show pulsing buffering bar after 3 seconds

resources/playbar.blp

@@ -2,6 +2,16 @@ using Gtk 4.0;
 using Adw 1;
 
 template $AudreyUiPlaybar: Adw.Bin {
+  child: Overlay {
+    [overlay]
+    ProgressBar pulse_bar {
+      styles [
+        "osd"
+      ]
+      visible: bind template.show-pulse-bar;
+      valign: start;
+    }
+
     child: CenterBox {
       hexpand: true;
 
@@ -84,6 +94,7 @@ template $AudreyUiPlaybar: Adw.Bin {
             orientation: horizontal;
             width-request: 400;
             sensitive: bind template.idle-active inverted;
+
             adjustment: Adjustment {
               lower: 0;
               value: bind template.position;
@@ -172,4 +183,5 @@ template $AudreyUiPlaybar: Adw.Bin {
         }
       }
     };
+  };
 }

src/ui/playbar.rs

@@ -11,6 +11,10 @@ mod imp {
     #[properties(wrapper_type = super::Playbar)]
     #[template(resource = "/eu/callcc/audrey/playbar.ui")]
     pub struct Playbar {
+        #[template_child]
+        #[property(get)]
+        pulse_bar: TemplateChild<gtk::ProgressBar>,
+
         #[property(get, set)]
         song: RefCell<Option<PlaybinSong>>,
         #[property(get, set)]
@@ -34,6 +38,9 @@ mod imp {
         position: Cell<f64>,
         #[property(get, set)]
         duration: Cell<f64>,
+
+        #[property(get, set)]
+        _show_pulse_bar: Cell<bool>,
     }
 
     #[glib::object_subclass]

src/ui/window.rs

@@ -54,6 +54,8 @@ mod imp {
         #[property(type = u32, get = Self::playlist_count)]
         _playlist_count: (),
 
+        tick_callback: Cell<Option<gtk::TickCallbackId>>,
+
         pub(super) queued_seek: Cell<Option<f64>>,
 
         pub(crate) initial_setup_handle: RefCell<Option<JoinHandle<()>>>,
@@ -103,7 +105,9 @@ mod imp {
                 _idle_active: (),
                 _playlist_count: (),
 
-                queued_seek: Cell::new(None),
+                tick_callback: Default::default(),
+
+                queued_seek: Default::default(),
 
                 initial_setup_handle: Default::default(),
                 mpv_event_loop_handle: Default::default(),
@@ -202,7 +206,9 @@ mod imp {
                             },
 
                             Event::StartFile(_) => {
+                                event!(Level::INFO, "start file event");
                                 window.notify("song");
+                                window.imp().buffering_start();
                                 // TODO: load cover art
                             }
 
@@ -258,12 +264,12 @@ mod imp {
 
                             Event::Seek => {
                                 event!(Level::INFO, "seek event");
-                                // TODO: if doing "buffering" progress bar, show it after a timeout here
+                                window.imp().buffering_start();
                             }
 
                             Event::PlaybackRestart => {
                                 event!(Level::INFO, "playback restart event");
-                                // TODO: if doing "buffering" progress bar, hide it here
+                                window.imp().buffering_end();
 
                                 if let Some(queued_seek) = window.imp().queued_seek.take() {
                                     // a seek was tried before and failed, try again now
@@ -478,6 +484,25 @@ mod imp {
                 Some(song)
             }
         }
+
+        fn buffering_start(&self) {
+            let started_buffering = std::time::Instant::now();
+            self.tick_callback
+                .replace(Some(self.obj().add_tick_callback(move |window, _| {
+                    // 3 second period from gnome hig
+                    if started_buffering.elapsed() > std::time::Duration::from_secs(3) {
+                        window.imp().playbar.set_show_pulse_bar(true);
+                        window.imp().playbar.pulse_bar().pulse();
+                    }
+                    glib::ControlFlow::Continue
+                })))
+                .map(gtk::TickCallbackId::remove);
+        }
+
+        fn buffering_end(&self) {
+            self.tick_callback.take().map(gtk::TickCallbackId::remove);
+            self.playbar.set_show_pulse_bar(false);
+        }
     }
 
     impl Drop for Window {