7 files changed, 179 insertions, 45 deletions

diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index 97078794..c3afbd92 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -1691,8 +1691,12 @@ pub fn completion(cx: &mut Context) {
 
             // TODO: if no completion, show some message or something
             if !items.is_empty() {
-                let completion = Completion::new(items, trigger_offset);
-                compositor.push(Box::new(completion));
+                use crate::compositor::AnyComponent;
+                let size = compositor.size();
+                let ui = compositor.find("hx::ui::editor::EditorView").unwrap();
+                if let Some(ui) = ui.as_any_mut().downcast_mut::<ui::EditorView>() {
+                    ui.set_completion(items, trigger_offset, size);
+                };
             }
         },
     );
diff --git a/helix-term/src/compositor.rs b/helix-term/src/compositor.rs
index 4869032b..6e81cc81 100644
--- a/helix-term/src/compositor.rs
+++ b/helix-term/src/compositor.rs
@@ -34,7 +34,7 @@ pub struct Context<'a> {
     pub callbacks: &'a mut LspCallbacks,
 }
 
-pub trait Component {
+pub trait Component: Any + AnyComponent {
     /// Process input events, return true if handled.
     fn handle_event(&mut self, event: Event, ctx: &mut Context) -> EventResult {
         EventResult::Ignored
@@ -60,6 +60,10 @@ pub trait Component {
         // that way render can use it
         None
     }
+
+    fn type_name(&self) -> &'static str {
+        std::any::type_name::<Self>()
+    }
 }
 
 use anyhow::Error;
@@ -142,4 +146,84 @@ impl Compositor {
         }
         None
     }
+
+    pub fn find(&mut self, type_name: &str) -> Option<&mut dyn Component> {
+        self.layers
+            .iter_mut()
+            .find(|component| component.type_name() == type_name)
+            .map(|component| component.as_mut())
+    }
+}
+
+// View casting, taken straight from Cursive
+
+use std::any::Any;
+
+/// A view that can be downcasted to its concrete type.
+///
+/// This trait is automatically implemented for any `T: Component`.
+pub trait AnyComponent {
+    /// Downcast self to a `Any`.
+    fn as_any(&self) -> &dyn Any;
+
+    /// Downcast self to a mutable `Any`.
+    fn as_any_mut(&mut self) -> &mut dyn Any;
+
+    /// Returns a boxed any from a boxed self.
+    ///
+    /// Can be used before `Box::downcast()`.
+    ///
+    /// # Examples
+    ///
+    /// ```rust
+    /// # use cursive_core::views::TextComponent;
+    /// # use cursive_core::view::Component;
+    /// let boxed: Box<Component> = Box::new(TextComponent::new("text"));
+    /// let text: Box<TextComponent> = boxed.as_boxed_any().downcast().unwrap();
+    /// ```
+    fn as_boxed_any(self: Box<Self>) -> Box<dyn Any>;
+}
+
+impl<T: Component> AnyComponent for T {
+    /// Downcast self to a `Any`.
+    fn as_any(&self) -> &dyn Any {
+        self
+    }
+
+    /// Downcast self to a mutable `Any`.
+    fn as_any_mut(&mut self) -> &mut dyn Any {
+        self
+    }
+
+    fn as_boxed_any(self: Box<Self>) -> Box<dyn Any> {
+        self
+    }
+}
+
+impl dyn AnyComponent {
+    /// Attempts to downcast `self` to a concrete type.
+    pub fn downcast_ref<T: Any>(&self) -> Option<&T> {
+        self.as_any().downcast_ref()
+    }
+
+    /// Attempts to downcast `self` to a concrete type.
+    pub fn downcast_mut<T: Any>(&mut self) -> Option<&mut T> {
+        self.as_any_mut().downcast_mut()
+    }
+
+    /// Attempts to downcast `Box<Self>` to a concrete type.
+    pub fn downcast<T: Any>(self: Box<Self>) -> Result<Box<T>, Box<Self>> {
+        // Do the check here + unwrap, so the error
+        // value is `Self` and not `dyn Any`.
+        if self.as_any().is::<T>() {
+            Ok(self.as_boxed_any().downcast().unwrap())
+        } else {
+            Err(self)
+        }
+    }
+
+    /// Checks if this view is of type `T`.
+    pub fn is<T: Any>(&mut self) -> bool {
+        self.as_any().is::<T>()
+    }
 }
diff --git a/helix-term/src/ui/completion.rs b/helix-term/src/ui/completion.rs
index 53241c57..637fc5f4 100644
--- a/helix-term/src/ui/completion.rs
+++ b/helix-term/src/ui/completion.rs
@@ -12,6 +12,7 @@ use std::borrow::Cow;
 use helix_core::{Position, Transaction};
 use helix_view::Editor;
 
+use crate::commands;
 use crate::ui::{Menu, Popup, PromptEvent};
 
 use helix_lsp::lsp;
@@ -112,44 +113,50 @@ impl Completion {
             trigger_offset,
         }
     }
+
+    pub fn update(&mut self, cx: &mut commands::Context) {
+        // recompute menu based on matches
+        let menu = self.popup.contents_mut();
+        let (view, doc) = cx.editor.current();
+
+        // cx.hooks()
+        // cx.add_hook(enum type,  ||)
+        // cx.trigger_hook(enum type, &str, ...) <-- there has to be enough to identify doc/view
+        // callback with editor & compositor
+        //
+        // trigger_hook sends event into channel, that's consumed in the global loop and
+        // triggers all registered callbacks
+        // TODO: hooks should get processed immediately so maybe do it after select!(), before
+        // looping?
+
+        let cursor = doc.selection(view.id).cursor();
+        if self.trigger_offset <= cursor {
+            let fragment = doc.text().slice(self.trigger_offset..=cursor);
+            let text = Cow::from(fragment);
+            // TODO: logic is same as ui/picker
+            menu.score(&text);
+        }
+    }
+
+    pub fn is_empty(&self) -> bool {
+        self.popup.contents().is_empty()
+    }
 }
 
+// need to:
+// - trigger on the right trigger char
+//   - detect previous open instance and recycle
+// - update after input, but AFTER the document has changed
+// - if no more matches, need to auto close
+//
+// missing bits:
+// - a more robust hook system: emit to a channel, process in main loop
+// - a way to find specific layers in compositor
+// - components register for hooks, then unregister when terminated
+// ... since completion is a special case, maybe just build it into doc/render?
+
 impl Component for Completion {
     fn handle_event(&mut self, event: Event, cx: &mut Context) -> EventResult {
-        // input
-        if let Event::Key(KeyEvent {
-            code: KeyCode::Char(ch),
-            ..
-        }) = event
-        {
-            // recompute menu based on matches
-            let menu = self.popup.contents();
-            let (view, doc) = cx.editor.current();
-
-            // cx.hooks()
-            // cx.add_hook(enum type,  ||)
-            // cx.trigger_hook(enum type, &str, ...) <-- there has to be enough to identify doc/view
-            // callback with editor & compositor
-            //
-            // trigger_hook sends event into channel, that's consumed in the global loop and
-            // triggers all registered callbacks
-            // TODO: hooks should get processed immediately so maybe do it after select!(), before
-            // looping?
-
-            let cursor = doc.selection(view.id).cursor();
-            if self.trigger_offset <= cursor {
-                let fragment = doc.text().slice(self.trigger_offset..cursor);
-                // ^ problem seems to be that we handle events here before the editor layer, so the
-                // keypress isn't included in the editor layer yet...
-                // so we can't use ..= for now.
-                let text = Cow::from(fragment);
-                // TODO: logic is same as ui/picker
-                menu.score(&text);
-
-                // TODO: if after scoring the selection is 0 items, remove popup
-            }
-        }
-
         self.popup.handle_event(event, cx)
     }
 
diff --git a/helix-term/src/ui/editor.rs b/helix-term/src/ui/editor.rs
index 24c46bde..16a77b6c 100644
--- a/helix-term/src/ui/editor.rs
+++ b/helix-term/src/ui/editor.rs
@@ -3,7 +3,7 @@ use crate::{
     compositor::{Component, Compositor, Context, EventResult},
     key,
     keymap::{self, Keymaps},
-    ui::text_color,
+    ui::{text_color, Completion},
 };
 
 use helix_core::{
@@ -29,6 +29,7 @@ pub struct EditorView {
     on_next_key: Option<Box<dyn FnOnce(&mut commands::Context, KeyEvent)>>,
     status_msg: Option<String>,
     last_insert: (commands::Command, Vec<KeyEvent>),
+    completion: Option<Completion>,
 }
 
 const OFFSET: u16 = 7; // 1 diagnostic + 5 linenr + 1 gutter
@@ -40,6 +41,7 @@ impl EditorView {
             on_next_key: None,
             status_msg: None,
             last_insert: (commands::normal_mode, Vec::new()),
+            completion: None,
         }
     }
 
@@ -435,15 +437,15 @@ impl EditorView {
         );
     }
 
-    fn insert_mode(&self, cxt: &mut commands::Context, event: KeyEvent) {
+    fn insert_mode(&self, cx: &mut commands::Context, event: KeyEvent) {
         if let Some(command) = self.keymap[&Mode::Insert].get(&event) {
-            command(cxt);
+            command(cx);
         } else if let KeyEvent {
             code: KeyCode::Char(ch),
             ..
         } = event
         {
-            commands::insert::insert_char(cxt, ch);
+            commands::insert::insert_char(cx, ch);
         }
     }
 
@@ -476,6 +478,18 @@ impl EditorView {
             }
         }
     }
+
+    pub fn set_completion(
+        &mut self,
+        items: Vec<helix_lsp::lsp::CompletionItem>,
+        trigger_offset: usize,
+        size: Rect,
+    ) {
+        let mut completion = Completion::new(items, trigger_offset);
+        // TODO : propagate required size on resize to completion too
+        completion.required_size((size.width, size.height));
+        self.completion = Some(completion);
+    }
 }
 
 impl Component for EditorView {
@@ -512,7 +526,15 @@ impl Component for EditorView {
                             // record last_insert key
                             self.last_insert.1.push(event);
 
-                            self.insert_mode(&mut cxt, event)
+                            self.insert_mode(&mut cxt, event);
+
+                            if let Some(completion) = &mut self.completion {
+                                completion.update(&mut cxt);
+                                if completion.is_empty() {
+                                    self.completion = None;
+                                }
+                                // TODO: if exiting InsertMode, remove completion
+                            }
                         }
                         mode => self.command_mode(mode, &mut cxt, event),
                     }
@@ -547,6 +569,11 @@ impl Component for EditorView {
             let doc = cx.editor.document(view.doc).unwrap();
             self.render_view(doc, view, view.area, surface, &cx.editor.theme, is_focused);
         }
+
+        if let Some(completion) = &self.completion {
+            completion.render(area, surface, cx)
+            // render completion here
+        }
     }
 
     fn cursor_position(&self, area: Rect, editor: &Editor) -> Option<Position> {
diff --git a/helix-term/src/ui/menu.rs b/helix-term/src/ui/menu.rs
index fbd25a6d..30ac044c 100644
--- a/helix-term/src/ui/menu.rs
+++ b/helix-term/src/ui/menu.rs
@@ -123,11 +123,19 @@ impl<T> Menu<T> {
                 .map(|(index, _score)| &self.options[*index])
         })
     }
+
+    pub fn is_empty(&self) -> bool {
+        self.matches.is_empty()
+    }
+
+    pub fn len(&self) -> usize {
+        self.matches.len()
+    }
 }
 
 use super::PromptEvent as MenuEvent;
 
-impl<T> Component for Menu<T> {
+impl<T: 'static> Component for Menu<T> {
     fn handle_event(&mut self, event: Event, cx: &mut Context) -> EventResult {
         let event = match event {
             Event::Key(event) => event,
diff --git a/helix-term/src/ui/picker.rs b/helix-term/src/ui/picker.rs
index 6ac35fba..ef2fe2a8 100644
--- a/helix-term/src/ui/picker.rs
+++ b/helix-term/src/ui/picker.rs
@@ -118,7 +118,7 @@ impl<T> Picker<T> {
 // - on input change:
 //  - score all the names in relation to input
 
-impl<T> Component for Picker<T> {
+impl<T: 'static> Component for Picker<T> {
     fn handle_event(&mut self, event: Event, cx: &mut Context) -> EventResult {
         let key_event = match event {
             Event::Key(event) => event,
diff --git a/helix-term/src/ui/popup.rs b/helix-term/src/ui/popup.rs
index f1666451..44e79c4f 100644
--- a/helix-term/src/ui/popup.rs
+++ b/helix-term/src/ui/popup.rs
@@ -46,7 +46,11 @@ impl<T: Component> Popup<T> {
         }
     }
 
-    pub fn contents(&mut self) -> &mut T {
+    pub fn contents(&self) -> &T {
+        &self.contents
+    }
+
+    pub fn contents_mut(&mut self) -> &mut T {
         &mut self.contents
     }
 }