shuffle modifiers before assigning

MiraAPI/Modifiers/ModifierManager.cs

@@ -5,6 +5,7 @@ using System.Runtime.Serialization;
 using MiraAPI.Modifiers.Types;
 using MiraAPI.PluginLoading;
 using MiraAPI.Roles;
+using MiraAPI.Utilities;
 using Reactor.Utilities;
 using Reactor.Utilities.Extensions;
 using Random = System.Random;
@@ -125,6 +126,7 @@ public static class ModifierManager
             .Select(x => Activator.CreateInstance(x.Value) as GameModifier)
             .OfType<GameModifier>()
             .Where(x => x.GetAmountPerGame() > 0 && x.GetAssignmentChance() > 0)
+            .Shuffle()
             .OrderByDescending(x => x.Priority())
             .ToArray();
 

MiraAPI/Utilities/EnumerableExtensions.cs

@@ -0,0 +1,49 @@
+using System;
+using System.Collections.Generic;
+using System.Linq;
+
+namespace MiraAPI.Utilities;
+
+/// <summary>
+/// Extensions for IEnumerable.
+/// </summary>
+public static class EnumerableExtensions
+{
+    /// <summary>
+    /// Shuffle the elements of the source enumerable using a new instance of Random.
+    /// </summary>
+    /// <param name="source">The source enumerable.</param>
+    /// <typeparam name="T">The type of the elements.</typeparam>
+    /// <returns>>The shuffled enumerable.</returns>
+    public static IEnumerable<T> Shuffle<T>(this IEnumerable<T> source)
+    {
+        return source.Shuffle(new Random());
+    }
+
+    /// <summary>
+    /// Shuffle the elements of the source enumerable using the provided Random instance.
+    /// </summary>
+    /// <param name="source">The source enumerable.</param>
+    /// <param name="rng">The Random instance to use for shuffling.</param>
+    /// <typeparam name="T">The type of the elements.</typeparam>
+    /// <returns>>The shuffled enumerable.</returns>
+    public static IEnumerable<T> Shuffle<T>(this IEnumerable<T> source, Random rng)
+    {
+        ArgumentNullException.ThrowIfNull(source);
+        ArgumentNullException.ThrowIfNull(rng);
+
+        return source.ShuffleIterator(rng);
+    }
+
+    private static IEnumerable<T> ShuffleIterator<T>(this IEnumerable<T> source, Random rng)
+    {
+        var buffer = source.ToList();
+        for (var i = 0; i < buffer.Count; i++)
+        {
+            var j = rng.Next(i, buffer.Count);
+            yield return buffer[j];
+
+            buffer[j] = buffer[i];
+        }
+    }
+}