implemented expanding and collapsing directories

src/directory.rs

@@ -80,6 +80,8 @@ impl Directory {
     }
 
     pub fn insert(&mut self, name: String, is_file: bool) {
+        self.selected_mut().expanded = true;
+        
         let current_depth = self.selected().depth;
 
         let depth = if self.selected().is_file {
@@ -322,8 +324,11 @@ impl Directory {
             KeyCode::End => {
                 self.selection = u16::try_from(self.dirs.len()-1).unwrap_or(u16::MAX);
                 if self.selection > self.display_start + self.height {
-                    self.display_start = self.selection - self.height
+                    self.display_start = self.selection - self.height;
                 }
+            },
+            KeyCode::Tab if !self.selected().is_file => {
+                self.selected_mut().expanded ^= true;
             }
             _ => (),
         }
@@ -373,38 +378,57 @@ impl Directory {
     }
 
     fn display_lines(&self) -> impl Iterator<Item = String> + '_ {
-        self.dirs.iter().enumerate().scan(
-            Vec::new(),
-            |indent_parts, (i, current)| {
-                let is_last_at_this_depth = is_last_at_this_depth(&self.dirs[i+1..], current.depth);
-                let (new_part, continue_part) = if is_last_at_this_depth {
-                    (TreePart::Last, TreePart::Blank)
-                } else {
-                    (TreePart::First, TreePart::Wait)
-                };
+        let scan_fn = |(indent_parts, unexpanded_depth): &mut (Vec<TreePart>, Option<u8>), (i, current): (usize, &Item)| -> Option<String> {
+            if unexpanded_depth.is_some_and(|d| current.depth > d) {
+                return Some(String::new());
+            }
 
-                if i == 0 { return Some(current.name.clone() + "/") }
+            if current.expanded {
+                *unexpanded_depth = None;
+            } else {
+                *unexpanded_depth = Some(current.depth);
+            }
             
+            let is_last_at_this_depth = is_last_at_this_depth(&self.dirs[i+1..], current.depth);
+            let (new_part, continue_part) = if is_last_at_this_depth {
+                (TreePart::Last, TreePart::Blank)
+            } else {
+                (TreePart::First, TreePart::Wait)
+            };
+
+            let mut result = if i == 0 {
+                String::new()
+            } else {
                 if current.depth as usize > indent_parts.len() {
                     indent_parts.push(continue_part);
                 } else {
                     indent_parts[current.depth as usize-1] = continue_part;
                 }
 
-                let result = indent_parts[0 .. current.depth as usize - 1]
-                    .iter()
-                    .fold(String::new(), |result, t| result + t.display())
-                    + new_part.display()
-                    + &current.name
-                    + if current.is_file {
-                        ""
-                    } else {
-                        "/"
-                    };
+                indent_parts[0 .. current.depth as usize - 1]
+                .iter()
+                .fold(String::new(), |result, t| result + t.display())
+                + new_part.display()
+            };
 
-                Some(result)
+            result += &current.name;
+
+            if !current.is_file {
+                result += "/";
             }
-        )
+            if !current.expanded {
+                result += "...";
+            };
+
+            Some(result)
+        };
+
+        let initial_state = (Vec::new(), None);
+
+        self.dirs.iter()
+            .enumerate()
+            .scan(initial_state, scan_fn)
+            .filter(|s| !s.is_empty())
     }
 }