Add source grouping mode

osu.Game/Screens/Select/Filter/GroupMode.cs

@@ -34,6 +34,9 @@ namespace osu.Game.Screens.Select.Filter
         // [Description("Favourites")]
         // Favourites,
 
+        [Description("Last Played")]
+        LastPlayed,
+
         [Description("Length")]
         Length,
 
@@ -46,8 +49,8 @@ namespace osu.Game.Screens.Select.Filter
         [Description("Ranked Status")]
         RankedStatus,
 
-        [Description("Last Played")]
-        LastPlayed,
+        [Description("Source")]
+        Source,
 
         [Description("Title")]
         Title,

osu.Game/Screens/SelectV2/BeatmapCarouselFilterGrouping.cs

@@ -202,6 +202,9 @@ namespace osu.Game.Screens.SelectV2
                         return defineGroupByLength(length);
                     }, items);
 
+                case GroupMode.Source:
+                    return getGroupsBy(b => defineGroupBySource(b.BeatmapSet!.Metadata.Source), items);
+
                 // TODO: need implementation
                 //
                 // case GroupMode.Collections:
@@ -225,6 +228,7 @@ namespace osu.Game.Screens.SelectV2
         {
             return items.GroupBy(i => getGroup((BeatmapInfo)i.Model))
                         .OrderBy(s => s.Key.Order)
+                        .ThenBy(s => s.Key.Title)
                         .Select(g => new GroupMapping(g.Key, g.ToList()))
                         .ToList();
         }
@@ -354,6 +358,14 @@ namespace osu.Game.Screens.SelectV2
             return new GroupDefinition(11, "Over 10 minutes");
         }
 
+        private GroupDefinition defineGroupBySource(string source)
+        {
+            if (string.IsNullOrEmpty(source))
+                return new GroupDefinition(1, "Unsourced");
+
+            return new GroupDefinition(0, source);
+        }
+
         private static T? aggregateMax<T>(BeatmapInfo b, Func<BeatmapInfo, T> func)
         {
             var beatmaps = b.BeatmapSet!.Beatmaps.Where(bb => !bb.Hidden);