From 2ab4a7293ec507b691fbf5fcd1208634fbe74aa2 Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Thu, 16 Apr 2020 17:26:09 +0900
Subject: [PATCH] Clean up enum sorting attribute code

---
 .../API/Requests/SearchBeatmapSetsRequest.cs  | 18 +------
 .../BeatmapListing/BeatmapSearchFilterRow.cs  | 28 ++--------
 osu.Game/Utils/OrderAttribute.cs              | 52 +++++++++++++++++++
 3 files changed, 56 insertions(+), 42 deletions(-)
 create mode 100644 osu.Game/Utils/OrderAttribute.cs

diff --git a/osu.Game/Online/API/Requests/SearchBeatmapSetsRequest.cs b/osu.Game/Online/API/Requests/SearchBeatmapSetsRequest.cs
index aef0788b49..1206563b18 100644
--- a/osu.Game/Online/API/Requests/SearchBeatmapSetsRequest.cs
+++ b/osu.Game/Online/API/Requests/SearchBeatmapSetsRequest.cs
@@ -1,12 +1,12 @@
 // Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
 // See the LICENCE file in the repository root for full licence text.
 
-using System;
 using System.ComponentModel;
 using osu.Framework.IO.Network;
 using osu.Game.Overlays;
 using osu.Game.Overlays.Direct;
 using osu.Game.Rulesets;
+using osu.Game.Utils;
 
 namespace osu.Game.Online.API.Requests
 {
@@ -139,20 +139,4 @@ namespace osu.Game.Online.API.Requests
         [Order(5)]
         Italian
     }
-
-    [AttributeUsage(AttributeTargets.Field)]
-    public class OrderAttribute : Attribute
-    {
-        public readonly int Order;
-
-        public OrderAttribute(int order)
-        {
-            Order = order;
-        }
-    }
-
-    [AttributeUsage(AttributeTargets.Enum)]
-    public class HasOrderedElementsAttribute : Attribute
-    {
-    }
 }
diff --git a/osu.Game/Overlays/BeatmapListing/BeatmapSearchFilterRow.cs b/osu.Game/Overlays/BeatmapListing/BeatmapSearchFilterRow.cs
index bc0a011e31..64b3afcae1 100644
--- a/osu.Game/Overlays/BeatmapListing/BeatmapSearchFilterRow.cs
+++ b/osu.Game/Overlays/BeatmapListing/BeatmapSearchFilterRow.cs
@@ -2,7 +2,6 @@
 // See the LICENCE file in the repository root for full licence text.
 
 using System;
-using System.Linq;
 using JetBrains.Annotations;
 using osu.Framework.Allocation;
 using osu.Framework.Bindables;
@@ -14,10 +13,10 @@ using osu.Framework.Input.Events;
 using osu.Game.Graphics;
 using osu.Game.Graphics.Sprites;
 using osu.Game.Graphics.UserInterface;
-using osu.Game.Online.API.Requests;
 using osuTK;
 using osuTK.Graphics;
 using Humanizer;
+using osu.Game.Utils;
 
 namespace osu.Game.Overlays.BeatmapListing
 {
@@ -82,30 +81,9 @@ namespace osu.Game.Overlays.BeatmapListing
 
                 TabContainer.Spacing = new Vector2(10, 0);
 
-                var type = typeof(T);
-
-                if (type.IsEnum)
+                if (typeof(T).IsEnum)
                 {
-                    if (Attribute.GetCustomAttribute(type, typeof(HasOrderedElementsAttribute)) != null)
-                    {
-                        var enumValues = Enum.GetValues(type).Cast<T>().ToArray();
-                        var enumNames = Enum.GetNames(type);
-
-                        int[] enumPositions = Array.ConvertAll(enumNames, n =>
-                        {
-                            var orderAttr = (OrderAttribute)type.GetField(n).GetCustomAttributes(typeof(OrderAttribute), false)[0];
-                            return orderAttr.Order;
-                        });
-
-                        Array.Sort(enumPositions, enumValues);
-
-                        foreach (var val in enumValues)
-                            AddItem(val);
-
-                        return;
-                    }
-
-                    foreach (var val in (T[])Enum.GetValues(type))
+                    foreach (var val in OrderAttributeUtils.GetValuesInOrder<T>())
                         AddItem(val);
                 }
             }
diff --git a/osu.Game/Utils/OrderAttribute.cs b/osu.Game/Utils/OrderAttribute.cs
new file mode 100644
index 0000000000..4959caa726
--- /dev/null
+++ b/osu.Game/Utils/OrderAttribute.cs
@@ -0,0 +1,52 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace osu.Game.Utils
+{
+    public static class OrderAttributeUtils
+    {
+        /// <summary>
+        /// Get values of an enum in order. Supports custom ordering via <see cref="OrderAttribute"/>.
+        /// </summary>
+        public static IEnumerable<T> GetValuesInOrder<T>()
+        {
+            var type = typeof(T);
+
+            if (!type.IsEnum)
+                throw new InvalidOperationException("T must be an enum");
+
+            IEnumerable<T> items = (T[])Enum.GetValues(type);
+
+            if (Attribute.GetCustomAttribute(type, typeof(HasOrderedElementsAttribute)) == null)
+                return items;
+
+            return items.OrderBy(i =>
+            {
+                if (type.GetField(i.ToString()).GetCustomAttributes(typeof(OrderAttribute), false).FirstOrDefault() is OrderAttribute attr)
+                    return attr.Order;
+
+                return 0;
+            });
+        }
+    }
+
+    [AttributeUsage(AttributeTargets.Field)]
+    public class OrderAttribute : Attribute
+    {
+        public readonly int Order;
+
+        public OrderAttribute(int order)
+        {
+            Order = order;
+        }
+    }
+
+    [AttributeUsage(AttributeTargets.Enum)]
+    public class HasOrderedElementsAttribute : Attribute
+    {
+    }
+}