Fixed bugs the following bugs:

* Opening the cost overview could lead to a crash if a cost entry did not cover all tenants.
* The amount in the unit calculation window was not updated when changes were made.
* After creation of a new billing the main window could be closed without getting a save dialog.

Added autosave functionality.

README.md

@@ -0,0 +1,3 @@
+# UCalc
+
+UCalc oder MietRechner ist eine Anwendung zur Berechnung der Nebenkosten.

ucalc/App.xaml.cs

@@ -1,5 +1,6 @@
 using System;
 using System.IO;
+using System.Windows;
 using UCalc.Data;
 
 namespace UCalc
@@ -7,7 +8,9 @@ namespace UCalc
     public partial class App
     {
         private readonly RecentlyOpenedList _recentlyOpenedList;
+        private readonly Autosaver _autosaver;
         public static RecentlyOpenedList RecentlyOpenedList => ((App) Current)._recentlyOpenedList;
+        public static Autosaver Autosaver => ((App) Current)._autosaver;
 
         public App()
         {
@@ -15,6 +18,14 @@ namespace UCalc
             Directory.CreateDirectory(appDataPath);
 
             _recentlyOpenedList = new RecentlyOpenedList($"{appDataPath}/recently.txt");
+            _autosaver = new Autosaver($"{appDataPath}/running.txt", $"{appDataPath}/autosave.mr");
+        }
+
+        protected override void OnExit(ExitEventArgs e)
+        {
+            _autosaver.OnExit();
+
+            base.OnExit(e);
         }
     }
 }

ucalc/Autosaver.cs

@@ -0,0 +1,106 @@
+using System;
+using System.IO;
+using System.Threading;
+using UCalc.Data;
+using UCalc.Models;
+
+namespace UCalc
+{
+    public class Autosaver
+    {
+        private readonly string _runningPath;
+        private SaverThread _saverThread;
+        public string AutosavePath { get; }
+        public bool CanRecover { get; private set; }
+
+        public Model OpenModel
+        {
+            set
+            {
+                CanRecover = false;
+
+                if (value != null)
+                {
+                    _saverThread = new SaverThread(15, AutosavePath, value);
+                }
+                else if (_saverThread != null)
+                {
+                    _saverThread.Terminate();
+                    _saverThread = null;
+                }
+            }
+        }
+
+        public Autosaver(string runningPath, string autosavePath)
+        {
+            _runningPath = runningPath;
+            AutosavePath = autosavePath;
+
+            CanRecover = File.Exists(runningPath) && File.Exists(autosavePath);
+
+            File.WriteAllText(runningPath, "");
+        }
+
+        public void OnExit()
+        {
+            if (!CanRecover)
+            {
+                try
+                {
+                    File.Delete(_runningPath);
+                }
+                catch (IOException)
+                {
+                    // Do nothing
+                }
+            }
+        }
+
+        private class SaverThread
+        {
+            private volatile bool _terminate;
+            private readonly int _saveIntervalInS;
+            private readonly string _autosavePath;
+            private readonly Model _model;
+
+            public SaverThread(int saveIntervalInS, string autosavePath, Model model)
+            {
+                _terminate = false;
+                _saveIntervalInS = saveIntervalInS;
+                _autosavePath = autosavePath;
+                _model = model;
+
+                new Thread(ThreadFunc).Start();
+            }
+
+            public void Terminate()
+            {
+                _terminate = true;
+            }
+
+            private void ThreadFunc()
+            {
+                var start = DateTime.Now;
+
+                while (!_terminate)
+                {
+                    Thread.Sleep(500);
+
+                    if ((DateTime.Now - start).Seconds >= _saveIntervalInS)
+                    {
+                        try
+                        {
+                            BillingLoader.Store(_autosavePath, _model.Dump());
+                        }
+                        catch (Exception)
+                        {
+                            // Do nothing
+                        }
+
+                        start = DateTime.Now;
+                    }
+                }
+            }
+        }
+    }
+}

ucalc/BillingWindow.xaml.cs

@@ -47,7 +47,7 @@ namespace UCalc
         public BillingWindow(string filePath, Billing billing)
         {
             FilePath = filePath;
-            Model = new Model(billing);
+            Model = new Model(billing, filePath == null);
             SaveCommand = new DelegateCommand(parameter => { Save(); });
             SaveAsCommand = new DelegateCommand(parameter => { Save(true); });
             PrintCommand = new DelegateCommand(parameter => { Print(); });
@@ -56,6 +56,8 @@ namespace UCalc
 
             Title =
                 $"MietRechner - Abrechnung von {billing.StartDate.ToString(Constants.DateFormat)} - {billing.EndDate.Date.ToString(Constants.DateFormat)}";
+
+            App.Autosaver.OpenModel = Model;
         }
 
         private void OnClosing(object sender, CancelEventArgs e)
@@ -90,6 +92,8 @@ namespace UCalc
 
         private void OnClosed(object sender, EventArgs e)
         {
+            App.Autosaver.OpenModel = null;
+
             Application.Current.MainWindow?.Show();
         }
 

ucalc/CostEntryDetailsWindow.xaml.cs

@@ -46,6 +46,11 @@ namespace UCalc
             Details.UnitCount.PropertyChanged += DetailsPropertyChanged;
             Details.DiscountsInUnits.CollectionChanged += DetailsDiscountChanged;
 
+            foreach (var discountInUnits in Details.DiscountsInUnits)
+            {
+                discountInUnits.PropertyChanged += DetailsPropertyChanged;
+            }
+
             DetailsPropertyChanged(null, null);
 
             if (Details.TotalAmount.ConvertedValue != 0 || Details.UnitCount.ConvertedValue != 0 ||
@@ -91,6 +96,8 @@ namespace UCalc
                 discount.PropertyChanged -= DetailsPropertyChanged;
                 discount.PropertyChanged += DetailsPropertyChanged;
             }
+
+            DetailsPropertyChanged(sender, null);
         }
 
         private void OnCEClick(object sender, RoutedEventArgs e)

ucalc/Data/BillingCalculator.cs

@@ -663,9 +663,15 @@ namespace UCalc.Data
                     new Tuple<decimal, decimal, decimal>(0, 0, 0),
                     (sum, tenantResult) =>
                     {
-                        var costResult = tenantResult.Costs[cost];
-                        return new Tuple<decimal, decimal, decimal>(sum.Item1 + costResult.TotalAmount,
-                            sum.Item2 + costResult.PastAmount, sum.Item3 + costResult.FutureAmount);
+                        if (tenantResult.Costs.TryGetValue(cost, out var costResult))
+                        {
+                            return new Tuple<decimal, decimal, decimal>(sum.Item1 + costResult.TotalAmount,
+                                sum.Item2 + costResult.PastAmount, sum.Item3 + costResult.FutureAmount);
+                        }
+                        else
+                        {
+                            return sum;
+                        }
                     });
 
                 str.Append("Auf Mieter umgelegt:\n");

ucalc/MainWindow.xaml.cs

@@ -1,4 +1,5 @@
-using System.IO;
+using System;
+using System.IO;
 using System.Windows;
 using System.Windows.Controls;
 using System.Windows.Controls.Primitives;
@@ -10,9 +11,37 @@ namespace UCalc
 {
     public partial class MainWindow
     {
+        private bool _showRecover;
+
         public MainWindow()
         {
             InitializeComponent();
+
+            _showRecover = App.Autosaver.CanRecover;
+        }
+
+        protected override void OnContentRendered(EventArgs e)
+        {
+            base.OnContentRendered(e);
+
+            if (_showRecover)
+            {
+                _showRecover = false;
+
+                switch (MessageBox.Show(
+                    "Die Anwendung wurde das letzte Mal nicht richtig beendet. Es existiert allerdings eine Sicherheitskopie. Möchten Sie diese laden?",
+                    "Sicherheitskopie laden?",
+                    MessageBoxButton.YesNo, MessageBoxImage.Question))
+                {
+                    case MessageBoxResult.Yes:
+                        OpenBilling(App.Autosaver.AutosavePath, true);
+                        break;
+                    case MessageBoxResult.No:
+                        break;
+                    default:
+                        throw new ArgumentOutOfRangeException();
+                }
+            }
         }
 
         private void OnNewClick(object sender, RoutedEventArgs e)
@@ -67,14 +96,17 @@ namespace UCalc
             OpenBilling(recentlyOpenedItem.Path);
         }
 
-        private void OpenBilling(string path)
+        private void OpenBilling(string path, bool isRecovery = false)
         {
             try
             {
                 var billing = BillingLoader.Load(path);
-                App.RecentlyOpenedList.Add(new RecentlyOpenedItem(path));
+                if (!isRecovery)
+                {
+                    App.RecentlyOpenedList.Add(new RecentlyOpenedItem(path));
+                }
 
-                new BillingWindow(path, billing).Show();
+                new BillingWindow(isRecovery ? null : path, billing).Show();
                 Hide();
             }
             catch (IOException e)

ucalc/Models/Model.cs

@@ -161,12 +161,19 @@ namespace UCalc.Models
         private readonly Validator _validator;
         public BillingProperty Root { get; }
 
-        public Model(Billing billing)
+        public Model(Billing billing, bool modified)
         {
             _validator = new Validator(this);
 
             using var validator = BeginValidation(true);
+
             Root = new BillingProperty(billing.StartDate, billing.EndDate, this, null, billing);
+            if (modified)
+            {
+                var oldName = Root.Landlord.Name.Value;
+                Root.Landlord.Name.Value = $"{oldName}_";
+                Root.Landlord.Name.Value = oldName;
+            }
         }
 
         public Validator BeginValidation(bool postPone = false)

ucalc/Models/Properties.cs

@@ -106,11 +106,12 @@ namespace UCalc.Models
                 }
 
                 _value = value;
-                OnPropertyChanged();
 
                 using var validator = Model.BeginValidation();
                 Modified = true;
                 validator.Validate(this);
+
+                OnPropertyChanged();
             }
         }
 

ucalc/Pages/SideBar.xaml.cs

@@ -50,7 +50,7 @@ namespace UCalc.Pages
 
         private void OnAboutClick(object sender, RoutedEventArgs e)
         {
-            MessageBox.Show("MietRechner Version 2.0\n\nCopyright © 2020 by Tobias Erbshäußer", "Über MietRechner",
+            MessageBox.Show("MietRechner Version 2.1\n\nCopyright © 2020-2021 by Tobias Erbshäußer", "Über MietRechner",
                 MessageBoxButton.OK, MessageBoxImage.Information);
         }
     }