SEBSP-107: Implemented screen proctoring finalization.

SafeExamBrowser.Client/ClientContext.cs

@@ -13,6 +13,7 @@ using SafeExamBrowser.Browser.Contracts;
 using SafeExamBrowser.Communication.Contracts.Hosts;
 using SafeExamBrowser.Configuration.Contracts;
 using SafeExamBrowser.Configuration.Contracts.Integrity;
+using SafeExamBrowser.Proctoring.Contracts;
 using SafeExamBrowser.Server.Contracts;
 using SafeExamBrowser.Settings;
 using SafeExamBrowser.UserInterface.Contracts.Shell;
@@ -54,6 +55,11 @@ namespace SafeExamBrowser.Client
 		/// </summary>
 		internal IIntegrityModule IntegrityModule { get; set; }
 
+		/// <summary>
+		/// The proctoring controller to be used if the current session has proctoring enabled.
+		/// </summary>
+		internal IProctoringController Proctoring { get; set; }
+
 		/// <summary>
 		/// The server proxy to be used if the current session mode is <see cref="SessionMode.Server"/>.
 		/// </summary>

SafeExamBrowser.Client/ClientController.cs

@@ -30,6 +30,8 @@ using SafeExamBrowser.Logging.Contracts;
 using SafeExamBrowser.Monitoring.Contracts.Applications;
 using SafeExamBrowser.Monitoring.Contracts.Display;
 using SafeExamBrowser.Monitoring.Contracts.System;
+using SafeExamBrowser.Proctoring.Contracts;
+using SafeExamBrowser.Proctoring.Contracts.Events;
 using SafeExamBrowser.Server.Contracts;
 using SafeExamBrowser.Server.Contracts.Data;
 using SafeExamBrowser.Settings;
@@ -68,6 +70,7 @@ namespace SafeExamBrowser.Client
 		private IBrowserApplication Browser => context.Browser;
 		private IClientHost ClientHost => context.ClientHost;
 		private IIntegrityModule IntegrityModule => context.IntegrityModule;
+		private IProctoringController Proctoring => context.Proctoring;
 		private IServerProxy Server => context.Server;
 		private AppSettings Settings => context.Settings;
 
@@ -230,16 +233,6 @@ namespace SafeExamBrowser.Client
 			}
 		}
 
-		private void Taskbar_LoseFocusRequested(bool forward)
-		{
-			Browser.Focus(forward);
-		}
-
-		private void Browser_LoseFocusRequested(bool forward)
-		{
-			taskbar.Focus(forward);
-		}
-
 		private void DeregisterEvents()
 		{
 			actionCenter.QuitButtonClicked -= Shell_QuitButtonClicked;
@@ -249,6 +242,7 @@ namespace SafeExamBrowser.Client
 			registry.ValueChanged -= Registry_ValueChanged;
 			runtime.ConnectionLost -= Runtime_ConnectionLost;
 			systemMonitor.SessionChanged -= SystemMonitor_SessionChanged;
+			taskbar.LoseFocusRequested -= Taskbar_LoseFocusRequested;
 			taskbar.QuitButtonClicked -= Shell_QuitButtonClicked;
 
 			if (Browser != null)
@@ -327,6 +321,29 @@ namespace SafeExamBrowser.Client
 			}
 		}
 
+		private void PrepareShutdown()
+		{
+			FinalizeProctoring();
+		}
+
+		private void FinalizeProctoring()
+		{
+			if (Proctoring != default && Proctoring.HasRemainingWork())
+			{
+				var dialog = uiFactory.CreateProctoringFinalizationDialog();
+				var handler = new RemainingWorkUpdatedEventHandler((args) => dialog.Update(args));
+
+				Task.Run(() =>
+				{
+					Proctoring.RemainingWorkUpdated += handler;
+					Proctoring.ExecuteRemainingWork();
+					Proctoring.RemainingWorkUpdated -= handler;
+				});
+
+				dialog.Show();
+			}
+		}
+
 		private void ScheduleIntegrityVerification()
 		{
 			const int FIVE_MINUTES = 300000;
@@ -510,6 +527,8 @@ namespace SafeExamBrowser.Client
 		{
 			if (success)
 			{
+				PrepareShutdown();
+
 				var communication = runtime.RequestReconfiguration(filePath, url);
 
 				if (communication.Success)
@@ -531,6 +550,11 @@ namespace SafeExamBrowser.Client
 			}
 		}
 
+		private void Browser_LoseFocusRequested(bool forward)
+		{
+			taskbar.Focus(forward);
+		}
+
 		private void Browser_UserIdentifierDetected(string identifier)
 		{
 			if (Settings.SessionMode == SessionMode.Server)
@@ -876,6 +900,11 @@ namespace SafeExamBrowser.Client
 			}
 		}
 
+		private void Taskbar_LoseFocusRequested(bool forward)
+		{
+			Browser.Focus(forward);
+		}
+
 		private void TerminationActivator_Activated()
 		{
 			PauseActivators();
@@ -1023,19 +1052,19 @@ namespace SafeExamBrowser.Client
 		private bool TryInitiateShutdown()
 		{
 			var hasQuitPassword = !string.IsNullOrEmpty(Settings.Security.QuitPasswordHash);
-			var requestShutdown = false;
+			var initiateShutdown = false;
 			var succes = false;
 
 			if (hasQuitPassword)
 			{
-				requestShutdown = TryValidateQuitPassword();
+				initiateShutdown = TryValidateQuitPassword();
 			}
 			else
 			{
-				requestShutdown = TryConfirmShutdown();
+				initiateShutdown = TryConfirmShutdown();
 			}
 
-			if (requestShutdown)
+			if (initiateShutdown)
 			{
 				succes = TryRequestShutdown();
 			}
@@ -1084,6 +1113,8 @@ namespace SafeExamBrowser.Client
 
 		private bool TryRequestShutdown()
 		{
+			PrepareShutdown();
+
 			var communication = runtime.RequestShutdown();
 
 			if (!communication.Success)

SafeExamBrowser.Client/CompositionRoot.cs

@@ -301,6 +301,8 @@ namespace SafeExamBrowser.Client
 				uiFactory);
 			var operation = new ProctoringOperation(actionCenter, context, controller, logger, taskbar, uiFactory);
 
+			context.Proctoring = controller;
+
 			return operation;
 		}
 

SafeExamBrowser.I18n.Contracts/TextKey.cs

@@ -232,6 +232,14 @@ namespace SafeExamBrowser.I18n.Contracts
 		PasswordDialog_QuitPasswordRequiredTitle,
 		PasswordDialog_SettingsPasswordRequired,
 		PasswordDialog_SettingsPasswordRequiredTitle,
+		// TODO: Translate text for ProctoringFinalizationDialog_... to remaining languages!
+		ProctoringFinalizationDialog_Confirm,
+		ProctoringFinalizationDialog_FailureMessage,
+		ProctoringFinalizationDialog_InfoMessage,
+		ProctoringFinalizationDialog_Status,
+		ProctoringFinalizationDialog_StatusAndTime,
+		ProctoringFinalizationDialog_StatusWaiting,
+		ProctoringFinalizationDialog_Title,
 		RuntimeWindow_ApplicationRunning,
 		ServerFailureDialog_Abort,
 		ServerFailureDialog_Fallback,

SafeExamBrowser.I18n/Data/de.xml

@@ -654,6 +654,27 @@
     <Entry key="PasswordDialog_SettingsPasswordRequiredTitle">
         Passwort erforderlich
     </Entry>
+    <Entry key="ProctoringFinalizationDialog_Confirm">
+        Bestätigen
+    </Entry>
+    <Entry key="ProctoringFinalizationDialog_FailureMessage">
+        Die verbleibenden Operationen konnten nicht abgeschlossen werden, da ein Problem mit dem Netzwerk und/oder dem Bildschirmüberwachungs-Dienst vorliegt. Die zwischengespeicherten Daten befinden sich im folgenden Verzeichnis:
+    </Entry>
+    <Entry key="ProctoringFinalizationDialog_InfoMessage">
+        Bitte warten Sie, während die Bildschirmüberwachung ihre restlichen Operationen ausführt. Dies kann eine Weile dauern, je nach Status des Netzwerkes und Bildschirmüberwachungs-Dienstes.
+    </Entry>
+    <Entry key="ProctoringFinalizationDialog_Status">
+        Ausführen der Übertragungsoperation %%_COUNT_%% von %%_TOTAL_%%.
+    </Entry>
+    <Entry key="ProctoringFinalizationDialog_StatusAndTime">
+        Warten auf die Ausführung der Übertragungsoperation %%_COUNT_%% von %%_TOTAL_%% um %%_TIME_%%...
+    </Entry>
+    <Entry key="ProctoringFinalizationDialog_StatusWaiting">
+        Warten auf die Wiederaufnahme von %%_COUNT_%% Übertragungsoperationen um %%_TIME_%%...
+    </Entry>
+    <Entry key="ProctoringFinalizationDialog_Title">
+        Finalisierung der Bildschirmüberwachung
+    </Entry>
     <Entry key="RuntimeWindow_ApplicationRunning">
         SEB wird ausgeführt.
     </Entry>

SafeExamBrowser.I18n/Data/en.xml

@@ -654,6 +654,27 @@
     <Entry key="PasswordDialog_SettingsPasswordRequiredTitle">
         Password Required
     </Entry>
+    <Entry key="ProctoringFinalizationDialog_Confirm">
+        Confirm
+    </Entry>
+    <Entry key="ProctoringFinalizationDialog_FailureMessage">
+        The remaining operations could not be completed as there is a problem with the network and/or screen proctoring service. The cached data can be found in the following directory:
+    </Entry>
+    <Entry key="ProctoringFinalizationDialog_InfoMessage">
+        Please wait while the screen procotoring is executing its remaining operations. This may take a while, depending on the network and screen proctoring service status.
+    </Entry>
+    <Entry key="ProctoringFinalizationDialog_Status">
+        Executing transmission operation %%_COUNT_%% of %%_TOTAL_%%.
+    </Entry>
+    <Entry key="ProctoringFinalizationDialog_StatusAndTime">
+        Waiting to execute transmission operation %%_COUNT_%% of %%_TOTAL_%% at %%_TIME_%%...
+    </Entry>
+    <Entry key="ProctoringFinalizationDialog_StatusWaiting">
+        Waiting to resume %%_COUNT_%% transmission operations at %%_TIME_%%...
+    </Entry>
+    <Entry key="ProctoringFinalizationDialog_Title">
+        Screen Proctoring Finalization
+    </Entry>
     <Entry key="RuntimeWindow_ApplicationRunning">
         SEB is running.
     </Entry>

SafeExamBrowser.Proctoring.Contracts/Events/RemainingWorkUpdatedEventArgs.cs

@@ -0,0 +1,58 @@
+/*
+ * Copyright (c) 2023 ETH Zürich, Educational Development and Technology (LET)
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+using System;
+
+namespace SafeExamBrowser.Proctoring.Contracts.Events
+{
+	/// <summary>
+	/// The event arguments used for the remaining work updated event fired by the <see cref="IProctoringController"/>.
+	/// </summary>
+	public class RemainingWorkUpdatedEventArgs
+	{
+		/// <summary>
+		/// The path of the local cache, if <see cref="HasFailed"/> is <c>true</c>.
+		/// </summary>
+		public string CachePath { get; set; }
+
+		/// <summary>
+		/// Indicates that the execution of the remaining work has failed.
+		/// </summary>
+		public bool HasFailed { get; set; }
+
+		/// <summary>
+		/// Indicates that the execution of the remaining work has finished.
+		/// </summary>
+		public bool IsFinished { get; set; }
+
+		/// <summary>
+		/// Indicates that the execution is paused resp. waiting to be resumed.
+		/// </summary>
+		public bool IsWaiting { get; set; }
+
+		/// <summary>
+		/// The point in time when the next transmission will take place, if available.
+		/// </summary>
+		public DateTime? Next { get; set; }
+
+		/// <summary>
+		/// The number of already executed work items.
+		/// </summary>
+		public int Progress { get; set; }
+
+		/// <summary>
+		/// The point in time when the execution will resume, if <see cref="IsWaiting"/> is <c>true</c>.
+		/// </summary>
+		public DateTime Resume { get; set; }
+
+		/// <summary>
+		/// The total number of work items to be executed.
+		/// </summary>
+		public int Total { get; set; }
+	}
+}

SafeExamBrowser.Proctoring.Contracts/Events/RemainingWorkUpdatedEventHandler.cs

@@ -0,0 +1,15 @@
+/*
+ * Copyright (c) 2023 ETH Zürich, Educational Development and Technology (LET)
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+namespace SafeExamBrowser.Proctoring.Contracts.Events
+{
+	/// <summary>
+	/// Event handler used to indicate that the remaining work status has been updated.
+	/// </summary>
+	public delegate void RemainingWorkUpdatedEventHandler(RemainingWorkUpdatedEventArgs args);
+}

SafeExamBrowser.Proctoring.Contracts/IProctoringController.cs

@@ -38,6 +38,21 @@ namespace SafeExamBrowser.Proctoring.Contracts
 		/// </summary>
 		event ProctoringEventHandler HandRaised;
 
+		/// <summary>
+		/// Event fired when the status of the remaining work has been updated.
+		/// </summary>
+		event RemainingWorkUpdatedEventHandler RemainingWorkUpdated;
+
+		/// <summary>
+		/// Executes any remaining work like e.g. the transmission of cached screen shots. Make sure to do so before calling <see cref="Terminate"/>.
+		/// </summary>
+		void ExecuteRemainingWork();
+
+		/// <summary>
+		/// Indicates whether there is any remaining work which needs to be done before the proctoring can be terminated.
+		/// </summary>
+		bool HasRemainingWork();
+
 		/// <summary>
 		/// Initializes the given settings and starts the proctoring if the settings are valid.
 		/// </summary>
@@ -54,7 +69,7 @@ namespace SafeExamBrowser.Proctoring.Contracts
 		void RaiseHand(string message = default);
 
 		/// <summary>
-		/// Stops the proctoring functionality.
+		/// Stops the proctoring functionality. Make sure to call <see cref="ExecuteRemainingWork"/> beforehand if necessary.
 		/// </summary>
 		void Terminate();
 	}

SafeExamBrowser.Proctoring.Contracts/SafeExamBrowser.Proctoring.Contracts.csproj

@@ -56,6 +56,8 @@
   </ItemGroup>
   <ItemGroup>
     <Compile Include="Events\ProctoringEventHandler.cs" />
+    <Compile Include="Events\RemainingWorkUpdatedEventArgs.cs" />
+    <Compile Include="Events\RemainingWorkUpdatedEventHandler.cs" />
     <Compile Include="IProctoringController.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
   </ItemGroup>

SafeExamBrowser.Proctoring/JitsiMeet/JitsiMeetImplementation.cs

@@ -13,7 +13,6 @@ using System.Threading;
 using System.Windows;
 using Microsoft.Web.WebView2.Wpf;
 using SafeExamBrowser.Configuration.Contracts;
-using SafeExamBrowser.Core.Contracts.Notifications.Events;
 using SafeExamBrowser.Core.Contracts.Resources.Icons;
 using SafeExamBrowser.I18n.Contracts;
 using SafeExamBrowser.Logging.Contracts;
@@ -41,8 +40,6 @@ namespace SafeExamBrowser.Proctoring.JitsiMeet
 
 		internal override string Name => nameof(JitsiMeet);
 
-		public override event NotificationChangedEventHandler NotificationChanged;
-
 		internal JitsiMeetImplementation(
 			AppConfig appConfig,
 			IFileSystem fileSystem,
@@ -194,7 +191,6 @@ namespace SafeExamBrowser.Proctoring.JitsiMeet
 		internal override void Terminate()
 		{
 			Stop();
-			TerminateNotification();
 			logger.Info("Terminated proctoring.");
 		}
 
@@ -210,11 +206,6 @@ namespace SafeExamBrowser.Proctoring.JitsiMeet
 			}
 		}
 
-		protected override void TerminateNotification()
-		{
-			// Nothing to do here for now.
-		}
-
 		private string LoadContent(ProctoringSettings settings)
 		{
 			var assembly = Assembly.GetAssembly(typeof(ProctoringController));
@@ -249,7 +240,7 @@ namespace SafeExamBrowser.Proctoring.JitsiMeet
 			IconResource = new XamlIconResource { Uri = new Uri("pack://application:,,,/SafeExamBrowser.UserInterface.Desktop;component/Images/Proctoring_Active.xaml") };
 			Tooltip = text.Get(TextKey.Notification_ProctoringActiveTooltip);
 
-			NotificationChanged?.Invoke();
+			InvokeNotificationChanged();
 		}
 
 		private void ShowNotificationInactive()
@@ -258,7 +249,7 @@ namespace SafeExamBrowser.Proctoring.JitsiMeet
 			IconResource = new XamlIconResource { Uri = new Uri("pack://application:,,,/SafeExamBrowser.UserInterface.Desktop;component/Images/Proctoring_Inactive.xaml") };
 			Tooltip = text.Get(TextKey.Notification_ProctoringInactiveTooltip);
 
-			NotificationChanged?.Invoke();
+			InvokeNotificationChanged();
 		}
 	}
 }

SafeExamBrowser.Proctoring/ProctoringController.cs

@@ -8,6 +8,7 @@
 
 using System;
 using System.Collections.Generic;
+using KGySoft.CoreLibraries;
 using SafeExamBrowser.Browser.Contracts;
 using SafeExamBrowser.Configuration.Contracts;
 using SafeExamBrowser.Core.Contracts.Notifications;
@@ -38,6 +39,11 @@ namespace SafeExamBrowser.Proctoring
 
 		public event ProctoringEventHandler HandLowered;
 		public event ProctoringEventHandler HandRaised;
+		public event RemainingWorkUpdatedEventHandler RemainingWorkUpdated
+		{
+			add { implementations.ForEach(i => i.RemainingWorkUpdated += value); }
+			remove { implementations.ForEach(i => i.RemainingWorkUpdated -= value); }
+		}
 
 		public ProctoringController(
 			AppConfig appConfig,
@@ -57,6 +63,43 @@ namespace SafeExamBrowser.Proctoring
 			implementations = new List<ProctoringImplementation>();
 		}
 
+		public void ExecuteRemainingWork()
+		{
+			foreach (var implementation in implementations)
+			{
+				try
+				{
+					implementation.ExecuteRemainingWork();
+				}
+				catch (Exception e)
+				{
+					logger.Error($"Failed to execute remaining work for '{implementation.Name}'!", e);
+				}
+			}
+		}
+
+		public bool HasRemainingWork()
+		{
+			var hasWork = false;
+
+			foreach (var implementation in implementations)
+			{
+				try
+				{
+					if (implementation.HasRemainingWork())
+					{
+						hasWork = true;
+					}
+				}
+				catch (Exception e)
+				{
+					logger.Error($"Failed to check whether has remaining work for '{implementation.Name}'!", e);
+				}
+			}
+
+			return hasWork;
+		}
+
 		public void Initialize(ProctoringSettings settings)
 		{
 			implementations = factory.CreateAllActive(settings);

SafeExamBrowser.Proctoring/ProctoringImplementation.cs

@@ -9,6 +9,7 @@
 using SafeExamBrowser.Core.Contracts.Notifications;
 using SafeExamBrowser.Core.Contracts.Notifications.Events;
 using SafeExamBrowser.Core.Contracts.Resources.Icons;
+using SafeExamBrowser.Proctoring.Contracts.Events;
 using SafeExamBrowser.Server.Contracts.Events.Proctoring;
 
 namespace SafeExamBrowser.Proctoring
@@ -21,7 +22,8 @@ namespace SafeExamBrowser.Proctoring
 		public string Tooltip { get; protected set; }
 		public IconResource IconResource { get; protected set; }
 
-		public abstract event NotificationChangedEventHandler NotificationChanged;
+		internal event RemainingWorkUpdatedEventHandler RemainingWorkUpdated;
+		public event NotificationChangedEventHandler NotificationChanged;
 
 		void INotification.Activate()
 		{
@@ -40,7 +42,20 @@ namespace SafeExamBrowser.Proctoring
 		internal abstract void Stop();
 		internal abstract void Terminate();
 
+		internal virtual void ExecuteRemainingWork() { }
+		internal virtual bool HasRemainingWork() => false;
+
 		protected virtual void ActivateNotification() { }
 		protected virtual void TerminateNotification() { }
+
+		protected void InvokeNotificationChanged()
+		{
+			NotificationChanged?.Invoke();
+		}
+
+		protected void InvokeRemainingWorkUpdated(RemainingWorkUpdatedEventArgs args)
+		{
+			RemainingWorkUpdated?.Invoke(args);
+		}
 	}
 }

SafeExamBrowser.Proctoring/SafeExamBrowser.Proctoring.csproj

@@ -93,6 +93,7 @@
     <Compile Include="ProctoringFactory.cs" />
     <Compile Include="ProctoringImplementation.cs" />
     <Compile Include="Properties\AssemblyInfo.cs" />
+    <Compile Include="ScreenProctoring\Buffer.cs" />
     <Compile Include="ScreenProctoring\Cache.cs" />
     <Compile Include="ScreenProctoring\Data\IntervalTrigger.cs" />
     <Compile Include="ScreenProctoring\Data\KeyboardTrigger.cs" />

SafeExamBrowser.Proctoring/ScreenProctoring/Buffer.cs

@@ -0,0 +1,92 @@
+/*
+ * Copyright (c) 2023 ETH Zürich, Educational Development and Technology (LET)
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using SafeExamBrowser.Logging.Contracts;
+using SafeExamBrowser.Proctoring.ScreenProctoring.Data;
+using SafeExamBrowser.Proctoring.ScreenProctoring.Imaging;
+
+namespace SafeExamBrowser.Proctoring.ScreenProctoring
+{
+	internal class Buffer
+	{
+		private readonly object @lock = new object();
+
+		private readonly List<(MetaData metaData, DateTime schedule, ScreenShot screenShot)> list;
+		private readonly ILogger logger;
+
+		internal int Count
+		{
+			get
+			{
+				lock (@lock)
+				{
+					return list.Count;
+				}
+			}
+		}
+
+		internal Buffer(ILogger logger)
+		{
+			this.list = new List<(MetaData, DateTime, ScreenShot)>();
+			this.logger = logger;
+		}
+
+		internal bool Any()
+		{
+			lock (@lock)
+			{
+				return list.Any();
+			}
+		}
+
+		internal void Dequeue()
+		{
+			lock (@lock)
+			{
+				if (list.Any())
+				{
+					var (_, schedule, screenShot) = list.First();
+
+					list.RemoveAt(0);
+					logger.Debug($"Removed data for '{screenShot.CaptureTime:HH:mm:ss} -> {schedule:HH:mm:ss}', {Count} item(s) remaining.");
+				}
+			}
+		}
+
+		internal void Enqueue(MetaData metaData, DateTime schedule, ScreenShot screenShot)
+		{
+			lock (@lock)
+			{
+				list.Add((metaData, schedule, screenShot));
+				list.Sort((a, b) => DateTime.Compare(a.schedule, b.schedule));
+
+				logger.Debug($"Buffered data for '{screenShot.CaptureTime:HH:mm:ss} -> {schedule:HH:mm:ss}', now holding {Count} item(s).");
+			}
+		}
+
+		internal bool TryPeek(out MetaData metaData, out DateTime schedule, out ScreenShot screenShot)
+		{
+			lock (@lock)
+			{
+				metaData = default;
+				schedule = default;
+				screenShot = default;
+
+				if (list.Any())
+				{
+					(metaData, schedule, screenShot) = list.First();
+				}
+
+				return metaData != default && screenShot != default;
+			}
+		}
+	}
+}

SafeExamBrowser.Proctoring/ScreenProctoring/Cache.cs

@@ -7,7 +7,7 @@
  */
 
 using System;
-using System.Collections.Generic;
+using System.Collections.Concurrent;
 using System.IO;
 using System.Linq;
 using System.Security.Cryptography;
@@ -27,20 +27,21 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 
 		private readonly AppConfig appConfig;
 		private readonly ILogger logger;
-		private readonly Queue<(string fileName, int checksum, string hash)> queue;
+		private readonly ConcurrentQueue<(string fileName, int checksum, string hash)> queue;
 
-		private string Directory { get; set; }
+		internal int Count => queue.Count;
+		internal string Directory { get; private set; }
 
 		public Cache(AppConfig appConfig, ILogger logger)
 		{
 			this.appConfig = appConfig;
 			this.logger = logger;
-			this.queue = new Queue<(string, int, string)>();
+			this.queue = new ConcurrentQueue<(string, int, string)>();
 		}
 
 		internal bool Any()
 		{
-			return false;
+			return queue.Any();
 		}
 
 		internal bool TryEnqueue(MetaData metaData, ScreenShot screenShot)
@@ -57,7 +58,7 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 
 				success = true;
 
-				logger.Debug($"Cached data for '{fileName}'.");
+				logger.Debug($"Cached data for '{fileName}', now holding {Count} item(s).");
 			}
 			catch (Exception e)
 			{
@@ -74,23 +75,21 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 			metaData = default;
 			screenShot = default;
 
-			if (queue.Any())
+			if (queue.Any() && queue.TryPeek(out var item))
 			{
-				var (fileName, checksum, hash) = queue.Peek();
-
 				try
 				{
-					LoadData(fileName, out metaData, out screenShot);
+					LoadData(item.fileName, out metaData, out screenShot);
-					LoadImage(fileName, screenShot);
+					LoadImage(item.fileName, screenShot);
-					Dequeue(fileName, checksum, hash, metaData, screenShot);
+					Dequeue(item.fileName, item.checksum, item.hash, metaData, screenShot);
 
 					success = true;
 
-					logger.Debug($"Uncached data for '{fileName}'.");
+					logger.Debug($"Removed data for '{item.fileName}', {Count} item(s) remaining.");
 				}
 				catch (Exception e)
 				{
-					logger.Error($"Failed to uncache data for '{fileName}'!", e);
+					logger.Error($"Failed to remove data for '{item.fileName}'!", e);
 				}
 			}
 
@@ -116,7 +115,7 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 			File.Delete(dataPath);
 			File.Delete(imagePath);
 
-			queue.Dequeue();
+			while (!queue.TryDequeue(out _)) ;
 		}
 
 		private void Enqueue(string fileName, MetaData metaData, ScreenShot screenShot)

SafeExamBrowser.Proctoring/ScreenProctoring/ScreenProctoringImplementation.cs

@@ -9,7 +9,6 @@
 using System;
 using SafeExamBrowser.Browser.Contracts;
 using SafeExamBrowser.Configuration.Contracts;
-using SafeExamBrowser.Core.Contracts.Notifications.Events;
 using SafeExamBrowser.Core.Contracts.Resources.Icons;
 using SafeExamBrowser.I18n.Contracts;
 using SafeExamBrowser.Logging.Contracts;
@@ -34,8 +33,6 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 
 		internal override string Name => nameof(ScreenProctoring);
 
-		public override event NotificationChangedEventHandler NotificationChanged;
-
 		internal ScreenProctoringImplementation(
 			AppConfig appConfig,
 			IApplicationMonitor applicationMonitor,
@@ -54,6 +51,29 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 			this.text = text;
 		}
 
+		internal override void ExecuteRemainingWork()
+		{
+			logger.Info("Starting execution of remaining work...");
+			spooler.ExecuteRemainingWork(InvokeRemainingWorkUpdated);
+			logger.Info("Terminated execution of remaining work.");
+		}
+
+		internal override bool HasRemainingWork()
+		{
+			var hasWork = spooler.HasRemainingWork();
+
+			if (hasWork)
+			{
+				logger.Info("There is remaining work to be done.");
+			}
+			else
+			{
+				logger.Info("There is no remaining work to be done.");
+			}
+
+			return hasWork;
+		}
+
 		internal override void Initialize()
 		{
 			var start = true;
@@ -132,10 +152,7 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 
 		internal override void Terminate()
 		{
-			// TODO: Cache transmission or user information!
-
 			Stop();
-			TerminateNotification();
 
 			logger.Info("Terminated proctoring.");
 		}
@@ -189,7 +206,7 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 				Tooltip = text.Get(TextKey.Notification_ProctoringInactiveTooltip);
 			}
 
-			NotificationChanged?.Invoke();
+			InvokeNotificationChanged();
 		}
 	}
 }

SafeExamBrowser.Proctoring/ScreenProctoring/TransmissionSpooler.cs

@@ -8,12 +8,11 @@
 
 using System;
 using System.Collections.Concurrent;
-using System.Collections.Generic;
-using System.Linq;
 using System.Threading;
 using System.Timers;
 using SafeExamBrowser.Configuration.Contracts;
 using SafeExamBrowser.Logging.Contracts;
+using SafeExamBrowser.Proctoring.Contracts.Events;
 using SafeExamBrowser.Proctoring.ScreenProctoring.Data;
 using SafeExamBrowser.Proctoring.ScreenProctoring.Imaging;
 using SafeExamBrowser.Proctoring.ScreenProctoring.Service;
@@ -23,9 +22,10 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 {
 	internal class TransmissionSpooler
 	{
-		const int BAD = 10;
+		private const int BAD = 10;
-		const int GOOD = 0;
+		private const int GOOD = 0;
 
+		private readonly Buffer buffer;
 		private readonly Cache cache;
 		private readonly ILogger logger;
 		private readonly ConcurrentQueue<(MetaData metaData, ScreenShot screenShot)> queue;
@@ -33,8 +33,8 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 		private readonly ServiceProxy service;
 		private readonly Timer timer;
 
-		private Queue<(MetaData metaData, DateTime schedule, ScreenShot screenShot)> buffer;
 		private int health;
+		private bool networkIssue;
 		private bool recovering;
 		private DateTime resume;
 		private Thread thread;
@@ -42,7 +42,7 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 
 		internal TransmissionSpooler(AppConfig appConfig, IModuleLogger logger, ServiceProxy service)
 		{
-			this.buffer = new Queue<(MetaData, DateTime, ScreenShot)>();
+			this.buffer = new Buffer(logger.CloneFor(nameof(Buffer)));
 			this.cache = new Cache(appConfig, logger.CloneFor(nameof(Cache)));
 			this.logger = logger;
 			this.queue = new ConcurrentQueue<(MetaData, ScreenShot)>();
@@ -56,6 +56,55 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 			queue.Enqueue((metaData, screenShot));
 		}
 
+		internal void ExecuteRemainingWork(Action<RemainingWorkUpdatedEventArgs> updateStatus)
+		{
+			var previous = buffer.Count + cache.Count;
+			var progress = 0;
+			var total = previous;
+
+			while (HasRemainingWork() && service.IsConnected && (!networkIssue || recovering))
+			{
+				var remaining = buffer.Count + cache.Count;
+
+				if (total < remaining)
+				{
+					total = remaining;
+				}
+				else if (previous < remaining)
+				{
+					total += remaining - previous;
+				}
+
+				previous = remaining;
+				progress = total - remaining;
+
+				updateStatus(new RemainingWorkUpdatedEventArgs
+				{
+					IsWaiting = recovering,
+					Next = buffer.TryPeek(out _, out var schedule, out _) ? schedule : default(DateTime?),
+					Progress = progress,
+					Resume = resume,
+					Total = total
+				});
+
+				Thread.Sleep(100);
+			}
+
+			if (networkIssue)
+			{
+				updateStatus(new RemainingWorkUpdatedEventArgs { HasFailed = true, CachePath = cache.Directory });
+			}
+			else
+			{
+				updateStatus(new RemainingWorkUpdatedEventArgs { IsFinished = true });
+			}
+		}
+
+		internal bool HasRemainingWork()
+		{
+			return buffer.Any() || cache.Any();
+		}
+
 		internal void Start()
 		{
 			const int FIFTEEN_SECONDS = 15000;
@@ -167,14 +216,14 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 		{
 			BufferFromCache();
 			BufferFromQueue();
-			TryTransmitFromBuffer();
+			TransmitFromBuffer();
 		}
 
 		private void ExecuteNormally()
 		{
-			TryTransmitFromBuffer();
+			TransmitFromBuffer();
-			TryTransmitFromCache();
+			TransmitFromCache();
-			TryTransmitFromQueue();
+			TransmitFromQueue();
 		}
 
 		private void ExecuteRecovery()
@@ -194,17 +243,11 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 			}
 		}
 
-		private void Buffer(MetaData metaData, DateTime schedule, ScreenShot screenShot)
-		{
-			buffer.Enqueue((metaData, schedule, screenShot));
-			buffer = new Queue<(MetaData, DateTime, ScreenShot)>(buffer.OrderBy((b) => b.schedule));
-		}
-
 		private void BufferFromCache()
 		{
 			if (cache.TryDequeue(out var metaData, out var screenShot))
 			{
-				Buffer(metaData, CalculateSchedule(metaData), screenShot);
+				buffer.Enqueue(metaData, CalculateSchedule(metaData), screenShot);
 			}
 		}
 
@@ -212,21 +255,16 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 		{
 			if (TryDequeue(out var metaData, out var screenShot))
 			{
-				Buffer(metaData, CalculateSchedule(metaData), screenShot);
+				buffer.Enqueue(metaData, CalculateSchedule(metaData), screenShot);
 			}
 		}
 
 		private void CacheFromBuffer()
 		{
-			if (TryPeekFromBuffer(out var metaData, out _, out var screenShot))
+			if (buffer.TryPeek(out var metaData, out _, out var screenShot) && cache.TryEnqueue(metaData, screenShot))
 			{
-				var success = cache.TryEnqueue(metaData, screenShot);
+				buffer.Dequeue();
-
+				screenShot.Dispose();
-				if (success)
-				{
-					buffer.Dequeue();
-					screenShot.Dispose();
-				}
 			}
 		}
 
@@ -234,15 +272,13 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 		{
 			if (TryDequeue(out var metaData, out var screenShot))
 			{
-				var success = cache.TryEnqueue(metaData, screenShot);
+				if (cache.TryEnqueue(metaData, screenShot))
-
-				if (success)
 				{
 					screenShot.Dispose();
 				}
 				else
 				{
-					Buffer(metaData, DateTime.Now, screenShot);
+					buffer.Enqueue(metaData, DateTime.Now, screenShot);
 				}
 			}
 		}
@@ -255,6 +291,48 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 			return schedule;
 		}
 
+		private void TransmitFromBuffer()
+		{
+			var hasItem = buffer.TryPeek(out var metaData, out var schedule, out var screenShot);
+			var ready = schedule <= DateTime.Now;
+
+			if (hasItem && ready && TryTransmit(metaData, screenShot))
+			{
+				buffer.Dequeue();
+				screenShot.Dispose();
+			}
+		}
+
+		private void TransmitFromCache()
+		{
+			if (cache.TryDequeue(out var metaData, out var screenShot))
+			{
+				if (TryTransmit(metaData, screenShot))
+				{
+					screenShot.Dispose();
+				}
+				else
+				{
+					buffer.Enqueue(metaData, DateTime.Now, screenShot);
+				}
+			}
+		}
+
+		private void TransmitFromQueue()
+		{
+			if (TryDequeue(out var metaData, out var screenShot))
+			{
+				if (TryTransmit(metaData, screenShot))
+				{
+					screenShot.Dispose();
+				}
+				else
+				{
+					buffer.Enqueue(metaData, DateTime.Now, screenShot);
+				}
+			}
+		}
+
 		private bool TryDequeue(out MetaData metaData, out ScreenShot screenShot)
 		{
 			metaData = default;
@@ -269,80 +347,6 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 			return metaData != default && screenShot != default;
 		}
 
-		private bool TryPeekFromBuffer(out MetaData metaData, out DateTime schedule, out ScreenShot screenShot)
-		{
-			metaData = default;
-			schedule = default;
-			screenShot = default;
-
-			if (buffer.Any())
-			{
-				(metaData, schedule, screenShot) = buffer.Peek();
-			}
-
-			return metaData != default && screenShot != default;
-		}
-
-		private bool TryTransmitFromBuffer()
-		{
-			var success = false;
-
-			if (TryPeekFromBuffer(out var metaData, out var schedule, out var screenShot) && schedule <= DateTime.Now)
-			{
-				success = TryTransmit(metaData, screenShot);
-
-				if (success)
-				{
-					buffer.Dequeue();
-					screenShot.Dispose();
-				}
-			}
-
-			return success;
-		}
-
-		private bool TryTransmitFromCache()
-		{
-			var success = true;
-
-			if (cache.TryDequeue(out var metaData, out var screenShot))
-			{
-				success = TryTransmit(metaData, screenShot);
-
-				if (success)
-				{
-					screenShot.Dispose();
-				}
-				else
-				{
-					Buffer(metaData, DateTime.Now, screenShot);
-				}
-			}
-
-			return success;
-		}
-
-		private bool TryTransmitFromQueue()
-		{
-			var success = false;
-
-			if (TryDequeue(out var metaData, out var screenShot))
-			{
-				success = TryTransmit(metaData, screenShot);
-
-				if (success)
-				{
-					screenShot.Dispose();
-				}
-				else
-				{
-					Buffer(metaData, DateTime.Now, screenShot);
-				}
-			}
-
-			return success;
-		}
-
 		private bool TryTransmit(MetaData metaData, ScreenShot screenShot)
 		{
 			var success = false;
@@ -351,10 +355,12 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 			{
 				var response = service.Send(metaData, screenShot);
 
+				networkIssue = !response.Success;
+				success = response.Success;
+
 				if (response.Success)
 				{
 					health = UpdateHealth(response.Value);
-					success = true;
 				}
 			}
 			else
@@ -371,6 +377,8 @@ namespace SafeExamBrowser.Proctoring.ScreenProctoring
 			{
 				var response = service.GetHealth();
 
+				networkIssue = !response.Success;
+
 				if (response.Success)
 				{
 					health = UpdateHealth(response.Value);

SafeExamBrowser.UserInterface.Contracts/IUserInterfaceFactory.cs

@@ -103,6 +103,11 @@ namespace SafeExamBrowser.UserInterface.Contracts
 		/// </summary>
 		ISystemControl CreatePowerSupplyControl(IPowerSupply powerSupply, Location location);
 
+		/// <summary>
+		/// Creates a new dialog to display the status of the proctoring finalization.
+		/// </summary>
+		IProctoringFinalizationDialog CreateProctoringFinalizationDialog();
+
 		/// <summary>
 		/// Creates a new proctoring window loaded with the given proctoring control.
 		/// </summary>

SafeExamBrowser.UserInterface.Contracts/Proctoring/IProctoringFinalizationDialog.cs

@@ -0,0 +1,28 @@
+/*
+ * Copyright (c) 2023 ETH Zürich, Educational Development and Technology (LET)
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+using SafeExamBrowser.Proctoring.Contracts.Events;
+
+namespace SafeExamBrowser.UserInterface.Contracts.Proctoring
+{
+	/// <summary>
+	/// The dialog to display the status of the proctoring finalization.
+	/// </summary>
+	public interface IProctoringFinalizationDialog
+	{
+		/// <summary>
+		/// Shows the dialog as topmost window.
+		/// </summary>
+		void Show();
+
+		/// <summary>
+		/// Updates the status of the finalization.
+		/// </summary>
+		void Update(RemainingWorkUpdatedEventArgs status);
+	}
+}

SafeExamBrowser.UserInterface.Contracts/SafeExamBrowser.UserInterface.Contracts.csproj

@@ -103,6 +103,7 @@
     <Compile Include="Windows\ILockScreen.cs" />
     <Compile Include="Windows\IPasswordDialog.cs" />
     <Compile Include="Windows\Data\PasswordDialogResult.cs" />
+    <Compile Include="Proctoring\IProctoringFinalizationDialog.cs" />
     <Compile Include="Windows\IRuntimeWindow.cs" />
     <Compile Include="Windows\IServerFailureDialog.cs" />
     <Compile Include="Windows\ISplashScreen.cs" />

SafeExamBrowser.UserInterface.Desktop/SafeExamBrowser.UserInterface.Desktop.csproj

@@ -171,6 +171,9 @@
     <Compile Include="Windows\PasswordDialog.xaml.cs">
       <DependentUpon>PasswordDialog.xaml</DependentUpon>
     </Compile>
+    <Compile Include="Windows\ProctoringFinalizationDialog.xaml.cs">
+      <DependentUpon>ProctoringFinalizationDialog.xaml</DependentUpon>
+    </Compile>
     <Compile Include="Windows\ProctoringWindow.xaml.cs">
       <DependentUpon>ProctoringWindow.xaml</DependentUpon>
     </Compile>
@@ -391,6 +394,10 @@
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>
     </Page>
+    <Page Include="Windows\ProctoringFinalizationDialog.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:Compile</Generator>
+    </Page>
     <Page Include="Windows\ProctoringWindow.xaml">
       <SubType>Designer</SubType>
       <Generator>MSBuild:Compile</Generator>

SafeExamBrowser.UserInterface.Desktop/UserInterfaceFactory.cs

@@ -177,6 +177,11 @@ namespace SafeExamBrowser.UserInterface.Desktop
 			}
 		}
 
+		public IProctoringFinalizationDialog CreateProctoringFinalizationDialog()
+		{
+			return Application.Current.Dispatcher.Invoke(() => new ProctoringFinalizationDialog(text));
+		}
+
 		public IProctoringWindow CreateProctoringWindow(IProctoringControl control)
 		{
 			return Application.Current.Dispatcher.Invoke(() => new ProctoringWindow(control));

SafeExamBrowser.UserInterface.Desktop/Windows/ProctoringFinalizationDialog.xaml

@@ -0,0 +1,53 @@
+<Window x:Class="SafeExamBrowser.UserInterface.Desktop.Windows.ProctoringFinalizationDialog"
+        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+        xmlns:fa="http://schemas.fontawesome.io/icons/"
+        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+        xmlns:local="clr-namespace:SafeExamBrowser.UserInterface.Desktop.Windows"
+        mc:Ignorable="d" Height="250" Width="650" ResizeMode="NoResize" Topmost="True" WindowStartupLocation="CenterScreen">
+    <Window.Resources>
+        <ResourceDictionary>
+            <ResourceDictionary.MergedDictionaries>
+                <ResourceDictionary Source="../Templates/Colors.xaml" />
+            </ResourceDictionary.MergedDictionaries>
+        </ResourceDictionary>
+    </Window.Resources>
+    <Grid>
+        <Grid.RowDefinitions>
+            <RowDefinition Height="*" />
+            <RowDefinition Height="Auto" />
+        </Grid.RowDefinitions>
+        <Grid Grid.Row="0" Margin="20">
+            <Grid Name="ProgressPanel">
+                <Grid.RowDefinitions>
+                    <RowDefinition Height="*" />
+                    <RowDefinition Height="Auto" />
+                    <RowDefinition Height="*" />
+                </Grid.RowDefinitions>
+                <TextBlock Grid.Row="0" Name="Info" TextWrapping="WrapWithOverflow" VerticalAlignment="Bottom" />
+                <Grid Grid.Row="1">
+                    <ProgressBar Name="Progress" Height="25" Margin="0,20" />
+                    <TextBlock Name="Percentage" FontWeight="Bold" HorizontalAlignment="Center" VerticalAlignment="Center" />
+                </Grid>
+                <TextBlock Grid.Row="2" Name="Status" FontStyle="Italic" TextWrapping="WrapWithOverflow" VerticalAlignment="Top" />
+            </Grid>
+            <Grid Name="FailurePanel">
+                <Grid.ColumnDefinitions>
+                    <ColumnDefinition Width="Auto" />
+                    <ColumnDefinition Width="*" />
+                </Grid.ColumnDefinitions>
+                <fa:ImageAwesome Grid.Column="0" Foreground="LightGray" Icon="Warning" Margin="10,0,20,0" Width="50" />
+                <WrapPanel Grid.Column="1" Orientation="Vertical" VerticalAlignment="Center">
+                    <TextBlock Name="Message" TextWrapping="WrapWithOverflow" />
+                    <TextBlock Name="CachePath" FontFamily="Courier New" Margin="0,20,0,0" TextWrapping="WrapWithOverflow" />
+                </WrapPanel>
+            </Grid>
+        </Grid>
+        <Grid Grid.Row="1" Name="ButtonPanel" Background="{StaticResource BackgroundBrush}">
+            <WrapPanel Orientation="Horizontal" Margin="20" HorizontalAlignment="Right" VerticalAlignment="Center">
+                <Button Name="Button" Cursor="Hand" Padding="10,5" MinWidth="75" />
+            </WrapPanel>
+        </Grid>
+    </Grid>
+</Window>

SafeExamBrowser.UserInterface.Desktop/Windows/ProctoringFinalizationDialog.xaml.cs

@@ -0,0 +1,114 @@
+/*
+ * Copyright (c) 2023 ETH Zürich, Educational Development and Technology (LET)
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+using System.Windows;
+using System.Windows.Input;
+using SafeExamBrowser.I18n.Contracts;
+using SafeExamBrowser.Proctoring.Contracts.Events;
+using SafeExamBrowser.UserInterface.Contracts.Proctoring;
+using SafeExamBrowser.UserInterface.Shared.Utilities;
+
+namespace SafeExamBrowser.UserInterface.Desktop.Windows
+{
+	public partial class ProctoringFinalizationDialog : Window, IProctoringFinalizationDialog
+	{
+		private readonly IText text;
+
+		public ProctoringFinalizationDialog(IText text)
+		{
+			this.text = text;
+
+			InitializeComponent();
+			InitializeDialog();
+		}
+
+		public new void Show()
+		{
+			Dispatcher.Invoke(() => ShowDialog());
+		}
+
+		public void Update(RemainingWorkUpdatedEventArgs status)
+		{
+			Dispatcher.Invoke(() =>
+			{
+				if (status.HasFailed)
+				{
+					ShowFailure(status);
+				}
+				else if (status.IsFinished)
+				{
+					Close();
+				}
+				else
+				{
+					ShowProgress(status);
+				}
+			});
+		}
+
+		private void InitializeDialog()
+		{
+			Button.Click += (o, args) => Close();
+			Button.Content = text.Get(TextKey.ProctoringFinalizationDialog_Confirm);
+			Loaded += (o, args) => this.DisableCloseButton();
+			Title = text.Get(TextKey.ProctoringFinalizationDialog_Title);
+		}
+
+		private void ShowFailure(RemainingWorkUpdatedEventArgs status)
+		{
+			ButtonPanel.Visibility = Visibility.Visible;
+			CachePath.Text = status.CachePath;
+			Cursor = Cursors.Arrow;
+			FailurePanel.Visibility = Visibility.Visible;
+			Message.Text = text.Get(TextKey.ProctoringFinalizationDialog_FailureMessage);
+			ProgressPanel.Visibility = Visibility.Collapsed;
+
+			this.EnableCloseButton();
+		}
+
+		private void ShowProgress(RemainingWorkUpdatedEventArgs status)
+		{
+			ButtonPanel.Visibility = Visibility.Collapsed;
+			Cursor = Cursors.Wait;
+			FailurePanel.Visibility = Visibility.Collapsed;
+			Info.Text = text.Get(TextKey.ProctoringFinalizationDialog_InfoMessage);
+			ProgressPanel.Visibility = Visibility.Visible;
+
+			if (status.IsWaiting)
+			{
+				var count = $"{status.Total - status.Progress}";
+				var time = $"{status.Resume.ToLongTimeString()}";
+
+				Percentage.Text = "";
+				Progress.IsIndeterminate = true;
+				Status.Text = text.Get(TextKey.ProctoringFinalizationDialog_StatusWaiting).Replace("%%_COUNT_%%", count).Replace("%%_TIME_%%", time);
+			}
+			else
+			{
+				var count = $"{status.Progress}";
+				var total = $"{status.Total}";
+
+				Percentage.Text = $"{status.Progress / (double) (status.Total > 0 ? status.Total : 1) * 100:N0}%";
+				Progress.IsIndeterminate = false;
+				Progress.Maximum = status.Total;
+				Progress.Value = status.Progress;
+
+				if (status.Next.HasValue)
+				{
+					Status.Text = text.Get(TextKey.ProctoringFinalizationDialog_StatusAndTime).Replace("%%_TIME_%%", $"{status.Next.Value.ToLongTimeString()}");
+				}
+				else
+				{
+					Status.Text = text.Get(TextKey.ProctoringFinalizationDialog_Status);
+				}
+
+				Status.Text = Status.Text.Replace("%%_COUNT_%%", count).Replace("%%_TOTAL_%%", total);
+			}
+		}
+	}
+}

SafeExamBrowser.UserInterface.Mobile/SafeExamBrowser.UserInterface.Mobile.csproj

@@ -179,6 +179,9 @@
     <Compile Include="Properties\AssemblyInfo.cs">
       <SubType>Code</SubType>
     </Compile>
+    <Compile Include="Windows\ProctoringFinalizationDialog.xaml.cs">
+      <DependentUpon>ProctoringFinalizationDialog.xaml</DependentUpon>
+    </Compile>
     <Compile Include="Windows\ProctoringWindow.xaml.cs">
       <DependentUpon>ProctoringWindow.xaml</DependentUpon>
     </Compile>
@@ -522,6 +525,10 @@
       <Generator>MSBuild:Compile</Generator>
       <SubType>Designer</SubType>
     </Page>
+    <Page Include="Windows\ProctoringFinalizationDialog.xaml">
+      <SubType>Designer</SubType>
+      <Generator>MSBuild:Compile</Generator>
+    </Page>
     <Page Include="Windows\ProctoringWindow.xaml">
       <Generator>MSBuild:Compile</Generator>
       <SubType>Designer</SubType>

SafeExamBrowser.UserInterface.Mobile/UserInterfaceFactory.cs

@@ -177,6 +177,11 @@ namespace SafeExamBrowser.UserInterface.Mobile
 			}
 		}
 
+		public IProctoringFinalizationDialog CreateProctoringFinalizationDialog()
+		{
+			return Application.Current.Dispatcher.Invoke(() => new ProctoringFinalizationDialog(text));
+		}
+
 		public IProctoringWindow CreateProctoringWindow(IProctoringControl control)
 		{
 			return Application.Current.Dispatcher.Invoke(() => new ProctoringWindow(control));

SafeExamBrowser.UserInterface.Mobile/Windows/ProctoringFinalizationDialog.xaml

@@ -0,0 +1,56 @@
+<Window x:Class="SafeExamBrowser.UserInterface.Mobile.Windows.ProctoringFinalizationDialog"
+        xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
+        xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
+        xmlns:d="http://schemas.microsoft.com/expression/blend/2008"
+        xmlns:fa="http://schemas.fontawesome.io/icons/"
+        xmlns:mc="http://schemas.openxmlformats.org/markup-compatibility/2006"
+        xmlns:local="clr-namespace:SafeExamBrowser.UserInterface.Mobile.Windows"
+        mc:Ignorable="d" Background="Transparent" Height="750" Width="1000" FontSize="16" ResizeMode="NoResize" Topmost="True" AllowsTransparency="True" WindowStyle="None">
+    <Window.Resources>
+        <ResourceDictionary>
+            <ResourceDictionary.MergedDictionaries>
+                <ResourceDictionary Source="../Templates/Colors.xaml" />
+            </ResourceDictionary.MergedDictionaries>
+        </ResourceDictionary>
+    </Window.Resources>
+    <Grid Background="#66000000">
+        <Grid.RowDefinitions>
+            <RowDefinition Height="*" />
+            <RowDefinition Height="Auto" />
+            <RowDefinition Height="Auto" />
+            <RowDefinition Height="*" />
+        </Grid.RowDefinitions>
+        <Grid Grid.Row="0" />
+        <Grid Grid.Row="1" Background="White">
+            <Grid Name="ProgressPanel" Margin="50">
+                <Grid.RowDefinitions>
+                    <RowDefinition Height="*" />
+                    <RowDefinition Height="Auto" />
+                    <RowDefinition Height="*" />
+                </Grid.RowDefinitions>
+                <TextBlock Grid.Row="0" Name="Info" TextWrapping="WrapWithOverflow" VerticalAlignment="Bottom" />
+                <Grid Grid.Row="1">
+                    <ProgressBar Name="Progress" Height="35" Margin="0,25" />
+                    <TextBlock Name="Percentage" FontWeight="Bold" HorizontalAlignment="Center" VerticalAlignment="Center" />
+                </Grid>
+                <TextBlock Grid.Row="2" Name="Status" FontStyle="Italic" TextWrapping="WrapWithOverflow" VerticalAlignment="Top" />
+            </Grid>
+            <Grid Name="FailurePanel" Margin="50">
+                <Grid.ColumnDefinitions>
+                    <ColumnDefinition Width="Auto" />
+                    <ColumnDefinition Width="*" />
+                </Grid.ColumnDefinitions>
+                <fa:ImageAwesome Grid.Column="0" Foreground="LightGray" Icon="Warning" Margin="10,0,50,0" Width="50" />
+                <WrapPanel Grid.Column="1" Orientation="Vertical" VerticalAlignment="Center">
+                    <TextBlock Name="Message" TextWrapping="WrapWithOverflow" />
+                    <TextBlock Name="CachePath" FontFamily="Courier New" Margin="0,25,0,0" TextWrapping="WrapWithOverflow" />
+                </WrapPanel>
+            </Grid>
+        </Grid>
+        <Grid Grid.Row="2" Name="ButtonPanel" Background="{StaticResource BackgroundBrush}">
+            <WrapPanel Orientation="Horizontal" Margin="50,25" HorizontalAlignment="Right" VerticalAlignment="Center">
+                <Button Name="Button" Cursor="Hand" Padding="10,5" MinWidth="75" />
+            </WrapPanel>
+        </Grid>
+    </Grid>
+</Window>

SafeExamBrowser.UserInterface.Mobile/Windows/ProctoringFinalizationDialog.xaml.cs

@@ -0,0 +1,135 @@
+/*
+ * Copyright (c) 2023 ETH Zürich, Educational Development and Technology (LET)
+ * 
+ * This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/.
+ */
+
+using System.ComponentModel;
+using System.Windows;
+using System.Windows.Input;
+using SafeExamBrowser.I18n.Contracts;
+using SafeExamBrowser.Proctoring.Contracts.Events;
+using SafeExamBrowser.UserInterface.Contracts.Proctoring;
+
+namespace SafeExamBrowser.UserInterface.Mobile.Windows
+{
+	public partial class ProctoringFinalizationDialog : Window, IProctoringFinalizationDialog
+	{
+		private readonly IText text;
+
+		public ProctoringFinalizationDialog(IText text)
+		{
+			this.text = text;
+
+			InitializeComponent();
+			InitializeDialog();
+		}
+
+		public new void Show()
+		{
+			Dispatcher.Invoke(() =>
+			{
+				InitializeBounds();
+				ShowDialog();
+			});
+		}
+
+		public void Update(RemainingWorkUpdatedEventArgs status)
+		{
+			Dispatcher.Invoke(() =>
+			{
+				if (status.HasFailed)
+				{
+					ShowFailure(status);
+				}
+				else if (status.IsFinished)
+				{
+					Close();
+				}
+				else
+				{
+					ShowProgress(status);
+				}
+			});
+		}
+
+		private void InitializeBounds()
+		{
+			Left = 0;
+			Top = 0;
+			Height = SystemParameters.PrimaryScreenHeight;
+			Width = SystemParameters.PrimaryScreenWidth;
+		}
+
+		private void InitializeDialog()
+		{
+			Button.Click += (o, args) => Close();
+			Button.Content = text.Get(TextKey.ProctoringFinalizationDialog_Confirm);
+			Title = text.Get(TextKey.ProctoringFinalizationDialog_Title);
+
+			InitializeBounds();
+
+			SystemParameters.StaticPropertyChanged += SystemParameters_StaticPropertyChanged;
+		}
+
+		private void ShowFailure(RemainingWorkUpdatedEventArgs status)
+		{
+			ButtonPanel.Visibility = Visibility.Visible;
+			CachePath.Text = status.CachePath;
+			Cursor = Cursors.Arrow;
+			FailurePanel.Visibility = Visibility.Visible;
+			Message.Text = text.Get(TextKey.ProctoringFinalizationDialog_FailureMessage);
+			ProgressPanel.Visibility = Visibility.Collapsed;
+		}
+
+		private void ShowProgress(RemainingWorkUpdatedEventArgs status)
+		{
+			ButtonPanel.Visibility = Visibility.Collapsed;
+			Cursor = Cursors.Wait;
+			FailurePanel.Visibility = Visibility.Collapsed;
+			Info.Text = text.Get(TextKey.ProctoringFinalizationDialog_InfoMessage);
+			ProgressPanel.Visibility = Visibility.Visible;
+
+			if (status.IsWaiting)
+			{
+				var count = $"{status.Total - status.Progress}";
+				var time = $"{status.Resume.ToLongTimeString()}";
+
+				Percentage.Text = "";
+				Progress.IsIndeterminate = true;
+				Status.Text = text.Get(TextKey.ProctoringFinalizationDialog_StatusWaiting).Replace("%%_COUNT_%%", count).Replace("%%_TIME_%%", time);
+			}
+			else
+			{
+				var count = $"{status.Progress}";
+				var total = $"{status.Total}";
+
+				Percentage.Text = $"{status.Progress / (double) (status.Total > 0 ? status.Total : 1) * 100:N0}%";
+				Progress.IsIndeterminate = false;
+				Progress.Maximum = status.Total;
+				Progress.Value = status.Progress;
+
+				if (status.Next.HasValue)
+				{
+					Status.Text = text.Get(TextKey.ProctoringFinalizationDialog_StatusAndTime).Replace("%%_TIME_%%", $"{status.Next.Value.ToLongTimeString()}");
+				}
+				else
+				{
+					Status.Text = text.Get(TextKey.ProctoringFinalizationDialog_Status);
+				}
+
+				Status.Text = Status.Text.Replace("%%_COUNT_%%", count).Replace("%%_TOTAL_%%", total);
+			}
+		}
+
+		private void SystemParameters_StaticPropertyChanged(object sender, PropertyChangedEventArgs e)
+		{
+			if (e.PropertyName == nameof(SystemParameters.WorkArea))
+			{
+				Dispatcher.InvokeAsync(InitializeBounds);
+			}
+		}
+	}
+}

SafeExamBrowser.UserInterface.Shared/Utilities/WindowExtensions.cs

@@ -17,8 +17,8 @@ namespace SafeExamBrowser.UserInterface.Shared.Utilities
 	{
 		private const int GWL_STYLE = -16;
 		private const uint MF_BYCOMMAND = 0x00000000;
-		private const uint MF_GRAYED = 0x00000001;
 		private const uint MF_ENABLED = 0x00000000;
+		private const uint MF_GRAYED = 0x00000001;
 		private const uint SC_CLOSE = 0xF060;
 		private const uint SWP_SHOWWINDOW = 0x0040;
 		private const int WS_SYSMENU = 0x80000;
@@ -36,6 +36,17 @@ namespace SafeExamBrowser.UserInterface.Shared.Utilities
 			}
 		}
 
+		public static void EnableCloseButton(this Window window)
+		{
+			var helper = new WindowInteropHelper(window);
+			var systemMenu = GetSystemMenu(helper.Handle, false);
+
+			if (systemMenu != IntPtr.Zero)
+			{
+				EnableMenuItem(systemMenu, SC_CLOSE, MF_BYCOMMAND | MF_ENABLED);
+			}
+		}
+
 		public static void HideCloseButton(this Window window)
 		{
 			var helper = new WindowInteropHelper(window);