1use super::try_rect;
 2use crate::{
 3    geometry::vector::Vector2F, AfterLayoutContext, AppContext, Element, Event, EventContext,
 4    LayoutContext, MutableAppContext, PaintContext, SizeConstraint,
 5};
 6use std::cell::RefCell;
 7
 8pub struct EventHandler {
 9    child: Box<dyn Element>,
10    mouse_down: Option<RefCell<Box<dyn FnMut(&mut EventContext, &AppContext) -> bool>>>,
11    origin: Option<Vector2F>,
12}
13
14impl EventHandler {
15    pub fn new(child: Box<dyn Element>) -> Self {
16        Self {
17            child,
18            mouse_down: None,
19            origin: None,
20        }
21    }
22
23    pub fn on_mouse_down<F>(mut self, callback: F) -> Self
24    where
25        F: 'static + FnMut(&mut EventContext, &AppContext) -> bool,
26    {
27        self.mouse_down = Some(RefCell::new(Box::new(callback)));
28        self
29    }
30}
31
32impl Element for EventHandler {
33    fn layout(
34        &mut self,
35        constraint: SizeConstraint,
36        ctx: &mut LayoutContext,
37        app: &AppContext,
38    ) -> Vector2F {
39        self.child.layout(constraint, ctx, app)
40    }
41
42    fn after_layout(&mut self, ctx: &mut AfterLayoutContext, app: &mut MutableAppContext) {
43        self.child.after_layout(ctx, app);
44    }
45
46    fn paint(&mut self, origin: Vector2F, ctx: &mut PaintContext, app: &AppContext) {
47        self.origin = Some(origin);
48        self.child.paint(origin, ctx, app);
49    }
50
51    fn size(&self) -> Option<Vector2F> {
52        self.child.size()
53    }
54
55    fn dispatch_event(&self, event: &Event, ctx: &mut EventContext, app: &AppContext) -> bool {
56        match event {
57            Event::LeftMouseDown { position, .. } => {
58                if let Some(callback) = self.mouse_down.as_ref() {
59                    let rect = try_rect(self.origin, self.size()).unwrap();
60                    if rect.contains_point(*position) {
61                        return callback.borrow_mut()(ctx, app);
62                    }
63                }
64                false
65            }
66            _ => false,
67        }
68    }
69}