1use editor::{Editor, EditorSettings};
 2use gpui::{
 3    Context, Entity, IntoElement, ParentElement, Render, Subscription, WeakEntity, Window, div,
 4};
 5use language::LanguageName;
 6use settings::Settings as _;
 7use ui::{Button, ButtonCommon, Clickable, FluentBuilder, LabelSize, Tooltip};
 8use workspace::{StatusItemView, Workspace, item::ItemHandle};
 9
10use crate::{LanguageSelector, Toggle};
11
12pub struct ActiveBufferLanguage {
13    active_language: Option<Option<LanguageName>>,
14    workspace: WeakEntity<Workspace>,
15    _observe_active_editor: Option<Subscription>,
16}
17
18impl ActiveBufferLanguage {
19    pub fn new(workspace: &Workspace) -> Self {
20        Self {
21            active_language: None,
22            workspace: workspace.weak_handle(),
23            _observe_active_editor: None,
24        }
25    }
26
27    fn update_language(&mut self, editor: Entity<Editor>, _: &mut Window, cx: &mut Context<Self>) {
28        self.active_language = Some(None);
29
30        let editor = editor.read(cx);
31        if let Some((_, buffer, _)) = editor.active_excerpt(cx)
32            && let Some(language) = buffer.read(cx).language() {
33                self.active_language = Some(Some(language.name()));
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        if !EditorSettings::get_global(cx)
43            .status_bar
44            .active_language_button
45        {
46            return div();
47        }
48
49        div().when_some(self.active_language.as_ref(), |el, active_language| {
50            let active_language_text = if let Some(active_language_text) = active_language {
51                active_language_text.to_string()
52            } else {
53                "Unknown".to_string()
54            };
55
56            el.child(
57                Button::new("change-language", active_language_text)
58                    .label_size(LabelSize::Small)
59                    .on_click(cx.listener(|this, _, window, cx| {
60                        if let Some(workspace) = this.workspace.upgrade() {
61                            workspace.update(cx, |workspace, cx| {
62                                LanguageSelector::toggle(workspace, window, cx)
63                            });
64                        }
65                    }))
66                    .tooltip(|window, cx| {
67                        Tooltip::for_action("Select Language", &Toggle, window, cx)
68                    }),
69            )
70        })
71    }
72}
73
74impl StatusItemView for ActiveBufferLanguage {
75    fn set_active_pane_item(
76        &mut self,
77        active_pane_item: Option<&dyn ItemHandle>,
78        window: &mut Window,
79        cx: &mut Context<Self>,
80    ) {
81        if let Some(editor) = active_pane_item.and_then(|item| item.downcast::<Editor>()) {
82            self._observe_active_editor =
83                Some(cx.observe_in(&editor, window, Self::update_language));
84            self.update_language(editor, window, cx);
85        } else {
86            self.active_language = None;
87            self._observe_active_editor = None;
88        }
89
90        cx.notify();
91    }
92}