Add keymap picker UI

Co-authored-by: Max <max@zed.dev>

crates/welcome/src/base_keymap_picker.rs

@@ -0,0 +1,175 @@
+use fuzzy::{match_strings, StringMatch, StringMatchCandidate};
+use gpui::{
+    actions,
+    elements::{ChildView, Element as _, Label},
+    AnyViewHandle, Entity, MutableAppContext, View, ViewContext, ViewHandle,
+};
+use picker::{Picker, PickerDelegate};
+use settings::{settings_file::SettingsFile, BaseKeymap, Settings};
+use workspace::Workspace;
+
+pub struct BaseKeymapSelector {
+    matches: Vec<StringMatch>,
+    picker: ViewHandle<Picker<Self>>,
+    selected_index: usize,
+}
+
+actions!(welcome, [ToggleBaseKeymapSelector]);
+
+pub fn init(cx: &mut MutableAppContext) {
+    Picker::<BaseKeymapSelector>::init(cx);
+    cx.add_action({
+        move |workspace, _: &ToggleBaseKeymapSelector, cx| BaseKeymapSelector::toggle(workspace, cx)
+    });
+}
+
+pub enum Event {
+    Dismissed,
+}
+
+impl BaseKeymapSelector {
+    fn toggle(workspace: &mut Workspace, cx: &mut ViewContext<Workspace>) {
+        workspace.toggle_modal(cx, |_, cx| {
+            let this = cx.add_view(|cx| Self::new(cx));
+            cx.subscribe(&this, Self::on_event).detach();
+            this
+        });
+    }
+
+    fn new(cx: &mut ViewContext<Self>) -> Self {
+        let base = cx.global::<Settings>().base_keymap;
+        let selected_index = BaseKeymap::OPTIONS
+            .iter()
+            .position(|(_, value)| *value == base)
+            .unwrap_or(0);
+
+        let this = cx.weak_handle();
+        Self {
+            picker: cx.add_view(|cx| Picker::new("Select a base keymap", this, cx)),
+            matches: Vec::new(),
+            selected_index,
+        }
+    }
+
+    fn on_event(
+        workspace: &mut Workspace,
+        _: ViewHandle<BaseKeymapSelector>,
+        event: &Event,
+        cx: &mut ViewContext<Workspace>,
+    ) {
+        match event {
+            Event::Dismissed => {
+                workspace.dismiss_modal(cx);
+            }
+        }
+    }
+}
+
+impl Entity for BaseKeymapSelector {
+    type Event = Event;
+}
+
+impl View for BaseKeymapSelector {
+    fn ui_name() -> &'static str {
+        "BaseKeymapSelector"
+    }
+
+    fn render(&mut self, cx: &mut gpui::RenderContext<'_, Self>) -> gpui::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 BaseKeymapSelector {
+    fn match_count(&self) -> usize {
+        self.matches.len()
+    }
+
+    fn selected_index(&self) -> usize {
+        self.selected_index
+    }
+
+    fn set_selected_index(&mut self, ix: usize, _: &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 = BaseKeymap::names()
+            .enumerate()
+            .map(|(id, name)| StringMatchCandidate {
+                id,
+                char_bag: name.into(),
+                string: name.into(),
+            })
+            .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 confirm(&mut self, cx: &mut ViewContext<Self>) {
+        if let Some(selection) = self.matches.get(self.selected_index) {
+            let base_keymap = BaseKeymap::from_names(&selection.string);
+            SettingsFile::update(cx, move |settings| settings.base_keymap = Some(base_keymap));
+        }
+        cx.emit(Event::Dismissed);
+    }
+
+    fn dismiss(&mut self, cx: &mut ViewContext<Self>) {
+        cx.emit(Event::Dismissed)
+    }
+
+    fn render_match(
+        &self,
+        ix: usize,
+        mouse_state: &mut gpui::MouseState,
+        selected: bool,
+        cx: &gpui::AppContext,
+    ) -> gpui::ElementBox {
+        let theme = &cx.global::<Settings>().theme;
+        let keymap_match = &self.matches[ix];
+        let style = theme.picker.item.style_for(mouse_state, selected);
+
+        Label::new(keymap_match.string.clone(), style.label.clone())
+            .with_highlights(keymap_match.positions.clone())
+            .contained()
+            .with_style(style.container)
+            .boxed()
+    }
+}