1use editor::Editor;
 2use gpui::{div, IntoElement, ParentElement, Render, Subscription, View, ViewContext, WeakView};
 3use language::LanguageName;
 4use ui::{Button, ButtonCommon, Clickable, FluentBuilder, LabelSize, Tooltip};
 5use workspace::{item::ItemHandle, StatusItemView, Workspace};
 6
 7use crate::LanguageSelector;
 8
 9gpui::actions!(language_selector, [Toggle]);
10
11pub struct ActiveBufferLanguage {
12    active_language: Option<Option<LanguageName>>,
13    workspace: WeakView<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: View<Editor>, cx: &mut ViewContext<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, cx: &mut ViewContext<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, _, cx| {
53                        if let Some(workspace) = this.workspace.upgrade() {
54                            workspace.update(cx, |workspace, cx| {
55                                LanguageSelector::toggle(workspace, cx)
56                            });
57                        }
58                    }))
59                    .tooltip(|cx| Tooltip::for_action("Select Language", &Toggle, cx)),
60            )
61        })
62    }
63}
64
65impl StatusItemView for ActiveBufferLanguage {
66    fn set_active_pane_item(
67        &mut self,
68        active_pane_item: Option<&dyn ItemHandle>,
69        cx: &mut ViewContext<Self>,
70    ) {
71        if let Some(editor) = active_pane_item.and_then(|item| item.downcast::<Editor>()) {
72            self._observe_active_editor = Some(cx.observe(&editor, Self::update_language));
73            self.update_language(editor, cx);
74        } else {
75            self.active_language = None;
76            self._observe_active_editor = None;
77        }
78
79        cx.notify();
80    }
81}