1use editor::Editor;
 2use gpui::{
 3    Context, Entity, IntoElement, ParentElement, Render, Subscription, WeakEntity, Window, div,
 4};
 5use language::LanguageName;
 6use ui::{Button, ButtonCommon, Clickable, FluentBuilder, LabelSize, Tooltip};
 7use workspace::{StatusItemView, Workspace, item::ItemHandle};
 8
 9use crate::{LanguageSelector, Toggle};
10
11pub struct ActiveBufferLanguage {
12    active_language: Option<Option<LanguageName>>,
13    workspace: WeakEntity<Workspace>,
14    _observe_active_editor: Option<Subscription>,
15}
16
17impl ActiveBufferLanguage {
18    pub fn new(workspace: &Workspace) -> Self {
19        Self {
20            active_language: None,
21            workspace: workspace.weak_handle(),
22            _observe_active_editor: None,
23        }
24    }
25
26    fn update_language(&mut self, editor: Entity<Editor>, _: &mut Window, cx: &mut Context<Self>) {
27        self.active_language = Some(None);
28
29        let editor = editor.read(cx);
30        if let Some((_, buffer, _)) = editor.active_excerpt(cx) {
31            if let Some(language) = buffer.read(cx).language() {
32                self.active_language = Some(Some(language.name()));
33            }
34        }
35
36        cx.notify();
37    }
38}
39
40impl Render for ActiveBufferLanguage {
41    fn render(&mut self, _: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
42        div().when_some(self.active_language.as_ref(), |el, active_language| {
43            let active_language_text = if let Some(active_language_text) = active_language {
44                active_language_text.to_string()
45            } else {
46                "Unknown".to_string()
47            };
48
49            el.child(
50                Button::new("change-language", active_language_text)
51                    .label_size(LabelSize::Small)
52                    .on_click(cx.listener(|this, _, window, cx| {
53                        if let Some(workspace) = this.workspace.upgrade() {
54                            workspace.update(cx, |workspace, cx| {
55                                LanguageSelector::toggle(workspace, window, cx)
56                            });
57                        }
58                    }))
59                    .tooltip(|window, cx| {
60                        Tooltip::for_action("Select Language", &Toggle, window, cx)
61                    }),
62            )
63        })
64    }
65}
66
67impl StatusItemView for ActiveBufferLanguage {
68    fn set_active_pane_item(
69        &mut self,
70        active_pane_item: Option<&dyn ItemHandle>,
71        window: &mut Window,
72        cx: &mut Context<Self>,
73    ) {
74        if let Some(editor) = active_pane_item.and_then(|item| item.downcast::<Editor>()) {
75            self._observe_active_editor =
76                Some(cx.observe_in(&editor, window, Self::update_language));
77            self.update_language(editor, window, cx);
78        } else {
79            self.active_language = None;
80            self._observe_active_editor = None;
81        }
82
83        cx.notify();
84    }
85}