use crate::ItemHandle;use gpui::{    AnyView, App, Context, Entity, EntityId, EventEmitter, ParentElement as _, Render, Styled,    Window,};use ui::prelude::*;use ui::{h_flex, v_flex}; pub enum ToolbarItemEvent {    ChangeLocation(ToolbarItemLocation),} pub trait ToolbarItemView: Render + EventEmitter<ToolbarItemEvent> {    fn set_active_pane_item(        &mut self,        active_pane_item: Option<&dyn crate::ItemHandle>,        window: &mut Window,        cx: &mut Context<Self>,    ) -> ToolbarItemLocation;     fn pane_focus_update(        &mut self,        _pane_focused: bool,        _window: &mut Window,        _cx: &mut Context<Self>,    ) {    }} trait ToolbarItemViewHandle: Send {    fn id(&self) -> EntityId;    fn to_any(&self) -> AnyView;    fn set_active_pane_item(        &self,        active_pane_item: Option<&dyn ItemHandle>,        window: &mut Window,        cx: &mut App,    ) -> ToolbarItemLocation;    fn focus_changed(&mut self, pane_focused: bool, window: &mut Window, cx: &mut App);} #[derive(Copy, Clone, Debug, PartialEq)]pub enum ToolbarItemLocation {    Hidden,    PrimaryLeft,    PrimaryRight,    Secondary,} pub struct Toolbar {    active_item: Option<Box<dyn ItemHandle>>,    hidden: bool,    can_navigate: bool,    items: Vec<(Box<dyn ToolbarItemViewHandle>, ToolbarItemLocation)>,} impl Toolbar {    fn has_any_visible_items(&self) -> bool {        self.items            .iter()            .any(|(_item, location)| *location != ToolbarItemLocation::Hidden)    }     fn left_items(&self) -> impl Iterator<Item = &dyn ToolbarItemViewHandle> {        self.items.iter().filter_map(|(item, location)| {            if *location == ToolbarItemLocation::PrimaryLeft {                Some(item.as_ref())            } else {                None            }        })    }     fn right_items(&self) -> impl Iterator<Item = &dyn ToolbarItemViewHandle> {        self.items.iter().filter_map(|(item, location)| {            if *location == ToolbarItemLocation::PrimaryRight {                Some(item.as_ref())            } else {                None            }        })    }     fn secondary_items(&self) -> impl Iterator<Item = &dyn ToolbarItemViewHandle> {        self.items.iter().rev().filter_map(|(item, location)| {            if *location == ToolbarItemLocation::Secondary {                Some(item.as_ref())            } else {                None            }        })    }} impl Render for Toolbar {    fn render(&mut self, _window: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {        if !self.has_any_visible_items() {            return div();        }         let secondary_items = self.secondary_items().map(|item| item.to_any());         let has_left_items = self.left_items().count() > 0;        let has_right_items = self.right_items().count() > 0;         v_flex()            .group("toolbar")            .p(DynamicSpacing::Base08.rems(cx))            .when(has_left_items || has_right_items, |this| {                this.gap(DynamicSpacing::Base08.rems(cx))            })            .border_b_1()            .border_color(cx.theme().colors().border_variant)            .bg(cx.theme().colors().toolbar_background)            .when(has_left_items || has_right_items, |this| {                this.child(                    h_flex()                        .min_h(rems_from_px(24.))                        .justify_between()                        .gap(DynamicSpacing::Base08.rems(cx))                        .when(has_left_items, |this| {                            this.child(                                h_flex()                                    .flex_auto()                                    .justify_start()                                    .overflow_x_hidden()                                    .children(self.left_items().map(|item| item.to_any())),                            )                        })                        .when(has_right_items, |this| {                            this.child(                                h_flex()                                    .map(|el| {                                        if has_left_items {                                            // We're using `flex_none` here to prevent some flickering that can occur when the                                            // size of the left items container changes.                                            el.flex_none()                                        } else {                                            el.flex_auto()                                        }                                    })                                    .justify_end()                                    .children(self.right_items().map(|item| item.to_any())),                            )                        }),                )            })            .children(secondary_items)    }} impl Default for Toolbar {    fn default() -> Self {        Self::new()    }} impl Toolbar {    pub fn new() -> Self {        Self {            active_item: None,            items: Default::default(),            hidden: false,            can_navigate: true,        }    }     pub fn set_can_navigate(&mut self, can_navigate: bool, cx: &mut Context<Self>) {        self.can_navigate = can_navigate;        cx.notify();    }     pub fn add_item<T>(&mut self, item: Entity<T>, window: &mut Window, cx: &mut Context<Self>)    where        T: 'static + ToolbarItemView,    {        let location = item.set_active_pane_item(self.active_item.as_deref(), window, cx);        cx.subscribe(&item, |this, item, event, cx| {            if let Some((_, current_location)) = this                .items                .iter_mut()                .find(|(i, _)| i.id() == item.entity_id())            {                match event {                    ToolbarItemEvent::ChangeLocation(new_location) => {                        if new_location != current_location {                            *current_location = *new_location;                            cx.notify();                        }                    }                }            }        })        .detach();        self.items.push((Box::new(item), location));        cx.notify();    }     pub fn set_active_item(        &mut self,        item: Option<&dyn ItemHandle>,        window: &mut Window,        cx: &mut Context<Self>,    ) {        self.active_item = item.map(|item| item.boxed_clone());        self.hidden = self            .active_item            .as_ref()            .map(|item| !item.show_toolbar(cx))            .unwrap_or(false);         for (toolbar_item, current_location) in self.items.iter_mut() {            let new_location = toolbar_item.set_active_pane_item(item, window, cx);            if new_location != *current_location {                *current_location = new_location;                cx.notify();            }        }    }     pub fn focus_changed(&mut self, focused: bool, window: &mut Window, cx: &mut Context<Self>) {        for (toolbar_item, _) in self.items.iter_mut() {            toolbar_item.focus_changed(focused, window, cx);        }    }     pub fn item_of_type<T: ToolbarItemView>(&self) -> Option<Entity<T>> {        self.items            .iter()            .find_map(|(item, _)| item.to_any().downcast().ok())    }     pub fn hidden(&self) -> bool {        self.hidden    }} impl<T: ToolbarItemView> ToolbarItemViewHandle for Entity<T> {    fn id(&self) -> EntityId {        self.entity_id()    }     fn to_any(&self) -> AnyView {        self.clone().into()    }     fn set_active_pane_item(        &self,        active_pane_item: Option<&dyn ItemHandle>,        window: &mut Window,        cx: &mut App,    ) -> ToolbarItemLocation {        self.update(cx, |this, cx| {            this.set_active_pane_item(active_pane_item, window, cx)        })    }     fn focus_changed(&mut self, pane_focused: bool, window: &mut Window, cx: &mut App) {        self.update(cx, |this, cx| {            this.pane_focus_update(pane_focused, window, cx);            cx.notify();        });    }}