lsp: Hover documentation draft.

6 files changed, 213 insertions, 10 deletions

diff --git a/helix-lsp/src/client.rs b/helix-lsp/src/client.rs
index b229cd1a..77e877e4 100644
--- a/helix-lsp/src/client.rs
+++ b/helix-lsp/src/client.rs
@@ -201,11 +201,12 @@ impl Client {
                         context_support: None, // additional context information Some(true)
                         ..Default::default()
                     }),
-                    // { completion: {
-                    //      dynamic_registration: bool
-                    //      completion_item: { snippet, documentation_format, ... }
-                    //      completion_item_kind: {  }
-                    // } }
+                    hover: Some(lsp::HoverClientCapabilities {
+                        // if not specified, rust-analyzer returns plaintext marked as markdown but
+                        // badly formatted.
+                        content_format: Some(vec![lsp::MarkupKind::Markdown]),
+                        ..Default::default()
+                    }),
                     ..Default::default()
                 }),
                 ..Default::default()
@@ -458,4 +459,51 @@ impl Client {
 
         Ok(items)
     }
+
+    pub async fn text_document_signature_help(
+        &self,
+        text_document: lsp::TextDocumentIdentifier,
+        position: lsp::Position,
+    ) -> anyhow::Result<Option<lsp::SignatureHelp>> {
+        let params = lsp::SignatureHelpParams {
+            text_document_position_params: lsp::TextDocumentPositionParams {
+                text_document,
+                position,
+            },
+            // TODO: support these tokens
+            work_done_progress_params: lsp::WorkDoneProgressParams {
+                work_done_token: None,
+            },
+            context: None,
+            // lsp::SignatureHelpContext
+        };
+
+        let response = self
+            .request::<lsp::request::SignatureHelpRequest>(params)
+            .await?;
+
+        Ok(response)
+    }
+
+    pub async fn text_document_hover(
+        &self,
+        text_document: lsp::TextDocumentIdentifier,
+        position: lsp::Position,
+    ) -> anyhow::Result<Option<lsp::Hover>> {
+        let params = lsp::HoverParams {
+            text_document_position_params: lsp::TextDocumentPositionParams {
+                text_document,
+                position,
+            },
+            // TODO: support these tokens
+            work_done_progress_params: lsp::WorkDoneProgressParams {
+                work_done_token: None,
+            },
+            // lsp::SignatureHelpContext
+        };
+
+        let response = self.request::<lsp::request::HoverRequest>(params).await?;
+
+        Ok(response)
+    }
 }
diff --git a/helix-term/src/commands.rs b/helix-term/src/commands.rs
index 6b1109ba..c5c2ecf1 100644
--- a/helix-term/src/commands.rs
+++ b/helix-term/src/commands.rs
@@ -11,7 +11,7 @@ use helix_core::{
 use once_cell::sync::Lazy;
 
 use crate::compositor::Compositor;
-use crate::ui::{self, Prompt, PromptEvent};
+use crate::ui::{self, Popup, Prompt, PromptEvent};
 
 use helix_view::{
     document::Mode,
@@ -1000,6 +1000,63 @@ pub fn completion(cx: &mut Context) {
     }
 }
 
+pub fn hover(cx: &mut Context) {
+    use helix_lsp::lsp;
+
+    let doc = cx.doc();
+
+    let language_server = match doc.language_server.as_ref() {
+        Some(language_server) => language_server,
+        None => return,
+    };
+
+    // TODO: factor out a doc.position_identifier() that returns lsp::TextDocumentPositionIdentifier
+
+    // TODO: blocking here is not ideal, make commands async fn?
+    // not like we can process additional input meanwhile though
+    let pos = helix_lsp::util::pos_to_lsp_pos(doc.text().slice(..), doc.selection().cursor());
+
+    // TODO: handle fails
+    let res = smol::block_on(language_server.text_document_hover(doc.identifier(), pos))
+        .unwrap_or_default();
+
+    if let Some(hover) = res {
+        // hover.contents / .range <- used for visualizing
+        let contents = match hover.contents {
+            lsp::HoverContents::Scalar(contents) => {
+                // markedstring(string/languagestring to be highlighted)
+                // TODO
+                unimplemented!("{:?}", contents)
+            }
+            lsp::HoverContents::Array(contents) => {
+                unimplemented!("{:?}", contents)
+            }
+            // TODO: render markdown
+            lsp::HoverContents::Markup(contents) => contents.value,
+        };
+
+        // skip if contents empty
+
+        // Popup: box frame + Box<Component> for internal content.
+        // it will use the contents.size_hint/required size to figure out sizing & positioning
+        // can also use render_buffer to render the content.
+        // render_buffer(highlights/scopes, text, surface, theme)
+        //
+        let mut popup = Popup::new(contents);
+
+        cx.callback = Some(Box::new(
+            move |compositor: &mut Compositor, editor: &mut Editor| {
+                let area = tui::layout::Rect::default(); // TODO: unused remove from cursor_position
+                let mut pos = compositor.cursor_position(area, editor);
+                pos.row += 1; // shift down by one row
+                popup.set_position(pos);
+
+                compositor.push(Box::new(popup));
+            },
+        ));
+    }
+}
+
 // view movements
 pub fn next_view(cx: &mut Context) {
     cx.editor.tree.focus_next()
diff --git a/helix-term/src/keymap.rs b/helix-term/src/keymap.rs
index 81665bbe..ac4a2bf2 100644
--- a/helix-term/src/keymap.rs
+++ b/helix-term/src/keymap.rs
@@ -203,6 +203,8 @@ pub fn default() -> Keymaps {
 
                 // move under <space>c
                 vec![ctrl!('c')] => commands::toggle_comments,
+                // was K, figure out a key
+                vec![ctrl!('k')] => commands::hover,
             ),
             Mode::Insert => hashmap!(
                 vec![Key {
diff --git a/helix-term/src/ui/editor.rs b/helix-term/src/ui/editor.rs
index af9d0414..b071292c 100644
--- a/helix-term/src/ui/editor.rs
+++ b/helix-term/src/ui/editor.rs
@@ -100,6 +100,7 @@ impl EditorView {
         let mut spans = Vec::new();
         let mut visual_x = 0;
         let mut line = 0u16;
+        let text = view.doc.text();
 
         'outer: for event in highlights {
             match event.unwrap() {
@@ -113,7 +114,6 @@ impl EditorView {
                     // TODO: filter out spans out of viewport for now..
 
                     // TODO: do these before iterating
-                    let text = view.doc.text();
                     let start = text.byte_to_char(start);
                     let end = text.byte_to_char(end);
 
@@ -160,8 +160,7 @@ impl EditorView {
                             let grapheme = Cow::from(grapheme);
                             let width = grapheme_width(&grapheme) as u16;
 
-                            // ugh, improve with a traverse method
-                            // or interleave highlight spans with selection and diagnostic spans
+                            // ugh,interleave highlight spans with diagnostic spans
                             let is_diagnostic = view.doc.diagnostics.iter().any(|diagnostic| {
                                 diagnostic.range.0 <= char_index && diagnostic.range.1 > char_index
                             });
@@ -191,12 +190,12 @@ impl EditorView {
         // render selections
 
         if is_focused {
-            let text = view.doc.text().slice(..);
             let screen = {
                 let start = text.line_to_char(view.first_line);
                 let end = text.line_to_char(last_line + 1);
                 Range::new(start, end)
             };
+            let text = text.slice(..);
             let cursor_style = Style::default().bg(Color::Rgb(255, 255, 255));
 
             // cedar
diff --git a/helix-term/src/ui/mod.rs b/helix-term/src/ui/mod.rs
index e1899144..ea1d22ab 100644
--- a/helix-term/src/ui/mod.rs
+++ b/helix-term/src/ui/mod.rs
@@ -1,11 +1,13 @@
 mod editor;
 mod menu;
 mod picker;
+mod popup;
 mod prompt;
 
 pub use editor::EditorView;
 pub use menu::Menu;
 pub use picker::Picker;
+pub use popup::Popup;
 pub use prompt::{Prompt, PromptEvent};
 
 pub use tui::layout::Rect;
diff --git a/helix-term/src/ui/popup.rs b/helix-term/src/ui/popup.rs
new file mode 100644
index 00000000..ca860707
--- /dev/null
+++ b/helix-term/src/ui/popup.rs
@@ -0,0 +1,95 @@
+use crate::compositor::{Component, Compositor, Context, EventResult};
+use crossterm::event::{Event, KeyCode, KeyEvent, KeyModifiers};
+use tui::buffer::Buffer as Surface;
+use tui::{
+    layout::Rect,
+    style::{Color, Style},
+    widgets::{Block, Borders},
+};
+
+use std::borrow::Cow;
+
+use helix_core::Position;
+use helix_view::Editor;
+
+pub struct Popup {
+    contents: String,
+    position: Position,
+}
+
+impl Popup {
+    // TODO: it's like a slimmed down picker, share code? (picker = menu + prompt with different
+    // rendering)
+    pub fn new(contents: String) -> Self {
+        Self {
+            contents,
+            position: Position::default(),
+        }
+    }
+
+    pub fn set_position(&mut self, pos: Position) {
+        self.position = pos;
+    }
+}
+
+impl Component for Popup {
+    fn handle_event(&mut self, event: Event, cx: &mut Context) -> EventResult {
+        let event = match event {
+            Event::Key(event) => event,
+            _ => return EventResult::Ignored,
+        };
+
+        let close_fn = EventResult::Consumed(Some(Box::new(
+            |compositor: &mut Compositor, editor: &mut Editor| {
+                // remove the layer
+                compositor.pop();
+            },
+        )));
+
+        match event {
+            // esc or ctrl-c aborts the completion and closes the menu
+            KeyEvent {
+                code: KeyCode::Esc, ..
+            }
+            | KeyEvent {
+                code: KeyCode::Char('c'),
+                modifiers: KeyModifiers::CONTROL,
+            } => {
+                return close_fn;
+            }
+            _ => (),
+        }
+        // for some events, we want to process them but send ignore, specifically all input except
+        // tab/enter/ctrl-k or whatever will confirm the selection/ ctrl-n/ctrl-p for scroll.
+        // EventResult::Consumed(None)
+        EventResult::Consumed(None)
+    }
+    fn render(&self, area: Rect, surface: &mut Surface, cx: &mut Context) {
+        // render a box at x, y. Width equal to max width of item.
+        const MAX: usize = 15;
+        let rows = std::cmp::min(self.contents.lines().count(), MAX) as u16; // inefficient
+        let area = Rect::new(self.position.col as u16, self.position.row as u16, 80, rows);
+
+        // clear area
+        let background = cx.editor.theme.get("ui.popup");
+        for y in area.top()..area.bottom() {
+            for x in area.left()..area.right() {
+                let cell = surface.get_mut(x, y);
+                cell.reset();
+                // cell.symbol.clear();
+                cell.set_style(background);
+            }
+        }
+
+        // -- Render the contents:
+
+        let style = Style::default().fg(Color::Rgb(164, 160, 232)); // lavender
+
+        use tui::text::Text;
+        use tui::widgets::{Paragraph, Widget, Wrap};
+        let contents = Text::from(self.contents.clone());
+        let par = Paragraph::new(contents).wrap(Wrap { trim: false });
+
+        par.render(area, surface);
+    }
+}