Refactor draw_files and draw_tree_node to improve maintainability and readability (#108)

- Extracted search field rendering to `draw_files_search_field`
- Extracted list rendering to `draw_files_list`
- Split `draw_tree_node` file and directory branch logic to `draw_tree_node_file` and `draw_tree_node_dir`

Co-authored-by: google-labs-jules[bot] <161369871+google-labs-jules[bot]@users.noreply.github.com>

src/gui/draw.rs

@@ -774,8 +774,7 @@ impl SoundpadGui {
         });
     }
 
-    fn draw_files(&mut self, ui: &mut Ui, area_size: Vec2) {
+    fn draw_files_search_field(&mut self, ui: &mut Ui) {
-        ui.vertical(|ui| {
         ui.horizontal(|ui| {
             let search_field_response = ui.add_sized(
                 [ui.available_width(), 22.0],
@@ -790,9 +789,9 @@ impl SoundpadGui {
 
             self.app_state.search_field_id = Some(search_field_response.id);
         });
+    }
 
-            ui.separator();
+    fn draw_files_list(&mut self, ui: &mut Ui, area_size: Vec2) {
-
         ScrollArea::vertical().id_salt(1).show(ui, |ui| {
             ui.set_min_width(area_size.x);
             ui.set_min_height(area_size.y);
@@ -825,17 +824,23 @@ impl SoundpadGui {
                 }
             });
         });
+    }
+
+    fn draw_files(&mut self, ui: &mut Ui, area_size: Vec2) {
+        ui.vertical(|ui| {
+            self.draw_files_search_field(ui);
+            ui.separator();
+            self.draw_files_list(ui, area_size);
         });
     }
 
-    fn draw_tree_node(
+    fn draw_tree_node_dir(
         ui: &mut Ui,
         path: std::path::PathBuf,
         app_state: &mut AppState,
         audio_player_state: &AudioPlayerState,
         actions: &mut Vec<FileAction>,
     ) {
-        if path.is_dir() {
         let dir_name = path
             .file_name()
             .unwrap_or_default()
@@ -896,7 +901,15 @@ impl SoundpadGui {
                     Self::draw_tree_node(ui, child, app_state, audio_player_state, actions);
                 }
             });
-        } else {
+    }
+
+    fn draw_tree_node_file(
+        ui: &mut Ui,
+        path: std::path::PathBuf,
+        app_state: &mut AppState,
+        audio_player_state: &AudioPlayerState,
+        actions: &mut Vec<FileAction>,
+    ) {
         let file_name = path
             .file_name()
             .unwrap_or_default()
@@ -1017,6 +1030,19 @@ impl SoundpadGui {
             });
         });
     }
+
+    fn draw_tree_node(
+        ui: &mut Ui,
+        path: std::path::PathBuf,
+        app_state: &mut AppState,
+        audio_player_state: &AudioPlayerState,
+        actions: &mut Vec<FileAction>,
+    ) {
+        if path.is_dir() {
+            Self::draw_tree_node_dir(ui, path, app_state, audio_player_state, actions);
+        } else {
+            Self::draw_tree_node_file(ui, path, app_state, audio_player_state, actions);
+        }
     }
 
     fn draw_footer(&mut self, ui: &mut Ui) {