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|
use crate::widget::state;
use crate::widget::Id;
pub trait Operation<T> {
fn container(
&mut self,
id: Option<&Id>,
operate_on_children: &mut dyn FnMut(&mut dyn Operation<T>),
);
fn focusable(
&mut self,
_state: &mut dyn state::Focusable,
_id: Option<&Id>,
) {
}
fn finish(&self) -> Outcome<T> {
Outcome::None
}
}
pub enum Outcome<T> {
None,
Some(T),
Chain(Box<dyn Operation<T>>),
}
pub fn focus<T>(target: Id) -> impl Operation<T> {
struct Focus {
target: Id,
}
impl<T> Operation<T> for Focus {
fn focusable(
&mut self,
state: &mut dyn state::Focusable,
id: Option<&Id>,
) {
match id {
Some(id) if id == &self.target => {
state.focus();
}
_ => {
state.unfocus();
}
}
}
fn container(
&mut self,
_id: Option<&Id>,
operate_on_children: &mut dyn FnMut(&mut dyn Operation<T>),
) {
operate_on_children(self)
}
}
Focus { target }
}
#[derive(Debug, Clone, Copy, PartialEq, Eq, Default)]
pub struct FocusCount {
focused: Option<usize>,
total: usize,
}
pub fn count_focusable<T, O>(f: fn(FocusCount) -> O) -> impl Operation<T>
where
O: Operation<T> + 'static,
{
struct CountFocusable<O> {
count: FocusCount,
next: fn(FocusCount) -> O,
}
impl<T, O> Operation<T> for CountFocusable<O>
where
O: Operation<T> + 'static,
{
fn focusable(
&mut self,
state: &mut dyn state::Focusable,
_id: Option<&Id>,
) {
if state.is_focused() {
self.count.focused = Some(self.count.total);
}
self.count.total += 1;
}
fn container(
&mut self,
_id: Option<&Id>,
operate_on_children: &mut dyn FnMut(&mut dyn Operation<T>),
) {
operate_on_children(self)
}
fn finish(&self) -> Outcome<T> {
Outcome::Chain(Box::new((self.next)(self.count)))
}
}
CountFocusable {
count: FocusCount::default(),
next: f,
}
}
pub fn focus_previous<T>() -> impl Operation<T> {
struct FocusPrevious {
count: FocusCount,
current: usize,
}
impl<T> Operation<T> for FocusPrevious {
fn focusable(
&mut self,
state: &mut dyn state::Focusable,
_id: Option<&Id>,
) {
if self.count.total == 0 {
return;
}
match self.count.focused {
None if self.current == self.count.total - 1 => state.focus(),
Some(0) if self.current == 0 => state.unfocus(),
Some(0) => {}
Some(focused) if focused == self.current => state.unfocus(),
Some(focused) if focused - 1 == self.current => state.focus(),
_ => {}
}
self.current += 1;
}
fn container(
&mut self,
_id: Option<&Id>,
operate_on_children: &mut dyn FnMut(&mut dyn Operation<T>),
) {
operate_on_children(self)
}
}
count_focusable(|count| FocusPrevious { count, current: 0 })
}
pub fn focus_next<T>() -> impl Operation<T> {
struct FocusNext {
count: FocusCount,
current: usize,
}
impl<T> Operation<T> for FocusNext {
fn focusable(
&mut self,
state: &mut dyn state::Focusable,
_id: Option<&Id>,
) {
match self.count.focused {
None if self.current == 0 => state.focus(),
Some(focused) if focused == self.current => state.unfocus(),
Some(focused) if focused + 1 == self.current => state.focus(),
_ => {}
}
self.current += 1;
}
fn container(
&mut self,
_id: Option<&Id>,
operate_on_children: &mut dyn FnMut(&mut dyn Operation<T>),
) {
operate_on_children(self)
}
}
count_focusable(|count| FocusNext { count, current: 0 })
}
|
