Introduce a new language picker that displays available languages

Right now this panics when trying to select a language, so that's
what we're going to implement next.

Co-Authored-By: Julia Risley <julia@zed.dev>

Cargo.lock

@@ -3286,6 +3286,21 @@ dependencies = [
  "util",
 ]
 
+[[package]]
+name = "language_selector"
+version = "0.1.0"
+dependencies = [
+ "editor",
+ "fuzzy",
+ "gpui",
+ "language",
+ "picker",
+ "project",
+ "settings",
+ "theme",
+ "workspace",
+]
+
 [[package]]
 name = "lazy_static"
 version = "1.4.0"
@@ -8399,6 +8414,7 @@ dependencies = [
  "isahc",
  "journal",
  "language",
+ "language_selector",
  "lazy_static",
  "libc",
  "log",

Cargo.toml

@@ -28,6 +28,7 @@ members = [
     "crates/gpui_macros",
     "crates/journal",
     "crates/language",
+    "crates/language_selector",
     "crates/live_kit_client",
     "crates/live_kit_server",
     "crates/lsp",

crates/language_selector/Cargo.toml

@@ -0,0 +1,20 @@
+[package]
+name = "language_selector"
+version = "0.1.0"
+edition = "2021"
+publish = false
+
+[lib]
+path = "src/language_selector.rs"
+doctest = false
+
+[dependencies]
+editor = { path = "../editor" }
+fuzzy = { path = "../fuzzy" }
+language = { path = "../language" }
+gpui = { path = "../gpui" }
+picker = { path = "../picker" }
+project = { path = "../project" }
+theme = { path = "../theme" }
+settings = { path = "../settings" }
+workspace = { path = "../workspace" }

crates/language_selector/src/language_selector.rs

@@ -0,0 +1,196 @@
+use std::sync::Arc;
+
+use fuzzy::{match_strings, StringMatch, StringMatchCandidate};
+use gpui::{
+    actions, elements::*, AnyViewHandle, AppContext, Entity, MouseState, MutableAppContext,
+    RenderContext, View, ViewContext, ViewHandle,
+};
+use language::LanguageRegistry;
+use picker::{Picker, PickerDelegate};
+use settings::Settings;
+use workspace::{AppState, Workspace};
+
+actions!(language_selector, [Toggle]);
+
+pub fn init(app_state: Arc<AppState>, cx: &mut MutableAppContext) {
+    Picker::<LanguageSelector>::init(cx);
+    cx.add_action({
+        let language_registry = app_state.languages.clone();
+        move |workspace, _: &Toggle, cx| {
+            LanguageSelector::toggle(workspace, language_registry.clone(), cx)
+        }
+    });
+}
+
+pub enum Event {
+    Dismissed,
+}
+
+pub struct LanguageSelector {
+    language_registry: Arc<LanguageRegistry>,
+    matches: Vec<StringMatch>,
+    picker: ViewHandle<Picker<Self>>,
+    selected_index: usize,
+}
+
+impl LanguageSelector {
+    fn new(language_registry: Arc<LanguageRegistry>, cx: &mut ViewContext<Self>) -> Self {
+        let handle = cx.weak_handle();
+        let picker = cx.add_view(|cx| Picker::new("Select Language...", handle, cx));
+
+        let mut matches = language_registry
+            .language_names()
+            .into_iter()
+            .enumerate()
+            .map(|(candidate_id, name)| StringMatch {
+                candidate_id,
+                score: 0.0,
+                positions: Default::default(),
+                string: name,
+            })
+            .collect::<Vec<_>>();
+        matches.sort_unstable_by(|mat1, mat2| mat1.string.cmp(&mat2.string));
+
+        Self {
+            language_registry,
+            matches,
+            picker,
+            selected_index: 0,
+        }
+    }
+
+    fn toggle(
+        workspace: &mut Workspace,
+        registry: Arc<LanguageRegistry>,
+        cx: &mut ViewContext<Workspace>,
+    ) {
+        workspace.toggle_modal(cx, |_, cx| {
+            let this = cx.add_view(|cx| Self::new(registry, cx));
+            cx.subscribe(&this, Self::on_event).detach();
+            this
+        });
+    }
+
+    fn on_event(
+        workspace: &mut Workspace,
+        _: ViewHandle<LanguageSelector>,
+        event: &Event,
+        cx: &mut ViewContext<Workspace>,
+    ) {
+        match event {
+            Event::Dismissed => {
+                workspace.dismiss_modal(cx);
+            }
+        }
+    }
+}
+
+impl Entity for LanguageSelector {
+    type Event = Event;
+}
+
+impl View for LanguageSelector {
+    fn ui_name() -> &'static str {
+        "LanguageSelector"
+    }
+
+    fn render(&mut self, cx: &mut RenderContext<Self>) -> ElementBox {
+        ChildView::new(self.picker.clone(), cx).boxed()
+    }
+
+    fn focus_in(&mut self, _: AnyViewHandle, cx: &mut ViewContext<Self>) {
+        if cx.is_self_focused() {
+            cx.focus(&self.picker);
+        }
+    }
+}
+
+impl PickerDelegate for LanguageSelector {
+    fn match_count(&self) -> usize {
+        self.matches.len()
+    }
+
+    fn confirm(&mut self, cx: &mut ViewContext<Self>) {
+        todo!();
+        cx.emit(Event::Dismissed);
+    }
+
+    fn dismiss(&mut self, cx: &mut ViewContext<Self>) {
+        cx.emit(Event::Dismissed);
+    }
+
+    fn selected_index(&self) -> usize {
+        self.selected_index
+    }
+
+    fn set_selected_index(&mut self, ix: usize, cx: &mut ViewContext<Self>) {
+        self.selected_index = ix;
+    }
+
+    fn update_matches(&mut self, query: String, cx: &mut ViewContext<Self>) -> gpui::Task<()> {
+        let background = cx.background().clone();
+        let candidates = self
+            .language_registry
+            .language_names()
+            .into_iter()
+            .enumerate()
+            .map(|(id, name)| StringMatchCandidate {
+                id,
+                char_bag: name.as_str().into(),
+                string: name.clone(),
+            })
+            .collect::<Vec<_>>();
+
+        cx.spawn(|this, mut cx| async move {
+            let matches = if query.is_empty() {
+                candidates
+                    .into_iter()
+                    .enumerate()
+                    .map(|(index, candidate)| StringMatch {
+                        candidate_id: index,
+                        string: candidate.string,
+                        positions: Vec::new(),
+                        score: 0.0,
+                    })
+                    .collect()
+            } else {
+                match_strings(
+                    &candidates,
+                    &query,
+                    false,
+                    100,
+                    &Default::default(),
+                    background,
+                )
+                .await
+            };
+
+            this.update(&mut cx, |this, cx| {
+                this.matches = matches;
+                this.selected_index = this
+                    .selected_index
+                    .min(this.matches.len().saturating_sub(1));
+                cx.notify();
+            });
+        })
+    }
+
+    fn render_match(
+        &self,
+        ix: usize,
+        mouse_state: &mut MouseState,
+        selected: bool,
+        cx: &AppContext,
+    ) -> ElementBox {
+        let settings = cx.global::<Settings>();
+        let theme = &settings.theme;
+        let theme_match = &self.matches[ix];
+        let style = theme.picker.item.style_for(mouse_state, selected);
+
+        Label::new(theme_match.string.clone(), style.label.clone())
+            .with_highlights(theme_match.positions.clone())
+            .contained()
+            .with_style(style.container)
+            .boxed()
+    }
+}

crates/zed/Cargo.toml

@@ -40,6 +40,7 @@ go_to_line = { path = "../go_to_line" }
 gpui = { path = "../gpui" }
 journal = { path = "../journal" }
 language = { path = "../language" }
+language_selector = { path = "../language_selector" }
 lsp = { path = "../lsp" }
 outline = { path = "../outline" }
 plugin_runtime = { path = "../plugin_runtime" }

crates/zed/src/main.rs

@@ -185,6 +185,7 @@ fn main() {
         workspace::init(app_state.clone(), cx);
 
         journal::init(app_state.clone(), cx);
+        language_selector::init(app_state.clone(), cx);
         theme_selector::init(app_state.clone(), cx);
         zed::init(&app_state, cx);
         collab_ui::init(app_state.clone(), cx);