From ba5932c1dd4eaff2d6e61a9b4dabc3e52dc5e36b Mon Sep 17 00:00:00 2001
From: Dean Herbert <pe@ppy.sh>
Date: Fri, 11 Apr 2025 02:11:45 +0900
Subject: [PATCH] Revert "Use median for statistic display"

This reverts commit fa06643bb6c0aacde659640ae0a65c68ab9b0c61.

Revert "Remove mean hit error calculation"

This reverts commit b3c578e5455c572e34e2def301ba657182747149.
---
 osu.Game/Rulesets/Scoring/HitEventExtensions.cs | 17 +++++++++++++++++
 .../Ranking/Statistics/AverageHitError.cs       |  6 +++---
 2 files changed, 20 insertions(+), 3 deletions(-)

diff --git a/osu.Game/Rulesets/Scoring/HitEventExtensions.cs b/osu.Game/Rulesets/Scoring/HitEventExtensions.cs
index 39fc8b357b..01d800a351 100644
--- a/osu.Game/Rulesets/Scoring/HitEventExtensions.cs
+++ b/osu.Game/Rulesets/Scoring/HitEventExtensions.cs
@@ -54,6 +54,23 @@ namespace osu.Game.Rulesets.Scoring
             return result;
         }
 
+        /// <summary>
+        /// Calculates the average hit offset/error for a sequence of <see cref="HitEvent"/>s, where negative numbers mean the user hit too early on average.
+        /// </summary>
+        /// <returns>
+        /// A non-null <see langword="double"/> value if unstable rate could be calculated,
+        /// and <see langword="null"/> if unstable rate cannot be calculated due to <paramref name="hitEvents"/> being empty.
+        /// </returns>
+        public static double? CalculateAverageHitError(this IEnumerable<HitEvent> hitEvents)
+        {
+            double[] timeOffsets = hitEvents.Where(AffectsUnstableRate).Select(ev => ev.TimeOffset).ToArray();
+
+            if (timeOffsets.Length == 0)
+                return null;
+
+            return timeOffsets.Average();
+        }
+
         /// <summary>
         /// Calculates the median hit offset/error for a sequence of <see cref="HitEvent"/>s, where negative numbers mean the user hit too early on average.
         /// </summary>
diff --git a/osu.Game/Screens/Ranking/Statistics/AverageHitError.cs b/osu.Game/Screens/Ranking/Statistics/AverageHitError.cs
index 29df085c62..fb7107cc88 100644
--- a/osu.Game/Screens/Ranking/Statistics/AverageHitError.cs
+++ b/osu.Game/Screens/Ranking/Statistics/AverageHitError.cs
@@ -8,18 +8,18 @@ using osu.Game.Rulesets.Scoring;
 namespace osu.Game.Screens.Ranking.Statistics
 {
     /// <summary>
-    /// Displays the average hit error statistic for a given play.
+    /// Displays the unstable rate statistic for a given play.
     /// </summary>
     public partial class AverageHitError : SimpleStatisticItem<double?>
     {
         /// <summary>
         /// Creates and computes an <see cref="AverageHitError"/> statistic.
         /// </summary>
-        /// <param name="hitEvents">Sequence of <see cref="HitEvent"/>s to calculate the average hit error based on.</param>
+        /// <param name="hitEvents">Sequence of <see cref="HitEvent"/>s to calculate the unstable rate based on.</param>
         public AverageHitError(IEnumerable<HitEvent> hitEvents)
             : base("Average Hit Error")
         {
-            Value = hitEvents.CalculateMedianHitError();
+            Value = hitEvents.CalculateAverageHitError();
         }
 
         protected override string DisplayValue(double? value) => value == null ? "(not available)" : $"{Math.Abs(value.Value):N2} ms {(value.Value < 0 ? "early" : "late")}";