refactor(engine): flatten

- add `just stats`
- add basic doctests

engine/jack_structs.rs

@@ -0,0 +1,53 @@
+use crate::*;
+
+/// Wraps [JackState], and through it [jack::Client] when connected.
+///
+/// ```
+/// let jack: tek_engine::Jack = Default::default();
+/// ```
+#[derive(Clone, Debug, Default)]
+pub struct Jack<'j> (pub(crate) Arc<RwLock<JackState<'j>>>);
+
+/// This is a connection which may be [Inactive], [Activating], or [Active].
+/// In the [Active] and [Inactive] states, [JackState::client] returns a
+/// [jack::Client], which you can use to talk to the JACK API.
+///
+/// ```
+/// let state: tek_engine::JackState = Default::default();
+/// ```
+#[derive(Debug, Default)]
+pub enum JackState<'j> {
+    /// Unused
+    #[default] Inert,
+    /// Before activation.
+    Inactive(Client),
+    /// During activation.
+    Activating,
+    /// After activation. Must not be dropped for JACK thread to persist.
+    Active(DynamicAsyncClient<'j>),
+}
+
+/// Event enum for JACK events.
+///
+/// ```
+/// let event: tek_engine::JackState = JackEvent::XRun;
+/// ```
+#[derive(Debug, Clone, PartialEq)] pub enum JackEvent {
+    ThreadInit,
+    Shutdown(ClientStatus, Arc<str>),
+    Freewheel(bool),
+    SampleRate(Frames),
+    ClientRegistration(Arc<str>, bool),
+    PortRegistration(PortId, bool),
+    PortRename(PortId, Arc<str>, Arc<str>),
+    PortsConnected(PortId, PortId, bool),
+    GraphReorder,
+    XRun,
+}
+
+/// Generic notification handler that emits [JackEvent]
+///
+/// ```
+/// let notify = tek_engine::JackNotify(|_: JackEvent|{});
+/// ```
+pub struct JackNotify<T: Fn(JackEvent) + Send>(pub T);