Use COUNT member in enums

The client is doing it itself now anyway.

client/src/activities_view.vala

@@ -1,134 +1,140 @@
 namespace StudySystemClient {
-	public class ActivitiesView : Gtk.Box {
+	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;
 
 		public ActivitiesView(Client client)  {
-			margin_top = margin_bottom = margin_start = margin_end = 0;
+			base();
+			add_css_class("card-container");
 			this.client = client;
-
-			var scrolled_window = new Gtk.ScrolledWindow();
-			scrolled_window.hscrollbar_policy = Gtk.PolicyType.NEVER;
-			scrolled_window.vexpand = true;
-
-			var card_container = new Gtk.FlowBox();
-			card_container.homogeneous = true;
-			card_container.min_children_per_line = 1;
-			card_container.max_children_per_line = 1;
-			card_container.selection_mode = Gtk.SelectionMode.NONE;
-			card_container.valign = Gtk.Align.START;
-			scrolled_window.add_css_class("card-container");
-
-			var activities = new Activity[] {
-				{ "Linguistics", ActivityType.EXERCISES },
-				{ "Cybernetics", ActivityType.EXERCISES },
-				{ "Linguistics", ActivityType.READING },
-				{ "Physics", ActivityType.READING },
-				{ "Cybernetics", ActivityType.READING },
-				{ "Physics", ActivityType.EXERCISES },
-			};
-			foreach (var activity in activities) {
-				var card = new ActivityCard(activity);
-				card.session_logged.connect(log_session);
-				card_container.append(card);
+			updater = new Updater(this, client);
+			refresher = new Refresher(updater, REFRESH_PERIOD_MS);
+			pending_sort = false;
+			this.map.connect(() => {
+					updater.refresh.begin();
+					refresher.start();
+				});
 		}
 
-			scrolled_window.set_child(card_container);
-			this.append(scrolled_window);
+		internal IterableBox.Iterator<Type, ActivityCard> iterator() {
+			return container.iterator();
+		}
+
+		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);
-				stderr.printf("Successfully logged session\n");
+				yield updater.refresh();
 			} catch (ClientError e) {
 				stderr.printf("Error logging session: %s\n", e.message);
 			}
 		}
-	}
 
-	private class ActivityCard : Gtk.Frame {
-		public signal void session_logged(string subject, ActivityType type,
-										  int minutes);
-
-		public ActivityCard(Activity activity) {
-			add_css_class("card");
-
-			var content = new Gtk.Box(Gtk.Orientation.HORIZONTAL, 12);
-
-			var text = new Gtk.Box(Gtk.Orientation.VERTICAL, 6);
-			text.hexpand = true;
-
-			var subject = new Gtk.Label(activity.subject);
-			subject.halign = Gtk.Align.START;
-			subject.add_css_class("activity-subject");
-			text.append(subject);
-
-			var type = new Gtk.Label(activity.type.to_string());
-			type.halign = Gtk.Align.START;
-			text.append(type);
-
-			content.append(text);
-
-			var button
-				= new Gtk.Button.from_icon_name("appointment-new-symbolic");
-			button.vexpand = false;
-			button.valign = Gtk.Align.CENTER;
-			button.set_tooltip_text("Log session");
-			button.add_css_class("log-session-button");
-			content.append(button);
-
-			set_child(content);
-
-			var log_session_popover = new LogSessionPopover();
-			log_session_popover.set_parent(button);
-			button.clicked.connect(() => log_session_popover.popup());
-			log_session_popover.session_logged.connect((minutes) => {
-					session_logged(activity.subject, activity.type, minutes);
-				});
+		private void handle_pending_sort() {
+			if (pending_sort) {
+				container.sort(compare_cards);
+				pending_sort = false;
 			}
 		}
 
-	private class LogSessionPopover : Gtk.Popover {
-		public signal void session_logged(int minutes);
-
-		private const int DEFAULT_LENGTH = 30;
-
-		private Gtk.SpinButton input;
-
-		public LogSessionPopover() {
-			var content = new Gtk.Box(Gtk.Orientation.HORIZONTAL, 6);
-
-			var label = new Gtk.Label("Minutes");
-			label.halign = Gtk.Align.START;
-			content.append(label);
-
-			var adjustment
-				= new Gtk.Adjustment(DEFAULT_LENGTH, 10, 480, 10, 10, 0);
-			input = new Gtk.SpinButton(adjustment, 1, 0);
-			input.numeric = true;
-			content.append(input);
-
-			var button = new Gtk.Button.from_icon_name("emblem-ok-symbolic");
-			button.halign = Gtk.Align.END;
-			button.set_tooltip_text("Submit");
-			button.add_css_class("suggested-action");
-			button.clicked.connect(submit);
-			content.append(button);
-
-			set_child(content);
-
-			closed.connect(reset);
+		private bool log_in_progress() {
+			foreach (var card in container) {
+				if (card.logging)
+					return true;
+			}
+			return false;
 		}
 
-		private void submit() {
-			session_logged((int)input.value);
-			reset();
-			popdown();
+		private static int compare_cards(ActivityCard card1,
+										 ActivityCard card2) {
+			if (card1.activity.priority < card2.activity.priority)
+				return -1;
+			else if (card1.activity.priority > card2.activity.priority)
+				return 1;
+			else
+				return 0;
+		}
 	}
 
-		private void reset() {
-			input.value = DEFAULT_LENGTH;
+	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;
 		}
 	}
 }

client/src/activity.vala

@@ -7,7 +7,9 @@ namespace StudySystemClient {
 
 	public enum ActivityType {
 		READING = 0,
-		EXERCISES = 1;
+		EXERCISES = 1,
+
+		COUNT;
 
 		public string to_string() {
 			switch (this) {

client/src/activity_card.vala

@@ -0,0 +1,122 @@
+namespace StudySystemClient {
+	public class ActivityCard : Gtk.Frame {
+		public signal void session_logged(string subject, ActivityType type,
+										  int minutes);
+		public signal void log_closed();
+
+		public Activity activity { get; private set; }
+		public bool logging { get; private set; }
+
+		private Gtk.Label priority_label;
+
+		public ActivityCard(Activity activity) {
+			hexpand = true;
+			add_css_class("card");
+
+			this.activity = activity;
+			logging = false;
+
+			var subject = new Gtk.Label(activity.subject);
+			subject.halign = Gtk.Align.START;
+			subject.add_css_class("activity-subject");
+
+			var type = new Gtk.Label(activity.type.to_string());
+			type.add_css_class("activity-type");
+			var separator = new Gtk.Label("·");
+			separator.add_css_class("activity-priority");
+
+			priority_label = new Gtk.Label(priority_text(activity.priority));
+			priority_label.add_css_class("activity-priority");
+
+			var details = new Gtk.Box(Gtk.Orientation.HORIZONTAL, 6);
+			details.append(type);
+			details.append(separator);
+			details.append(priority_label);
+
+			var text = new Gtk.Box(Gtk.Orientation.VERTICAL, 6);
+			text.hexpand = true;
+			text.append(subject);
+			text.append(details);
+
+			var content = new Gtk.Box(Gtk.Orientation.HORIZONTAL, 12);
+			content.append(text);
+
+			var button
+				= new Gtk.Button.from_icon_name("appointment-new-symbolic");
+			button.vexpand = false;
+			button.valign = Gtk.Align.CENTER;
+			button.set_tooltip_text("Log session");
+			button.add_css_class("log-session-button");
+			content.append(button);
+
+			set_child(content);
+
+			var log_session_popover = new LogSessionPopover();
+			log_session_popover.set_parent(button);
+			log_session_popover.closed.connect(() => {
+					logging = false;
+					log_closed();
+				});
+			log_session_popover.session_logged.connect((minutes) => {
+					session_logged(activity.subject, activity.type, minutes);
+				});
+
+			button.clicked.connect(() => {
+					logging = true;
+					log_session_popover.popup();
+				});
+		}
+
+		public void update_priority(double new_priority) {
+			activity = { activity.subject, activity.type, new_priority };
+			priority_label.set_text(priority_text(new_priority));
+		}
+
+		private static string priority_text(double priority) {
+			return "%0.2f".printf(priority);
+		}
+	}
+
+	private class LogSessionPopover : Gtk.Popover {
+		public signal void session_logged(int minutes);
+
+		private const int DEFAULT_LENGTH = 30;
+
+		private Gtk.SpinButton input;
+
+		public LogSessionPopover() {
+			var content = new Gtk.Box(Gtk.Orientation.HORIZONTAL, 6);
+
+			var label = new Gtk.Label("Minutes");
+			label.halign = Gtk.Align.START;
+			content.append(label);
+
+			var adjustment
+				= new Gtk.Adjustment(DEFAULT_LENGTH, 10, 480, 10, 10, 0);
+			input = new Gtk.SpinButton(adjustment, 1, 0);
+			input.numeric = true;
+			content.append(input);
+
+			var button = new Gtk.Button.from_icon_name("emblem-ok-symbolic");
+			button.halign = Gtk.Align.END;
+			button.set_tooltip_text("Submit");
+			button.add_css_class("suggested-action");
+			button.clicked.connect(submit);
+			content.append(button);
+
+			set_child(content);
+
+			closed.connect(reset);
+		}
+
+		private void submit() {
+			session_logged((int)input.value);
+			reset();
+			popdown();
+		}
+
+		private void reset() {
+			input.value = DEFAULT_LENGTH;
+		}
+	}
+}

client/src/client.vala

@@ -5,10 +5,16 @@ namespace StudySystemClient {
 	}
 
 	public class Client {
+		public signal void connection_status(bool connected);
+
+		public bool connected { get { return connection.connected; } }
+
 		private Connection connection;
 
 		public Client(string cert_dir) throws Error {
-			connection = new Connection(cert_dir);
+			connection = new Connection(cert_dir, (connected) => {
+					connection_status(connected);
+				});
 		}
 
 		public async void ping() throws ClientError {

client/src/connection.vala

@@ -1,17 +1,27 @@
 namespace StudySystemClient {
 	public class Connection {
+		public delegate void StatusCallback(bool connected);
+
+		public bool connected { get; private set; }
+
+		private StatusCallback status_callback;
 		private SessionManager session_manager;
 		private TransactionManager transaction_manager;
 		private Worker worker;
 
-		public Connection(string cert_dir) throws Error {
+		public Connection(string cert_dir,
+						  owned StatusCallback status_callback)
+		throws Error {
 			var loopback = new InetAddress.loopback(SocketFamily.IPV6);
 			var session_factory
 				= new SessionFactory(loopback, 12888, cert_dir);
+			this.status_callback = (owned) status_callback;
 			session_manager = new SessionManager(
-				session_factory, (msg) => receive(msg));
+				session_factory, (msg) => receive(msg),
+				(connected) => update_status(connected));
 			transaction_manager = new TransactionManager();
 			worker = new Worker(session_manager);
+			connected = true;
 		}
 
 		public async Response.Body? send(Request.Body body) {
@@ -35,6 +45,16 @@ namespace StudySystemClient {
 					return false;
 				}, GLib.Priority.DEFAULT_IDLE);
 		}
+
+		private void update_status(bool connected) {
+			Idle.add(() => {
+					if (connected != this.connected) {
+						this.connected = connected;
+						status_callback(connected);
+					}
+					return false;
+				}, GLib.Priority.DEFAULT_IDLE);
+		}
 	}
 
 	private class Continuation {
@@ -84,29 +104,19 @@ namespace StudySystemClient {
 		}
 	}
 
-	private class Worker {
-		private uint TASK_PERIOD_MS = 10;
+	private class Worker : Periodic {
+		private const uint TASK_PERIOD_MS = 10;
 
 		private SessionManager session_manager;
-		private bool exit;
-		private Thread<void> thread;
 
 		public Worker(SessionManager session_manager) {
+			base(TASK_PERIOD_MS);
 			this.session_manager = session_manager;
-			exit = false;
-			thread = new Thread<void>("connection_worker", body);
+			start();
 		}
 
-		~Worker() {
-			exit = true;
-			thread.join();
-		}
-
-		private void body() {
-			while (!exit) {
+		protected override void task() {
 			session_manager.task();
-				Thread.usleep(1000 * TASK_PERIOD_MS);
-			}
 		}
 	}
 }

client/src/iterable_box.vala

@@ -0,0 +1,52 @@
+namespace StudySystemClient {
+	public class IterableBox<T> : Gtk.Box {
+		private List<T> elements;
+
+		public IterableBox(Gtk.Orientation orientation, int spacing) {
+			this.orientation = orientation;
+			this.spacing = spacing;
+			elements = new List<T>();
+		}
+
+		public new void append(T element) {
+			elements.append(element);
+			base.append(element as Gtk.Widget);
+		}
+
+		public new void remove(T element) {
+			elements.remove(element);
+			base.remove(element as Gtk.Widget);
+		}
+
+		public Iterator<Type, T> iterator() {
+			return new Iterator<Type, T>(elements);
+		}
+
+		public void sort(CompareDataFunc<T> comparison) {
+			elements.sort_with_data(comparison);
+			foreach (var element in elements)
+				reorder_child_after(element as Gtk.Widget, null);
+		}
+
+		public class Iterator<Type, T> {
+			private unowned List<T> head;
+			private unowned T value;
+
+			public Iterator(List<T> elements) {
+				head = elements;
+			}
+
+			public bool next() {
+				if (head.is_empty())
+					return false;
+				value = head.data;
+				head = head.next;
+				return true;
+			}
+
+			public unowned T get() {
+				return value;
+			}
+		}
+	}
+}

client/src/list_view.vala

@@ -0,0 +1,20 @@
+namespace StudySystemClient {
+	public class ListView<T> : Gtk.Box {
+		protected IterableBox<T> container;
+
+		public ListView() {
+			hexpand = vexpand = true;
+			margin_top = margin_bottom = margin_start = margin_end = 0;
+
+			container = new IterableBox<T>(Gtk.Orientation.VERTICAL, 6);
+			container.valign = Gtk.Align.START;
+
+			var scrolled_window = new Gtk.ScrolledWindow();
+			scrolled_window.hscrollbar_policy = Gtk.PolicyType.NEVER;
+			scrolled_window.hexpand = scrolled_window.vexpand = true;
+			scrolled_window.set_child(container);
+
+			append(scrolled_window);
+		}
+	}
+}

client/src/main_window.vala

@@ -12,8 +12,38 @@ namespace StudySystemClient {
 			header_bar.title_widget = title;
 			set_titlebar(header_bar);
 
+			var connection_indicator = new ConnectionIndicator(client);
 			var activities_view = new ActivitiesView(client);
-			set_child(activities_view);
+
+			var content = new Gtk.Box(Gtk.Orientation.VERTICAL, 0);
+			content.append(connection_indicator);
+			content.append(activities_view);
+
+			set_child(content);
+		}
+	}
+
+	private class ConnectionIndicator : Gtk.Box {
+		public ConnectionIndicator(Client client) {
+			var icon
+				= new Gtk.Image.from_icon_name("network-offline-symbolic");
+			var label = new Gtk.Label("Disconnected");
+
+			var content = new Gtk.Box(Gtk.Orientation.HORIZONTAL, 8);
+			content.margin_top = content.margin_bottom
+				= content.margin_start = content.margin_end = 12;
+			content.hexpand = true;
+			content.halign = Gtk.Align.CENTER;
+			content.append(icon);
+			content.append(label);
+
+			var revealer = new Gtk.Revealer();
+			revealer.set_child(content);
+			append(revealer);
+
+			client.connection_status.connect((connected) => {
+					revealer.reveal_child = !connected;
+				});
 		}
 	}
 }

client/src/meson.build

@@ -10,12 +10,17 @@ configure_file(
 lib = library(
   'study-system-client',
   sources: files(
-    'activity.vala',
     'activities_view.vala',
+    'activity.vala',
+    'activity_card.vala',
     'client.vala',
     'connection.vala',
     'der.vala',
+    'iterable_box.vala',
+    'list_view.vala',
     'main_window.vala',
+    'periodic.vala',
+    'refresher.vala',
     'request.vala',
     'response.vala',
     'session_manager.vala',

client/src/periodic.vala

@@ -0,0 +1,35 @@
+namespace StudySystemClient {
+	public abstract class Periodic {
+		private uint period_ms;
+		private bool exit;
+		private Thread<void> thread;
+
+		protected Periodic(uint period_ms) {
+			this.period_ms = period_ms;
+			exit = true;
+		}
+
+		~Periodic() {
+			if (!exit) {
+				exit = true;
+				thread.join();
+			}
+		}
+
+		protected abstract void task();
+
+		public void start() {
+			if (exit) {
+				exit = false;
+				thread = new Thread<void>("Periodic task", body);
+			}
+		}
+
+		private void body() {
+			while (!exit) {
+				task();
+				Thread.usleep(1000 * period_ms);
+			}
+		}
+	}
+}

client/src/refresher.vala

@@ -0,0 +1,23 @@
+namespace StudySystemClient {
+	public interface IRefreshable {
+		public abstract async void refresh();
+	}
+
+	private class Refresher : Periodic {
+		private weak IRefreshable target;
+
+		public Refresher(IRefreshable target, uint period_ms) {
+			base(period_ms);
+			this.target = target;
+		}
+
+		protected override void task() {
+			if (target != null) {
+				Idle.add(() => {
+						target.refresh.begin();
+						return false;
+					});
+			}
+		}
+	}
+}

client/src/response.vala

@@ -40,7 +40,7 @@ namespace StudySystemClient.Response {
 		protected enum Tag {
 			ERROR = 0,
 			ACK = 1,
-			PRIORITIZED_ACTIVITIES = 2,
+			ACTIVITIES = 2,
 		}
 
 		internal static Body from_datum(Der.Datum datum) throws DecodeError {
@@ -54,9 +54,8 @@ namespace StudySystemClient.Response {
 				return new Error.from_datum(choice.value);
 			case Tag.ACK:
 				return new Ack.from_datum(choice.value);
-			case Tag.PRIORITIZED_ACTIVITIES:
-				throw new DecodeError.NOT_IMPLEMENTED(
-					"PrioritizedActivities not yet implemented");
+			case Tag.ACTIVITIES:
+				return new Activities.from_datum(choice.value);
 			default:
 				throw new DecodeError.INVALID_BODY(
 					"Invalid ResponseBody tag");
@@ -68,7 +67,9 @@ namespace StudySystemClient.Response {
 		public enum Value {
 			INVALID_REQUEST = 0,
 			INVALID_ARGUMENTS = 1,
-			SERVER_ERROR = 2;
+			SERVER_ERROR = 2,
+
+			COUNT;
 
 			public string to_string() {
 				switch (this) {
@@ -92,9 +93,9 @@ namespace StudySystemClient.Response {
 				throw new DecodeError.INVALID_BODY(
 					"Error was not an ENUMERATED");
 			}
-			if (enumerated.value < 0 || enumerated.value > 2) {
+			if (enumerated.value < 0 || enumerated.value >= Value.COUNT) {
 				throw new DecodeError.INVALID_BODY(
-					"Error type was not in range 0..2");
+					"Error type was not in range 0..$(Value.COUNT)");
 			}
 			value = (Value)enumerated.value;
 		}
@@ -163,7 +164,7 @@ namespace StudySystemClient.Response {
 			string name, Der.Datum datum) throws DecodeError {
 			if (datum is Der.Enumerated) {
 				var value = datum.value;
-				if (0 <= value <= 1)
+				if (0 <= value < ActivityType.COUNT)
 					return (ActivityType)value;
 				throw new DecodeError.INVALID_BODY(
 					"Invalid value for ActivityType: %lld", value);

client/src/session_manager.vala

@@ -3,19 +3,23 @@ namespace StudySystemClient {
 		public delegate void ReceiveCallback(owned uint8[] msg);
 
 		private const uint INIT_RECONNECT_WAIT_MS = 500;
-		private const uint MAX_RECONNECT_WAIT_MS = 60000;
+		private const uint MAX_RECONNECT_WAIT_MS = 30000;
 		private const double RECONNECT_BACKOFF = 1.6;
 
 		private SessionFactory session_factory;
 		private ReceiveCallback receive_callback;
+		private Connection.StatusCallback status_callback;
 		private Session? session;
 		private AsyncQueue<OutgoingMessage> queue;
 		private uint reconnect_wait_ms;
 
-		public SessionManager(SessionFactory session_factory,
-							  owned ReceiveCallback receive_callback) {
+		public SessionManager(
+			SessionFactory session_factory,
+			owned ReceiveCallback receive_callback,
+			owned Connection.StatusCallback status_callback) {
 			this.session_factory = session_factory;
 			this.receive_callback = (owned) receive_callback;
+			this.status_callback = (owned) status_callback;
 			this.session = null;
 			queue = new AsyncQueue<OutgoingMessage>();
 			reconnect_wait_ms = INIT_RECONNECT_WAIT_MS;
@@ -40,6 +44,7 @@ namespace StudySystemClient {
 			if (msg.should_retry())
 				queue.push(msg);
 			session = null;
+			status_callback(false);
 		}
 
 		private void try_start_session() {
@@ -47,7 +52,9 @@ namespace StudySystemClient {
 				session = session_factory.start_session();
 				session.received.connect((msg) => receive_callback(msg));
 				reconnect_wait_ms = INIT_RECONNECT_WAIT_MS;
+				status_callback(true);
 			} catch (Error _) {
+				status_callback(false);
 				Thread.usleep(1000 * reconnect_wait_ms);
 				update_reconnect_wait();
 			}
@@ -65,7 +72,7 @@ namespace StudySystemClient {
 	public class SessionFactory {
 		private const string CA_FILENAME = "/ca.pem";
 		private const string CERT_FILENAME = "/client.pem";
-		private const uint TIMEOUT_S = 5;
+		private const uint TIMEOUT_S = 2;
 
 		private InetSocketAddress host;
 		private TlsCertificate cert;

client/styles.css

@@ -1,11 +1,11 @@
 .card-container {
-	background-color: mix(@theme_base_color, @theme_bg_color, 0.7);
+	background-color: color-mix(in oklab, @theme_base_color,
+								@theme_bg_color 60%);
 	padding: 6px;
 }
 
 .card {
-	border: 1px solid alpha(@theme_fg_color, 0.2);
-	box-shadow: 0 1px 2px alpha(black, 0.15);
+	box-shadow: 0 1px 2px rgba(0, 0, 0, 0.15);
 	background-color: @theme_bg_color;
 	padding: 12px 16px;
 }
@@ -14,6 +14,10 @@
 	font-weight: bold;
 }
 
+.activity-priority {
+	color: color-mix(in oklab, @theme_fg_color 60%, @theme_bg_color);
+}
+
 /*
  * The visual center (i.e. the center of the clock) of the
  * "appointment-new-symbolic" icon is slightly displaced from the

server/src/session_server.erl

@@ -12,6 +12,7 @@ start_link(Socket) ->
 	gen_server:start_link(?MODULE, Socket, []).
 
 init(Socket) ->
+	ok = ssl:controlling_process(Socket, self()),
 	ok = ssl:setopts(Socket, [{active, true}]),
 	process_flag(trap_exit, true),
 	{ok, #{socket => Socket, transactions => #{}}}.
@@ -38,9 +39,7 @@ handle_info({'EXIT', Pid, Reason},
 	TransactionId = maps:get(Pid, Transactions),
 	Response = case Reason of
 				   {response, Value} -> Value;
-				   _ ->
-					   io:format("Error handling request: ~p~n", [Reason]),
-					   {error, serverError}
+				   _ -> {error, serverError}
 			   end,
 	send(Socket, TransactionId, Response),
 	{noreply, State#{transactions := maps:remove(Pid, Transactions)}};
@@ -59,19 +58,24 @@ code_change(_OldVsn, State, _Extra) ->
 
 handle_request(Request) ->
 	timer:kill_after(500),
-	exit(map_request(Request)).
+	exit({response, map_request(Request)}).
 
 map_request({ping, 'NULL'}) ->
-	{response, {ack, 'NULL'}};
+	{ack, 'NULL'};
+map_request({listActivities, 'NULL'}) ->
+	{activities, Activities} = subject_router:get_activities(),
+	{activities,
+	 [{'Activity', Subject, Type, round(Priority * 100)}
+	  || {Subject, Type, Priority} <- Activities]};
 map_request({logSession, {'Session', Subject, Type, Timestamp, Minutes}}) ->
 	Session = {unicode:characters_to_list(Subject),
 			   Type, Timestamp, Minutes},
 	case subject_router:log_session(Session) of
-		ok -> {response, {ack, 'NULL'}};
-		{error, invalid_subject} -> {response, {error, invalidArguments}}
+		ok -> {ack, 'NULL'};
+		{error, _Error} -> {error, invalidArguments}
 	end;
 map_request(_) ->
-	{response, {error, invalidArguments}}.
+	{error, invalidArguments}.
 
 send(Socket, TransactionId, Response) ->
 	{ok, Encoded} = 'StudySystemProtocol':encode(

server/src/subject_router.erl

@@ -4,7 +4,7 @@
 -module(subject_router).
 -behaviour(gen_server).
 
--export([start_link/0, log_session/1]).
+-export([start_link/0, log_session/1, get_activities/0]).
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
 		 terminate/2, code_change/3]).
 
@@ -14,6 +14,9 @@ start_link() ->
 log_session(Session) ->
 	gen_server:call(?MODULE, {log_session, Session}).
 
+get_activities() ->
+	gen_server:call(?MODULE, get_activities).
+
 init([]) ->
 	{MonitorRef, Pids} = pg:monitor(study_system_server, subject_servers),
 	SubjectTable = ets:new(subject_table, [private]),
@@ -25,11 +28,19 @@ handle_call({log_session, {Subject, Type, Timestamp, Minutes}},
 			_From, State = #{subject_table := SubjectTable}) ->
 	case ets:lookup(SubjectTable, Subject) of
 		[{Subject, Pid}] ->
-			Pid ! {new_session, Type, Timestamp, Minutes},
-			{reply, ok, State};
+			{reply,
+			 subject_server:log_session(Pid, Type, Timestamp, Minutes),
+			 State};
 		[] ->
 			{reply, {error, invalid_subject}, State}
 	end;
+handle_call(get_activities, _From,
+			State = #{subject_table := SubjectTable}) ->
+	Pids = lists:flatten(ets:match(SubjectTable, {'_', '$1'})),
+	Activities = lists:flatmap(
+				   fun(Pid) -> subject_server:get_activities(Pid) end,
+				   Pids),
+	{reply, {activities, Activities}, State};
 handle_call(_Request, _From, State) ->
 	{reply, ok, State}.
 
@@ -62,7 +73,7 @@ register_servers(SubjectTable, Pids) ->
 
 register_server(SubjectTable, Pid) ->
 	try
-		{subject, Subject} = gen_server:call(Pid, get_subject),
+		{subject, Subject} = subject_server:get_subject(Pid),
 		ets:insert(SubjectTable, {Subject, Pid})
 	catch
 		_:_ -> ok

server/src/subject_server.erl

@@ -4,31 +4,52 @@
 -module(subject_server).
 -behaviour(gen_server).
 
--export([start_link/1]).
+-export([start_link/1, get_subject/1, get_activities/1, log_session/4]).
 -export([init/1, handle_call/3, handle_cast/2, handle_info/2,
 		 terminate/2, code_change/3]).
 
 start_link(Subject) ->
 	gen_server:start_link(?MODULE, Subject, []).
 
+get_subject(Pid) ->
+	gen_server:call(Pid, get_subject).
+
+get_activities(Pid) ->
+	gen_server:call(Pid, get_activities).
+
+log_session(Pid, Type, Timestamp, Minutes) ->
+	gen_server:call(Pid, {log_session, {Type, Timestamp, Minutes}}).
+
 init(Subject) ->
 	pg:join(study_system_server, subject_servers, self()),
-	{ok, #{subject => Subject}}.
+	{ok, #{subject => Subject,
+		   priorities => #{reading => rand:uniform(),
+						   exercises => rand:uniform()}}}.
 
 handle_call(get_subject, _From, State = #{subject := Subject}) ->
 	{reply, {subject, Subject}, State};
+handle_call(get_activities, _From,
+			State = #{subject := Subject,
+					  priorities := #{reading := ReadingPriority,
+									  exercises := ExercisesPriority}}) ->
+	Reading = {Subject, reading, ReadingPriority},
+	Exercises = {Subject, exercises, ExercisesPriority},
+	{reply, [Reading, Exercises], State};
+handle_call({log_session, {Type, Timestamp, Minutes}}, _From,
+			State = #{subject := Subject, priorities := Priorities}) ->
+	case Priorities of
+		#{Type := Priority} ->
+			UpdatedPriorities = Priorities#{Type := Priority * 0.667},
+			{reply, ok, State#{priorities := UpdatedPriorities}};
+		_ ->
+			{reply, {error, invalid_type}, State}
+	end;
 handle_call(_Request, _From, State) ->
 	{reply, ok, State}.
 
 handle_cast(_Msg, State) ->
 	{noreply, State}.
 
-handle_info({new_session, Type, Timestamp, Minutes},
-			State = #{subject := Subject}) ->
-	io:format(
-	  "Received new ~p session: type ~p, timestamp ~p, minutes ~p~n",
-	  [Subject, Type, Timestamp, Minutes]),
-	{noreply, State};
 handle_info(_Info, State) ->
 	{noreply, State}.
 

server/src/tcp_server.erl

@@ -41,8 +41,7 @@ handle_info(accept, State = #state{socket = Socket}) ->
 handle_info({handshake, TlsSocket}, State) ->
 	case ssl:handshake(TlsSocket, 5000) of
 		{ok, ClientSocket} ->
-			{ok, Pid} = session_sup:start_session(ClientSocket),
-			ok = ssl:controlling_process(ClientSocket, Pid);
+			{ok, _Pid} = session_sup:start_session(ClientSocket);
 		{error, _Reason} ->
 			ok
 	end,