Feat: begin sample explorer overhaul

src/state/sample_browser.rs

@@ -1,3 +1,4 @@
+use std::cell::Cell;
 use std::fs;
 use std::path::{Path, PathBuf};
 
@@ -62,12 +63,19 @@ impl SampleNode {
             SampleNode::Folder { expanded, .. } => TreeLineKind::Folder { expanded: *expanded },
             SampleNode::File { .. } => TreeLineKind::File,
         };
+        let child_count = match self {
+            SampleNode::Root { children, .. } | SampleNode::Folder { children, .. } => {
+                children.iter().filter(|c| matches!(c, SampleNode::File { .. })).count()
+            }
+            SampleNode::File { .. } => 0,
+        };
         out.push(TreeLine {
             depth,
             kind,
             label: self.label().to_string(),
             folder: parent_folder.to_string(),
             index: file_index,
+            child_count,
         });
         if self.expanded() {
             let folder_name = self.label();
@@ -321,6 +329,7 @@ impl SampleTree {
                 expanded,
             } if name == target_name => {
                 let show_children = !collapsed && *expanded;
+                let file_count = children.iter().filter(|c| matches!(c, SampleNode::File { .. })).count();
                 out.push(TreeLine {
                     depth: 0,
                     kind: TreeLineKind::Folder {
@@ -329,6 +338,7 @@ impl SampleTree {
                     label: name.clone(),
                     folder: String::new(),
                     index: 0,
+                    child_count: file_count,
                 });
                 if show_children {
                     let mut idx = 0;
@@ -340,6 +350,7 @@ impl SampleTree {
                                 label: fname.clone(),
                                 folder: name.clone(),
                                 index: idx,
+                                child_count: 0,
                             });
                             idx += 1;
                         }
@@ -362,6 +373,7 @@ pub struct SampleBrowserState {
     pub scroll_offset: usize,
     pub search_query: String,
     pub search_active: bool,
+    pub visible_height: Cell<usize>,
     filter: Option<Vec<String>>,
 }
 
@@ -373,6 +385,7 @@ impl SampleBrowserState {
             scroll_offset: 0,
             search_query: String::new(),
             search_active: false,
+            visible_height: Cell::new(20),
             filter: None,
         }
     }
@@ -427,6 +440,10 @@ impl SampleBrowserState {
         if self.scroll_offset > self.cursor {
             self.scroll_offset = self.cursor;
         }
+        let vh = self.visible_height.get();
+        if vh > 0 && self.cursor >= self.scroll_offset + vh {
+            self.scroll_offset = self.cursor - vh + 1;
+        }
     }
 
     pub fn move_up(&mut self) {
@@ -438,15 +455,16 @@ impl SampleBrowserState {
         }
     }
 
-    pub fn move_down(&mut self, visible_height: usize) {
+    pub fn move_down(&mut self) {
         let count = self.visible_count();
         if count == 0 {
             return;
         }
         if self.cursor + 1 < count {
             self.cursor += 1;
-            if self.cursor >= self.scroll_offset + visible_height {
-                self.scroll_offset = self.cursor - visible_height + 1;
+            let vh = self.visible_height.get();
+            if vh > 0 && self.cursor >= self.scroll_offset + vh {
+                self.scroll_offset = self.cursor - vh + 1;
             }
         }
     }