Calculate completion popup sizing

Fixes #220

helix-term/src/ui/menu.rs

@@ -8,6 +8,7 @@ use fuzzy_matcher::skim::SkimMatcherV2 as Matcher;
 use fuzzy_matcher::FuzzyMatcher;
 
 use helix_view::{graphics::Rect, Editor};
+use tui::layout::Constraint;
 
 pub trait Item {
     // TODO: sort_text
@@ -26,6 +27,8 @@ pub struct Menu<T: Item> {
     /// (index, score)
     matches: Vec<(usize, i64)>,
 
+    widths: Vec<Constraint>,
+
     callback_fn: Box<dyn Fn(&mut Editor, Option<&T>, MenuEvent)>,
 
     scroll: usize,
@@ -44,6 +47,7 @@ impl<T: Item> Menu<T> {
             matcher: Box::new(Matcher::default()),
             matches: Vec::new(),
             cursor: None,
+            widths: Vec::new(),
             callback_fn: Box::new(callback_fn),
             scroll: 0,
             size: (0, 0),
@@ -218,8 +222,33 @@ impl<T: Item + 'static> Component for Menu<T> {
         EventResult::Ignored
     }
 
+    // TODO: completion sorting
+
     fn required_size(&mut self, viewport: (u16, u16)) -> Option<(u16, u16)> {
-        let width = std::cmp::min(30, viewport.0);
+        let n = self
+            .options
+            .first()
+            .map(|option| option.row().cells.len())
+            .unwrap_or_default();
+        let max_lens = self.options.iter().fold(vec![0; n], |mut acc, option| {
+            let row = option.row();
+            // maintain max for each column
+            for (i, cell) in row.cells.iter().enumerate() {
+                let width = cell.content.width();
+                if width > acc[i] {
+                    acc[i] = width;
+                }
+            }
+
+            acc
+        });
+        let len = (max_lens.iter().sum::<usize>()) + n + 1; // +1: reserve some space for scrollbar
+        let width = len.min(viewport.0 as usize);
+
+        self.widths = max_lens
+            .into_iter()
+            .map(|len| Constraint::Length(len as u16))
+            .collect();
 
         const MAX: usize = 10;
         let height = std::cmp::min(self.options.len(), MAX);
@@ -263,13 +292,12 @@ impl<T: Item + 'static> Component for Menu<T> {
         let scroll_line = (win_height - scroll_height) * scroll
             / std::cmp::max(1, len.saturating_sub(win_height));
 
-        use tui::layout::Constraint;
         let rows = options.iter().map(|option| option.row());
         let table = Table::new(rows)
             .style(style)
             .highlight_style(selected)
             .column_spacing(1)
-            .widths(&[Constraint::Percentage(50), Constraint::Percentage(50)]);
+            .widths(&self.widths);
 
         use tui::widgets::TableState;
 

helix-tui/src/widgets/table.rs

@@ -36,7 +36,7 @@ use std::collections::HashMap;
 /// capabilities of [`Text`].
 #[derive(Debug, Clone, PartialEq, Default)]
 pub struct Cell<'a> {
-    content: Text<'a>,
+    pub content: Text<'a>,
     style: Style,
 }
 
@@ -81,7 +81,7 @@ where
 /// By default, a row has a height of 1 but you can change this using [`Row::height`].
 #[derive(Debug, Clone, PartialEq, Default)]
 pub struct Row<'a> {
-    cells: Vec<Cell<'a>>,
+    pub cells: Vec<Cell<'a>>,
     height: u16,
     style: Style,
     bottom_margin: u16,