buflist: Add support for multiple columns

src/components/buflist.rs

@@ -36,6 +36,19 @@ impl Buflist {
       config,
     }
   }
+
+  pub fn num_columns(&mut self, area: Rect, buffers: &crate::buffers::Buffers) -> u16 {
+    let borders_height = 2;
+    buffers
+      .len()
+      .div_ceil((area.height - borders_height).into())
+      .try_into()
+      .unwrap_or(u16::MAX)
+  }
+
+  pub fn borders_width(&self) -> u16 {
+    2
+  }
 }
 
 impl Component for Buflist {
@@ -54,35 +67,59 @@ impl Component for Buflist {
     area: Rect,
     buffers: &crate::buffers::Buffers,
   ) -> Result<()> {
+    let block = Block::new().borders(Borders::ALL);
+    let inner_area = block.inner(area);
+    block.render(area, frame.buffer_mut());
+
+    let area = inner_area;
+
     let num_digits = u32::min(5, buffers.len().ilog10() + 1) as usize;
     let right_pad = " ".repeat(area.width.into());
     let mut stack = Vec::new(); // List of parent buffers of the current one
-    frame.render_widget(
-      Paragraph::new(
-        buffers
-          .iter()
-          .enumerate()
-          .map(|(i, buf)| {
-            match buffers
-              .parents()
-              .get(&buf.id())
-              .into_iter()
-              .flatten()
-              .flat_map(|parent| stack.iter().position(|id| *id == *parent))
-              .max() // if in multiple spaces, the last one is most likely to matter
-            {
-              Some(parent_position) => stack.truncate(parent_position + 1),
-              None => stack.clear(),
-            }
-            stack.push(buf.id());
-            let buf_number = format!("{}.", i + 1);
-            let mut base_style = Style::default();
-            if i == buffers.active_index() {
-              base_style = base_style.on_blue();
-            }
-            let tree_pad = " ".repeat(stack.len() - 1);
-            let buf_number_style = base_style.green();
-            let left_pad = " ".repeat((num_digits + 1).saturating_sub(buf_number.len()));
+    let mut buffers_iter = buffers.iter().enumerate();
+    let max_columns = u16::min(
+      self.config.layout.buflist.max_columns,
+      area.width.div_ceil(self.config.layout.buflist.column_width),
+    );
+    let column_width = self.config.layout.buflist.column_width;
+    for col in 0..max_columns {
+      let x = area.y + col * column_width;
+      let allow_overflow = if col == max_columns - 2 {
+        self.config.layout.buflist.penultimate_right_overflow
+      } else if col == max_columns - 1 {
+        // Always allow the last column to overflow
+        true
+      } else {
+        false
+      };
+      for y in area.x..(area.x + area.height) {
+        let Some((i, buf)) = buffers_iter.next() else {
+          return Ok(());
+        };
+        match buffers
+          .parents()
+          .get(&buf.id())
+          .into_iter()
+          .flatten()
+          .flat_map(|parent| stack.iter().position(|id| *id == *parent))
+          .max() // if in multiple spaces, the last one is most likely to matter
+        {
+          Some(parent_position) => stack.truncate(parent_position + 1),
+          None => stack.clear(),
+        }
+        stack.push(buf.id());
+        let buf_number = format!("{}.", i + 1);
+        let mut base_style = Style::default();
+        if i == buffers.active_index() {
+          base_style = base_style.on_blue();
+        } else {
+          base_style = base_style.bg(Color::Reset);
+        }
+        let tree_pad = " ".repeat(stack.len() - 1);
+        let buf_number_style = base_style.green();
+        let left_pad = " ".repeat((num_digits + 1).saturating_sub(buf_number.len()));
+        frame.render_widget(
+          Paragraph::new::<Line<'_>>(
             vec![
               Span::styled(left_pad, base_style),
               Span::styled(buf_number, buf_number_style),
@@ -90,13 +127,25 @@ impl Component for Buflist {
               Span::styled(buf.short_name(), base_style),
               Span::styled(right_pad.clone(), base_style),
             ]
-            .into()
-          })
-          .collect::<Vec<Line<'_>>>(),
-      )
-      .block(Block::new().borders(Borders::ALL)),
-      area,
-    );
+            .into(),
+          ),
+          Rect {
+            x,
+            y,
+            width: if allow_overflow {
+              area.width
+            } else {
+              column_width
+            },
+            height: 2,
+          }
+          .intersection(area),
+        );
+      }
+    }
+
+    // TODO: Do something with the remaining buffers, if any. eg. print "XX more buffers"
+    // at the end or display a scrollbar
 
     Ok(())
   }

src/components/home.rs

@@ -118,7 +118,17 @@ impl Component for Home {
   ) -> Result<()> {
     let layout = Layout::default()
       .direction(Direction::Horizontal)
-      .constraints(vec![Constraint::Percentage(20), Constraint::Percentage(80)])
+      .constraints(vec![
+        Constraint::Length(
+          self.config.layout.buflist.column_width
+            * u16::min(
+              self.buflist.num_columns(area, buffers),
+              self.config.layout.buflist.max_columns,
+            )
+            + self.buflist.borders_width(),
+        ),
+        Constraint::Min(self.config.layout.backlog.min_width),
+      ])
       .split(area);
 
     self

src/config.rs

@@ -40,6 +40,24 @@ fn default_device_name() -> String {
   }
 }
 
+#[derive(Clone, Debug, Deserialize)]
+pub struct BuflistLayoutConfig {
+  pub column_width: u16,
+  pub max_columns: u16,
+  pub penultimate_right_overflow: bool,
+}
+
+#[derive(Clone, Debug, Deserialize)]
+pub struct BacklogLayoutConfig {
+  pub min_width: u16,
+}
+
+#[derive(Clone, Debug, Deserialize)]
+pub struct LayoutConfig {
+  pub buflist: BuflistLayoutConfig,
+  pub backlog: BacklogLayoutConfig,
+}
+
 #[derive(Clone, Debug, Deserialize)]
 pub struct Config {
   #[serde(default, flatten)]
@@ -47,6 +65,7 @@ pub struct Config {
   pub accounts: nonempty::NonEmpty<AccountConfig>,
   #[serde(default)]
   pub keybindings: KeyBindings,
+  pub layout: LayoutConfig,
   #[serde(default)]
   pub styles: Styles,
 }

src/default_config.toml

@@ -5,3 +5,19 @@
 "<Ctrl-z>" = "/suspend"
 "<Alt-left>" = "/previous"
 "<Alt-right>" = "/next"
+
+# Configuration for the list of rooms on the right.
+[layout.buflist]
+# How long room names can be before being truncated.
+column_width = 30
+# Maximum number of columns allowed. Rooms which do not fit will not be visible.
+# If the screen is not large enough, fewer columns may be displayed.
+max_columns = 3
+# If the last column has unused space at the end, allows the last-but-one column to use
+# it when its own room names are too long
+penultimate_right_overflow = true
+
+[layout.backlog]
+# Minimum width of the main chat history area and text input.
+# This takes precedence over the buflist settings.
+min_width = 30