bitbox03/ui: split UI from async machine

diff --git a/src/rust/Cargo.lock b/src/rust/Cargo.lock
index 60a6b0a..338a954 100644
--- a/src/rust/Cargo.lock
+++ b/src/rust/Cargo.lock
@@ -313,6 +313,7 @@ dependencies = [
  "bitbox-lvgl",
  "png-decoder",
  "tracing",
+ "util",
  "zeroize",
 ]
 
diff --git a/src/rust/bitbox03/Cargo.toml b/src/rust/bitbox03/Cargo.toml
index b689e1c..738030e 100644
--- a/src/rust/bitbox03/Cargo.toml
+++ b/src/rust/bitbox03/Cargo.toml
@@ -6,6 +6,7 @@ edition = "2024"
 [dependencies]
 bitbox-lvgl = { path = "../bitbox-lvgl" }
 bitbox-hal = { path = "../bitbox-hal" }
+util = { path = "../util" }
 tracing = { version = "0.1.41", features = ["log"], default-features = false }
 png-decoder = { version="0.2"}
 zeroize = {workspace=true}
diff --git a/src/rust/bitbox03/src/ui.rs b/src/rust/bitbox03/src/ui.rs
index dd0d717..24a653f 100644
--- a/src/rust/bitbox03/src/ui.rs
+++ b/src/rust/bitbox03/src/ui.rs
@@ -1,13 +1,13 @@
-use alloc::rc::Rc;
 use alloc::vec::Vec;
 use bitbox_hal as hal;
 use bitbox_lvgl::{
-    self as lvgl, LabelExt, LvAlign, LvButton, LvDisplay, LvHandle, LvLabel, LvLabelLongMode,
-    LvObj, LvOpacityLevel, LvPart, LvSpangroup, ObjExt, SpangroupExt,
+    self as lvgl, LabelExt, LvAlign, LvDisplay, LvHandle, LvLabel, LvObj, LvOpacityLevel, LvPart,
+    LvSpangroup, ObjExt, SpangroupExt,
 };
-use core::cell::RefCell;
-use core::task::{Poll, Waker};
 use tracing::info;
+use util::futures::completion;
+
+mod confirm;
 
 const LOGO: &[u8] = include_bytes!("../splash.png");
 
@@ -47,129 +47,8 @@ impl hal::ui::Ui for BitBox03Ui {
         &mut self,
         params: &bitbox_hal::ui::ConfirmParams<'_>,
     ) -> Result<(), bitbox_hal::ui::UserAbort> {
-        struct SharedState {
-            waker: Option<Waker>,
-            result: Option<Result<(), hal::ui::UserAbort>>,
-        }
-
-        let shared_state = Rc::new(RefCell::new(SharedState {
-            waker: None,
-            result: None,
-        }));
-
-        let screen = LvObj::new().unwrap();
-        screen.set_layout(lvgl::LvLayout::LV_LAYOUT_FLEX);
-        screen.set_flex_flow(lvgl::LvFlexFlow::LV_FLEX_FLOW_COLUMN);
-        screen.set_style_bg_color(lvgl::color::black(), 0);
-        screen.set_style_text_color(lvgl::color::white(), 0);
-        screen.set_style_pad_top(40, 0);
-        screen.set_style_pad_right(50, 0);
-        screen.set_style_pad_bottom(40, 0);
-        screen.set_style_pad_left(50, 0);
-        screen.set_style_pad_row(24, 0);
-
-        let title = LvLabel::new(&screen).unwrap();
-        title.set_width(380);
-        title.set_long_mode(LvLabelLongMode::LV_LABEL_LONG_MODE_WRAP);
-        title.set_text(params.title).unwrap();
-        title.set_style_text_font(
-            lvgl::fonts::INTER_BOLD_48,
-            lvgl::LvState::LV_STATE_DEFAULT as u32,
-        );
-
-        let body = LvLabel::new(&screen).unwrap();
-        body.set_width(380);
-        body.set_long_mode(LvLabelLongMode::LV_LABEL_LONG_MODE_WRAP);
-        body.set_text(params.body).unwrap();
-        body.set_style_text_font(
-            lvgl::fonts::INTER_REGULAR_32,
-            lvgl::LvState::LV_STATE_DEFAULT as u32,
-        );
-        body.set_style_flex_grow(1, 0);
-
-        let actions = LvObj::with_parent(&screen).unwrap();
-        actions.set_width(380);
-        actions.set_height(72);
-        actions.set_layout(lvgl::LvLayout::LV_LAYOUT_FLEX);
-        actions.set_flex_flow(lvgl::LvFlexFlow::LV_FLEX_FLOW_ROW);
-        actions.set_style_pad_top(0, 0);
-        actions.set_style_pad_bottom(0, 0);
-        actions.set_style_pad_left(0, 0);
-        actions.set_style_pad_right(0, 0);
-        actions.set_style_pad_column(20, 0);
-        actions.set_style_margin_top(16, 0);
-        actions.set_style_border_width(0, 0);
-        actions.set_style_bg_opa(LvOpacityLevel::LV_OPA_TRANSP as u8, 0);
-
-        let reject = LvButton::new(&actions).unwrap();
-        reject.set_size(180, 72);
-        reject.set_style_bg_color(lvgl::color::hex(0x30333a), 0);
-        reject.set_style_bg_opa(LvOpacityLevel::LV_OPA_COVER as u8, 0);
-        reject.set_style_border_width(2, 0);
-        reject.set_style_border_color(lvgl::color::white(), 0);
-        let reject_state = Rc::clone(&shared_state);
-        reject
-            .add_click_cb(move || {
-                let mut shared_state = reject_state.borrow_mut();
-                if shared_state.result.is_none() {
-                    shared_state.result = Some(Err(hal::ui::UserAbort));
-                    if let Some(waker) = shared_state.waker.as_ref() {
-                        waker.wake_by_ref();
-                    }
-                }
-            })
-            .expect("failed to register reject callback");
-        let reject_label = LvLabel::new(&reject).unwrap();
-        reject_label.set_text("No").unwrap();
-        reject_label.set_style_text_font(
-            lvgl::fonts::INTER_BOLD_32,
-            lvgl::LvState::LV_STATE_DEFAULT as u32,
-        );
-        reject_label.set_style_text_color(lvgl::color::white(), 0);
-        reject_label.align(LvAlign::LV_ALIGN_CENTER, 0, 0);
-
-        let accept = LvButton::new(&actions).unwrap();
-        accept.set_size(180, 72);
-        accept.set_style_bg_color(lvgl::color::white(), 0);
-        accept.set_style_bg_opa(LvOpacityLevel::LV_OPA_COVER as u8, 0);
-        accept.set_style_border_width(2, 0);
-        accept.set_style_border_color(lvgl::color::black(), 0);
-        let accept_state = Rc::clone(&shared_state);
-        accept
-            .add_click_cb(move || {
-                let mut shared_state = accept_state.borrow_mut();
-                if shared_state.result.is_none() {
-                    shared_state.result = Some(Ok(()));
-                    if let Some(waker) = shared_state.waker.as_ref() {
-                        waker.wake_by_ref();
-                    }
-                }
-            })
-            .expect("failed to register accept callback");
-        let accept_label = LvLabel::new(&accept).unwrap();
-        accept_label.set_text("Yes").unwrap();
-        accept_label.set_style_text_font(
-            lvgl::fonts::INTER_BOLD_32,
-            lvgl::LvState::LV_STATE_DEFAULT as u32,
-        );
-        accept_label.set_style_text_color(lvgl::color::black(), 0);
-        accept_label.align(LvAlign::LV_ALIGN_CENTER, 0, 0);
-
-        let _screen = self.push_guard(screen);
-
-        core::future::poll_fn({
-            let shared_state = &shared_state;
-            move |cx| {
-                let mut shared_state = shared_state.borrow_mut();
-                if let Some(result) = shared_state.result.take() {
-                    Poll::Ready(result)
-                } else {
-                    shared_state.waker = Some(cx.waker().clone());
-                    Poll::Pending
-                }
-            }
-        })
-        .await
+        self.with_result_screen(|responder| confirm::build_confirm_screen(params, responder))
+            .await
     }
 
     async fn verify_recipient(
@@ -368,6 +247,16 @@ impl BitBox03Ui {
         ScreenGuard { ui: self }
     }
 
+    async fn with_result_screen<T, F>(&mut self, build_screen: F) -> T
+    where
+        F: FnOnce(completion::UiResponder<T>) -> LvObj,
+    {
+        let (responder, result) = completion::completion();
+        let screen = build_screen(responder);
+        let _screen = self.push_guard(screen);
+        result.await
+    }
+
     pub fn push(&mut self, screen: LvObj) {
         if let Some(display) = &self.display {
             let current = display.screen_active().expect("No active screen?!");
diff --git a/src/rust/bitbox03/src/ui/confirm.rs b/src/rust/bitbox03/src/ui/confirm.rs
new file mode 100644
index 0000000..ec29ae9
--- /dev/null
+++ b/src/rust/bitbox03/src/ui/confirm.rs
@@ -0,0 +1,96 @@
+// SPDX-License-Identifier: Apache-2.0
+
+use bitbox_hal::ui::{ConfirmParams, UserAbort};
+use bitbox_lvgl::{
+    self as lvgl, LabelExt, LvAlign, LvButton, LvLabel, LvLabelLongMode, LvObj, LvOpacityLevel,
+    ObjExt,
+};
+use util::futures::completion::UiResponder;
+
+pub(super) fn build_confirm_screen(
+    params: &ConfirmParams<'_>,
+    responder: UiResponder<Result<(), UserAbort>>,
+) -> LvObj {
+    let screen = LvObj::new().unwrap();
+    screen.set_layout(lvgl::LvLayout::LV_LAYOUT_FLEX);
+    screen.set_flex_flow(lvgl::LvFlexFlow::LV_FLEX_FLOW_COLUMN);
+    screen.set_style_bg_color(lvgl::color::black(), 0);
+    screen.set_style_text_color(lvgl::color::white(), 0);
+    screen.set_style_pad_top(40, 0);
+    screen.set_style_pad_right(50, 0);
+    screen.set_style_pad_bottom(40, 0);
+    screen.set_style_pad_left(50, 0);
+    screen.set_style_pad_row(24, 0);
+
+    let title = LvLabel::new(&screen).unwrap();
+    title.set_width(380);
+    title.set_long_mode(LvLabelLongMode::LV_LABEL_LONG_MODE_WRAP);
+    title.set_text(params.title).unwrap();
+    title.set_style_text_font(
+        lvgl::fonts::INTER_BOLD_48,
+        lvgl::LvState::LV_STATE_DEFAULT as u32,
+    );
+
+    let body = LvLabel::new(&screen).unwrap();
+    body.set_width(380);
+    body.set_long_mode(LvLabelLongMode::LV_LABEL_LONG_MODE_WRAP);
+    body.set_text(params.body).unwrap();
+    body.set_style_text_font(
+        lvgl::fonts::INTER_REGULAR_32,
+        lvgl::LvState::LV_STATE_DEFAULT as u32,
+    );
+    body.set_style_flex_grow(1, 0);
+
+    let actions = LvObj::with_parent(&screen).unwrap();
+    actions.set_width(380);
+    actions.set_height(72);
+    actions.set_layout(lvgl::LvLayout::LV_LAYOUT_FLEX);
+    actions.set_flex_flow(lvgl::LvFlexFlow::LV_FLEX_FLOW_ROW);
+    actions.set_style_pad_top(0, 0);
+    actions.set_style_pad_bottom(0, 0);
+    actions.set_style_pad_left(0, 0);
+    actions.set_style_pad_right(0, 0);
+    actions.set_style_pad_column(20, 0);
+    actions.set_style_margin_top(16, 0);
+    actions.set_style_border_width(0, 0);
+    actions.set_style_bg_opa(LvOpacityLevel::LV_OPA_TRANSP as u8, 0);
+
+    let reject = LvButton::new(&actions).unwrap();
+    reject.set_size(180, 72);
+    reject.set_style_bg_color(lvgl::color::hex(0x30333a), 0);
+    reject.set_style_bg_opa(LvOpacityLevel::LV_OPA_COVER as u8, 0);
+    reject.set_style_border_width(2, 0);
+    reject.set_style_border_color(lvgl::color::white(), 0);
+    let reject_responder = responder.clone();
+    reject
+        .add_click_cb(move || reject_responder.resolve(Err(UserAbort)))
+        .expect("failed to register reject callback");
+    let reject_label = LvLabel::new(&reject).unwrap();
+    reject_label.set_text("No").unwrap();
+    reject_label.set_style_text_font(
+        lvgl::fonts::INTER_BOLD_32,
+        lvgl::LvState::LV_STATE_DEFAULT as u32,
+    );
+    reject_label.set_style_text_color(lvgl::color::white(), 0);
+    reject_label.align(LvAlign::LV_ALIGN_CENTER, 0, 0);
+
+    let accept = LvButton::new(&actions).unwrap();
+    accept.set_size(180, 72);
+    accept.set_style_bg_color(lvgl::color::white(), 0);
+    accept.set_style_bg_opa(LvOpacityLevel::LV_OPA_COVER as u8, 0);
+    accept.set_style_border_width(2, 0);
+    accept.set_style_border_color(lvgl::color::black(), 0);
+    accept
+        .add_click_cb(move || responder.resolve(Ok(())))
+        .expect("failed to register accept callback");
+    let accept_label = LvLabel::new(&accept).unwrap();
+    accept_label.set_text("Yes").unwrap();
+    accept_label.set_style_text_font(
+        lvgl::fonts::INTER_BOLD_32,
+        lvgl::LvState::LV_STATE_DEFAULT as u32,
+    );
+    accept_label.set_style_text_color(lvgl::color::black(), 0);
+    accept_label.align(LvAlign::LV_ALIGN_CENTER, 0, 0);
+
+    screen
+}
diff --git a/src/rust/util/src/futures.rs b/src/rust/util/src/futures.rs
new file mode 100644
index 0000000..adf7b09
--- /dev/null
+++ b/src/rust/util/src/futures.rs
@@ -0,0 +1,3 @@
+// SPDX-License-Identifier: Apache-2.0
+
+pub mod completion;
diff --git a/src/rust/util/src/futures/completion.rs b/src/rust/util/src/futures/completion.rs
new file mode 100644
index 0000000..b136796
--- /dev/null
+++ b/src/rust/util/src/futures/completion.rs
@@ -0,0 +1,145 @@
+// SPDX-License-Identifier: Apache-2.0
+
+use alloc::rc::Rc;
+use core::cell::RefCell;
+use core::future::Future;
+use core::pin::Pin;
+use core::task::{Context, Poll, Waker};
+
+struct SharedState<T> {
+    waker: Option<Waker>,
+    result: Option<T>,
+}
+
+pub struct UiResponder<T> {
+    shared_state: Rc<RefCell<SharedState<T>>>,
+}
+
+pub struct UiResult<T> {
+    shared_state: Rc<RefCell<SharedState<T>>>,
+}
+
+pub fn completion<T>() -> (UiResponder<T>, UiResult<T>) {
+    let shared_state = Rc::new(RefCell::new(SharedState {
+        waker: None,
+        result: None,
+    }));
+    (
+        UiResponder {
+            shared_state: Rc::clone(&shared_state),
+        },
+        UiResult { shared_state },
+    )
+}
+
+impl<T> UiResponder<T> {
+    pub fn resolve(&self, value: T) {
+        let mut shared_state = self.shared_state.borrow_mut();
+        if shared_state.result.is_none() {
+            shared_state.result = Some(value);
+            if let Some(waker) = shared_state.waker.as_ref() {
+                waker.wake_by_ref();
+            }
+        }
+    }
+}
+
+impl<T> Clone for UiResponder<T> {
+    fn clone(&self) -> Self {
+        Self {
+            shared_state: Rc::clone(&self.shared_state),
+        }
+    }
+}
+
+impl<T> Future for UiResult<T> {
+    type Output = T;
+
+    fn poll(self: Pin<&mut Self>, cx: &mut Context<'_>) -> Poll<Self::Output> {
+        let mut shared_state = self.shared_state.borrow_mut();
+        if let Some(result) = shared_state.result.take() {
+            Poll::Ready(result)
+        } else {
+            shared_state.waker = Some(cx.waker().clone());
+            Poll::Pending
+        }
+    }
+}
+
+#[cfg(test)]
+mod tests {
+    extern crate std;
+
+    use super::*;
+    use core::pin::pin;
+    use std::sync::Arc;
+    use std::sync::atomic::{AtomicUsize, Ordering};
+    use std::task::Wake;
+
+    struct CountingWake {
+        wake_count: AtomicUsize,
+    }
+
+    impl CountingWake {
+        fn new() -> Self {
+            Self {
+                wake_count: AtomicUsize::new(0),
+            }
+        }
+
+        fn wake_count(&self) -> usize {
+            self.wake_count.load(Ordering::SeqCst)
+        }
+    }
+
+    impl Wake for CountingWake {
+        fn wake(self: Arc<Self>) {
+            self.wake_count.fetch_add(1, Ordering::SeqCst);
+        }
+
+        fn wake_by_ref(self: &Arc<Self>) {
+            self.wake_count.fetch_add(1, Ordering::SeqCst);
+        }
+    }
+
+    #[test]
+    fn test_completion_resolve_before_poll() {
+        let (responder, result) = completion();
+        responder.resolve(42);
+
+        let waker = std::task::Waker::from(Arc::new(CountingWake::new()));
+        let mut cx = Context::from_waker(&waker);
+        let mut result = pin!(result);
+
+        assert!(matches!(result.as_mut().poll(&mut cx), Poll::Ready(42)));
+    }
+
+    #[test]
+    fn test_completion_resolve_wakes() {
+        let (responder, result) = completion();
+        let wake = Arc::new(CountingWake::new());
+        let waker = std::task::Waker::from(Arc::clone(&wake));
+        let mut cx = Context::from_waker(&waker);
+        let mut result = pin!(result);
+
+        assert!(matches!(result.as_mut().poll(&mut cx), Poll::Pending));
+        assert_eq!(wake.wake_count(), 0);
+
+        responder.resolve(42);
+        assert_eq!(wake.wake_count(), 1);
+        assert!(matches!(result.as_mut().poll(&mut cx), Poll::Ready(42)));
+    }
+
+    #[test]
+    fn test_completion_first_resolution_wins() {
+        let (responder, result) = completion();
+        responder.resolve(42);
+        responder.resolve(99);
+
+        let waker = std::task::Waker::from(Arc::new(CountingWake::new()));
+        let mut cx = Context::from_waker(&waker);
+        let mut result = pin!(result);
+
+        assert!(matches!(result.as_mut().poll(&mut cx), Poll::Ready(42)));
+    }
+}
diff --git a/src/rust/util/src/lib.rs b/src/rust/util/src/lib.rs
index 4faa048..2ba2a6d 100644
--- a/src/rust/util/src/lib.rs
+++ b/src/rust/util/src/lib.rs
@@ -8,6 +8,7 @@ pub mod bytes;
 pub mod cell;
 pub mod datetime;
 pub mod decimal;
+pub mod futures;
 pub mod log;
 pub mod name;
 pub mod strings;
diff --git a/test/simulator-graphical-bb03/Cargo.lock b/test/simulator-graphical-bb03/Cargo.lock
index 1e9ec6b..f4805a0 100644
--- a/test/simulator-graphical-bb03/Cargo.lock
+++ b/test/simulator-graphical-bb03/Cargo.lock
@@ -478,6 +478,7 @@ dependencies = [
  "bitbox-lvgl",
  "png-decoder",
  "tracing",
+ "util",
  "zeroize",
 ]