Added playlist logic.

Harmonia.Core/Extensions/EnumerableExtensions.cs

@@ -0,0 +1,34 @@
+using Harmonia.Core.Models;
+using System.ComponentModel;
+using System.Reflection;
+
+namespace Harmonia.Core.Extensions;
+
+public static class EnumerableExtensions
+{
+    public static IOrderedEnumerable<T> SortBy<T>(this IEnumerable<T> source, SortOption[] sortOptions)
+    {
+        IOrderedEnumerable<T> orderedQuery = source.OrderBy(x => 0);
+        Type type = typeof(T);
+
+        foreach (SortOption sortOption in sortOptions)
+        {
+            PropertyInfo? property = type.GetProperty(sortOption.FieldName);
+
+            if (property == null)
+                continue;
+
+            switch (sortOption.Direction)
+            {
+                case ListSortDirection.Ascending:
+                    orderedQuery = orderedQuery.ThenBy(x => property.GetValue(x));
+                    break;
+                case ListSortDirection.Descending:
+                    orderedQuery = orderedQuery.ThenByDescending(x => property.GetValue(x));
+                    break;
+            }
+        }
+
+        return orderedQuery;
+    }
+}