From 2837ffff4abdc7052bfa9eafc8b93fd307e155f6 Mon Sep 17 00:00:00 2001
From: unspeaker <hora.nqma@protonmail.com>
Date: Sun, 30 Jun 2024 22:47:17 +0300
Subject: [PATCH] modularize core

---
 src/config.rs                           |   2 +-
 src/core/device.rs                      |  90 ++++++
 src/core/handle.rs                      |  89 ++++++
 src/core/jack.rs                        |  35 +++
 src/core/keymap.rs                      |  39 +++
 src/core/mod.rs                         | 121 ++++++++
 src/{layout/collect.rs => core/note.rs} |   0
 src/core/port.rs                        |  50 ++++
 src/core/process.rs                     |   0
 src/core/render.rs                      |  54 ++++
 src/{ => core}/time.rs                  |   3 +-
 src/device.rs                           | 370 ------------------------
 src/device/README.md                    |  21 --
 src/device/chain/mod.rs                 |   9 +-
 src/device/chain/plugin.rs              |   2 +-
 src/device/chain/plugin/lv2.rs          |   2 +-
 src/device/chain/plugin/vst2.rs         |   2 +-
 src/device/chain/sampler.rs             |   2 +-
 src/device/launcher/grid.rs             |   2 +-
 src/device/launcher/handle.rs           |   6 +-
 src/device/launcher/mod.rs              |  17 +-
 src/device/looper.rs                    |   2 +-
 src/device/mixer.rs                     |   3 +-
 src/device/mod.rs                       |   7 +
 src/device/sequencer/handle.rs          |   9 +-
 src/device/sequencer/horizontal.rs      |   2 +-
 src/device/sequencer/keys.rs            |   2 +-
 src/device/sequencer/mod.rs             |  97 ++-----
 src/device/sequencer/phrase.rs          |   3 +-
 src/device/sequencer/process.rs         |   7 +-
 src/device/sequencer/vertical.rs        |  13 +-
 src/device/track.rs                     |   4 +-
 src/device/transport.rs                 |  37 ++-
 src/draw.rs                             | 111 -------
 src/layout/container.rs                 |   3 +-
 src/layout/focus.rs                     |   3 +-
 src/layout/lozenge.rs                   |   2 +-
 src/layout/mod.rs                       |  25 +-
 src/layout/scroll.rs                    |   2 -
 src/layout/table.rs                     |   2 +-
 src/main.rs                             |  11 +-
 src/note.rs                             |  26 --
 src/prelude.rs                          | 112 -------
 43 files changed, 629 insertions(+), 770 deletions(-)
 create mode 100644 src/core/device.rs
 create mode 100644 src/core/handle.rs
 create mode 100644 src/core/jack.rs
 create mode 100644 src/core/keymap.rs
 create mode 100644 src/core/mod.rs
 rename src/{layout/collect.rs => core/note.rs} (100%)
 create mode 100644 src/core/port.rs
 create mode 100644 src/core/process.rs
 create mode 100644 src/core/render.rs
 rename src/{ => core}/time.rs (99%)
 delete mode 100644 src/device.rs
 delete mode 100644 src/device/README.md
 create mode 100644 src/device/mod.rs
 delete mode 100644 src/draw.rs
 delete mode 100644 src/note.rs
 delete mode 100644 src/prelude.rs

diff --git a/src/config.rs b/src/config.rs
index 6d245117..543965af 100644
--- a/src/config.rs
+++ b/src/config.rs
@@ -1,4 +1,4 @@
-use crate::prelude::*;
+use crate::core::*;
 
 const CONFIG_FILE_NAME:  &'static str = "tek.toml";
 const PROJECT_FILE_NAME: &'static str = "project.toml";
diff --git a/src/core/device.rs b/src/core/device.rs
new file mode 100644
index 00000000..18f9d6ba
--- /dev/null
+++ b/src/core/device.rs
@@ -0,0 +1,90 @@
+use crate::core::*;
+
+/// A UI component that may have presence on the JACK grap.
+pub trait Device: Render + Handle + PortList + Send + Sync {
+    fn boxed (self) -> Box<dyn Device> where Self: Sized + 'static {
+        Box::new(self)
+    }
+}
+
+/// All things that implement the required traits can be treated as `Device`.
+impl<T: Render + Handle + PortList + Send + Sync> Device for T {}
+
+/// A device dynamicammy composed of state and handlers.
+pub struct DynamicDevice<T> {
+    pub state:   Arc<Mutex<T>>,
+    pub render:  Mutex<Box<dyn FnMut(&T, &mut Buffer, Rect)->Usually<Rect> + Send>>,
+    pub handle:  Arc<Mutex<Box<dyn FnMut(&mut T, &AppEvent)->Usually<bool> + Send>>>,
+    pub process: Arc<Mutex<Box<dyn FnMut(&mut T, &Client, &ProcessScope)->Control + Send>>>,
+    pub client: Option<DynamicAsyncClient>
+}
+
+impl<T> Handle for DynamicDevice<T> {
+    fn handle (&mut self, event: &AppEvent) -> Usually<bool> {
+        self.handle.lock().unwrap()(&mut *self.state.lock().unwrap(), event)
+    }
+}
+
+impl<T> Render for DynamicDevice<T> {
+    fn render (&self, buf: &mut Buffer, area: Rect) -> Usually<Rect> {
+        self.render.lock().unwrap()(&*self.state.lock().unwrap(), buf, area)
+    }
+}
+
+impl<T: PortList + Send + Sync + 'static> PortList for DynamicDevice<T> {
+    fn audio_ins  (&self) -> Usually<Vec<String>> {
+        self.state().audio_ins()
+    }
+    fn audio_outs (&self) -> Usually<Vec<String>> {
+        self.state().audio_outs()
+    }
+    fn midi_ins   (&self) -> Usually<Vec<String>> {
+        self.state().midi_ins()
+    }
+    fn midi_outs  (&self) -> Usually<Vec<String>> {
+        self.state().midi_outs()
+    }
+}
+
+type DynamicAsyncClient    = AsyncClient<DynamicNotifications, DynamicProcessHandler>;
+type DynamicNotifications  = Notifications<Box<dyn Fn(AppEvent) + Send + Sync>>;
+type DynamicProcessHandler = ClosureProcessHandler<BoxedProcessHandler>;
+
+impl<T: Send + Sync + 'static> DynamicDevice<T> {
+    pub fn new <'a, R, H, P> (render: R, handle: H, process: P, state: T) -> Self where
+        R: FnMut(&T, &mut Buffer, Rect)    -> Usually<Rect> + Send + 'static,
+        H: FnMut(&mut T, &AppEvent)        -> Usually<bool> + Send + 'static,
+        P: FnMut(&mut T, &Client, &ProcessScope) -> Control + Send + 'static,
+    {
+        Self {
+            state:   Arc::new(Mutex::new(state)),
+            render:  Mutex::new(Box::new(render)),
+            handle:  Arc::new(Mutex::new(Box::new(handle))),
+            process: Arc::new(Mutex::new(Box::new(process))),
+            client:  None,
+        }
+    }
+    pub fn state (&self) -> std::sync::MutexGuard<'_, T> {
+        self.state.lock().unwrap()
+    }
+    pub fn activate (mut self, client: Client) -> Usually<Self> {
+        self.client = Some(client.activate_async(Notifications(Box::new({
+            let state  = self.state.clone();
+            let handle = self.handle.clone();
+            move|event|{
+                let mut state = state.lock().unwrap();
+                let mut handle = handle.lock().unwrap();
+                handle(&mut state, &event).unwrap();
+            }
+        }) as Box<dyn Fn(AppEvent) + Send + Sync>), ClosureProcessHandler::new(Box::new({
+            let state   = self.state.clone();
+            let process = self.process.clone();
+            move|client: &Client, scope: &ProcessScope|{
+                let mut state = state.lock().unwrap();
+                let mut process = process.lock().unwrap();
+                (process)(&mut state, client, scope)
+            }
+        }) as BoxedProcessHandler))?);
+        Ok(self)
+    }
+}
diff --git a/src/core/handle.rs b/src/core/handle.rs
new file mode 100644
index 00000000..f213256a
--- /dev/null
+++ b/src/core/handle.rs
@@ -0,0 +1,89 @@
+use crate::core::*;
+
+/// Trait for things that handle input events.
+pub trait Handle {
+    /// Handle an input event.
+    /// Returns Ok(true) if the device handled the event.
+    /// This is the mechanism which allows nesting of components;.
+    fn handle (&mut self, _e: &AppEvent) -> Usually<bool> {
+        Ok(false)
+    }
+}
+
+#[derive(Debug)]
+pub enum AppEvent {
+    /// Terminal input
+    Input(::crossterm::event::Event),
+    /// Update values but not the whole form.
+    Update,
+    /// Update the whole form.
+    Redraw,
+    /// Device gains focus
+    Focus,
+    /// Device loses focus
+    Blur,
+    /// JACK notification
+    Jack(JackEvent)
+}
+
+#[derive(Debug)]
+pub enum JackEvent {
+    ThreadInit,
+    Shutdown(ClientStatus, String),
+    Freewheel(bool),
+    SampleRate(Frames),
+    ClientRegistration(String, bool),
+    PortRegistration(PortId, bool),
+    PortRename(PortId, String, String),
+    PortsConnected(PortId, PortId, bool),
+    GraphReorder,
+    XRun,
+}
+
+pub struct Notifications<T: Fn(AppEvent) + Send>(pub T);
+
+impl<T: Fn(AppEvent) + Send> NotificationHandler for Notifications<T> {
+    fn thread_init (&self, _: &Client) {
+        self.0(AppEvent::Jack(JackEvent::ThreadInit));
+    }
+
+    fn shutdown (&mut self, status: ClientStatus, reason: &str) {
+        self.0(AppEvent::Jack(JackEvent::Shutdown(status, reason.into())));
+    }
+
+    fn freewheel (&mut self, _: &Client, enabled: bool) {
+        self.0(AppEvent::Jack(JackEvent::Freewheel(enabled)));
+    }
+
+    fn sample_rate (&mut self, _: &Client, frames: Frames) -> Control {
+        self.0(AppEvent::Jack(JackEvent::SampleRate(frames)));
+        Control::Quit
+    }
+
+    fn client_registration (&mut self, _: &Client, name: &str, reg: bool) {
+        self.0(AppEvent::Jack(JackEvent::ClientRegistration(name.into(), reg)));
+    }
+
+    fn port_registration (&mut self, _: &Client, id: PortId, reg: bool) {
+        self.0(AppEvent::Jack(JackEvent::PortRegistration(id, reg)));
+    }
+
+    fn port_rename (&mut self, _: &Client, id: PortId, old: &str, new: &str) -> Control {
+        self.0(AppEvent::Jack(JackEvent::PortRename(id, old.into(), new.into())));
+        Control::Continue
+    }
+
+    fn ports_connected (&mut self, _: &Client, a: PortId, b: PortId, are: bool) {
+        self.0(AppEvent::Jack(JackEvent::PortsConnected(a, b, are)));
+    }
+
+    fn graph_reorder (&mut self, _: &Client) -> Control {
+        self.0(AppEvent::Jack(JackEvent::GraphReorder));
+        Control::Continue
+    }
+
+    fn xrun (&mut self, _: &Client) -> Control {
+        self.0(AppEvent::Jack(JackEvent::XRun));
+        Control::Continue
+    }
+}
diff --git a/src/core/jack.rs b/src/core/jack.rs
new file mode 100644
index 00000000..4e877f66
--- /dev/null
+++ b/src/core/jack.rs
@@ -0,0 +1,35 @@
+use crate::core::*;
+
+pub type BoxedNotificationHandler =
+    Box<dyn Fn(AppEvent) + Send>;
+
+pub type BoxedProcessHandler =
+    Box<dyn FnMut(&Client, &ProcessScope)-> Control + Send>;
+
+pub type Jack<N> =
+    AsyncClient<N, ClosureProcessHandler<BoxedProcessHandler>>;
+
+pub use ::jack::{
+    AsyncClient,
+    AudioIn,
+    AudioOut,
+    Client,
+    ClientOptions,
+    ClientStatus,
+    ClosureProcessHandler,
+    Control,
+    Frames,
+    MidiIn,
+    MidiOut,
+    NotificationHandler,
+    Port,
+    PortFlags,
+    PortId,
+    PortSpec,
+    ProcessHandler,
+    ProcessScope,
+    RawMidi,
+    Transport,
+    TransportState,
+    TransportStatePosition
+};
diff --git a/src/core/keymap.rs b/src/core/keymap.rs
new file mode 100644
index 00000000..d9ea4919
--- /dev/null
+++ b/src/core/keymap.rs
@@ -0,0 +1,39 @@
+use crate::core::*;
+
+pub type KeyHandler<T> = &'static dyn Fn(&mut T)->Usually<bool>;
+
+pub type KeyBinding<T> = (
+    KeyCode, KeyModifiers, &'static str, &'static str, KeyHandler<T>
+);
+
+pub type KeyMap<T> = [KeyBinding<T>];
+
+pub fn handle_keymap <T> (
+    state: &mut T, event: &AppEvent, keymap: &KeyMap<T>,
+) -> Usually<bool> {
+    match event {
+        AppEvent::Input(Event::Key(event)) => {
+            for (code, modifiers, _, _, command) in keymap.iter() {
+                if *code == event.code && modifiers.bits() == event.modifiers.bits() {
+                    return command(state)
+                }
+            }
+        },
+        _ => {}
+    };
+    Ok(false)
+}
+
+#[macro_export] macro_rules! key {
+    ($k:ident $(($char:literal))?, $m:ident, $n: literal, $d: literal, $f: expr) => {
+        (KeyCode::$k $(($char))?, KeyModifiers::$m, $n, $d, &$f)
+    };
+}
+
+#[macro_export] macro_rules! keymap {
+    ($T:ty { $([$k:ident $(($char:literal))?, $m:ident, $n: literal, $d: literal, $f: expr]),* $(,)? }) => {
+        &[
+            $((KeyCode::$k $(($char))?, KeyModifiers::$m, $n, $d, &$f as KeyHandler<$T>)),*
+        ] as &'static [KeyBinding<$T>]
+    }
+}
diff --git a/src/core/mod.rs b/src/core/mod.rs
new file mode 100644
index 00000000..b55650b9
--- /dev/null
+++ b/src/core/mod.rs
@@ -0,0 +1,121 @@
+pub type Usually<T> = Result<T, Box<dyn Error>>;
+
+macro_rules! submod {
+    ($($name:ident)*) => { $(mod $name; pub use self::$name::*;)* };
+}
+
+submod!( device handle jack keymap note port process render time );
+
+pub use std::error::Error;
+pub use std::io::{stdout, Stdout, Write};
+pub use std::thread::{spawn, JoinHandle};
+pub use std::time::Duration;
+pub use std::collections::BTreeMap;
+pub use std::sync::{
+    Arc,
+    Mutex, MutexGuard,
+    atomic::{
+        Ordering,
+        AtomicBool,
+        AtomicUsize
+    }, 
+    mpsc::{self, channel, Sender, Receiver}
+};
+
+pub use ::crossterm::{
+    ExecutableCommand, QueueableCommand,
+    event::{Event, KeyEvent, KeyCode, KeyModifiers},
+    terminal::{
+        self,
+        Clear, ClearType,
+        EnterAlternateScreen, LeaveAlternateScreen,
+        enable_raw_mode, disable_raw_mode
+    },
+};
+
+pub use ::ratatui::{
+    prelude::{
+        Buffer, Rect, Style, Color, CrosstermBackend, Layout, Stylize, Direction,
+        Line, Constraint
+    },
+    widgets::{Widget, WidgetRef},
+    //style::Stylize,
+};
+
+pub use ::midly::{
+    MidiMessage,
+    live::LiveEvent,
+    num::u7
+};
+
+pub use crate::{key, keymap};
+
+/// Run a device as the root of the app.
+pub fn run (device: impl Device + Send + Sync + 'static) -> Result<(), Box<dyn Error>> {
+    let device = Arc::new(Mutex::new(device));
+    let exited = Arc::new(AtomicBool::new(false));
+
+    // Spawn input (handle) thread
+    let _input_thread = {
+        let poll = std::time::Duration::from_millis(100);
+        let exited = exited.clone();
+        let device = device.clone();
+        spawn(move || loop {
+            // Exit if flag is set
+            if exited.fetch_and(true, Ordering::Relaxed) {
+                break
+            }
+            // Listen for events and send them to the main thread
+            if ::crossterm::event::poll(poll).is_ok() {
+                let event = ::crossterm::event::read().unwrap();
+                match event {
+                    Event::Key(KeyEvent {
+                        code:      KeyCode::Char('c'),
+                        modifiers: KeyModifiers::CONTROL,
+                        ..
+                    }) => {
+                        exited.store(true, Ordering::Relaxed);
+                    },
+                    _ => if device.lock().unwrap().handle(&AppEvent::Input(event)).is_err() {
+                        break
+                    }
+                }
+            }
+        })
+    };
+
+    // Set up terminal
+    stdout().execute(EnterAlternateScreen)?;
+    enable_raw_mode()?;
+    let mut terminal = ratatui::Terminal::new(CrosstermBackend::new(stdout()))?;
+
+    // Set up panic hook
+    let better_panic_handler = better_panic::Settings::auto()
+        .verbosity(better_panic::Verbosity::Full)
+        .create_panic_handler();
+    std::panic::set_hook(Box::new(move |info: &std::panic::PanicInfo|{
+        stdout().execute(LeaveAlternateScreen).unwrap();
+        crossterm::terminal::disable_raw_mode().unwrap();
+        better_panic_handler(info);
+    }));
+
+    // Main (render) loop
+    let sleep = std::time::Duration::from_millis(16);
+    loop {
+        terminal.draw(|frame|{
+            let area = frame.size();
+            let buffer = frame.buffer_mut();
+            device.lock().unwrap().render(buffer, area).expect("Failed to render content.");
+        }).expect("Failed to render frame");
+        if exited.fetch_and(true, Ordering::Relaxed) {
+            break
+        }
+        std::thread::sleep(sleep);
+    };
+
+    // Cleanup
+    stdout().execute(LeaveAlternateScreen)?;
+    crossterm::terminal::disable_raw_mode()?;
+
+    Ok(())
+}
diff --git a/src/layout/collect.rs b/src/core/note.rs
similarity index 100%
rename from src/layout/collect.rs
rename to src/core/note.rs
diff --git a/src/core/port.rs b/src/core/port.rs
new file mode 100644
index 00000000..ee6b7243
--- /dev/null
+++ b/src/core/port.rs
@@ -0,0 +1,50 @@
+use crate::core::*;
+
+/// Trait for things that may expose JACK ports.
+pub trait PortList {
+    fn audio_ins  (&self) -> Usually<Vec<String>> {
+        Ok(vec![])
+    }
+    fn audio_outs (&self) -> Usually<Vec<String>> {
+        Ok(vec![])
+    }
+    fn midi_ins   (&self) -> Usually<Vec<String>> {
+        Ok(vec![])
+    }
+    fn midi_outs  (&self) -> Usually<Vec<String>> {
+        Ok(vec![])
+    }
+    fn connect (&mut self, _connect: bool, _source: &str, _target: &str)
+        -> Usually<()>
+    {
+        Ok(())
+    }
+    fn connect_all (&mut self, connections: &[(bool, &str, &str)])
+        -> Usually<()>
+    {
+        for (connect, source, target) in connections.iter() {
+            self.connect(*connect, source, target)?;
+        }
+        Ok(())
+    }
+}
+
+pub struct DevicePort<T: PortSpec> {
+    pub name:    String,
+    pub port:    Port<T>,
+    pub connect: Vec<String>,
+}
+
+impl<T: PortSpec + Default> DevicePort<T> {
+    pub fn new (client: &Client, name: &str, connect: &[&str]) -> Usually<Self> {
+        let mut connects = vec![];
+        for port in connect.iter() {
+            connects.push(port.to_string());
+        }
+        Ok(Self {
+            name: name.to_string(),
+            port: client.register_port(name, T::default())?,
+            connect: connects,
+        })
+    }
+}
diff --git a/src/core/process.rs b/src/core/process.rs
new file mode 100644
index 00000000..e69de29b
diff --git a/src/core/render.rs b/src/core/render.rs
new file mode 100644
index 00000000..5560a6d3
--- /dev/null
+++ b/src/core/render.rs
@@ -0,0 +1,54 @@
+use crate::core::*;
+
+/// Trait for things that render to the display.
+pub trait Render {
+    // Render something to an area of the buffer.
+    // Returns area used by component.
+    // This is insufficient but for the most basic dynamic layout algorithms.
+    fn render (&self, _b: &mut Buffer, _a: Rect) -> Usually<Rect> {
+        Ok(Rect { x: 0, y: 0, width: 0, height: 0 })
+    }
+    fn min_width (&self) -> u16 {
+        0
+    }
+    fn max_width (&self) -> u16 {
+        u16::MAX
+    }
+    fn min_height (&self) -> u16 {
+        0
+    }
+    fn max_height (&self) -> u16 {
+        u16::MAX
+    }
+}
+
+impl Render for Box<dyn Device> {
+    fn render (&self, b: &mut Buffer, a: Rect) -> Usually<Rect> {
+        (**self).render(b, a)
+    }
+}
+
+impl WidgetRef for &dyn Render {
+    fn render_ref (&self, area: Rect, buf: &mut Buffer) {
+        Render::render(*self, buf, area).expect("Failed to render device.");
+    }
+}
+
+impl WidgetRef for dyn Render {
+    fn render_ref (&self, area: Rect, buf: &mut Buffer) {
+        Render::render(self, buf, area).expect("Failed to render device.");
+    }
+}
+
+pub trait Blit {
+    // Render something to X, Y coordinates in a buffer, ignoring width/height.
+    fn blit (&self, buf: &mut Buffer, x: u16, y: u16, style: Option<Style>);
+}
+
+impl<T: AsRef<str>> Blit for T {
+    fn blit (&self, buf: &mut Buffer, x: u16, y: u16, style: Option<Style>) {
+        if x < buf.area.width && y < buf.area.height {
+            buf.set_string(x, y, self.as_ref(), style.unwrap_or(Style::default()))
+        }
+    }
+}
diff --git a/src/time.rs b/src/core/time.rs
similarity index 99%
rename from src/time.rs
rename to src/core/time.rs
index 5e6854e1..e65ddbab 100644
--- a/src/time.rs
+++ b/src/core/time.rs
@@ -1,4 +1,4 @@
-use crate::prelude::*;
+use crate::core::*;
 
 pub struct Timebase {
     /// Frames per second
@@ -144,3 +144,4 @@ impl Timebase {
             .collect()
     }
 }
+
diff --git a/src/device.rs b/src/device.rs
deleted file mode 100644
index 8225eec5..00000000
--- a/src/device.rs
+++ /dev/null
@@ -1,370 +0,0 @@
-use crate::prelude::*;
-
-mod chain;
-mod launcher;
-mod looper;
-mod mixer;
-mod sequencer;
-mod track;
-mod transport;
-
-pub use self::track::Track;
-pub use self::launcher::{Launcher, Scene};
-pub use self::sequencer::{Sequencer, Phrase};
-pub use self::chain::{Chain, Plugin, Sampler, Sample, Voice};
-
-pub use self::looper::Looper;
-pub use self::mixer::Mixer;
-pub use self::transport::Transport;
-
-use crossterm::event;
-use ::jack::{Port, PortSpec, Client};
-
-/// A UI component that may have presence on the JACK grap.
-pub trait Device: Render + Handle + PortList + Send + Sync {
-    fn boxed (self) -> Box<dyn Device> where Self: Sized + 'static {
-        Box::new(self)
-    }
-}
-
-/// All things that implement the required traits can be treated as `Device`.
-impl<T: Render + Handle + PortList + Send + Sync> Device for T {}
-
-/// Run a device as the root of the app.
-pub fn run (device: impl Device + Send + Sync + 'static) -> Result<(), Box<dyn Error>> {
-    let device = Arc::new(Mutex::new(device));
-    let exited = Arc::new(AtomicBool::new(false));
-
-    // Spawn input (handle) thread
-    let _input_thread = {
-        let poll = std::time::Duration::from_millis(100);
-        let exited = exited.clone();
-        let device = device.clone();
-        spawn(move || loop {
-            // Exit if flag is set
-            if exited.fetch_and(true, Ordering::Relaxed) {
-                break
-            }
-            // Listen for events and send them to the main thread
-            if event::poll(poll).is_ok() {
-                let event = event::read().unwrap();
-                match event {
-                    Event::Key(KeyEvent {
-                        code:      KeyCode::Char('c'),
-                        modifiers: KeyModifiers::CONTROL,
-                        ..
-                    }) => {
-                        exited.store(true, Ordering::Relaxed);
-                    },
-                    _ => if device.lock().unwrap().handle(&AppEvent::Input(event)).is_err() {
-                        break
-                    }
-                }
-            }
-        })
-    };
-
-    // Set up terminal
-    stdout().execute(EnterAlternateScreen)?;
-    enable_raw_mode()?;
-    let mut terminal = ratatui::Terminal::new(CrosstermBackend::new(stdout()))?;
-
-    // Set up panic hook
-    let better_panic_handler = better_panic::Settings::auto()
-        .verbosity(better_panic::Verbosity::Full)
-        .create_panic_handler();
-    std::panic::set_hook(Box::new(move |info: &std::panic::PanicInfo|{
-        stdout().execute(LeaveAlternateScreen).unwrap();
-        crossterm::terminal::disable_raw_mode().unwrap();
-        better_panic_handler(info);
-    }));
-
-    // Main (render) loop
-    let sleep = std::time::Duration::from_millis(16);
-    loop {
-        terminal.draw(|frame|{
-            let area = frame.size();
-            let buffer = frame.buffer_mut();
-            device.lock().unwrap().render(buffer, area).expect("Failed to render content.");
-        }).expect("Failed to render frame");
-        if exited.fetch_and(true, Ordering::Relaxed) {
-            break
-        }
-        std::thread::sleep(sleep);
-    };
-
-    // Cleanup
-    stdout().execute(LeaveAlternateScreen)?;
-    crossterm::terminal::disable_raw_mode()?;
-
-    Ok(())
-}
-
-/// Trait for things that handle input events.
-pub trait Handle {
-    /// Handle an input event.
-    /// Returns Ok(true) if the device handled the event.
-    /// This is the mechanism which allows nesting of components;.
-    fn handle (&mut self, _e: &AppEvent) -> Usually<bool> {
-        Ok(false)
-    }
-}
-
-#[derive(Debug)]
-pub enum AppEvent {
-    /// Terminal input
-    Input(::crossterm::event::Event),
-    /// Update values but not the whole form.
-    Update,
-    /// Update the whole form.
-    Redraw,
-    /// Device gains focus
-    Focus,
-    /// Device loses focus
-    Blur,
-    /// JACK notification
-    Jack(JackEvent)
-}
-
-/// Trait for things that render to the display.
-pub trait Render {
-    // Render something to an area of the buffer.
-    // Returns area used by component.
-    // This is insufficient but for the most basic dynamic layout algorithms.
-    fn render (&self, _b: &mut Buffer, _a: Rect) -> Usually<Rect> {
-        Ok(Rect { x: 0, y: 0, width: 0, height: 0 })
-    }
-    fn min_width (&self) -> u16 {
-        0
-    }
-    fn max_width (&self) -> u16 {
-        u16::MAX
-    }
-    fn min_height (&self) -> u16 {
-        0
-    }
-    fn max_height (&self) -> u16 {
-        u16::MAX
-    }
-}
-
-impl Render for Box<dyn Device> {
-    fn render (&self, b: &mut Buffer, a: Rect) -> Usually<Rect> {
-        (**self).render(b, a)
-    }
-}
-
-impl WidgetRef for &dyn Render {
-    fn render_ref (&self, area: Rect, buf: &mut Buffer) {
-        Render::render(*self, buf, area).expect("Failed to render device.");
-    }
-}
-
-impl WidgetRef for dyn Render {
-    fn render_ref (&self, area: Rect, buf: &mut Buffer) {
-        Render::render(self, buf, area).expect("Failed to render device.");
-    }
-}
-
-pub trait Blit {
-    // Render something to X, Y coordinates in a buffer, ignoring width/height.
-    fn blit (&self, buf: &mut Buffer, x: u16, y: u16, style: Option<Style>);
-}
-
-impl<T: AsRef<str>> Blit for T {
-    fn blit (&self, buf: &mut Buffer, x: u16, y: u16, style: Option<Style>) {
-        if x < buf.area.width && y < buf.area.height {
-            buf.set_string(x, y, self.as_ref(), style.unwrap_or(Style::default()))
-        }
-    }
-}
-
-/// Trait for things that may expose JACK ports.
-pub trait PortList {
-    fn audio_ins  (&self) -> Usually<Vec<String>> {
-        Ok(vec![])
-    }
-    fn audio_outs (&self) -> Usually<Vec<String>> {
-        Ok(vec![])
-    }
-    fn midi_ins   (&self) -> Usually<Vec<String>> {
-        Ok(vec![])
-    }
-    fn midi_outs  (&self) -> Usually<Vec<String>> {
-        Ok(vec![])
-    }
-    fn connect (&mut self, _connect: bool, _source: &str, _target: &str)
-        -> Usually<()>
-    {
-        Ok(())
-    }
-    fn connect_all (&mut self, connections: &[(bool, &str, &str)])
-        -> Usually<()>
-    {
-        for (connect, source, target) in connections.iter() {
-            self.connect(*connect, source, target)?;
-        }
-        Ok(())
-    }
-}
-
-pub struct DevicePort<T: PortSpec> {
-    pub name:    String,
-    pub port:    Port<T>,
-    pub connect: Vec<String>,
-}
-
-impl<T: PortSpec + Default> DevicePort<T> {
-    pub fn new (client: &Client, name: &str, connect: &[&str]) -> Usually<Self> {
-        let mut connects = vec![];
-        for port in connect.iter() {
-            connects.push(port.to_string());
-        }
-        Ok(Self {
-            name: name.to_string(),
-            port: client.register_port(name, T::default())?,
-            connect: connects,
-        })
-    }
-}
-
-/// A device dynamicammy composed of state and handlers.
-pub struct DynamicDevice<T> {
-    pub state:   Arc<Mutex<T>>,
-    pub render:  Mutex<Box<dyn FnMut(&T, &mut Buffer, Rect)->Usually<Rect> + Send>>,
-    pub handle:  Arc<Mutex<Box<dyn FnMut(&mut T, &AppEvent)->Usually<bool> + Send>>>,
-    pub process: Arc<Mutex<Box<dyn FnMut(&mut T, &Client, &ProcessScope)->Control + Send>>>,
-    pub client: Option<DynamicAsyncClient>
-}
-
-impl<T> Handle for DynamicDevice<T> {
-    fn handle (&mut self, event: &AppEvent) -> Usually<bool> {
-        self.handle.lock().unwrap()(&mut *self.state.lock().unwrap(), event)
-    }
-}
-
-impl<T> Render for DynamicDevice<T> {
-    fn render (&self, buf: &mut Buffer, area: Rect) -> Usually<Rect> {
-        self.render.lock().unwrap()(&*self.state.lock().unwrap(), buf, area)
-    }
-}
-
-impl<T: PortList + Send + Sync + 'static> PortList for DynamicDevice<T> {
-    fn audio_ins  (&self) -> Usually<Vec<String>> {
-        self.state().audio_ins()
-    }
-    fn audio_outs (&self) -> Usually<Vec<String>> {
-        self.state().audio_outs()
-    }
-    fn midi_ins   (&self) -> Usually<Vec<String>> {
-        self.state().midi_ins()
-    }
-    fn midi_outs  (&self) -> Usually<Vec<String>> {
-        self.state().midi_outs()
-    }
-}
-
-type DynamicAsyncClient    = AsyncClient<DynamicNotifications, DynamicProcessHandler>;
-type DynamicNotifications  = Notifications<Box<dyn Fn(AppEvent) + Send + Sync>>;
-type DynamicProcessHandler = ClosureProcessHandler<BoxedProcessHandler>;
-
-impl<T: Send + Sync + 'static> DynamicDevice<T> {
-    fn new <'a, R, H, P> (render: R, handle: H, process: P, state: T) -> Self where
-        R: FnMut(&T, &mut Buffer, Rect)    -> Usually<Rect> + Send + 'static,
-        H: FnMut(&mut T, &AppEvent)        -> Usually<bool> + Send + 'static,
-        P: FnMut(&mut T, &Client, &ProcessScope) -> Control + Send + 'static,
-    {
-        Self {
-            state:   Arc::new(Mutex::new(state)),
-            render:  Mutex::new(Box::new(render)),
-            handle:  Arc::new(Mutex::new(Box::new(handle))),
-            process: Arc::new(Mutex::new(Box::new(process))),
-            client:  None,
-        }
-    }
-    pub fn state (&self) -> std::sync::MutexGuard<'_, T> {
-        self.state.lock().unwrap()
-    }
-    fn activate (mut self, client: Client) -> Usually<Self> {
-        self.client = Some(client.activate_async(Notifications(Box::new({
-            let state  = self.state.clone();
-            let handle = self.handle.clone();
-            move|event|{
-                let mut state = state.lock().unwrap();
-                let mut handle = handle.lock().unwrap();
-                handle(&mut state, &event).unwrap();
-            }
-        }) as Box<dyn Fn(AppEvent) + Send + Sync>), ClosureProcessHandler::new(Box::new({
-            let state   = self.state.clone();
-            let process = self.process.clone();
-            move|client: &Client, scope: &ProcessScope|{
-                let mut state = state.lock().unwrap();
-                let mut process = process.lock().unwrap();
-                (process)(&mut state, client, scope)
-            }
-        }) as BoxedProcessHandler))?);
-        Ok(self)
-    }
-}
-
-#[derive(Debug)]
-pub enum JackEvent {
-    ThreadInit,
-    Shutdown(ClientStatus, String),
-    Freewheel(bool),
-    SampleRate(Frames),
-    ClientRegistration(String, bool),
-    PortRegistration(PortId, bool),
-    PortRename(PortId, String, String),
-    PortsConnected(PortId, PortId, bool),
-    GraphReorder,
-    XRun,
-}
-
-pub struct Notifications<T: Fn(AppEvent) + Send>(T);
-
-impl<T: Fn(AppEvent) + Send> NotificationHandler for Notifications<T> {
-    fn thread_init (&self, _: &Client) {
-        self.0(AppEvent::Jack(JackEvent::ThreadInit));
-    }
-
-    fn shutdown (&mut self, status: ClientStatus, reason: &str) {
-        self.0(AppEvent::Jack(JackEvent::Shutdown(status, reason.into())));
-    }
-
-    fn freewheel (&mut self, _: &Client, enabled: bool) {
-        self.0(AppEvent::Jack(JackEvent::Freewheel(enabled)));
-    }
-
-    fn sample_rate (&mut self, _: &Client, frames: Frames) -> Control {
-        self.0(AppEvent::Jack(JackEvent::SampleRate(frames)));
-        Control::Quit
-    }
-
-    fn client_registration (&mut self, _: &Client, name: &str, reg: bool) {
-        self.0(AppEvent::Jack(JackEvent::ClientRegistration(name.into(), reg)));
-    }
-
-    fn port_registration (&mut self, _: &Client, id: PortId, reg: bool) {
-        self.0(AppEvent::Jack(JackEvent::PortRegistration(id, reg)));
-    }
-
-    fn port_rename (&mut self, _: &Client, id: PortId, old: &str, new: &str) -> Control {
-        self.0(AppEvent::Jack(JackEvent::PortRename(id, old.into(), new.into())));
-        Control::Continue
-    }
-
-    fn ports_connected (&mut self, _: &Client, a: PortId, b: PortId, are: bool) {
-        self.0(AppEvent::Jack(JackEvent::PortsConnected(a, b, are)));
-    }
-
-    fn graph_reorder (&mut self, _: &Client) -> Control {
-        self.0(AppEvent::Jack(JackEvent::GraphReorder));
-        Control::Continue
-    }
-
-    fn xrun (&mut self, _: &Client) -> Control {
-        self.0(AppEvent::Jack(JackEvent::XRun));
-        Control::Continue
-    }
-}
diff --git a/src/device/README.md b/src/device/README.md
deleted file mode 100644
index fd8a2878..00000000
--- a/src/device/README.md
+++ /dev/null
@@ -1,21 +0,0 @@
-Device.inputs is Port[]
-Device.outputs is Port[]
-
-Transport is Device
-Transport.session is Device
-
-Mixer is Device
-Mixer.tracks is Device[]
-
-Chain is Device
-Chain.devices is Device[]
-
-Sequencer is Device
-
-Sampler is Device
-
-Plugin is Device
-
-Mixer -> [Track1, Track2... TrackN]
-
-Track -> [Device1, Device2... N]
diff --git a/src/device/chain/mod.rs b/src/device/chain/mod.rs
index a8b35462..337fadf6 100644
--- a/src/device/chain/mod.rs
+++ b/src/device/chain/mod.rs
@@ -1,9 +1,8 @@
-mod plugin;
-pub use self::plugin::*;
-mod sampler;
-pub use self::sampler::*;
+mod plugin;  pub use self::plugin::*;
+mod sampler; pub use self::sampler::*;
 
-use crate::prelude::*;
+use crate::core::*;
+use crate::layout::*;
 
 pub struct Chain {
     pub name:    String,
diff --git a/src/device/chain/plugin.rs b/src/device/chain/plugin.rs
index 1a28e145..24bfba76 100644
--- a/src/device/chain/plugin.rs
+++ b/src/device/chain/plugin.rs
@@ -1,4 +1,4 @@
-use crate::prelude::*;
+use crate::core::*;
 
 mod lv2;
 mod vst2;
diff --git a/src/device/chain/plugin/lv2.rs b/src/device/chain/plugin/lv2.rs
index 7d1e9d4f..ffb02270 100644
--- a/src/device/chain/plugin/lv2.rs
+++ b/src/device/chain/plugin/lv2.rs
@@ -1,4 +1,4 @@
-use crate::prelude::*;
+use crate::core::*;
 use super::*;
 
 pub fn plug (uri: &str) -> Usually<PluginKind> {
diff --git a/src/device/chain/plugin/vst2.rs b/src/device/chain/plugin/vst2.rs
index 4d2a3242..ad2a4888 100644
--- a/src/device/chain/plugin/vst2.rs
+++ b/src/device/chain/plugin/vst2.rs
@@ -1,4 +1,4 @@
-use crate::prelude::*;
+use crate::core::*;
 use super::*;
 
 impl ::vst::host::Host for Plugin {}
diff --git a/src/device/chain/sampler.rs b/src/device/chain/sampler.rs
index b56699af..b6488af3 100644
--- a/src/device/chain/sampler.rs
+++ b/src/device/chain/sampler.rs
@@ -1,4 +1,4 @@
-use crate::prelude::*;
+use crate::core::*;
 
 pub struct Voice {
     sample:   Arc<Sample>,
diff --git a/src/device/launcher/grid.rs b/src/device/launcher/grid.rs
index 1f944ced..9622e868 100644
--- a/src/device/launcher/grid.rs
+++ b/src/device/launcher/grid.rs
@@ -1,4 +1,4 @@
-use crate::prelude::*;
+use crate::core::*;
 use super::*;
 pub struct LauncherGridView<'a> {
     state:     &'a Launcher,
diff --git a/src/device/launcher/handle.rs b/src/device/launcher/handle.rs
index 14b13407..0974c680 100644
--- a/src/device/launcher/handle.rs
+++ b/src/device/launcher/handle.rs
@@ -1,4 +1,4 @@
-use crate::prelude::*;
+use crate::core::*;
 use super::*;
 pub fn handle (state: &mut Launcher, event: &AppEvent) -> Usually<bool> {
     Ok(handle_keymap(state, event, KEYMAP)? || match state.view {
@@ -54,13 +54,13 @@ fn activate (state: &mut Launcher) -> Usually<bool> {
         Some((track_id, track)),
     ) = (state.scene(), state.track()) {
         // Launch clip
-        if let Some(Some(phrase_id)) = scene.clips.get(track_id) {
+        if let Some(phrase_id) = scene.clips.get(track_id) {
             track.sequencer.state().sequence = *phrase_id;
         }
     } else if let Some((scene_id, scene)) = state.scene() {
         // Launch scene
         for (track_id, track) in state.tracks.iter().enumerate() {
-            if let Some(Some(phrase_id)) = scene.clips.get(track_id) {
+            if let Some(phrase_id) = scene.clips.get(track_id) {
                 track.sequencer.state().sequence = *phrase_id;
             }
         }
diff --git a/src/device/launcher/mod.rs b/src/device/launcher/mod.rs
index 77da1710..1407bd72 100644
--- a/src/device/launcher/mod.rs
+++ b/src/device/launcher/mod.rs
@@ -1,12 +1,13 @@
-use crate::prelude::*;
+use crate::core::*;
+use crate::layout::*;
+use crate::device::*;
 mod grid;
-pub use self::grid::*;
-mod handle;
+pub use self::grid::*; mod handle;
 pub use self::handle::*;
 pub struct Launcher {
     name:       String,
     timebase:   Arc<Timebase>,
-    transport:  Transport,
+    transport:  ::jack::Transport,
     playing:    TransportState,
     monitoring: bool,
     recording:  bool,
@@ -185,10 +186,10 @@ pub fn render (state: &Launcher, buf: &mut Buffer, mut area: Rect) -> Usually<Re
     //area.width  = 80; // DOS mode
     //area.height = 25;
     let Rect { x, y, width, height } = area;
-    crate::device::sequencer::draw_play_stop(buf, x + 1, y, &state.playing);
-    crate::device::sequencer::draw_rec(buf, x + 12, y, state.recording);
-    crate::device::sequencer::draw_mon(buf, x + 19, y, state.monitoring);
-    crate::device::sequencer::draw_dub(buf, x + 26, y, state.overdub);
+    crate::device::transport::draw_play_stop(buf, x + 1, y, &state.playing);
+    crate::device::transport::draw_rec(buf, x + 12, y, state.recording);
+    crate::device::transport::draw_mon(buf, x + 19, y, state.monitoring);
+    crate::device::transport::draw_dub(buf, x + 26, y, state.overdub);
     draw_bpm(buf, x + 33, y, state.timebase.tempo());
     draw_timer(buf, x + width - 1, y, &state.timebase, state.position);
     let mut y = y + 1;
diff --git a/src/device/looper.rs b/src/device/looper.rs
index 5b0c9714..9f4a60d6 100644
--- a/src/device/looper.rs
+++ b/src/device/looper.rs
@@ -1,4 +1,4 @@
-use crate::prelude::*;
+use crate::core::*;
 
 pub struct Looper {
     name: String
diff --git a/src/device/mixer.rs b/src/device/mixer.rs
index 1141c834..409d8871 100644
--- a/src/device/mixer.rs
+++ b/src/device/mixer.rs
@@ -1,4 +1,5 @@
-use crate::prelude::*;
+use crate::core::*;
+use crate::layout::*;
 
 pub struct Mixer {
     name:            String,
diff --git a/src/device/mod.rs b/src/device/mod.rs
new file mode 100644
index 00000000..b829d327
--- /dev/null
+++ b/src/device/mod.rs
@@ -0,0 +1,7 @@
+mod chain;     pub use self::chain::{Chain, Plugin, Sampler, Sample, Voice};
+mod launcher;  pub use self::launcher::{Launcher, Scene};
+mod looper;    pub use self::looper::Looper;
+mod mixer;     pub use self::mixer::Mixer;
+mod sequencer; pub use self::sequencer::{Sequencer, Phrase};
+mod track;     pub use self::track::Track;
+mod transport; pub use self::transport::Transport;
diff --git a/src/device/sequencer/handle.rs b/src/device/sequencer/handle.rs
index 4b47c48f..a3c156cf 100644
--- a/src/device/sequencer/handle.rs
+++ b/src/device/sequencer/handle.rs
@@ -1,4 +1,4 @@
-use crate::prelude::*;
+use crate::core::*;
 use super::*;
 pub fn handle (s: &mut Sequencer, event: &AppEvent) -> Usually<bool> {
     handle_keymap(s, event, KEYMAP)
@@ -39,7 +39,7 @@ pub const KEYMAP: &'static [KeyBinding<Sequencer>] = keymap!(Sequencer {
 });
 const fn focus_seq (i: usize) -> impl Fn(&mut Sequencer)->Usually<bool> {
     move |s: &mut Sequencer| {
-        s.sequence = i;
+        s.sequence = Some(i);
         Ok(true)
     }
 }
@@ -47,13 +47,16 @@ fn nop (_: &mut Sequencer) -> Usually<bool> {
     Ok(false)
 }
 fn note_add (s: &mut Sequencer) -> Usually<bool> {
+    if s.sequence.is_none() {
+        return Ok(false)
+    }
     let step     = (s.time_axis.0 + s.time_cursor) as u32;
     let start    = (step as usize * s.timebase.ppq() / s.resolution) as u32;
     let end      = ((step + 1) as usize * s.timebase.ppq() / s.resolution) as u32;
     let key      = u7::from_int_lossy((s.note_cursor + s.note_axis.0) as u8);
     let note_on  = MidiMessage::NoteOn { key, vel: 100.into() };
     let note_off = MidiMessage::NoteOff { key, vel: 100.into() };
-    let sequence = &mut s.phrases[s.sequence].notes;
+    let sequence = &mut s.phrases[s.sequence.unwrap()].notes;
     if sequence.contains_key(&start) {
         sequence.get_mut(&start).unwrap().push(note_on.clone());
     } else {
diff --git a/src/device/sequencer/horizontal.rs b/src/device/sequencer/horizontal.rs
index 1db68eb8..759705b9 100644
--- a/src/device/sequencer/horizontal.rs
+++ b/src/device/sequencer/horizontal.rs
@@ -1,4 +1,4 @@
-use crate::prelude::*;
+use crate::core::*;
 use super::*;
 
 pub fn draw (
diff --git a/src/device/sequencer/keys.rs b/src/device/sequencer/keys.rs
index 9e29103c..7389abfb 100644
--- a/src/device/sequencer/keys.rs
+++ b/src/device/sequencer/keys.rs
@@ -1,4 +1,4 @@
-use super::*;
+use crate::core::*;
 
 pub const KEY_WHITE: Style = Style {
     fg: Some(Color::Gray),
diff --git a/src/device/sequencer/mod.rs b/src/device/sequencer/mod.rs
index 7d4f0e4f..1bde4073 100644
--- a/src/device/sequencer/mod.rs
+++ b/src/device/sequencer/mod.rs
@@ -1,4 +1,5 @@
-use crate::prelude::*;
+use crate::core::*;
+use crate::layout::*;
 
 mod keys;    use self::keys::*;
 mod handle;  pub use self::handle::*;
@@ -22,7 +23,7 @@ pub struct Sequencer {
     /// FIXME: play start / end / loop in ppm
     pub steps:       usize,
     /// Phrase selector
-    pub sequence:    usize,
+    pub sequence:    Option<usize>,
     /// Map: tick -> MIDI events at tick
     pub phrases:     Vec<Phrase>,
     /// Red keys on piano roll.
@@ -51,12 +52,7 @@ pub struct Sequencer {
 }
 
 #[derive(Debug, Clone)]
-pub enum SequencerView {
-    Tiny,
-    Compact,
-    Horizontal,
-    Vertical,
-}
+pub enum SequencerView { Tiny, Compact, Horizontal, Vertical, }
 
 impl Sequencer {
     pub fn new (
@@ -74,8 +70,10 @@ impl Sequencer {
             timebase:    timebase.clone(),
             steps:       16,
             resolution:  4,
-            sequence:    0,
-            phrases:     phrases.unwrap_or(vec![]),
+            sequence:    Some(0),
+            phrases:     phrases.unwrap_or(vec![
+                Phrase::new("Phrase0", 4*timebase.ppq() as u32, None)
+            ]),
             notes_on:    vec![false;128],
 
             playing:     TransportState::Starting,
@@ -93,12 +91,12 @@ impl Sequencer {
     }
 
     pub fn phrase <'a> (&'a self) -> Option<&'a Phrase> {
-        self.phrases.get(self.sequence)
+        self.sequence.map(|s|self.phrases.get(s))?
     }
 }
 
 impl PortList for Sequencer {
-    fn midi_ins  (&self) -> Usually<Vec<String>> {
+    fn midi_ins (&self) -> Usually<Vec<String>> {
         Ok(vec![self.midi_in.name()?])
     }
     fn midi_outs (&self) -> Usually<Vec<String>> {
@@ -117,22 +115,22 @@ fn render (s: &Sequencer, buf: &mut Buffer, area: Rect) -> Usually<Rect> {
     let steps  = usecs / ustep;
     let header = draw_header(s, buf, area, steps)?;
     let piano  = match s.mode {
-        SequencerView::Tiny =>
-            Rect { x, y, width, height: 0 },
-        SequencerView::Compact =>
-            Rect { x, y, width, height: 0 },
-        SequencerView::Vertical => self::vertical::draw(s, buf, Rect {
-            x,
-            y: y + header.height,
-            width:  3 + note1 - note0,
-            height: 3 + time1 - time0,
-        }, steps)?,
-        SequencerView::Horizontal => self::horizontal::draw(s, buf, Rect {
-            x,
-            y: y + header.height,
-            width:  area.width.max(3 + time1 - time0),
-            height: 3 + note1 - note0,
-        }, steps)?,
+        SequencerView::Tiny     => Rect { x, y, width, height: 0 },
+        SequencerView::Compact  => Rect { x, y, width, height: 0 },
+        SequencerView::Vertical =>
+            self::vertical::draw(s, buf, Rect {
+                x,
+                y: y + header.height,
+                width:  3 + note1 - note0,
+                height: 3 + time1 - time0,
+            }, steps)?,
+        SequencerView::Horizontal =>
+            self::horizontal::draw(s, buf, Rect {
+                x,
+                y: y + header.height,
+                width:  area.width.max(3 + time1 - time0),
+                height: 3 + note1 - note0,
+            }, steps)?,
     };
     Ok(draw_box(buf, Rect {
         x,
@@ -150,12 +148,12 @@ pub fn draw_header (s: &Sequencer, buf: &mut Buffer, area: Rect, beat: usize) ->
     let steps = s.steps % s.resolution;
     draw_timer(buf, x + width - 2, y + 1, &format!("{rep}.{step:02} / {reps}.{steps}"));
     let style = Style::default().gray();
-    draw_play_stop(buf, x + 2, y + 1, &s.playing);
+    crate::device::transport::draw_play_stop(buf, x + 2, y + 1, &s.playing);
     let separator = format!("├{}┤", "-".repeat((area.width - 2).into()));
     separator.blit(buf, x, y + 2, Some(style.dim()));
-    draw_rec(buf, x + 13, y + 1, s.recording);
-    draw_dub(buf, x + 20, y + 1, s.overdub);
-    draw_mon(buf, x + 27, y + 1, s.monitoring);
+    crate::device::transport::draw_rec(buf, x + 13, y + 1, s.recording);
+    crate::device::transport::draw_dub(buf, x + 20, y + 1, s.overdub);
+    crate::device::transport::draw_mon(buf, x + 27, y + 1, s.monitoring);
     let _ = draw_clips(s, buf, area)?;
     Ok(Rect { x, y, width: area.width, height: 3 })
 }
@@ -165,45 +163,12 @@ pub fn draw_timer (
     let style = Some(Style::default().gray().bold().not_dim());
     timer.blit(buf, x - timer.len() as u16, y, style);
 }
-pub fn draw_play_stop (buf: &mut Buffer, x: u16, y: u16, state: &TransportState) {
-    let style = Style::default().gray();
-    match state {
-        TransportState::Rolling  => "▶ PLAYING",
-        TransportState::Starting => "READY ...",
-        TransportState::Stopped  => "⏹ STOPPED",
-    }.blit(buf, x, y, Some(match state {
-        TransportState::Stopped  => style.dim().bold(),
-        TransportState::Starting => style.not_dim().bold(),
-        TransportState::Rolling  => style.not_dim().white().bold()
-    }));
-}
-pub fn draw_rec (buf: &mut Buffer, x: u16, y: u16, on: bool) {
-    "⏺ REC".blit(buf, x, y, Some(if on {
-        Style::default().bold().red()
-    } else {
-        Style::default().bold().dim()
-    }))
-}
-pub fn draw_dub (buf: &mut Buffer, x: u16, y: u16, on: bool) {
-    "⏺ DUB".blit(buf, x, y, Some(if on {
-        Style::default().bold().yellow()
-    } else {
-        Style::default().bold().dim()
-    }))
-}
-pub fn draw_mon (buf: &mut Buffer, x: u16, y: u16, on: bool) {
-    "⏺ MON".blit(buf, x, y, Some(if on {
-        Style::default().bold().green()
-    } else {
-        Style::default().bold().dim()
-    }))
-}
 fn draw_clips (s: &Sequencer, buf: &mut Buffer, area: Rect) -> Usually<Rect> {
     let Rect { x, y, .. } = area;
     let style = Style::default().gray();
     for (i, sequence) in s.phrases.iter().enumerate() {
         let label = format!("▶ {}", &sequence.name);
-        label.blit(buf, x + 2, y + 3 + (i as u16)*2, Some(if i == s.sequence {
+        label.blit(buf, x + 2, y + 3 + (i as u16)*2, Some(if Some(i) == s.sequence {
             match s.playing {
                 TransportState::Rolling => style.white().bold(),
                 _ => style.not_dim().bold()
diff --git a/src/device/sequencer/phrase.rs b/src/device/sequencer/phrase.rs
index b53bd833..1b30ab69 100644
--- a/src/device/sequencer/phrase.rs
+++ b/src/device/sequencer/phrase.rs
@@ -1,5 +1,4 @@
-use crate::prelude::*;
-use super::*;
+use crate::core::*;
 
 pub type PhraseData = BTreeMap<u32, Vec<MidiMessage>>;
 
diff --git a/src/device/sequencer/process.rs b/src/device/sequencer/process.rs
index a07b3bac..66943acf 100644
--- a/src/device/sequencer/process.rs
+++ b/src/device/sequencer/process.rs
@@ -1,9 +1,12 @@
-use crate::prelude::*;
+use crate::core::*;
 use super::*;
 
 pub fn process (state: &mut Sequencer, _: &Client, scope: &ProcessScope) -> Control {
     // Get currently playing sequence
-    let sequence = state.phrases.get_mut(state.sequence);
+    if state.sequence.is_none() {
+        return Control::Continue
+    }
+    let sequence = state.phrases.get_mut(state.sequence.unwrap());
     if sequence.is_none() {
         return Control::Continue
     }
diff --git a/src/device/sequencer/vertical.rs b/src/device/sequencer/vertical.rs
index 7bdd12e1..6f485b6d 100644
--- a/src/device/sequencer/vertical.rs
+++ b/src/device/sequencer/vertical.rs
@@ -1,4 +1,4 @@
-use crate::prelude::*;
+use crate::core::*;
 use super::*;
 
 pub fn draw (
@@ -18,6 +18,9 @@ pub fn draw (
 }
 
 pub fn steps (s: &Sequencer, buf: &mut Buffer, area: Rect, beat: usize) {
+    if s.sequence.is_none() {
+        return
+    }
     let ppq = s.timebase.ppq() as u32;
     let bg = Style::default();
     let bw = bg.dim();
@@ -41,8 +44,8 @@ pub fn steps (s: &Sequencer, buf: &mut Buffer, area: Rect, beat: usize) {
                     (step + 2) as u32 * ppq / s.resolution as u32,
                 );
                 let (character, style) = match (
-                    contains_note_on(&s.phrases[s.sequence], key, a, b),
-                    contains_note_on(&s.phrases[s.sequence], key, b, c),
+                    contains_note_on(&s.phrases[s.sequence.unwrap()], key, a, b),
+                    contains_note_on(&s.phrases[s.sequence.unwrap()], key, b, c),
                 ) {
                     (true, true)   => ("█", wh),
                     (true, false)  => ("▀", wh),
@@ -106,8 +109,8 @@ pub fn keys (s: &Sequencer, buf: &mut Buffer, area: Rect, beat: usize) {
             (step + 2) as u32 * ppq / s.resolution as u32,
         );
         let key = ::midly::num::u7::from(key as u8);
-        is_on = is_on || contains_note_on(&s.phrases[s.sequence], key, a, b);
-        is_on = is_on || contains_note_on(&s.phrases[s.sequence], key, b, c);
+        is_on = is_on || contains_note_on(&s.phrases[s.sequence.unwrap()], key, a, b);
+        is_on = is_on || contains_note_on(&s.phrases[s.sequence.unwrap()], key, b, c);
         if is_on {
             color = Style::default().red();
         }
diff --git a/src/device/track.rs b/src/device/track.rs
index b53b5512..7803c336 100644
--- a/src/device/track.rs
+++ b/src/device/track.rs
@@ -1,4 +1,6 @@
-use crate::prelude::*;
+use crate::core::*;
+use crate::device::*;
+use crate::layout::*;
 pub struct Track {
     pub name:      String,
     pub sequencer: DynamicDevice<Sequencer>,
diff --git a/src/device/transport.rs b/src/device/transport.rs
index 42d6afaa..9cd2de10 100644
--- a/src/device/transport.rs
+++ b/src/device/transport.rs
@@ -1,4 +1,39 @@
-use crate::prelude::*;
+use crate::core::*;
+use crate::layout::*;
+
+pub fn draw_play_stop (buf: &mut Buffer, x: u16, y: u16, state: &TransportState) {
+    let style = Style::default().gray();
+    match state {
+        TransportState::Rolling  => "▶ PLAYING",
+        TransportState::Starting => "READY ...",
+        TransportState::Stopped  => "⏹ STOPPED",
+    }.blit(buf, x, y, Some(match state {
+        TransportState::Stopped  => style.dim().bold(),
+        TransportState::Starting => style.not_dim().bold(),
+        TransportState::Rolling  => style.not_dim().white().bold()
+    }));
+}
+pub fn draw_rec (buf: &mut Buffer, x: u16, y: u16, on: bool) {
+    "⏺ REC".blit(buf, x, y, Some(if on {
+        Style::default().bold().red()
+    } else {
+        Style::default().bold().dim()
+    }))
+}
+pub fn draw_dub (buf: &mut Buffer, x: u16, y: u16, on: bool) {
+    "⏺ DUB".blit(buf, x, y, Some(if on {
+        Style::default().bold().yellow()
+    } else {
+        Style::default().bold().dim()
+    }))
+}
+pub fn draw_mon (buf: &mut Buffer, x: u16, y: u16, on: bool) {
+    "⏺ MON".blit(buf, x, y, Some(if on {
+        Style::default().bold().green()
+    } else {
+        Style::default().bold().dim()
+    }))
+}
 
 pub struct Transport {
     name: String,
diff --git a/src/draw.rs b/src/draw.rs
deleted file mode 100644
index f639c046..00000000
--- a/src/draw.rs
+++ /dev/null
@@ -1,111 +0,0 @@
-use crate::prelude::*;
-
-    //let render_with_actions = |actions| |state, frame: &mut Frame| {
-        //let layout = Layout::default()
-            //.direction(Direction::Horizontal)
-            //.constraints(vec![
-                //Constraint::Percentage(30),
-                //Constraint::Percentage(70),
-            //])
-            //.split(frame.size());
-        //frame.render_widget_ref(ActionBar(actions), layout[0]);
-        //frame.render_widget_ref(state, layout[1]);
-        //Ok(())
-    //};
-
-pub struct ActionBar<'a>(pub &'a [(&'static str, &'static str)]);
-
-impl<'a> WidgetRef for ActionBar<'a> {
-    fn render_ref (&self, area: Rect, buf: &mut Buffer) {
-        let layout = Layout::default()
-            .direction(Direction::Vertical)
-            .constraints(self.0.iter().map(|_|Constraint::Length(3)).collect::<Vec<_>>())
-            .split(area);
-        for (index, action) in self.0.iter().enumerate() {
-            Line::raw(action.0).render(layout[index], buf);
-        }
-    }
-}
-
-pub fn draw_leaf (buffer: &mut Buffer, area: Rect, y: u16, x: u16, text: &str) {
-    let border = Style::default().gray().dim();
-    let label  = Style::default();
-    let side   = String::from("│");
-    let bottom = format!("╰{}╯", "─".repeat(text.len() as usize));
-    buffer.set_string(area.x + x, area.y + y, &side, border);
-    buffer.set_string(area.x + x + 1, area.y + y, format!("{text}"), label);
-    buffer.set_string(area.x + x + text.len() as u16 + 1, area.y + y, &side, border);
-    buffer.set_string(area.x + x, area.y + 1 + y, bottom, border);
-}
-
-pub fn draw_corners (buffer: &mut Buffer, area: Rect, style: Option<Style>) -> Rect {
-    let style = style.unwrap_or(Style::default());
-    buffer.set_string(area.x, area.y, "╭", style);
-    buffer.set_string(area.x + area.width - 1, area.y, "╮", style);
-    buffer.set_string(area.x, area.y + area.height - 1, "╰", style);
-    buffer.set_string(area.x + area.width - 1, area.y + area.height - 1, "╯", style);
-    area
-}
-
-pub fn draw_focus_corners (buffer: &mut Buffer, area: Rect) -> Rect {
-    draw_corners(buffer, area, Some(Style::default().yellow().bold().not_dim()))
-}
-
-//pub fn render_toolbar_vertical (
-    //stdout:  &mut std::io::Stdout,
-    //offset:  (u16, u16),
-    //actions: &[(&str, &str)],
-//) -> Result<(u16, u16), Box<dyn Error>> {
-    //let move_to = |col, row| MoveTo(offset.0 + col, offset.1 + row);
-    //let mut x: u16 = 1;
-    //let mut y: u16 = 0;
-    //for (name, description) in actions.iter() {
-        //stdout.queue(move_to(1, y))?.queue(
-            //PrintStyledContent(name.yellow().bold())
-        //)?.queue(move_to(1, y + 1))?.queue(
-            //PrintStyledContent(description.yellow())
-        //)?;
-        //y = y + 3;
-        //x = u16::max(x, usize::max(name.len(), description.len()) as u16);
-    //}
-    //Ok((x, y))
-//}
-
-//pub fn render_box (
-    //stdout: &mut std::io::Stdout,
-    //title: Option<&str>,
-    //x: u16,
-    //y: u16,
-    //mut w: u16,
-    //h: u16,
-    //active: bool
-//) -> Result<(), Box<dyn Error>> {
-    //if let Some(title) = title {
-        //w = u16::max(w, title.len() as u16 + 4);
-    //}
-    //let back: String = std::iter::repeat(" ").take(w.saturating_sub(2) as usize).collect();
-    //if active {
-        //let edge: String = std::iter::repeat("━").take(w.saturating_sub(2) as usize).collect();
-        //stdout.queue(MoveTo(x, y))?.queue(PrintStyledContent(format!("┏{edge}┓").bold().yellow()))?;
-        //if let Some(title) = title {
-            //stdout.queue(MoveTo(x+1, y))?.queue(PrintStyledContent(format!(" {title} ").yellow()))?;
-        //}
-        //for row in y+1..y+h {
-            //stdout.queue(MoveTo(x, row))?.queue(PrintStyledContent("┃".bold().yellow()))?;
-            //stdout.queue(MoveTo(x+w-1, row))?.queue(PrintStyledContent("┃".bold().yellow()))?;
-        //}
-        //stdout.queue(MoveTo(x, y+h))?.queue(PrintStyledContent(format!("┗{edge}┛").bold().yellow()))?;
-    //} else {
-        //let edge: String = std::iter::repeat("─").take(w.saturating_sub(2) as usize).collect();
-        //stdout.queue(MoveTo(x, y))?.queue(PrintStyledContent(format!("┌{edge}┐").grey().dim()))?;
-        //if let Some(title) = title {
-            //stdout.queue(MoveTo(x+1, y))?.queue(Print(format!(" {title} ")))?;
-        //}
-        //for row in y+1..y+h {
-            //stdout.queue(MoveTo(x, row))?.queue(PrintStyledContent("│".grey().dim()))?;
-            //stdout.queue(MoveTo(x+w-1, row))?.queue(PrintStyledContent("│".grey().dim()))?;
-        //}
-        //stdout.queue(MoveTo(x, y+h))?.queue(PrintStyledContent(format!("└{edge}┘").grey().dim()))?;
-    //}
-    //Ok(())
-//}
diff --git a/src/layout/container.rs b/src/layout/container.rs
index de976d56..4a463d65 100644
--- a/src/layout/container.rs
+++ b/src/layout/container.rs
@@ -1,5 +1,4 @@
-use crate::prelude::*;
-use super::*;
+use crate::core::*;
 
 pub struct Column(pub Vec<Box<dyn Device>>);
 
diff --git a/src/layout/focus.rs b/src/layout/focus.rs
index a1e9f92c..beafeff9 100644
--- a/src/layout/focus.rs
+++ b/src/layout/focus.rs
@@ -1,4 +1,5 @@
-use crate::prelude::*;
+use crate::core::*;
+use super::*;
 
 pub trait Focus {
     fn unfocus (&mut self);
diff --git a/src/layout/lozenge.rs b/src/layout/lozenge.rs
index 254dfc57..5e87bbb1 100644
--- a/src/layout/lozenge.rs
+++ b/src/layout/lozenge.rs
@@ -1,4 +1,4 @@
-use crate::prelude::*;
+use crate::core::*;
 
 const LOZENGE: [[&'static str;3];3] = [
     ["╭", "─", "╮"],
diff --git a/src/layout/mod.rs b/src/layout/mod.rs
index ed275382..e49cae34 100644
--- a/src/layout/mod.rs
+++ b/src/layout/mod.rs
@@ -1,15 +1,18 @@
-mod focus;
-pub use focus::*;
-mod container;
-pub use container::*;
-mod scroll;
-pub use scroll::*;
-mod table;
-pub use table::*;
-mod lozenge;
-pub use lozenge::*;
+mod focus;     pub use self::focus::*;
+mod container; pub use self::container::*;
+mod scroll;    pub use self::scroll::*;
+mod table;     pub use self::table::*;
+mod lozenge;   pub use self::lozenge::*;
 
-use crate::prelude::*;
+use crate::core::*;
+
+pub trait MaxHeight: Device {
+    fn max_height (&self) -> u16 {
+        u16::MAX
+    }
+}
+
+impl<T: Device> MaxHeight for T {}
 
 pub fn draw_box (buffer: &mut Buffer, area: Rect) -> Rect {
     draw_box_styled(buffer, area, Some(Style::default().gray().dim()))
diff --git a/src/layout/scroll.rs b/src/layout/scroll.rs
index 8acb7a91..9ed5293d 100644
--- a/src/layout/scroll.rs
+++ b/src/layout/scroll.rs
@@ -1,5 +1,3 @@
-use crate::prelude::*;
-
 pub struct ScrollY;
 
 pub struct ScrollX;
diff --git a/src/layout/table.rs b/src/layout/table.rs
index e9df9448..4652a0bc 100644
--- a/src/layout/table.rs
+++ b/src/layout/table.rs
@@ -1,4 +1,4 @@
-use crate::prelude::*;
+use crate::core::*;
 
 pub struct Cell<T> {
     text:   String,
diff --git a/src/main.rs b/src/main.rs
index 2b397eab..b88ba66d 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -1,3 +1,5 @@
+#![allow(macro_expanded_macro_exports_accessed_by_absolute_paths)]
+
 extern crate clap;
 extern crate jack;
 extern crate crossterm;
@@ -5,15 +7,14 @@ extern crate crossterm;
 use clap::{Parser};
 use std::error::Error;
 
+pub mod core;
 pub mod cli;
-pub mod device;
-pub mod prelude;
-pub mod draw;
 pub mod config;
+pub mod device;
 pub mod layout;
-pub mod time;
 
-use crate::prelude::*;
+use crate::core::*;
+use crate::device::*;
 
 macro_rules! sample {
     ($note:expr, $name:expr, $src:expr) => {
diff --git a/src/note.rs b/src/note.rs
deleted file mode 100644
index 581a51dd..00000000
--- a/src/note.rs
+++ /dev/null
@@ -1,26 +0,0 @@
-pub const C_4: u8 = 0;
-pub const C_3: u8 = 12;
-pub const C_2: u8 = 24;
-pub const C_1: u8 = 36;
-pub const C0:  u8 = 48;
-pub const C1:  u8 = 60;
-pub const C2:  u8 = 72;
-pub const C3:  u8 = 84;
-pub const C4:  u8 = 96;
-pub const C5:  u8 = 108;
-pub const C6:  u8 = 120;
-
-pub enum Pitch {
-    C = 0,
-    Cs,
-    D,
-    Ds,
-    E,
-    F,
-    Fs,
-    G,
-    Gs,
-    A,
-    As,
-    B
-}
diff --git a/src/prelude.rs b/src/prelude.rs
deleted file mode 100644
index 68340e90..00000000
--- a/src/prelude.rs
+++ /dev/null
@@ -1,112 +0,0 @@
-pub type Usually<T> = Result<T, Box<dyn Error>>;
-
-pub use crate::draw::*;
-pub use crate::device::*;
-pub use crate::time::*;
-pub use crate::layout::*;
-
-pub use std::error::Error;
-pub use std::io::{stdout, Stdout, Write};
-pub use std::thread::{spawn, JoinHandle};
-pub use std::time::Duration;
-pub use std::collections::BTreeMap;
-pub use std::sync::{
-    Arc,
-    Mutex, MutexGuard,
-    atomic::{
-        Ordering,
-        AtomicBool,
-        AtomicUsize
-    }, 
-    mpsc::{self, channel, Sender, Receiver}
-};
-
-pub use crossterm::{
-    ExecutableCommand, QueueableCommand,
-    event::{Event, KeyEvent, KeyCode, KeyModifiers},
-    terminal::{
-        self,
-        Clear, ClearType,
-        EnterAlternateScreen, LeaveAlternateScreen,
-        enable_raw_mode, disable_raw_mode
-    },
-};
-
-pub use ratatui::{
-    prelude::{
-        Buffer, Rect, Style, Color, CrosstermBackend, Layout, Stylize, Direction,
-        Line, Constraint
-    },
-    widgets::{Widget, WidgetRef},
-    //style::Stylize,
-};
-
-pub use ::midly::{MidiMessage, live::LiveEvent, num::u7};
-
-pub use jack::{
-    AsyncClient,
-    AudioIn,
-    AudioOut,
-    Client,
-    ClientOptions,
-    ClientStatus,
-    ClosureProcessHandler,
-    Control,
-    Frames,
-    MidiIn,
-    MidiOut,
-    NotificationHandler,
-    Port,
-    PortFlags,
-    PortId,
-    ProcessHandler,
-    ProcessScope,
-    RawMidi,
-    Transport,
-    TransportState,
-    TransportStatePosition
-};
-
-pub type BoxedNotificationHandler = Box<dyn Fn(AppEvent) + Send>;
-
-pub type BoxedProcessHandler = Box<dyn FnMut(&Client, &ProcessScope)-> Control + Send>;
-
-pub type Jack<N> = AsyncClient<N, ClosureProcessHandler<BoxedProcessHandler>>;
-
-pub type KeyHandler<T> = &'static dyn Fn(&mut T)->Usually<bool>;
-
-pub type KeyBinding<T> = (
-    KeyCode, KeyModifiers, &'static str, &'static str, KeyHandler<T>
-);
-
-#[macro_export] macro_rules! key {
-    ($k:ident $(($char:literal))?, $m:ident, $n: literal, $d: literal, $f: expr) => {
-        (KeyCode::$k $(($char))?, KeyModifiers::$m, $n, $d, &$f)
-    };
-}
-
-#[macro_export] macro_rules! keymap {
-    ($T:ty { $([$k:ident $(($char:literal))?, $m:ident, $n: literal, $d: literal, $f: expr]),* $(,)? }) => {
-        &[
-            $((KeyCode::$k $(($char))?, KeyModifiers::$m, $n, $d, &$f as KeyHandler<$T>)),*
-        ] as &'static [KeyBinding<$T>]
-    }
-}
-
-pub use crate::{key, keymap};
-
-pub fn handle_keymap <T> (
-    state: &mut T, event: &AppEvent, keymap: &[KeyBinding<T>],
-) -> Usually<bool> {
-    match event {
-        AppEvent::Input(Event::Key(event)) => {
-            for (code, modifiers, _, _, command) in keymap.iter() {
-                if *code == event.code && modifiers.bits() == event.modifiers.bits() {
-                    return command(state)
-                }
-            }
-        },
-        _ => {}
-    };
-    Ok(false)
-}