || {
        let talkback = ArcSwapOption::from(None);
        Arc::new(
            (move |message: Message<_, Never>| {
                info!("down: {message:?}");
                {
                    let et = downwards_expected_types.pop().unwrap();
                    assert_eq!(
                        message.variant_name(),
                        et,
                        "downwards type is expected: {et}"
                    );
                }
                if let Message::Handshake(source) = message {
                    talkback.store(Some(source));
                    let talkback = talkback.load();
                    let talkback = talkback.as_ref().unwrap();
                    talkback(Message::Pull);
                } else if let Message::Data(data) = message {
                    {
                        let e = downwards_expected.pop().unwrap();
                        assert_eq!(data, e, "downwards data is expected: {e}");
                    }
                    let talkback = talkback.load();
                    let talkback = talkback.as_ref().unwrap();
                    talkback(Message::Pull);
                }
            })
            .into(),
        )
    };

    let source = make_source();
    let taken = take(3)(source);
    let sink = make_sink();
    taken(Message::Handshake(sink));

    let nursery_out = nursery.timeout(Duration::from_millis(300), nursery_out);
    drop(nursery);
    nursery_out.await.ok();
}

/// See <https://github.com/staltz/callbag-take/blob/6ae7755ea5f014306704450a40eb72ffdb21d308/test.js#L105-L155>
#[cfg(not(all(target_arch = "wasm32", target_os = "wasi")))]
#[tracing::instrument]
#[test_log::test(async_std::test)]
#[cfg_attr(
    all(
        all(target_arch = "wasm32", not(target_os = "wasi")),
        feature = "browser",
    ),
    wasm_bindgen_test
)]
async fn it_takes_an_async_listenable_source() {
    let (nursery, nursery_out) = Nursery::new(async_executors::AsyncStd);
    let nursery = nursery.in_current_span();

    let upwards_expected = ["Handshake", "Terminate"];
    let upwards_expected = {
        let q = ArrayQueue::new(upwards_expected.len());
        for v in upwards_expected {
            q.push(v).ok();
        }
        Arc::new(q)
    };
    let downwards_expected_types = ["Handshake", "Data", "Data", "Data", "Terminate"];
    let downwards_expected_types = {
        let q = ArrayQueue::new(downwards_expected_types.len());
        for v in downwards_expected_types {
            q.push(v).ok();
        }
        Arc::new(q)
    };
    let downwards_expected = [10, 20, 30];
    let downwards_expected = {
        let q = ArrayQueue::new(downwards_expected.len());
        for v in downwards_expected {
            q.push(v).ok();
        }
        Arc::new(q)
    };

    let make_source = {
        let nursery = nursery.clone();
        move || {
            let sent = Arc::new(AtomicUsize::new(0));
            let interval_cleared = Arc::new(AtomicBool::new(false));
            let source_ref: Arc<RwLock<Option<Arc<Source<_>>>>> = Arc::new(RwLock::new(None));
            let source = Arc::new(
                {
                    let source_ref = Arc::clone(&source_ref);
                    move |message: Message<Never, _>| {
                        info!("up: {message:?}");
                        let interval_cleared = Arc::clone(&interval_cleared);
                        {
                            let e = upwards_expected.pop().unwrap();
                            assert_eq!(message.variant_name(), e, "upwards type is expected: {e}");
                        }
                        if let Message::Handshake(sink) = message {
                            nursery
                                .nurse({
                                    let nursery = nursery.clone();
                                    let sent = Arc::clone(&sent);
                                    let sink = Arc::clone(&sink);
                                    const DURATION: Duration = Duration::from_millis(100);
                                    async move {
                                        loop {
                                            nursery.sleep(DURATION).await;
                                            if interval_cleared.load(AtomicOrdering::Acquire) {
                                                break;
                                            }
                                            let sent =
                                                sent.fetch_add(1, AtomicOrdering::AcqRel) + 1;
                                            sink(Message::Data(sent * 10));
                                        }
                                    }
                                })
                                .unwrap();
                            let source = {
                                let source_ref = &mut *source_ref.write().unwrap();
                                source_ref.take().unwrap()
                            };
                            sink(Message::Handshake(source));
                        } else if let Message::Error(_) | Message::Terminate = message {
                            interval_cleared.store(true, AtomicOrdering::Release);
                        }
                    }
                }
                .into(),
            );
            {
                let mut source_ref = source_ref.write().unwrap();
                *source_ref = Some(Arc::clone(&source));
            }
            source
        }
    };

    let sink = Arc::new(
        (move |message: Message<_, Never>| {
            info!("down: {message:?}");
            {
                let et = downwards_expected_types.pop().unwrap();
                assert_eq!(
                    message.variant_name(),
                    et,
                    "downwards type is expected: {et}"
                );
            }
            if let Message::Data(data) = message {
                let e = downwards_expected.pop().unwrap();
                assert_eq!(data, e, "downwards data is expected: {e}");
            }
        })
        .into(),
    );

    let source = make_source();
    let taken = take(3)(source);
    taken(Message::Handshake(sink));

    let nursery_out = nursery.timeout(Duration::from_millis(700), nursery_out);
    drop(nursery);
    nursery_out.await.ok();
}

/// See <https://github.com/staltz/callbag-take/blob/6ae7755ea5f014306704450a40eb72ffdb21d308/test.js#L157-L216>
#[cfg(not(all(target_arch = "wasm32", target_os = "wasi")))]
#[tracing::instrument]
#[test_log::test(async_std::test)]
#[cfg_attr(
    all(
        all(target_arch = "wasm32", not(target_os = "wasi")),
        feature = "browser",
    ),
    wasm_bindgen_test
)]
async fn it_returns_a_source_that_disposes_upon_upwards_end() {
    let (nursery, nursery_out) = Nursery::new(async_executors::AsyncStd);
    let nursery = nursery.in_current_span();

    let upwards_expected = ["Handshake", "Terminate"];
    let upwards_expected = {
        let q = ArrayQueue::new(upwards_expected.len());
        for v in upwards_expected {
            q.push(v).ok();
        }
        Arc::new(q)
    };
    let downwards_expected_types = ["Handshake", "Data", "Data", "Data"];
    let downwards_expected_types = {
        let q = ArrayQueue::new(downwards_expected_types.len());
        for v in downwards_expected_types {
            q.push(v).ok();
        }
        Arc::new(q)
    };
    let downwards_expected = [10, 20, 30];
    let downwards_expected = {
        let q = ArrayQueue::new(downwards_expected.len());
        for v in downwards_expected {
            q.push(v).ok();
        }
        Arc::new(q)
    };

    let make_source = {
        let nursery = nursery.clone();
        move || {
            let sent = Arc::new(AtomicUsize::new(0));
            let interval_cleared = Arc::new(AtomicBool::new(false));
            let source_ref: Arc<RwLock<Option<Arc<Source<_>>>>> = Arc::new(RwLock::new(None));
            let source = Arc::new(
                {
                    let source_ref = Arc::clone(&source_ref);
                    move |message: Message<Never, _>| {
                        info!("up: {message:?}");
                        let interval_cleared = Arc::clone(&interval_cleared);
                        {
                            let e = upwards_expected.pop().unwrap();
                            assert_eq!(message.variant_name(), e, "upwards type is expected: {e}");
                        }
                        if let Message::Handshake(sink) = message {
                            nursery
                                .nurse({
                                    let nursery = nursery.clone();
                                    let sent = Arc::clone(&sent);
                                    let sink = Arc::clone(&sink);
                                    const DURATION: Duration = Duration::from_millis(100);
                                    async move {
                                        loop {
                                            nursery.sleep(DURATION).await;
                                            if interval_cleared.load(AtomicOrdering::Acquire) {
                                                break;
                                            }
                                            let sent =
                                                sent.fetch_add(1, AtomicOrdering::AcqRel) + 1;
                                            sink(Message::Data(sent * 10));
                                        }
                                    }
                                })
                                .unwrap();
                            let source = {
                                let source_ref = &mut *source_ref.write().unwrap();
                                source_ref.take().unwrap()
                            };
                            sink(Message::Handshake(source));
                        } else if let Message::Error(_) | Message::Terminate = message {
                            interval_cleared.store(true, AtomicOrdering::Release);
                        }
                    }
                }
                .into(),
            );
            {
                let mut source_ref = source_ref.write().unwrap();
                *source_ref = Some(Arc::clone(&source));
            }
            source
        }
    };

    let make_sink = move || {
        let talkback = ArcSwapOption::from(None);
        Arc::new(
            (move |message: Message<_, Never>| {
                info!("down: {message:?}");
                {
                    let et = downwards_expected_types.pop().unwrap();
                    assert_eq!(
                        message.variant_name(),
                        et,
                        "downwards type is expected: {et}"
                    );
                }
                if let Message::Handshake(source) = message {
                    talkback.store(Some(source));
                } else if let Message::Data(data) = message {
                    let e = downwards_expected.pop().unwrap();
                    assert_eq!(data, e, "downwards data is expected: {e}");
                }
                if downwards_expected.is_empty() {
                    let talkback = talkback.load();
                    let talkback = talkback.as_ref().unwrap();
                    talkback(Message::Terminate);
                }
            })
            .into(),
        )
    };

    let source = make_source();
    let taken = take(9)(source);
    let sink = make_sink();
    taken(Message::Handshake(sink));

    let nursery_out = nursery.timeout(Duration::from_millis(700), nursery_out);
    drop(nursery);
    nursery_out.await.ok();
}

/// See <https://github.com/staltz/callbag-take/blob/6ae7755ea5f014306704450a40eb72ffdb21d308/test.js#L218-L283>
#[tracing::instrument]
#[test_log::test]
#[cfg_attr(
    all(target_arch = "wasm32", not(target_os = "wasi")),
    wasm_bindgen_test
)]
fn it_does_not_redundantly_terminate_a_synchronous_pullable_source() {
    let terminations = Arc::new(AtomicUsize::new(0));

    let upwards_expected = ["Pull", "Pull", "Pull", "Terminate"];
    let upwards_expected = {
        let q = ArrayQueue::new(upwards_expected.len());
        for v in upwards_expected {
            q.push(v).ok();
        }
        Arc::new(q)
    };
    let downwards_expected_types = ["Handshake", "Data", "Data", "Data", "Terminate"];
    let downwards_expected_types = {
        let q = ArrayQueue::new(downwards_expected_types.len());
        for v in downwards_expected_types {
            q.push(v).ok();
        }
        Arc::new(q)
    };
    let downwards_expected = [7, 8, 9];
    let downwards_expected = {
        let q = ArrayQueue::new(downwards_expected.len());
        for v in downwards_expected {
            q.push(v).ok();
        }
        Arc::new(q)
    };

    let range_infinite = {
        let terminations = Arc::clone(&terminations);
        move |start| {
            Arc::new(
                (move |message| {
                    info!("up: {message:?}");
                    let terminations = Arc::clone(&terminations);
                    let upwards_expected = Arc::clone(&upwards_expected);
                    if let Message::Handshake(sink) = message {
                        let counter = Arc::new(AtomicUsize::new(start));
                        sink(Message::Handshake(Arc::new(
                            {
                                let sink = Arc::clone(&sink);
                                move |message: Message<Never, _>| {
                                    info!("up: {message:?}");
                                    {
                                        let e = upwards_expected.pop().unwrap();
                                        assert_eq!(
                                            message.variant_name(),
                                            e,
                                            "upwards type is expected: {e}"
                                        );
                                    }
                                    if let Message::Pull = message {
                                        let counter = counter.fetch_add(1, AtomicOrdering::AcqRel);
                                        sink(Message::Data(counter));
                                    } else if let Message::Error(_) | Message::Terminate = message {
                                        terminations.fetch_add(1, AtomicOrdering::AcqRel);
                                    }
                                }
                            }
                            .into(),
                        )));
                    }
                })
                .into(),
            )
        }
    };

    let make_sink = move || {
        let talkback = ArcSwapOption::from(None);
        Arc::new(
            (move |message: Message<_, Never>| {
                info!("down: {message:?}");
                {
                    let et = downwards_expected_types.pop().unwrap();
                    assert_eq!(
                        message.variant_name(),
                        et,
                        "downwards type is expected: {et}"
                    );
                }
                if let Message::Handshake(source) = message {
                    talkback.store(Some(source));
                    let talkback = talkback.load();
                    let talkback = talkback.as_ref().unwrap();
                    talkback(Message::Pull);
                } else if let Message::Data(data) = message {
                    {
                        let e = downwards_expected.pop().unwrap();
                        assert_eq!(data, e, "downwards data is expected: {e}");
                    }
                    let talkback = talkback.load();
                    let talkback = talkback.as_ref().unwrap();
                    talkback(Message::Pull);
                }
            })
            .into(),
        )
    };

    let source = range_infinite(7);
    let taken = take(3)(source);
    let sink = make_sink();
    taken(Message::Handshake(sink));

    assert_eq!(
        terminations.load(AtomicOrdering::Acquire),
        1,
        "only 1 source termination happened"
    );
}

/// See <https://github.com/staltz/callbag-take/blob/6ae7755ea5f014306704450a40eb72ffdb21d308/test.js#L285-L351>
#[tracing::instrument]
#[test_log::test]
#[cfg_attr(
    all(target_arch = "wasm32", not(target_os = "wasi")),
    wasm_bindgen_test
)]
fn it_does_not_mutually_terminate_a_sink() {
    let terminations = Arc::new(AtomicUsize::new(0));
    let logger_terminations = Arc::new(AtomicUsize::new(0));

    let range_infinite = {
        let terminations = Arc::clone(&terminations);
        move |start| {
            Arc::new(
                (move |message| {
                    info!("up: {message:?}");
                    let terminations = Arc::clone(&terminations);
                    if let Message::Handshake(sink) = message {
                        let counter = Arc::new(AtomicUsize::new(start));
                        sink(Message::Handshake(Arc::new(
                            {
                                let sink = Arc::clone(&sink);
                                move |message| {
                                    info!("up: {message:?}");
                                    if let Message::Pull = message {
                                        let counter = counter.fetch_add(1, AtomicOrdering::AcqRel);
                                        sink(Message::Data(counter));
                                    } else if let Message::Error(_) | Message::Terminate = message {
                                        terminations.fetch_add(1, AtomicOrdering::AcqRel);
                                    }
                                }
                            }
                            .into(),
                        )));
                    }
                })
                .into(),
            )
        }
    };

    let make_sink = move || {
        let talkback = ArcSwapOption::from(None);
        Arc::new(
            (move |message| {
                info!("down: {message:?}");
                if let Message::Handshake(source) = message {
                    talkback.store(Some(source));
                    let talkback = talkback.load();
                    let talkback = talkback.as_ref().unwrap();
                    talkback(Message::Pull);
                } else if let Message::Data(_data) = message {
                    let talkback = talkback.load();
                    let talkback = talkback.as_ref().unwrap();
                    talkback(Message::Pull);
                }
            })
            .into(),
        )
    };

    let logger = {
        let logger_terminations = Arc::clone(&logger_terminations);
        move |source: Source<usize>| {
            Arc::new(
                (move |message| {
                    info!("logger: {message:?}");
                    let logger_terminations = Arc::clone(&logger_terminations);
                    if let Message::Handshake(sink) = message {
                        let source_talkback: Arc<ArcSwapOption<Source<usize>>> =
                            Arc::new(ArcSwapOption::from(None));
                        let talkback = Arc::new(
                            {
                                let logger_terminations = Arc::clone(&logger_terminations);
                                let source_talkback = Arc::clone(&source_talkback);
                                move |message| {
                                    info!("logger (from down): {message:?}");
                                    if let Message::Error(_) | Message::Terminate = message {
                                        logger_terminations.fetch_add(1, AtomicOrdering::AcqRel);
                                    }
                                    let source_talkback = source_talkback.load();
                                    let source_talkback = source_talkback.as_ref().unwrap();
                                    source_talkback(message);
                                }
                            }
                            .into(),
                        );
                        source(Message::Handshake(Arc::new(
                            (move |message| {
                                info!("logger (from up): {message:?}");
                                if let Message::Error(_) | Message::Terminate = message {
                                    logger_terminations.fetch_add(1, AtomicOrdering::AcqRel);
                                } else if let Message::Handshake(source) = message {
                                    source_talkback.store(Some(source));
                                    sink(Message::Handshake(Arc::clone(&talkback)));
                                } else {
                                    sink(message);
                                }
                            })
                            .into(),
                        )));
                    }
                })
                .into(),
            )
        }
    };

    let source = range_infinite(7);
    let taken = take(3)(logger(take(3)(source)));
    let sink = make_sink();
    taken(Message::Handshake(sink));

    assert_eq!(
        terminations.load(AtomicOrdering::Acquire),
        1,
        "only 1 source termination happened"
    );
    assert_eq!(
        logger_terminations.load(AtomicOrdering::Acquire),
        1,
        "logger only observed 1 termination"
    );
}