Extract ActivitesView updating logic into own class

client/src/activities_view.vala

@@ -1,8 +1,9 @@
 namespace StudySystemClient {
-	public class ActivitiesView : ListView<ActivityCard>, IRefreshable {
+	public class ActivitiesView : ListView<ActivityCard> {
 		private const uint REFRESH_PERIOD_MS = 30000;
 
 		private Client client;
+		private Updater updater;
 		private Refresher refresher;
 		private bool pending_sort;
 
@@ -10,31 +11,42 @@ namespace StudySystemClient {
 			base();
 			add_css_class("card-container");
 			this.client = client;
-			refresher = new Refresher(this, REFRESH_PERIOD_MS);
+			updater = new Updater(this, client);
+			refresher = new Refresher(updater, REFRESH_PERIOD_MS);
 			pending_sort = false;
 			this.map.connect(() => {
+					updater.refresh.begin();
 					refresher.start();
-					refresh.begin();
 				});
 		}
 
-		private async void refresh() {
+		internal IterableBox.Iterator<Type, ActivityCard> iterator() {
-			if (!client.connected)
+			return container.iterator();
-				return;
-			try {
-				var activities = yield client.list_activities();
-				update_cards(activities);
-			} catch (ClientError e) {
-				stderr.printf("Error refreshing activities: %s\n",
-							  e.message);
 		}
+
+		internal void new_card(Activity activity) {
+			var card = new ActivityCard(activity);
+			card.session_logged.connect(log_session);
+			card.log_closed.connect(handle_pending_sort);
+			container.append(card);
+		}
+
+		internal void remove_card(ActivityCard card) {
+			container.remove(card);
+		}
+
+		internal void sort() {
+			if (log_in_progress())
+				pending_sort = true;
+			else
+				container.sort(compare_cards);
 		}
 
 		private async void log_session(string subject, ActivityType type,
 									   int minutes) {
 			try {
 				yield client.log_session(subject, type, minutes);
-				yield refresh();
+				yield updater.refresh();
 			} catch (ClientError e) {
 				stderr.printf("Error logging session: %s\n", e.message);
 			}
@@ -47,54 +59,6 @@ namespace StudySystemClient {
 			}
 		}
 
-		private void update_cards(Array<Activity> activities) {
-			update_existing_cards(activities);
-			for (uint i = 0; i < activities.length; ++i)
-				create_card(activities.index(i));
-			if (log_in_progress())
-				pending_sort = true;
-			else
-				container.sort(compare_cards);
-		}
-
-		private void update_existing_cards(Array<Activity> activities) {
-			var to_remove = new List<ActivityCard>();
-			foreach (var card in container) {
-				if (!update_existing_card(card, activities))
-					to_remove.append(card);
-			}
-			foreach (var card in to_remove)
-				container.remove(card);
-		}
-
-		private bool update_existing_card(ActivityCard card,
-										  Array<Activity> activities) {
-			var activity_index = find_activity(card, activities);
-			if (activity_index == null)
-				return false;
-			var priority = activities.index(activity_index).priority;
-			card.update_priority(priority);
-			activities._remove_index_fast(activity_index);
-			return true;
-		}
-
-		private uint? find_activity(ActivityCard card,
-									Array<Activity> activities) {
-			for (uint i = 0; i < activities.length; ++i) {
-				if (activities.index(i).subject == card.activity.subject
-					&& activities.index(i).type == card.activity.type)
-					return i;
-			}
-			return null;
-		}
-
-		private void create_card(Activity activity) {
-			var card = new ActivityCard(activity);
-			card.session_logged.connect(log_session);
-			card.log_closed.connect(handle_pending_sort);
-			container.append(card);
-		}
-
 		private bool log_in_progress() {
 			foreach (var card in container) {
 				if (card.logging)
@@ -113,4 +77,64 @@ namespace StudySystemClient {
 				return 0;
 		}
 	}
+
+	private class Updater : IRefreshable {
+		private weak ActivitiesView target;
+		private Client client;
+
+		public Updater(ActivitiesView target, Client client) {
+			this.target = target;
+			this.client = client;
+		}
+
+		public async void refresh() {
+			if (!client.connected || target == null)
+				return;
+			try {
+				var activities = yield client.list_activities();
+				apply_update(activities);
+				target.sort();
+			} catch (ClientError e) {
+				stderr.printf("Error refreshing activities: %s\n",
+							  e.message);
+			}
+		}
+
+		private void apply_update(Array<Activity> activities) {
+			update_existing(activities);
+			for (uint i = 0; i < activities.length; ++i)
+				target.new_card(activities.index(i));
+		}
+
+		private void update_existing(Array<Activity> activities) {
+			var to_remove = new List<ActivityCard>();
+			foreach (var card in target) {
+				if (!update_card(card, activities))
+					to_remove.append(card);
+			}
+			foreach (var card in to_remove)
+				target.remove_card(card);
+		}
+
+		private bool update_card(ActivityCard card,
+								 Array<Activity> activities) {
+			var activity_index = find_activity(card, activities);
+			if (activity_index == null)
+				return false;
+			var priority = activities.index(activity_index).priority;
+			card.update_priority(priority);
+			activities._remove_index_fast(activity_index);
+			return true;
+		}
+
+		private static uint? find_activity(ActivityCard card,
+										   Array<Activity> activities) {
+			for (uint i = 0; i < activities.length; ++i) {
+				if (activities.index(i).subject == card.activity.subject
+					&& activities.index(i).type == card.activity.type)
+					return i;
+			}
+			return null;
+		}
+	}
 }