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use std::{cell::RefCell, rc::Rc};
use cranpose_core::{DisposableEffect, remember};
use cranpose_macros::composable;
use crate::KeyEvent;
pub(crate) type KeyHandler = Rc<RefCell<Rc<dyn Fn(&KeyEvent) -> bool>>>;
/// Hands `handler` every key event no control took: none was focused, a
/// focused control let the key pass, and no text field is taking typing.
///
/// This is where an application puts the shortcuts that work anywhere in it,
/// a media player's play and stop keys, for instance. The handler returns
/// `true` for a key it used. While several are composed, the one composed
/// last is asked first, and a key goes no further once one takes it.
///
/// ```ignore
/// UnhandledKeyEvents(move |event| {
/// if event.event_type != KeyEventType::KeyDown {
/// return false;
/// }
/// match event.key_code {
/// KeyCode::X => { play(); true }
/// KeyCode::V => { stop(); true }
/// _ => false,
/// }
/// });
/// ```
#[composable]
pub fn UnhandledKeyEvents(handler: impl Fn(&KeyEvent) -> bool + 'static) {
let latest: KeyHandler = remember(|| {
let placeholder: Rc<dyn Fn(&KeyEvent) -> bool> = Rc::new(|_: &KeyEvent| false);
Rc::new(RefCell::new(placeholder))
})
.with(Rc::clone);
*latest.borrow_mut() = Rc::new(handler);
DisposableEffect((), move |scope| {
let id = crate::thread_state::cells(|cells| {
let id = cells.last_unhandled_key_handler_id.get() + 1;
cells.last_unhandled_key_handler_id.set(id);
id
});
crate::thread_state::with(|state| {
state.unhandled_key_handlers.borrow_mut().push((id, latest));
});
scope.on_dispose(move || {
crate::thread_state::try_with(|state| {
state
.unhandled_key_handlers
.borrow_mut()
.retain(|(held, _)| *held != id);
});
})
});
}
/// Offers `event` to the [`UnhandledKeyEvents`] handlers, the one composed
/// last first, and says whether one of them took it. The platform shells
/// call this with each key the focused controls and text fields let pass.
pub fn dispatch_unhandled_key_event(event: &KeyEvent) -> bool {
let handlers: Vec<KeyHandler> = crate::thread_state::with(|state| {
state
.unhandled_key_handlers
.borrow()
.iter()
.rev()
.map(|(_, handler)| Rc::clone(handler))
.collect()
});
handlers.into_iter().any(|handler| {
let current = Rc::clone(&handler.borrow());
current(event)
})
}