1use gpui::{
  2    div, prelude::*, px, AnyView, DismissEvent, FocusHandle, ManagedView, Render, Subscription,
  3    View, ViewContext, WindowContext,
  4};
  5use ui::{h_flex, v_flex};
  6
  7pub enum DismissDecision {
  8    Dismiss(bool),
  9    Pending,
 10}
 11
 12pub trait ModalView: ManagedView {
 13    fn on_before_dismiss(&mut self, _: &mut ViewContext<Self>) -> DismissDecision {
 14        DismissDecision::Dismiss(true)
 15    }
 16}
 17
 18trait ModalViewHandle {
 19    fn on_before_dismiss(&mut self, cx: &mut WindowContext) -> DismissDecision;
 20    fn view(&self) -> AnyView;
 21}
 22
 23impl<V: ModalView> ModalViewHandle for View<V> {
 24    fn on_before_dismiss(&mut self, cx: &mut WindowContext) -> DismissDecision {
 25        self.update(cx, |this, cx| this.on_before_dismiss(cx))
 26    }
 27
 28    fn view(&self) -> AnyView {
 29        self.clone().into()
 30    }
 31}
 32
 33pub struct ActiveModal {
 34    modal: Box<dyn ModalViewHandle>,
 35    _subscriptions: [Subscription; 2],
 36    previous_focus_handle: Option<FocusHandle>,
 37    focus_handle: FocusHandle,
 38}
 39
 40pub struct ModalLayer {
 41    active_modal: Option<ActiveModal>,
 42    dismiss_on_focus_lost: bool,
 43}
 44
 45impl ModalLayer {
 46    pub fn new() -> Self {
 47        Self {
 48            active_modal: None,
 49            dismiss_on_focus_lost: false,
 50        }
 51    }
 52
 53    pub fn toggle_modal<V, B>(&mut self, cx: &mut ViewContext<Self>, build_view: B)
 54    where
 55        V: ModalView,
 56        B: FnOnce(&mut ViewContext<V>) -> V,
 57    {
 58        if let Some(active_modal) = &self.active_modal {
 59            let is_close = active_modal.modal.view().downcast::<V>().is_ok();
 60            let did_close = self.hide_modal(cx);
 61            if is_close || !did_close {
 62                return;
 63            }
 64        }
 65        let new_modal = cx.new_view(build_view);
 66        self.show_modal(new_modal, cx);
 67    }
 68
 69    fn show_modal<V>(&mut self, new_modal: View<V>, cx: &mut ViewContext<Self>)
 70    where
 71        V: ModalView,
 72    {
 73        let focus_handle = cx.focus_handle();
 74        self.active_modal = Some(ActiveModal {
 75            modal: Box::new(new_modal.clone()),
 76            _subscriptions: [
 77                cx.subscribe(&new_modal, |this, _, _: &DismissEvent, cx| {
 78                    this.hide_modal(cx);
 79                }),
 80                cx.on_focus_out(&focus_handle, |this, cx| {
 81                    if this.dismiss_on_focus_lost {
 82                        this.hide_modal(cx);
 83                    }
 84                }),
 85            ],
 86            previous_focus_handle: cx.focused(),
 87            focus_handle,
 88        });
 89        cx.focus_view(&new_modal);
 90        cx.notify();
 91    }
 92
 93    fn hide_modal(&mut self, cx: &mut ViewContext<Self>) -> bool {
 94        let Some(active_modal) = self.active_modal.as_mut() else {
 95            self.dismiss_on_focus_lost = false;
 96            return false;
 97        };
 98
 99        match active_modal.modal.on_before_dismiss(cx) {
100            DismissDecision::Dismiss(dismiss) => {
101                self.dismiss_on_focus_lost = !dismiss;
102                if !dismiss {
103                    return false;
104                }
105            }
106            DismissDecision::Pending => {
107                self.dismiss_on_focus_lost = false;
108                return false;
109            }
110        }
111
112        if let Some(active_modal) = self.active_modal.take() {
113            if let Some(previous_focus) = active_modal.previous_focus_handle {
114                if active_modal.focus_handle.contains_focused(cx) {
115                    previous_focus.focus(cx);
116                }
117            }
118            cx.notify();
119        }
120        true
121    }
122
123    pub fn active_modal<V>(&self) -> Option<View<V>>
124    where
125        V: 'static,
126    {
127        let active_modal = self.active_modal.as_ref()?;
128        active_modal.modal.view().downcast::<V>().ok()
129    }
130
131    pub fn has_active_modal(&self) -> bool {
132        self.active_modal.is_some()
133    }
134}
135
136impl Render for ModalLayer {
137    fn render(&mut self, _: &mut ViewContext<Self>) -> impl IntoElement {
138        let Some(active_modal) = &self.active_modal else {
139            return div();
140        };
141
142        div().absolute().size_full().top_0().left_0().child(
143            v_flex()
144                .h(px(0.0))
145                .top_20()
146                .flex()
147                .flex_col()
148                .items_center()
149                .track_focus(&active_modal.focus_handle)
150                .child(h_flex().occlude().child(active_modal.modal.view())),
151        )
152    }
153}