Fold subtrees

src/store.rs

@@ -23,6 +23,10 @@ impl<I> Path<I> {
         Self(segments)
     }
 
+    pub fn parent_segments(&self) -> impl Iterator<Item = &I> {
+        self.0.iter().take(self.0.len() - 1)
+    }
+
     pub fn push(&mut self, segment: I) {
         self.0.push(segment)
     }

src/ui/chat/tree.rs

@@ -3,6 +3,7 @@ mod layout;
 mod tree_blocks;
 mod widgets;
 
+use std::collections::HashSet;
 use std::sync::Arc;
 
 use async_trait::async_trait;
@@ -39,13 +40,14 @@ struct InnerTreeViewState<M: Msg, S: MsgStore<M>> {
     last_visible_msgs: Vec<M::Id>,
 
     cursor: Cursor<M::Id>,
+    editor: EditorState,
 
     /// Scroll the view on the next render. Positive values scroll up and
     /// negative values scroll down.
     scroll: i32,
     correction: Option<Correction>,
 
-    editor: EditorState,
+    folded: HashSet<M::Id>,
 }
 
 impl<M: Msg, S: MsgStore<M>> InnerTreeViewState<M, S> {
@@ -56,9 +58,10 @@ impl<M: Msg, S: MsgStore<M>> InnerTreeViewState<M, S> {
             last_cursor_line: 0,
             last_visible_msgs: vec![],
             cursor: Cursor::Bottom,
+            editor: EditorState::new(),
             scroll: 0,
             correction: None,
-            editor: EditorState::new(),
+            folded: HashSet::new(),
         }
     }
 
@@ -98,6 +101,7 @@ impl<M: Msg, S: MsgStore<M>> InnerTreeViewState<M, S> {
     }
 
     pub fn list_action_key_bindings(&self, bindings: &mut KeyBindingsList) {
+        bindings.binding("space", "fold current message's subtree");
         bindings.binding("s", "toggle current message's seen status");
         bindings.binding("S", "mark all visible messages as seen");
         bindings.binding("ctrl+s", "mark all older messages as seen");
@@ -105,6 +109,14 @@ impl<M: Msg, S: MsgStore<M>> InnerTreeViewState<M, S> {
 
     async fn handle_action_key_event(&mut self, event: KeyEvent, id: Option<&M::Id>) -> bool {
         match event {
+            key!(' ') => {
+                if let Some(id) = id {
+                    if !self.folded.remove(id) {
+                        self.folded.insert(id.clone());
+                    }
+                    return true;
+                }
+            }
             key!('s') => {
                 if let Some(id) = id {
                     if let Some(msg) = self.store.tree(id).await.msg(id) {

src/ui/chat/tree/layout.rs

@@ -38,6 +38,12 @@ impl<M: Msg + ChatMsg, S: MsgStore<M>> InnerTreeViewState<M, S> {
         }
     }
 
+    fn make_path_visible(&mut self, path: &Path<M::Id>) {
+        for segment in path.parent_segments() {
+            self.folded.remove(segment);
+        }
+    }
+
     fn cursor_line(&self, blocks: &TreeBlocks<M::Id>) -> i32 {
         if let Cursor::Bottom = self.cursor {
             // The value doesn't matter as it will always be ignored.
@@ -84,18 +90,25 @@ impl<M: Msg + ChatMsg, S: MsgStore<M>> InnerTreeViewState<M, S> {
             blocks.blocks_mut().push_back(block);
         }
 
+        let folded = self.folded.contains(id);
+        let children = tree.children(id);
+        let folded_info = children
+            .filter(|_| folded)
+            .map(|c| c.len())
+            .filter(|c| *c > 0);
+
         // Main message body
         let highlighted = self.cursor.refers_to(id);
         let widget = if let Some(msg) = tree.msg(id) {
-            widgets::msg(highlighted, indent, msg)
+            widgets::msg(highlighted, indent, msg, folded_info)
         } else {
-            widgets::msg_placeholder(highlighted, indent)
+            widgets::msg_placeholder(highlighted, indent, folded_info)
         };
         let block = Block::new(frame, BlockId::Msg(id.clone()), widget);
         blocks.blocks_mut().push_back(block);
 
-        // Children, recursively
-        if let Some(children) = tree.children(id) {
+        // Children recursively (if not folded)
+        if let Some(children) = children.filter(|_| !folded) {
             for child in children {
                 self.layout_subtree(nick, frame, tree, indent + 1, child, blocks);
             }
@@ -458,6 +471,7 @@ impl<M: Msg + ChatMsg, S: MsgStore<M>> InnerTreeViewState<M, S> {
 
         let last_cursor_path = self.cursor_path(&self.last_cursor).await;
         let cursor_path = self.cursor_path(&self.cursor).await;
+        self.make_path_visible(&cursor_path);
 
         let mut blocks = self
             .layout_initial_seed(nick, frame, &last_cursor_path, &cursor_path)

src/ui/chat/tree/widgets.rs

@@ -6,6 +6,7 @@ mod time;
 
 use crossterm::style::{ContentStyle, Stylize};
 use toss::frame::Frame;
+use toss::styled::Styled;
 
 use super::super::ChatMsg;
 use crate::store::Msg;
@@ -40,6 +41,10 @@ fn style_indent(highlighted: bool) -> ContentStyle {
     }
 }
 
+fn style_info() -> ContentStyle {
+    ContentStyle::default().italic().dark_grey()
+}
+
 fn style_editor_highlight() -> ContentStyle {
     ContentStyle::default().black().on_cyan()
 }
@@ -48,8 +53,20 @@ fn style_pseudo_highlight() -> ContentStyle {
     ContentStyle::default().black().on_yellow()
 }
 
-pub fn msg<M: Msg + ChatMsg>(highlighted: bool, indent: usize, msg: &M) -> BoxedWidget {
-    let (nick, content) = msg.styled();
+pub fn msg<M: Msg + ChatMsg>(
+    highlighted: bool,
+    indent: usize,
+    msg: &M,
+    folded_info: Option<usize>,
+) -> BoxedWidget {
+    let (nick, mut content) = msg.styled();
+
+    if let Some(amount) = folded_info {
+        content = content
+            .then_plain("\n")
+            .then(format!("[{amount} more]"), style_info());
+    }
+
     HJoin::new(vec![
         Segment::new(seen::widget(msg.seen())),
         Segment::new(
@@ -69,7 +86,19 @@ pub fn msg<M: Msg + ChatMsg>(highlighted: bool, indent: usize, msg: &M) -> Boxed
     .into()
 }
 
-pub fn msg_placeholder(highlighted: bool, indent: usize) -> BoxedWidget {
+pub fn msg_placeholder(
+    highlighted: bool,
+    indent: usize,
+    folded_info: Option<usize>,
+) -> BoxedWidget {
+    let mut content = Styled::new(PLACEHOLDER, style_placeholder());
+
+    if let Some(amount) = folded_info {
+        content = content
+            .then_plain("\n")
+            .then(format!("[{amount} more]"), style_info());
+    }
+
     HJoin::new(vec![
         Segment::new(seen::widget(true)),
         Segment::new(
@@ -78,7 +107,7 @@ pub fn msg_placeholder(highlighted: bool, indent: usize) -> BoxedWidget {
                 .right(1),
         ),
         Segment::new(Indent::new(indent, style_indent(highlighted))),
-        Segment::new(Text::new((PLACEHOLDER, style_placeholder()))),
+        Segment::new(Text::new(content)),
     ])
     .into()
 }