SEBWIN-320: Implemented configuration reset functionality for reset utility.

SafeExamBrowser.Contracts/Lockdown/IFeatureConfiguration.cs

@@ -45,6 +45,11 @@ namespace SafeExamBrowser.Contracts.Lockdown
 		/// </summary>
 		void Initialize();
 
+		/// <summary>
+		/// Resets the feature to its default configuration. Returns <c>true</c> if successful, otherwise <c>false</c>.
+		/// </summary>
+		bool Reset();
+
 		/// <summary>
 		/// Restores the feature to its previous configuration (i.e. before it was enabled or disabled). Returns <c>true</c> if successful,
 		/// otherwise <c>false</c>.

SafeExamBrowser.Contracts/Lockdown/IFeatureConfigurationFactory.cs

@@ -7,6 +7,7 @@
  */
 
 using System;
+using System.Collections.Generic;
 
 namespace SafeExamBrowser.Contracts.Lockdown
 {
@@ -15,6 +16,11 @@ namespace SafeExamBrowser.Contracts.Lockdown
 	/// </summary>
 	public interface IFeatureConfigurationFactory
 	{
+		/// <summary>
+		/// Creates all feature configurations.
+		/// </summary>
+		IList<IFeatureConfiguration> CreateAll(Guid groupId, string sid, string userName);
+
 		/// <summary>
 		/// Creates an <see cref="IFeatureConfiguration"/> to control the option to change the password of a user account via the security screen.
 		/// </summary>

SafeExamBrowser.Contracts/SystemComponents/IUserInfo.cs

@@ -22,5 +22,10 @@ namespace SafeExamBrowser.Contracts.SystemComponents
 		/// Retrieves the security identifier of the currently logged in user.
 		/// </summary>
 		string GetUserSid();
+
+		/// <summary>
+		/// Tries to retrieve the security identifier for the specified user name. Returns <c>true</c> if successful, otherwise <c>false</c>.
+		/// </summary>
+		bool TryGetSidForUser(string userName, out string sid);
 	}
 }

SafeExamBrowser.Lockdown.UnitTests/FeatureConfigurationStub.cs

@@ -42,6 +42,11 @@ namespace SafeExamBrowser.Lockdown.UnitTests
 			throw new NotImplementedException();
 		}
 
+		public bool Reset()
+		{
+			throw new NotImplementedException();
+		}
+
 		public bool Restore()
 		{
 			throw new NotImplementedException();

SafeExamBrowser.Lockdown/FeatureConfigurationFactory.cs

@@ -7,6 +7,7 @@
  */
 
 using System;
+using System.Collections.Generic;
 using SafeExamBrowser.Contracts.Lockdown;
 using SafeExamBrowser.Contracts.Logging;
 using SafeExamBrowser.Lockdown.FeatureConfigurations.RegistryConfigurations.MachineHive;
@@ -24,6 +25,25 @@ namespace SafeExamBrowser.Lockdown
 			this.logger = logger;
 		}
 
+		public IList<IFeatureConfiguration> CreateAll(Guid groupId, string sid, string userName)
+		{
+			return new List<IFeatureConfiguration>
+			{
+				CreateChangePasswordConfiguration(groupId, sid, userName),
+				CreateChromeNotificationConfiguration(groupId, sid, userName),
+				CreateEaseOfAccessConfiguration(groupId),
+				CreateLockWorkstationConfiguration(groupId, sid, userName),
+				CreateNetworkOptionsConfiguration(groupId),
+				CreatePowerOptionsConfiguration(groupId),
+				CreateRemoteConnectionConfiguration(groupId),
+				CreateSignoutConfiguration(groupId, sid, userName),
+				CreateSwitchUserConfiguration(groupId),
+				CreateTaskManagerConfiguration(groupId, sid, userName),
+				CreateVmwareOverlayConfiguration(groupId, sid, userName),
+				CreateWindowsUpdateConfiguration(groupId)
+			};
+		}
+
 		public IFeatureConfiguration CreateChangePasswordConfiguration(Guid groupId, string sid, string userName)
 		{
 			return new ChangePasswordConfiguration(groupId, logger.CloneFor(nameof(ChangePasswordConfiguration)), sid, userName);

SafeExamBrowser.Lockdown/FeatureConfigurations/FeatureConfiguration.cs

@@ -33,6 +33,7 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations
 		public abstract bool EnableFeature();
 		public abstract FeatureConfigurationStatus GetStatus();
 		public abstract void Initialize();
+		public abstract bool Reset();
 		public abstract bool Restore();
 
 		public override string ToString()

SafeExamBrowser.Lockdown/FeatureConfigurations/RegistryConfigurations/MachineHive/EaseOfAccessConfiguration.cs

@@ -23,5 +23,10 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.RegistryConfigurations.
 		public EaseOfAccessConfiguration(Guid groupId, ILogger logger) : base(groupId, logger)
 		{
 		}
+
+		public override bool Reset()
+		{
+			return DeleteConfiguration();
+		}
 	}
 }

SafeExamBrowser.Lockdown/FeatureConfigurations/RegistryConfigurations/MachineHive/NetworkOptionsConfiguration.cs

@@ -23,5 +23,10 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.RegistryConfigurations.
 		public NetworkOptionsConfiguration(Guid groupId, ILogger logger) : base(groupId, logger)
 		{
 		}
+
+		public override bool Reset()
+		{
+			return DeleteConfiguration();
+		}
 	}
 }

SafeExamBrowser.Lockdown/FeatureConfigurations/RegistryConfigurations/MachineHive/PowerOptionsConfiguration.cs

@@ -23,5 +23,10 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.RegistryConfigurations.
 		public PowerOptionsConfiguration(Guid groupId, ILogger logger) : base(groupId, logger)
 		{
 		}
+
+		public override bool Reset()
+		{
+			return DeleteConfiguration();
+		}
 	}
 }

SafeExamBrowser.Lockdown/FeatureConfigurations/RegistryConfigurations/MachineHive/RemoteConnectionConfiguration.cs

@@ -12,6 +12,13 @@ using SafeExamBrowser.Contracts.Logging;
 
 namespace SafeExamBrowser.Lockdown.FeatureConfigurations.RegistryConfigurations.MachineHive
 {
+	/// <summary>
+	/// Specifies whether Remote Desktop connections are enabled.
+	/// 
+	/// See https://docs.microsoft.com/en-us/windows-hardware/customize/desktop/unattend/microsoft-windows-terminalservices-localsessionmanager-fdenytsconnections:
+	/// •	0 = Specifies that remote desktop connections are enabled.
+	/// •	1 = Specifies that remote desktop connections are denied. This is the default value.
+	/// </summary>
 	[Serializable]
 	internal class RemoteConnectionConfiguration : MachineHiveConfiguration
 	{
@@ -23,5 +30,10 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.RegistryConfigurations.
 		public RemoteConnectionConfiguration(Guid groupId, ILogger logger) : base(groupId, logger)
 		{
 		}
+
+		public override bool Reset()
+		{
+			return DisableFeature();
+		}
 	}
 }

SafeExamBrowser.Lockdown/FeatureConfigurations/RegistryConfigurations/MachineHive/SwitchUserConfiguration.cs

@@ -23,5 +23,10 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.RegistryConfigurations.
 		public SwitchUserConfiguration(Guid groupId, ILogger logger) : base(groupId, logger)
 		{
 		}
+
+		public override bool Reset()
+		{
+			return DeleteConfiguration();
+		}
 	}
 }

SafeExamBrowser.Lockdown/FeatureConfigurations/RegistryConfigurations/RegistryConfiguration.cs

@@ -30,6 +30,8 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.RegistryConfigurations
 			itemsToRestore = new List<RegistryDataItem>();
 		}
 
+		protected abstract bool IsHiveAvailable(RegistryDataItem item);
+
 		public override bool DisableFeature()
 		{
 			var success = true;
@@ -66,7 +68,7 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.RegistryConfigurations
 			}
 			else
 			{
-				logger.Warn("Failed to enabled feature!");
+				logger.Warn("Failed to enable feature!");
 			}
 
 			return success;
@@ -148,7 +150,26 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.RegistryConfigurations
 			return success;
 		}
 
-		protected abstract bool IsHiveAvailable(RegistryDataItem item);
+		protected bool DeleteConfiguration()
+		{
+			var success = true;
+
+			foreach (var item in Items)
+			{
+				success &= TryDelete(new RegistryDataItem { Key = item.Key, Value = item.Value });
+			}
+
+			if (success)
+			{
+				logger.Info("Successfully deleted feature configuration.");
+			}
+			else
+			{
+				logger.Warn("Failed to delete feature configuration!");
+			}
+
+			return success;
+		}
 
 		private RegistryDataItem ReadItem(string key, string value)
 		{

SafeExamBrowser.Lockdown/FeatureConfigurations/RegistryConfigurations/UserHive/ChangePasswordConfiguration.cs

@@ -23,5 +23,10 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.RegistryConfigurations.
 		public ChangePasswordConfiguration(Guid groupId, ILogger logger, string sid, string userName) : base(groupId, logger, sid, userName)
 		{
 		}
+
+		public override bool Reset()
+		{
+			return DeleteConfiguration();
+		}
 	}
 }

SafeExamBrowser.Lockdown/FeatureConfigurations/RegistryConfigurations/UserHive/ChromeNotificationConfiguration.cs

@@ -16,9 +16,9 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.RegistryConfigurations.
 	/// IMPORTANT: This registry configuration only has an effect after Chrome is restarted!
 	/// 
 	/// See https://www.chromium.org/administrators/policy-list-3#DefaultNotificationsSetting:
-	/// •	1 = Allow sites to show desktop notifications
-	/// •	2 = Do not allow any site to show desktop notifications
-	/// •	3 = Ask every time a site wants to show desktop notifications
+	/// •	1 = Allow sites to show desktop notifications.
+	/// •	2 = Do not allow any site to show desktop notifications.
+	/// •	3 = Ask every time a site wants to show desktop notifications.
 	/// </summary>
 	[Serializable]
 	internal class ChromeNotificationConfiguration : UserHiveConfiguration
@@ -31,5 +31,10 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.RegistryConfigurations.
 		public ChromeNotificationConfiguration(Guid groupId, ILogger logger, string sid, string userName) : base(groupId, logger, sid, userName)
 		{
 		}
+
+		public override bool Reset()
+		{
+			return DeleteConfiguration();
+		}
 	}
 }

SafeExamBrowser.Lockdown/FeatureConfigurations/RegistryConfigurations/UserHive/LockWorkstationConfiguration.cs

@@ -23,5 +23,10 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.RegistryConfigurations.
 		public LockWorkstationConfiguration(Guid groupId, ILogger logger, string sid, string userName) : base(groupId, logger, sid, userName)
 		{
 		}
+
+		public override bool Reset()
+		{
+			return DeleteConfiguration();
+		}
 	}
 }

SafeExamBrowser.Lockdown/FeatureConfigurations/RegistryConfigurations/UserHive/SignoutConfiguration.cs

@@ -23,5 +23,10 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.RegistryConfigurations.
 		public SignoutConfiguration(Guid groupId, ILogger logger, string sid, string userName) : base(groupId, logger, sid, userName)
 		{
 		}
+
+		public override bool Reset()
+		{
+			return DeleteConfiguration();
+		}
 	}
 }

SafeExamBrowser.Lockdown/FeatureConfigurations/RegistryConfigurations/UserHive/TaskManagerConfiguration.cs

@@ -23,5 +23,10 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.RegistryConfigurations.
 		public TaskManagerConfiguration(Guid groupId, ILogger logger, string sid, string userName) : base(groupId, logger, sid, userName)
 		{
 		}
+
+		public override bool Reset()
+		{
+			return DeleteConfiguration();
+		}
 	}
 }

SafeExamBrowser.Lockdown/FeatureConfigurations/RegistryConfigurations/UserHive/VmwareOverlayConfiguration.cs

@@ -24,5 +24,10 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.RegistryConfigurations.
 		public VmwareOverlayConfiguration(Guid groupId, ILogger logger, string sid, string userName) : base(groupId, logger, sid, userName)
 		{
 		}
+
+		public override bool Reset()
+		{
+			return EnableFeature();
+		}
 	}
 }

SafeExamBrowser.Lockdown/FeatureConfigurations/ServiceConfigurations/WindowsUpdateConfiguration.cs

@@ -23,5 +23,10 @@ namespace SafeExamBrowser.Lockdown.FeatureConfigurations.ServiceConfigurations
 		public WindowsUpdateConfiguration(Guid groupId, ILogger logger) : base(groupId, logger)
 		{
 		}
+
+		public override bool Reset()
+		{
+			return EnableFeature();
+		}
 	}
 }

SafeExamBrowser.ResetUtility/CompositionRoot.cs

@@ -14,11 +14,13 @@ using SafeExamBrowser.Contracts.Logging;
 using SafeExamBrowser.Lockdown;
 using SafeExamBrowser.Logging;
 using SafeExamBrowser.ResetUtility.Procedure;
+using SafeExamBrowser.SystemComponents;
 
 namespace SafeExamBrowser.ResetUtility
 {
 	internal class CompositionRoot
 	{
+		private ProcedureContext context;
 		private ILogger logger;
 
 		internal ProcedureStep InitialStep { get; private set; }
@@ -26,14 +28,8 @@ namespace SafeExamBrowser.ResetUtility
 
 		internal void BuildObjectGraph()
 		{
-			var context = new ProcedureContext();
-
 			InitializeLogging();
-
-			context.CreateBackup = CreateBackup;
-			context.Logger = logger;
-			context.MainMenu = BuildMainMenu(context);
-			context.Update = new SystemConfigurationUpdate(new ModuleLogger(logger, nameof(SystemConfigurationUpdate)));
+			InitializeContext();
 
 			InitialStep = new Initialization(context);
 			NativeMethods = new NativeMethods();
@@ -68,6 +64,17 @@ namespace SafeExamBrowser.ResetUtility
 			return new FeatureConfigurationBackup(filePath, new ModuleLogger(logger, nameof(FeatureConfigurationBackup)));
 		}
 
+		private void InitializeContext()
+		{
+			context = new ProcedureContext();
+			context.ConfigurationFactory = new FeatureConfigurationFactory(new ModuleLogger(logger, nameof(FeatureConfigurationFactory)));
+			context.CreateBackup = CreateBackup;
+			context.Logger = logger;
+			context.MainMenu = BuildMainMenu(context);
+			context.Update = new SystemConfigurationUpdate(new ModuleLogger(logger, nameof(SystemConfigurationUpdate)));
+			context.UserInfo = new UserInfo(new ModuleLogger(logger, nameof(UserInfo)));
+		}
+
 		private void InitializeLogging()
 		{
 			var appDataFolder = Path.Combine(Environment.GetFolderPath(Environment.SpecialFolder.LocalApplicationData), nameof(SafeExamBrowser));

SafeExamBrowser.ResetUtility/Procedure/ProcedureContext.cs

@@ -10,14 +10,17 @@ using System;
 using System.Collections.Generic;
 using SafeExamBrowser.Contracts.Lockdown;
 using SafeExamBrowser.Contracts.Logging;
+using SafeExamBrowser.Contracts.SystemComponents;
 
 namespace SafeExamBrowser.ResetUtility.Procedure
 {
 	internal class ProcedureContext
 	{
+		internal IFeatureConfigurationFactory ConfigurationFactory { get; set; }
 		internal Func<string, IFeatureConfigurationBackup> CreateBackup { get; set; }
 		internal ILogger Logger { get; set; }
 		internal IList<MainMenuOption> MainMenu { get; set; }
 		internal ISystemConfigurationUpdate Update { get; set; }
+		internal IUserInfo UserInfo { get; set; }
 	}
 }

SafeExamBrowser.ResetUtility/Procedure/ProcedureStep.cs

@@ -57,6 +57,25 @@ namespace SafeExamBrowser.ResetUtility.Procedure
 			Console.CursorVisible = false;
 		}
 
+		protected void ClearLine(int top)
+		{
+			Console.SetCursorPosition(0, top);
+			Console.WriteLine(new String(' ', Console.BufferWidth));
+			Console.SetCursorPosition(0, top);
+		}
+
+		protected string ReadLine()
+		{
+			Console.Write("> ");
+			Console.CursorVisible = true;
+
+			var input = Console.ReadLine();
+
+			Console.CursorVisible = false;
+
+			return input;
+		}
+
 		protected void ShowError(string message)
 		{
 			Console.ForegroundColor = ConsoleColor.Red;

SafeExamBrowser.ResetUtility/Procedure/Reset.cs

@@ -6,6 +6,11 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
+using System;
+using System.Collections.Generic;
+using System.Linq;
+using SafeExamBrowser.Contracts.Lockdown;
+
 namespace SafeExamBrowser.ResetUtility.Procedure
 {
 	internal class Reset : ProcedureStep
@@ -16,6 +21,15 @@ namespace SafeExamBrowser.ResetUtility.Procedure
 
 		internal override ProcedureStepResult Execute()
 		{
+			InitializeConsole();
+
+			var success = TryGetUserInfo(out var userName, out var sid);
+
+			if (success)
+			{
+				ResetAll(userName, sid);
+			}
+
 			return ProcedureStepResult.Continue;
 		}
 
@@ -23,5 +37,120 @@ namespace SafeExamBrowser.ResetUtility.Procedure
 		{
 			return new MainMenu(Context);
 		}
+
+		private bool TryGetUserInfo(out string userName, out string sid)
+		{
+			Console.ForegroundColor = ConsoleColor.DarkYellow;
+			Console.WriteLine("IMPORTANT: Some configuration values are user specific. In order to reset these values, the user specified below needs to be logged in!");
+			Console.ForegroundColor = ForegroundColor;
+			Console.WriteLine();
+			Console.WriteLine("Please enter the name of the user for which to reset all configuration values:");
+
+			userName = ReadLine();
+
+			StartProgressAnimation();
+			var success = Context.UserInfo.TryGetSidForUser(userName, out sid);
+			StopProgressAnimation();
+
+			while (!success)
+			{
+				Console.ForegroundColor = ConsoleColor.Red;
+				Console.WriteLine($"Could not find user '{userName}'!");
+				Console.ForegroundColor = ForegroundColor;
+
+				var tryAgain = new MenuOption { IsSelected = true, Text = "Try again" };
+				var mainMenu = new MenuOption { Text = "Return to main menu" };
+
+				ShowMenu(new List<MenuOption> { tryAgain, mainMenu });
+
+				if (mainMenu.IsSelected)
+				{
+					break;
+				}
+
+				ClearLine(Console.CursorTop - 1);
+				ClearLine(Console.CursorTop - 1);
+				ClearLine(Console.CursorTop - 1);
+				ClearLine(Console.CursorTop - 1);
+
+				userName = ReadLine();
+				success = Context.UserInfo.TryGetSidForUser(userName, out sid);
+			}
+
+			return success;
+		}
+
+		private void ResetAll(string userName, string sid)
+		{
+			var configurations = Context.ConfigurationFactory.CreateAll(Guid.NewGuid(), sid, userName);
+			var failed = new List<IFeatureConfiguration>();
+
+			Logger.Info($"Attempting to reset all configuration values for user '{userName}' with SID '{sid}'...");
+			Console.WriteLine();
+			Console.WriteLine("Initiating reset procedure...");
+
+			foreach (var configuration in configurations)
+			{
+				var success = configuration.Reset();
+
+				if (!success)
+				{
+					failed.Add(configuration);
+				}
+
+				ShowProgress(configurations.IndexOf(configuration) + 1, configurations.Count);
+			}
+
+			PerformUpdate();
+
+			if (failed.Any())
+			{
+				HandleFailure(failed);
+			}
+			else
+			{
+				HandleSuccess();
+			}
+
+			Console.WriteLine();
+			Console.WriteLine("Press any key to return to the main menu.");
+			Console.ReadKey();
+		}
+
+		private void PerformUpdate()
+		{
+			Console.WriteLine();
+			Console.WriteLine("Performing system configuration update, please wait...");
+			StartProgressAnimation();
+			Context.Update.Execute();
+			StopProgressAnimation();
+			Console.WriteLine("Update completed.");
+		}
+
+		private void HandleFailure(IList<IFeatureConfiguration> configurations)
+		{
+			Logger.Warn($"Failed to reset {configurations.Count} items!");
+			Console.WriteLine();
+			Console.ForegroundColor = ConsoleColor.Red;
+			Console.WriteLine($"Failed to reset {configurations.Count} items!");
+
+			foreach (var configuration in configurations)
+			{
+				Console.WriteLine($" - {configuration.GetType().Name}");
+			}
+
+			Console.ForegroundColor = ForegroundColor;
+			Console.WriteLine();
+			Console.WriteLine("Please consult the application log for more information.");
+		}
+
+		private void HandleSuccess()
+		{
+			Logger.Info("Successfully reset all changes!");
+			Console.WriteLine();
+			Console.ForegroundColor = ConsoleColor.DarkGreen;
+			Console.WriteLine("Successfully reset all changes!");
+			Console.ForegroundColor = ForegroundColor;
+		}
 	}
 }

SafeExamBrowser.ResetUtility/Procedure/Restore.cs

@@ -6,7 +6,6 @@
  * file, You can obtain one at http://mozilla.org/MPL/2.0/.
  */
 
-
 using System;
 using System.Collections.Generic;
 using System.IO;
@@ -104,13 +103,11 @@ namespace SafeExamBrowser.ResetUtility.Procedure
 
 		private void PerformUpdate()
 		{
-			Logger.Info("Starting system configuration update...");
 			Console.WriteLine();
 			Console.WriteLine("Performing system configuration update, please wait...");
 			StartProgressAnimation();
 			Context.Update.Execute();
 			StopProgressAnimation();
-			Logger.Info("Update completed.");
 			Console.WriteLine("Update completed.");
 		}
 
@@ -160,7 +157,7 @@ namespace SafeExamBrowser.ResetUtility.Procedure
 				next = new Reset(Context);
 			}
 
-			Logger.Info($"The user chose {(yes.IsSelected ? "" : "not ")}to perform a reset for now.");
+			Logger.Info($"The user chose {(yes.IsSelected ? "" : "not ")}to perform a reset.");
 		}
 	}
 }

SafeExamBrowser.ResetUtility/SafeExamBrowser.ResetUtility.csproj

@@ -92,6 +92,10 @@
       <Project>{e107026c-2011-4552-a7d8-3a0d37881df6}</Project>
       <Name>SafeExamBrowser.Logging</Name>
     </ProjectReference>
+    <ProjectReference Include="..\SafeExamBrowser.SystemComponents\SafeExamBrowser.SystemComponents.csproj">
+      <Project>{acee2ef1-14d2-4b52-8994-5c053055bb51}</Project>
+      <Name>SafeExamBrowser.SystemComponents</Name>
+    </ProjectReference>
   </ItemGroup>
   <ItemGroup>
     <Content Include="SafeExamBrowser.ico" />

SafeExamBrowser.Runtime/CompositionRoot.cs

@@ -71,7 +71,7 @@ namespace SafeExamBrowser.Runtime
 			var serviceProxy = new ServiceProxy(appConfig.ServiceAddress, new ProxyObjectFactory(), ModuleLogger(nameof(ServiceProxy)), Interlocutor.Runtime);
 			var sessionContext = new SessionContext();
 			var uiFactory = new UserInterfaceFactory(text);
-			var userInfo = new UserInfo();
+			var userInfo = new UserInfo(ModuleLogger(nameof(UserInfo)));
 
 			var bootstrapOperations = new Queue<IOperation>();
 			var sessionOperations = new Queue<IRepeatableOperation>();

SafeExamBrowser.SystemComponents/UserInfo.cs

@@ -7,13 +7,25 @@
  */
 
 using System;
+using System.Diagnostics;
 using System.Security.Principal;
+using System.Text.RegularExpressions;
+using SafeExamBrowser.Contracts.Logging;
 using SafeExamBrowser.Contracts.SystemComponents;
 
 namespace SafeExamBrowser.SystemComponents
 {
 	public class UserInfo : IUserInfo
 	{
+		private const string SID_REGEX_PATTERN = @"S-\d(-\d+)+";
+
+		private ILogger logger;
+
+		public UserInfo(ILogger logger)
+		{
+			this.logger = logger;
+		}
+
 		public string GetUserName()
 		{
 			return Environment.UserName;
@@ -23,5 +35,77 @@ namespace SafeExamBrowser.SystemComponents
 		{
 			return WindowsIdentity.GetCurrent().User.Value;
 		}
+
+		public bool TryGetSidForUser(string userName, out string sid)
+		{
+			var strategies = new Func<string, string>[] { NtAccount, Wmi };
+			var success = false;
+
+			sid = default(string);
+
+			foreach (var strategy in strategies)
+			{
+				try
+				{
+					sid = strategy.Invoke(userName);
+
+					if (IsValid(sid))
+					{
+						logger.Info($"Found SID '{sid}' via '{strategy.Method.Name}' for user name '{userName}'!");
+						success = true;
+
+						break;
+					}
+
+					logger.Warn($"Retrieved invalid SID '{sid}' via '{strategy.Method.Name}' for user name '{userName}'!");
+				}
+				catch (Exception e)
+				{
+					logger.Error($"Failed to get SID via '{strategy.Method.Name}' for user name '{userName}'!", e);
+				}
+			}
+
+			if (!success)
+			{
+				logger.Error($"All attempts to retrieve SID for user name '{userName}' failed!");
+			}
+
+			return success;
+		}
+
+		private string NtAccount(string userName)
+		{
+			var account = new NTAccount(userName);
+
+			if (account.IsValidTargetType(typeof(SecurityIdentifier)))
+			{
+				return account.Translate(typeof(SecurityIdentifier)).Value;
+			}
+
+			return null;
+		}
+
+		private string Wmi(string userName)
+		{
+			var process = new Process();
+
+			process.StartInfo.FileName = "cmd.exe";
+			process.StartInfo.Arguments = string.Format("/c \"wmic useraccount where name='{0}' get sid\"", userName);
+			process.StartInfo.UseShellExecute = false;
+			process.StartInfo.RedirectStandardOutput = true;
+			process.StartInfo.CreateNoWindow = true;
+			process.Start();
+			process.WaitForExit(5000);
+
+			var output = process.StandardOutput.ReadToEnd();
+			var match = Regex.Match(output, SID_REGEX_PATTERN);
+
+			return match.Success ? match.Value : null;
+		}
+
+		private bool IsValid(string sid)
+		{
+			return !String.IsNullOrWhiteSpace(sid) && Regex.IsMatch(sid, $"^{SID_REGEX_PATTERN}$");
+		}
 	}
 }