improved scrolling and loading

src/main.rs

@@ -31,6 +31,8 @@ enum View {
         selected: usize,
         start_index: usize,
         total: usize,
+        page_size: usize,
+        loading: bool,
     },
     Login,
 }
@@ -106,7 +108,6 @@ impl Default for App {
     }
 }
 
-
 impl App {
     fn current_view(&self) -> &View {
         self.view_stack.last().unwrap()
@@ -281,6 +282,8 @@ fn handle_key(app: &mut App, code: KeyCode) {
                                 selected: 0,
                                 start_index: 0,
                                 total: page.total,
+                                page_size: PAGE_SIZE,
+                                loading: false,
                             });
                             app.status = "Loaded".to_string();
                         }
@@ -309,10 +312,25 @@ fn handle_key(app: &mut App, code: KeyCode) {
                     else { app.selected -= 1; }
                     app.status = format!("Selected: {}", app.items[app.selected]);
                 }
-                View::Library { items, selected, .. } => {
+                View::Library { items, selected, total, .. } => {
                     if items.is_empty() { return; }
-                    if *selected == 0 { *selected = items.len() - 1; }
+
-                    else { *selected -= 1; }
+                    if *selected == 0 {
+                        // wrap-up wants the real end
+                        if items.len() < *total {
+                            ensure_loaded_to_end(app);
+                        }
+
+                        if let Some(View::Library { items, selected, .. }) = app.view_stack.last_mut() {
+                            if !items.is_empty() {
+                                *selected = items.len() - 1;
+                            }
+                        }
+                    } else {
+                        *selected -= 1;
+                    }
+
+                    maybe_prefetch(app);
                 }
                 _ => {}
             }
@@ -341,15 +359,13 @@ fn handle_key(app: &mut App, code: KeyCode) {
                                 }
                             }
                         } else {
-                            // wrap or stop—choose behavior:
+                            *selected = 0;
-                            // stop at end:
-                            // do nothing
-                            // OR wrap:
-                            // *selected = 0;
                         }
                     } else {
                         *selected += 1;
                     }
+
+                    maybe_prefetch(app);
                 }
                 _ => {}
             }
@@ -361,66 +377,85 @@ fn handle_key(app: &mut App, code: KeyCode) {
 
 
 fn load_next_library_page(app: &mut App) {
-    // Only meaningful if the current view is Library
+    // pull info + mark loading
-    let (query, next_start, total) = match app.view_stack.last() {
+    let (query, next_start, total, page_size) = match app.view_stack.last_mut() {
-        Some(View::Library { query, items, total, start_index, .. }) => {
+        Some(View::Library { query, items, total, start_index, loading, page_size, .. }) => {
+            if *loading { return; }
+            *loading = true;
             let loaded = items.len();
-            let next_start = start_index + loaded;
+            let next_start = *start_index + loaded;
-            (query.clone(), next_start, *total)
+            (query.clone(), next_start, *total, *page_size)
         }
         _ => return,
     };
 
-    // If we already loaded everything, do nothing
-    let loaded = match app.view_stack.last() {
-        Some(View::Library { items, .. }) => items.len(),
-        _ => 0,
-    };
-    if loaded >= total {
-        return;
-    }
-
     let cfg = match &app.config {
         Some(c) => c.clone(),
-        None => {
+        None => { app.status = "No config loaded".to_string(); finish_loading(app); return; }
-            app.status = "No config loaded".to_string();
-            return;
-        }
     };
 
     let user_id = match cfg.user_id.as_deref() {
         Some(u) => u,
-        None => {
+        None => { app.status = "Missing user_id in config (login again)".to_string(); finish_loading(app); return; }
-            app.status = "Missing user_id in config (login again)".to_string();
-            return;
-        }
     };
 
     let client = match core::jellyfin::JellyfinClient::from_config(&cfg) {
         Ok(c) => c,
-        Err(e) => {
+        Err(e) => { app.status = e; finish_loading(app); return; }
-            app.status = e;
-            return;
-        }
     };
 
-    app.status = format!("Loading more... ({}/{})", loaded, total);
+    let page = match client.list_items(user_id, query.clone(), next_start, page_size) {
-
-    let page = match client.list_items(user_id, query.clone(), next_start, PAGE_SIZE) {
         Ok(p) => p,
-        Err(e) => {
+        Err(e) => { app.status = format!("Fetch failed: {e}"); finish_loading(app); return; }
-            app.status = format!("Fetch failed: {e}");
-            return;
-        }
     };
 
-    // Append the new items into the current library view
     if let Some(View::Library { items, total, .. }) = app.view_stack.last_mut() {
         items.extend(page.items);
-        *total = page.total; // keep total fresh in case server changes
+        *total = page.total;
     }
 
-    app.status = "Loaded more".to_string();
+    finish_loading(app);
+}
+
+fn finish_loading(app: &mut App) {
+    if let Some(View::Library { loading, .. }) = app.view_stack.last_mut() {
+        *loading = false;
+    }
+}
+
+
+fn maybe_prefetch(app: &mut App) {
+    const PREFETCH_ROWS: usize = 0;
+
+    let should = match app.view_stack.last() {
+        Some(View::Library { items, selected, total, loading, .. }) => {
+            if *loading { false }
+            else if items.len() >= *total { false }
+            else {
+                let remaining_loaded = items.len().saturating_sub(*selected);
+                remaining_loaded <= PREFETCH_ROWS
+            }
+        }
+        _ => false,
+    };
+
+    if should {
+        load_next_library_page(app);
+    }
+}
+
+fn ensure_loaded_to_end(app: &mut App) {
+    loop {
+        let done = match app.view_stack.last() {
+            Some(View::Library { items, total, loading, .. }) => {
+                !*loading && items.len() >= *total
+            }
+            _ => true,
+        };
+        if done { break; }
+
+        load_next_library_page(app);
+    }
 }
 
 
@@ -445,14 +480,27 @@ fn ui(frame: &mut Frame, app: &App) {
         }
     }
 
-    // Bottom
+    // Bottom Left
     frame.render_widget(
         Paragraph::new(app.status.as_str())
             .block(Block::bordered().title("Status").merge_borders(MergeStrategy::Exact)),
         panes.left_output,
     );
+    
+    // Bottom Right
+    let info = match app.current_view() {
+        View::Library { items, total, loading, .. } => {
+            if *loading {
+                format!("loading… {}/{}", items.len(), total)
+            } else {
+                format!("{}/{}", items.len(), total)
+            }
+        }
+        _ => app.config_status.clone(),
+    };
+
     frame.render_widget(
-        Paragraph::new(app.config_status.as_str())
+        Paragraph::new(info)
             .block(Block::bordered().title("Info").merge_borders(MergeStrategy::Exact)),
         panes.right_output,
     );
@@ -475,7 +523,6 @@ fn compute_window(len: usize, selected: usize, viewport: usize) -> (usize, usize
     (start, end)
 }
 
-
 fn render_categories(frame: &mut Frame, app: &App, left: Rect, right: Rect) {
     // how many rows can we show inside the bordered block?
     let viewport = left.height.saturating_sub(2) as usize;
@@ -528,7 +575,6 @@ fn render_placeholder(frame: &mut Frame, name: &str, left: Rect, right: Rect) {
     );
 }
 
-
 fn render_library(
     frame: &mut Frame,
     title: &str,