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//! Useful, foundational hooks that 3rd parties can implement.
//! Currently implemented:
//! - [x] use_ref
//! - [x] use_state
//! - [ ] use_reducer
//! - [ ] use_effect
pub use use_ref_def::use_ref;
pub use use_state_def::use_state;
mod use_state_def {
use crate::innerlude::*;
use std::{cell::RefCell, ops::DerefMut, rc::Rc};
struct UseState<T: 'static> {
new_val: Rc<RefCell<Option<T>>>,
current_val: T,
caller: Box<dyn Fn(T) + 'static>,
}
/// Store state between component renders!
/// When called, this hook retrives a stored value and provides a setter to update that value.
/// When the setter is called, the component is re-ran with the new value.
///
/// This is behaves almost exactly the same way as React's "use_state".
///
/// Usage:
/// ```ignore
/// static Example: FC<()> = |ctx| {
/// let (counter, set_counter) = use_state(ctx, || 0);
/// let increment = || set_couter(counter + 1);
/// let decrement = || set_couter(counter + 1);
///
/// html! {
/// <div>
/// <h1>"Counter: {counter}" </h1>
/// <button onclick={increment}> "Increment" </button>
/// <button onclick={decrement}> "Decrement" </button>
/// </div>
/// }
/// }
/// ```
pub fn use_state<'a, 'c, T: 'static, F: FnOnce() -> T>(
ctx: &'c Context<'a>,
initial_state_fn: F,
) -> (&'a T, &'a impl Fn(T)) {
ctx.use_hook(
move || UseState {
new_val: Rc::new(RefCell::new(None)),
current_val: initial_state_fn(),
caller: Box::new(|_| println!("setter called!")),
},
move |hook| {
log::debug!("Use_state set called");
let inner = hook.new_val.clone();
let scheduled_update = ctx.schedule_update();
// get ownership of the new val and replace the current with the new
// -> as_ref -> borrow_mut -> deref_mut -> take
// -> rc -> &RefCell -> RefMut -> &Option<T> -> T
if let Some(new_val) = hook.new_val.as_ref().borrow_mut().deref_mut().take() {
hook.current_val = new_val;
}
// todo: swap out the caller with a subscription call and an internal update
hook.caller = Box::new(move |new_val| {
// update the setter with the new value
let mut new_inner = inner.as_ref().borrow_mut();
*new_inner = Some(new_val);
// Ensure the component gets updated
scheduled_update();
});
// box gets derefed into a ref which is then taken as ref with the hook
(&hook.current_val, &hook.caller)
},
|_| {},
)
}
}
mod use_ref_def {
use crate::innerlude::*;
use std::{cell::RefCell, ops::DerefMut};
pub struct UseRef<T: 'static> {
_current: RefCell<T>,
}
impl<T: 'static> UseRef<T> {
fn new(val: T) -> Self {
Self {
_current: RefCell::new(val),
}
}
pub fn modify(&self, modifier: impl FnOnce(&mut T)) {
let mut val = self._current.borrow_mut();
let val_as_ref = val.deref_mut();
modifier(val_as_ref);
}
pub fn current(&self) -> std::cell::Ref<'_, T> {
self._current.borrow()
}
}
/// Store a mutable value between renders!
/// To read the value, borrow the ref.
/// To change it, use modify.
/// Modifications to this value do not cause updates to the component
/// Attach to inner context reference, so context can be consumed
pub fn use_ref<'a, T: 'static>(
ctx: &'_ Context<'a>,
initial_state_fn: impl FnOnce() -> T + 'static,
) -> &'a UseRef<T> {
ctx.use_hook(|| UseRef::new(initial_state_fn()), |state| &*state, |_| {})
}
}