use crate::*;
use JackState::*;

/// Implement [Jack] constructor and methods
impl<'j> Jack<'j> {

    /// Register new [Client] and wrap it for shared use.
    pub fn new_run <T: HasJack<'j> + Audio + Send + Sync + 'static> (
        name: &impl AsRef<str>,
        init: impl FnOnce(Jack<'j>)->Usually<T>
    ) -> Usually<Arc<RwLock<T>>> {
        Jack::new(name)?.run(init)
    }

    pub fn new (name: &impl AsRef<str>) -> Usually<Self> {
        let client = Client::new(name.as_ref(), ClientOptions::NO_START_SERVER)?.0;
        Ok(Jack(Arc::new(RwLock::new(JackState::Inactive(client)))))
    }

    pub fn run <T: HasJack<'j> + Audio + Send + Sync + 'static>
        (self, init: impl FnOnce(Self)->Usually<T>) -> Usually<Arc<RwLock<T>>>
    {
        let client_state = self.0.clone();
        let app: Arc<RwLock<T>> = Arc::new(RwLock::new(init(self)?));
        let mut state = Activating;
        std::mem::swap(&mut*client_state.write().unwrap(), &mut state);
        if let Inactive(client) = state {
            // This is the misc notifications handler. It's a struct that wraps a [Box]
            // which performs type erasure on a callback that takes [JackEvent], which is
            // one of the available misc notifications.
            let notify = JackNotify(Box::new({
                let app = app.clone();
                move|event|(&mut*app.write().unwrap()).handle(event)
            }) as BoxedJackEventHandler);
            // This is the main processing handler. It's a struct that wraps a [Box]
            // which performs type erasure on a callback that takes [Client] and [ProcessScope]
            // and passes them down to the `app`'s `process` callback, which in turn
            // implements audio and MIDI input and output on a realtime basis.
            let process = ClosureProcessHandler::new(Box::new({
                let app = app.clone();
                move|c: &_, s: &_|if let Ok(mut app) = app.write() {
                    app.process(c, s)
                } else {
                    Control::Quit
                }
            }) as BoxedAudioHandler);
            // Launch a client with the two handlers.
            *client_state.write().unwrap() = Active(
                client.activate_async(notify, process)?
            );
        } else {
            unreachable!();
        }
        Ok(app)
    }

    /// Run something with the client.
    pub fn with_client <T> (&self, op: impl FnOnce(&Client)->T) -> T {
        match &*self.0.read().unwrap() {
            Inert            => panic!("jack client not activated"),
            Inactive(client) => op(client),
            Activating       => panic!("jack client has not finished activation"),
            Active(client)   => op(client.as_client()),
        }
    }
}

impl<'j> HasJack<'j> for Jack<'j> {
    fn jack (&self) -> &Jack<'j> {
        self
    }
}

impl<'j> HasJack<'j> for &Jack<'j> {
    fn jack (&self) -> &Jack<'j> {
        self
    }
}

impl<T: Fn(JackEvent) + Send> NotificationHandler for JackNotify<T> {
    fn thread_init(&self, _: &Client) {
        self.0(JackEvent::ThreadInit);
    }
    unsafe fn shutdown(&mut self, status: ClientStatus, reason: &str) {
        self.0(JackEvent::Shutdown(status, reason.into()));
    }
    fn freewheel(&mut self, _: &Client, enabled: bool) {
        self.0(JackEvent::Freewheel(enabled));
    }
    fn sample_rate(&mut self, _: &Client, frames: Frames) -> Control {
        self.0(JackEvent::SampleRate(frames));
        Control::Quit
    }
    fn client_registration(&mut self, _: &Client, name: &str, reg: bool) {
        self.0(JackEvent::ClientRegistration(name.into(), reg));
    }
    fn port_registration(&mut self, _: &Client, id: PortId, reg: bool) {
        self.0(JackEvent::PortRegistration(id, reg));
    }
    fn port_rename(&mut self, _: &Client, id: PortId, old: &str, new: &str) -> Control {
        self.0(JackEvent::PortRename(id, old.into(), new.into()));
        Control::Continue
    }
    fn ports_connected(&mut self, _: &Client, a: PortId, b: PortId, are: bool) {
        self.0(JackEvent::PortsConnected(a, b, are));
    }
    fn graph_reorder(&mut self, _: &Client) -> Control {
        self.0(JackEvent::GraphReorder);
        Control::Continue
    }
    fn xrun(&mut self, _: &Client) -> Control {
        self.0(JackEvent::XRun);
        Control::Continue
    }
}

impl JackPerfModel for PerfModel {
    fn update_from_jack_scope (&self, t0: Option<u64>, scope: &ProcessScope) {
        if let Some(t0) = t0 {
            let t1 = self.clock.raw();
            self.used.store(
                self.clock.delta_as_nanos(t0, t1) as f64,
                Relaxed,
            );
            self.window.store(
                scope.cycle_times().unwrap().period_usecs as f64,
                Relaxed,
            );
        }
    }
}