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

3 files changed, 57 insertions, 24 deletions

diff --git a/src/Ryujinx.Ui.Common/App/ApplicationData.cs b/src/Ryujinx.Ui.Common/App/ApplicationData.cs
index d9d3cf68..f0aa40be 100644
--- a/src/Ryujinx.Ui.Common/App/ApplicationData.cs
+++ b/src/Ryujinx.Ui.Common/App/ApplicationData.cs
@@ -10,27 +10,44 @@ using LibHac.Tools.FsSystem.NcaUtils;
 using Ryujinx.Common.Logging;
 using Ryujinx.HLE.FileSystem;
 using System;
+using System.Globalization;
 using System.IO;
+using System.Text.Json.Serialization;
 
 namespace Ryujinx.Ui.App.Common
 {
     public class ApplicationData
     {
-        public bool   Favorite      { get; set; }
-        public byte[] Icon          { get; set; }
-        public string TitleName     { get; set; }
-        public string TitleId       { get; set; }
-        public string Developer     { get; set; }
-        public string Version       { get; set; }
-        public string TimePlayed    { get; set; }
-        public double TimePlayedNum { get; set; }
-        public string LastPlayed    { get; set; }
-        public string FileExtension { get; set; }
-        public string FileSize      { get; set; }
-        public double FileSizeBytes { get; set; }
-        public string Path          { get; set; }
+        public bool      Favorite      { get; set; }
+        public byte[]    Icon          { get; set; }
+        public string    TitleName     { get; set; }
+        public string    TitleId       { get; set; }
+        public string    Developer     { get; set; }
+        public string    Version       { get; set; }
+        public string    TimePlayed    { get; set; }
+        public double    TimePlayedNum { get; set; }
+        public DateTime? LastPlayed    { get; set; }
+        public string    FileExtension { get; set; }
+        public string    FileSize      { get; set; }
+        public double    FileSizeBytes { get; set; }
+        public string    Path          { get; set; }
         public BlitStruct<ApplicationControlProperty> ControlHolder { get; set; }
-        
+
+        [JsonIgnore]
+        public string LastPlayedString
+        {
+            get
+            {
+                if (!LastPlayed.HasValue)
+                {
+                    // TODO: maybe put localized string here instead of just "Never"
+                    return "Never";
+                }
+
+                return LastPlayed.Value.ToLocalTime().ToString(CultureInfo.CurrentCulture);
+            }
+        }
+
         public static string GetApplicationBuildId(VirtualFileSystem virtualFileSystem, string titleFilePath)
         {
             using FileStream file = new(titleFilePath, FileMode.Open, FileAccess.Read);
diff --git a/src/Ryujinx.Ui.Common/App/ApplicationLibrary.cs b/src/Ryujinx.Ui.Common/App/ApplicationLibrary.cs
index b7b57f1a..0407036a 100644
--- a/src/Ryujinx.Ui.Common/App/ApplicationLibrary.cs
+++ b/src/Ryujinx.Ui.Common/App/ApplicationLibrary.cs
@@ -414,21 +414,28 @@ namespace Ryujinx.Ui.App.Common
                     ApplicationMetadata appMetadata = LoadAndSaveMetaData(titleId, appMetadata =>
                     {
                         appMetadata.Title = titleName;
-                    });
 
-                    if (appMetadata.LastPlayed != "Never")
-                    {
-                        if (!DateTime.TryParse(appMetadata.LastPlayed, out _))
+                        if (appMetadata.LastPlayedOld == default || appMetadata.LastPlayed.HasValue)
                         {
-                            Logger.Warning?.Print(LogClass.Application, $"Last played datetime \"{appMetadata.LastPlayed}\" is invalid for current system culture, skipping (did current culture change?)");
+                            // Don't do the migration if last_played doesn't exist or last_played_utc already has a value.
+                            return;
+                        }
 
-                            appMetadata.LastPlayed = "Never";
+                        // Migrate from string-based last_played to DateTime-based last_played_utc.
+                        if (DateTime.TryParse(appMetadata.LastPlayedOld, out DateTime lastPlayedOldParsed))
+                        {
+                            Logger.Info?.Print(LogClass.Application, $"last_played found: \"{appMetadata.LastPlayedOld}\", migrating to last_played_utc");
+                            appMetadata.LastPlayed = lastPlayedOldParsed;
+
+                            // Migration successful: deleting last_played from the metadata file.
+                            appMetadata.LastPlayedOld = default;
                         }
                         else
                         {
-                            appMetadata.LastPlayed = appMetadata.LastPlayed[..^3];
+                            // Migration failed: emitting warning but leaving the unparsable value in the metadata file so the user can fix it.
+                            Logger.Warning?.Print(LogClass.Application, $"Last played string \"{appMetadata.LastPlayedOld}\" is invalid for current system culture, skipping (did current culture change?)");
                         }
-                    }
+                    });
 
                     ApplicationData data = new()
                     {
diff --git a/src/Ryujinx.Ui.Common/App/ApplicationMetadata.cs b/src/Ryujinx.Ui.Common/App/ApplicationMetadata.cs
index e19f7483..0abd4680 100644
--- a/src/Ryujinx.Ui.Common/App/ApplicationMetadata.cs
+++ b/src/Ryujinx.Ui.Common/App/ApplicationMetadata.cs
@@ -1,10 +1,19 @@
-namespace Ryujinx.Ui.App.Common
+using System;
+using System.Text.Json.Serialization;
+
+namespace Ryujinx.Ui.App.Common
 {
     public class ApplicationMetadata
     {
         public string Title { get; set; }
         public bool   Favorite   { get; set; }
         public double TimePlayed { get; set; }
-        public string LastPlayed { get; set; } = "Never";
+
+        [JsonPropertyName("last_played_utc")]
+        public DateTime? LastPlayed { get; set; } = null;
+
+        [JsonPropertyName("last_played")]
+        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]
+        public string LastPlayedOld { get; set; }
     }
 }
\ No newline at end of file