4 files changed, 52 insertions, 8 deletions

diff --git a/helix-term/src/ui/completion.rs b/helix-term/src/ui/completion.rs
index 6c9e3a80..c75b24f1 100644
--- a/helix-term/src/ui/completion.rs
+++ b/helix-term/src/ui/completion.rs
@@ -69,14 +69,18 @@ impl menu::Item for CompletionItem {
 /// Wraps a Menu.
 pub struct Completion {
     popup: Popup<Menu<CompletionItem>>,
+    start_offset: usize,
+    #[allow(dead_code)]
     trigger_offset: usize,
     // TODO: maintain a completioncontext with trigger kind & trigger char
 }
 
 impl Completion {
     pub fn new(
+        editor: &Editor,
         items: Vec<CompletionItem>,
         offset_encoding: helix_lsp::OffsetEncoding,
+        start_offset: usize,
         trigger_offset: usize,
     ) -> Self {
         // let items: Vec<CompletionItem> = Vec::new();
@@ -175,16 +179,22 @@ impl Completion {
             };
         });
         let popup = Popup::new(menu);
-        Self {
+        let mut completion = Self {
             popup,
+            start_offset,
             trigger_offset,
-        }
+        };
+
+        // need to recompute immediately in case start_offset != trigger_offset
+        completion.recompute_filter(editor);
+
+        completion
     }
 
-    pub fn update(&mut self, cx: &mut commands::Context) {
+    pub fn recompute_filter(&mut self, editor: &Editor) {
         // recompute menu based on matches
         let menu = self.popup.contents_mut();
-        let (view, doc) = current!(cx.editor);
+        let (view, doc) = current_ref!(editor);
 
         // cx.hooks()
         // cx.add_hook(enum type,  ||)
@@ -200,14 +210,22 @@ impl Completion {
             .selection(view.id)
             .primary()
             .cursor(doc.text().slice(..));
-        if self.trigger_offset <= cursor {
-            let fragment = doc.text().slice(self.trigger_offset..cursor);
+        if self.start_offset <= cursor {
+            let fragment = doc.text().slice(self.start_offset..cursor);
             let text = Cow::from(fragment);
             // TODO: logic is same as ui/picker
             menu.score(&text);
+        } else {
+            // we backspaced before the start offset, clear the menu
+            // this will cause the editor to remove the completion popup
+            menu.clear();
         }
     }
 
+    pub fn update(&mut self, cx: &mut commands::Context) {
+        self.recompute_filter(cx.editor)
+    }
+
     pub fn is_empty(&self) -> bool {
         self.popup.contents().is_empty()
     }
diff --git a/helix-term/src/ui/editor.rs b/helix-term/src/ui/editor.rs
index 128fe948..037f04b8 100644
--- a/helix-term/src/ui/editor.rs
+++ b/helix-term/src/ui/editor.rs
@@ -37,7 +37,7 @@ pub struct EditorView {
     keymaps: Keymaps,
     on_next_key: Option<Box<dyn FnOnce(&mut commands::Context, KeyEvent)>>,
     last_insert: (commands::Command, Vec<KeyEvent>),
-    completion: Option<Completion>,
+    pub(crate) completion: Option<Completion>,
     spinners: ProgressSpinners,
     autoinfo: Option<Info>,
 }
@@ -984,12 +984,21 @@ impl EditorView {
 
     pub fn set_completion(
         &mut self,
+        editor: &Editor,
         items: Vec<helix_lsp::lsp::CompletionItem>,
         offset_encoding: helix_lsp::OffsetEncoding,
+        start_offset: usize,
         trigger_offset: usize,
         size: Rect,
     ) {
-        let mut completion = Completion::new(items, offset_encoding, trigger_offset);
+        let mut completion =
+            Completion::new(editor, items, offset_encoding, start_offset, trigger_offset);
+
+        if completion.is_empty() {
+            // skip if we got no completion results
+            return;
+        }
+
         // TODO : propagate required size on resize to completion too
         completion.required_size((size.width, size.height));
         self.completion = Some(completion);
@@ -1211,6 +1220,7 @@ impl Component for EditorView {
                 EventResult::Consumed(None)
             }
             Event::Key(key) => {
+                cxt.editor.reset_idle_timer();
                 let mut key = KeyEvent::from(key);
                 canonicalize_key(&mut key);
                 // clear status
@@ -1245,6 +1255,7 @@ impl Component for EditorView {
                                     if callback.is_some() {
                                         // assume close_fn
                                         self.completion = None;
+                                        cxt.editor.clear_idle_timer(); // don't retrigger
                                     }
                                 }
                             }
@@ -1258,6 +1269,7 @@ impl Component for EditorView {
                                     completion.update(&mut cxt);
                                     if completion.is_empty() {
                                         self.completion = None;
+                                        cxt.editor.clear_idle_timer(); // don't retrigger
                                     }
                                 }
                             }
diff --git a/helix-term/src/ui/menu.rs b/helix-term/src/ui/menu.rs
index dab0c34f..055593fd 100644
--- a/helix-term/src/ui/menu.rs
+++ b/helix-term/src/ui/menu.rs
@@ -90,6 +90,14 @@ impl<T: Item> Menu<T> {
         self.recalculate = true;
     }
 
+    pub fn clear(&mut self) {
+        self.matches.clear();
+
+        // reset cursor position
+        self.cursor = None;
+        self.scroll = 0;
+    }
+
     pub fn move_up(&mut self) {
         let len = self.matches.len();
         let pos = self.cursor.map_or(0, |i| (i + len.saturating_sub(1)) % len) % len;
diff --git a/helix-term/src/ui/picker.rs b/helix-term/src/ui/picker.rs
index ee1ec177..341235ee 100644
--- a/helix-term/src/ui/picker.rs
+++ b/helix-term/src/ui/picker.rs
@@ -271,12 +271,18 @@ impl<T> Picker<T> {
     }
 
     pub fn move_up(&mut self) {
+        if self.matches.is_empty() {
+            return;
+        }
         let len = self.matches.len();
         let pos = ((self.cursor + len.saturating_sub(1)) % len) % len;
         self.cursor = pos;
     }
 
     pub fn move_down(&mut self) {
+        if self.matches.is_empty() {
+            return;
+        }
         let len = self.matches.len();
         let pos = (self.cursor + 1) % len;
         self.cursor = pos;