Restore SEBPatch

SafeExamBrowser.UserInterface.Desktop/ViewModels/ProgressIndicatorViewModel.cs

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+/*
+ * Copyright (c) 2024 ETH Zürich, IT Services
+ * 
+ * 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.Timers;
+
+namespace SafeExamBrowser.UserInterface.Desktop.ViewModels
+{
+	internal class ProgressIndicatorViewModel : INotifyPropertyChanged
+	{
+		private readonly object @lock = new object();
+
+		private Timer busyTimer;
+		private int currentProgress;
+		private bool isIndeterminate;
+		private int maxProgress;
+		private string status;
+
+		public event PropertyChangedEventHandler PropertyChanged;
+
+		public bool BusyIndication
+		{
+			set
+			{
+				HandleBusyIndication(value);
+			}
+		}
+
+		public int CurrentProgress
+		{
+			get
+			{
+				return currentProgress;
+			}
+			set
+			{
+				currentProgress = value;
+				PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(CurrentProgress)));
+			}
+		}
+
+		public bool IsIndeterminate
+		{
+			get
+			{
+				return isIndeterminate;
+			}
+			set
+			{
+				isIndeterminate = value;
+				PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(IsIndeterminate)));
+			}
+		}
+
+		public int MaxProgress
+		{
+			get
+			{
+				return maxProgress;
+			}
+			set
+			{
+				maxProgress = value;
+				PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(MaxProgress)));
+			}
+		}
+
+		public string Status
+		{
+			get
+			{
+				return status;
+			}
+			set
+			{
+				status = value;
+				PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(nameof(Status)));
+			}
+		}
+
+		protected void OnPropertyChanged(string propertyName)
+		{
+			PropertyChanged?.Invoke(this, new PropertyChangedEventArgs(propertyName));
+		}
+
+		private void HandleBusyIndication(bool start)
+		{
+			lock (@lock)
+			{
+				if (busyTimer != null)
+				{
+					busyTimer.Elapsed -= BusyTimer_Elapsed;
+					busyTimer.Stop();
+					busyTimer.Close();
+				}
+
+				if (start)
+				{
+					busyTimer = new Timer
+					{
+						AutoReset = true,
+						Interval = 1500,
+					};
+					busyTimer.Elapsed += BusyTimer_Elapsed;
+					busyTimer.Start();
+				}
+			}
+		}
+
+		private void BusyTimer_Elapsed(object sender, ElapsedEventArgs e)
+		{
+			var next = Status ?? string.Empty;
+
+			if (next.EndsWith("..."))
+			{
+				next = Status.Substring(0, Status.Length - 3);
+			}
+			else
+			{
+				next += ".";
+			}
+
+			Status = next;
+			busyTimer.Interval = 750;
+		}
+	}
+}