1use editor::Editor;
 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::{StatusBarSettings, 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        {
34            self.active_language = Some(Some(language.name()));
35        }
36
37        cx.notify();
38    }
39}
40
41impl Render for ActiveBufferLanguage {
42    fn render(&mut self, _: &mut Window, cx: &mut Context<Self>) -> impl IntoElement {
43        if !StatusBarSettings::get_global(cx).active_language_button {
44            return div();
45        }
46
47        div().when_some(self.active_language.as_ref(), |el, active_language| {
48            let active_language_text = if let Some(active_language_text) = active_language {
49                active_language_text.to_string()
50            } else {
51                "Unknown".to_string()
52            };
53
54            el.child(
55                Button::new("change-language", active_language_text)
56                    .label_size(LabelSize::Small)
57                    .on_click(cx.listener(|this, _, window, cx| {
58                        if let Some(workspace) = this.workspace.upgrade() {
59                            workspace.update(cx, |workspace, cx| {
60                                LanguageSelector::toggle(workspace, window, cx)
61                            });
62                        }
63                    }))
64                    .tooltip(|window, cx| {
65                        Tooltip::for_action("Select Language", &Toggle, window, cx)
66                    }),
67            )
68        })
69    }
70}
71
72impl StatusItemView for ActiveBufferLanguage {
73    fn set_active_pane_item(
74        &mut self,
75        active_pane_item: Option<&dyn ItemHandle>,
76        window: &mut Window,
77        cx: &mut Context<Self>,
78    ) {
79        if let Some(editor) = active_pane_item.and_then(|item| item.downcast::<Editor>()) {
80            self._observe_active_editor =
81                Some(cx.observe_in(&editor, window, Self::update_language));
82            self.update_language(editor, window, cx);
83        } else {
84            self.active_language = None;
85            self._observe_active_editor = None;
86        }
87
88        cx.notify();
89    }
90}