Changed LastPlayed field from string to nullable DateTime (#4861)

* Changed LastPlayed field from string to nullable DateTime

Added ApplicationData.LastPlayedString property
Added NullableDateTimeConverter for the DateTime->string conversion in Avalonia

* Added migration from string-based last_played to DateTime-based last_played_utc

* Updated comment style

* Added MarkupExtension to NullableDateTimeConverter and changed its usage

Cleaned up leftover usings

* Missed one comment

4 files changed, 48 insertions, 12 deletions

diff --git a/src/Ryujinx.Ava/UI/Controls/ApplicationListView.axaml b/src/Ryujinx.Ava/UI/Controls/ApplicationListView.axaml
index fa8ebf62..227b4723 100644
--- a/src/Ryujinx.Ava/UI/Controls/ApplicationListView.axaml
+++ b/src/Ryujinx.Ava/UI/Controls/ApplicationListView.axaml
@@ -129,7 +129,7 @@
                                         TextWrapping="Wrap" />
                                     <TextBlock
                                         HorizontalAlignment="Stretch"
-                                        Text="{Binding LastPlayed}"
+                                        Text="{Binding LastPlayed, Converter={helpers:NullableDateTimeConverter}}"
                                         TextAlignment="Right"
                                         TextWrapping="Wrap" />
                                     <TextBlock
diff --git a/src/Ryujinx.Ava/UI/Helpers/NullableDateTimeConverter.cs b/src/Ryujinx.Ava/UI/Helpers/NullableDateTimeConverter.cs
new file mode 100644
index 00000000..1d862de0
--- /dev/null
+++ b/src/Ryujinx.Ava/UI/Helpers/NullableDateTimeConverter.cs
@@ -0,0 +1,38 @@
+using Avalonia.Data.Converters;
+using Avalonia.Markup.Xaml;
+using Ryujinx.Ava.Common.Locale;
+using System;
+using System.Globalization;
+
+namespace Ryujinx.Ava.UI.Helpers
+{
+    internal class NullableDateTimeConverter : MarkupExtension, IValueConverter
+    {
+        private static readonly NullableDateTimeConverter _instance = new();
+
+        public object Convert(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            if (value == null)
+            {
+                return LocaleManager.Instance[LocaleKeys.Never];
+            }
+
+            if (value is DateTime dateTime)
+            {
+                return dateTime.ToLocalTime().ToString(culture);
+            }
+
+            throw new NotSupportedException();
+        }
+
+        public object ConvertBack(object value, Type targetType, object parameter, CultureInfo culture)
+        {
+            throw new NotSupportedException();
+        }
+
+        public override object ProvideValue(IServiceProvider serviceProvider)
+        {
+            return _instance;
+        }
+    }
+}
\ No newline at end of file
diff --git a/src/Ryujinx.Ava/UI/Models/Generic/LastPlayedSortComparer.cs b/src/Ryujinx.Ava/UI/Models/Generic/LastPlayedSortComparer.cs
index 98caceb5..3627ada9 100644
--- a/src/Ryujinx.Ava/UI/Models/Generic/LastPlayedSortComparer.cs
+++ b/src/Ryujinx.Ava/UI/Models/Generic/LastPlayedSortComparer.cs
@@ -1,4 +1,3 @@
-using Ryujinx.Ava.Common.Locale;
 using Ryujinx.Ui.App.Common;
 using System;
 using System.Collections.Generic;
@@ -14,20 +13,20 @@ namespace Ryujinx.Ava.UI.Models.Generic
 
         public int Compare(ApplicationData x, ApplicationData y)
         {
-            string aValue = x.LastPlayed;
-            string bValue = y.LastPlayed;
+            var aValue = x.LastPlayed;
+            var bValue = y.LastPlayed;
 
-            if (aValue == LocaleManager.Instance[LocaleKeys.Never])
+            if (!aValue.HasValue)
             {
-                aValue = DateTime.UnixEpoch.ToString();
+                aValue = DateTime.UnixEpoch;
             }
 
-            if (bValue == LocaleManager.Instance[LocaleKeys.Never])
+            if (!bValue.HasValue)
             {
-                bValue = DateTime.UnixEpoch.ToString();
+                bValue = DateTime.UnixEpoch;
             }
 
-            return (IsAscending ? 1 : -1) * DateTime.Compare(DateTime.Parse(bValue), DateTime.Parse(aValue));
+            return (IsAscending ? 1 : -1) * DateTime.Compare(bValue.Value, aValue.Value);
         }
     }
 }
\ No newline at end of file
diff --git a/src/Ryujinx.Ava/UI/ViewModels/MainWindowViewModel.cs b/src/Ryujinx.Ava/UI/ViewModels/MainWindowViewModel.cs
index 4db78afe..f8dd4143 100644
--- a/src/Ryujinx.Ava/UI/ViewModels/MainWindowViewModel.cs
+++ b/src/Ryujinx.Ava/UI/ViewModels/MainWindowViewModel.cs
@@ -1524,10 +1524,9 @@ namespace Ryujinx.Ava.UI.ViewModels
         {
             ApplicationLibrary.LoadAndSaveMetaData(titleId, appMetadata =>
             {
-                if (DateTime.TryParse(appMetadata.LastPlayed, out DateTime lastPlayedDateTime))
+                if (appMetadata.LastPlayed.HasValue)
                 {
-                    double sessionTimePlayed = DateTime.UtcNow.Subtract(lastPlayedDateTime).TotalSeconds;
-
+                    double sessionTimePlayed = DateTime.UtcNow.Subtract(appMetadata.LastPlayed.Value).TotalSeconds;
                     appMetadata.TimePlayed += Math.Round(sessionTimePlayed, MidpointRounding.AwayFromZero);
                 }
             });