desktop-app: Extract application logic from rendering

Author: uklotzde

demo-app/src/library/mod.rs

@@ -131,10 +131,23 @@ impl Library {
         }
     }
 
+    pub fn could_reset_music_dir(&self) -> bool {
+        self.state()
+            .settings()
+            .read_observable()
+            .music_dir
+            .is_some()
+    }
+
     pub fn reset_music_dir(&self) {
         self.update_music_dir(None);
     }
 
+    pub fn could_spawn_rescan_collection_task(&self) -> bool {
+        self.pending_rescan_collection_task.is_none()
+            && self.state().collection().read_observable().is_ready()
+    }
+
     pub fn spawn_rescan_collection_task(&mut self, rt: &tokio::runtime::Handle) -> bool {
         if let Some(rescan_collection_task) = self.pending_rescan_collection_task.as_ref() {
             if rescan_collection_task.is_finished() {
@@ -165,10 +178,6 @@ impl Library {
         changed
     }
 
-    pub const fn has_pending_rescan_collection_task(&self) -> bool {
-        self.pending_rescan_collection_task.is_some()
-    }
-
     pub fn abort_pending_rescan_collection_task(&mut self) -> Option<SynchronizeVfsTask> {
         let pending_rescan_collection_task = self.pending_rescan_collection_task.take();
         let Some(rescan_collection_task) = pending_rescan_collection_task else {
@@ -200,6 +209,14 @@ impl Library {
         }
     }
 
+    pub fn could_spawn_fetch_more_track_search_results(&self) -> bool {
+        self.state
+            .track_search()
+            .read_observable()
+            .can_fetch_more()
+            .unwrap_or(false)
+    }
+
     pub fn spawn_fetch_more_track_search_results<E>(
         &self,
         tokio_rt: &tokio::runtime::Handle,

demo-app/src/main.rs

@@ -476,7 +476,7 @@ impl eframe::App for App {
                     ui.label("");
                     if ui
                         .add_enabled(
-                            settings_state.music_dir.is_some(),
+                            self.library.could_reset_music_dir(),
                             Button::new("Reset music directory"),
                         )
                         .clicked()
@@ -521,8 +521,7 @@ impl eframe::App for App {
                     ui.label("");
                     if ui
                         .add_enabled(
-                            collection_state.is_ready()
-                                && !self.library.has_pending_rescan_collection_task(),
+                            self.library.could_spawn_rescan_collection_task(),
                             Button::new("Rescan collection"),
                         )
                         .clicked()
@@ -556,7 +555,7 @@ impl eframe::App for App {
                 .show(ui, |ui| {
                     if ui
                         .add_enabled(
-                            track_search_state.can_fetch_more().unwrap_or(false),
+                            self.library.could_spawn_fetch_more_track_search_results(),
                             Button::new("Fetch more"),
                         )
                         .clicked()