src/directory.rs

@@ -205,6 +205,7 @@ impl Directory {
         let selected_subtree = self.subtree_indices(self.selection());
         let sibling_subtree = self.subtree_indices(index);
 
+        let delta = if selected_subtree.len() < sibling_subtree.len() {
             let select_len = selected_subtree.len();
             let sibling_len = sibling_subtree.len();
 
@@ -217,38 +218,22 @@ impl Directory {
                 *dst = item;
             }
 
-        self.selection += u16::try_from(sibling_len).unwrap_or(u16::MAX);
-    }
+            sibling_len
+        } else if selected_subtree.len() == sibling_subtree.len() {
+            let (selected, sibling) = self.dirs.split_at_mut(index);
 
-    fn move_up(&mut self) {
-        let current_depth = self.selected().depth;
+            let len = selected.len();
+            let lhs = &mut selected[len - selected_subtree.len() .. ];
+            let rhs = &mut sibling[0 .. sibling_subtree.len()];
 
-        let Some(index) = (0 .. self.selection())
-            .rev()
-            .take_while(|&i| self.dirs[i].depth >= current_depth)
-            .filter(|&i| self.dirs[i].depth == current_depth)
-            .next()
-        else {
-            return
+            lhs.swap_with_slice(rhs);
+
+            selected_subtree.len()
+        } else {
+            todo!()
         };
         
-        let selected_subtree = self.subtree_indices(self.selection());
-        let sibling_subtree = self.subtree_indices(index);
-
-        let select_len = selected_subtree.len();
-        let sibling_len = sibling_subtree.len();
-
-        let selected_copy = self.dirs[selected_subtree].to_owned();
-        let sibling_copy = self.dirs[sibling_subtree].to_owned();
-        let back_to_back = selected_copy.into_iter().chain(sibling_copy);
-
-        let full_range = index .. index+select_len+sibling_len;
-        for (dst, item) in self.dirs[full_range].iter_mut().zip(back_to_back) {
-            *dst = item;
-        }
-
-        self.selection -= u16::try_from(sibling_len).unwrap_or(u16::MAX);
-
+        self.selection += u16::try_from(delta).unwrap_or(u16::MAX);
     }
 
     fn selected(&self) -> &Item {
@@ -347,9 +332,6 @@ impl Directory {
             },
             KeyCode::Down => {
                 self.move_down();
-            },
-            KeyCode::Up => {
-                self.move_up();
             }
             _ => (),
         }