From 48dfa8f1ee5e95132ed9b724f255317a8f761d2d Mon Sep 17 00:00:00 2001
From: Ellpeck <me@ellpeck.de>
Date: Tue, 19 Jul 2022 15:20:19 +0200
Subject: [PATCH] Allow RandomExtensions to operate on any ICollection

---
 CHANGELOG.md                        |  1 +
 MLEM/Extensions/RandomExtensions.cs | 15 ++++++++-------
 2 files changed, 9 insertions(+), 7 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index df1ba53..9495cec 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -26,6 +26,7 @@ Improvements
 - Allow using multiple textures in a StaticSpriteBatch
 - Added GenericInput support for Buttons.None
 - Improved the way terminating formatting codes work by introducing SimpleEndCode
+- Allow RandomExtensions to operate on any ICollection
 
 Removals
 - Marked AStar.InfiniteCost as obsolete
diff --git a/MLEM/Extensions/RandomExtensions.cs b/MLEM/Extensions/RandomExtensions.cs
index 59752aa..0741046 100644
--- a/MLEM/Extensions/RandomExtensions.cs
+++ b/MLEM/Extensions/RandomExtensions.cs
@@ -9,18 +9,19 @@ namespace MLEM.Extensions {
     public static class RandomExtensions {
 
         /// <summary>
-        /// Gets a random entry from the given list with uniform chance.
+        /// Gets a random entry from the given collection with uniform chance.
         /// </summary>
         /// <param name="random">The random</param>
         /// <param name="entries">The entries to choose from</param>
         /// <typeparam name="T">The entries' type</typeparam>
         /// <returns>A random entry</returns>
-        public static T GetRandomEntry<T>(this Random random, IList<T> entries) {
-            return entries[random.Next(entries.Count)];
+        public static T GetRandomEntry<T>(this Random random, ICollection<T> entries) {
+            // ElementAt internally optimizes for IList access so we don't have to here
+            return entries.ElementAt(random.Next(entries.Count));
         }
 
         /// <summary>
-        /// Returns a random entry from the given list based on the specified weight function.
+        /// Returns a random entry from the given collection based on the specified weight function.
         /// A higher weight for an entry increases its likeliness of being picked.
         /// </summary>
         /// <param name="random">The random</param>
@@ -29,7 +30,7 @@ namespace MLEM.Extensions {
         /// <typeparam name="T">The entries' type</typeparam>
         /// <returns>A random entry, based on the entries' weight</returns>
         /// <exception cref="IndexOutOfRangeException">If the weight function returns different weights for the same entry</exception>
-        public static T GetRandomWeightedEntry<T>(this Random random, IList<T> entries, Func<T, int> weightFunc) {
+        public static T GetRandomWeightedEntry<T>(this Random random, ICollection<T> entries, Func<T, int> weightFunc) {
             var totalWeight = entries.Sum(weightFunc);
             var goalWeight = random.Next(totalWeight);
             var currWeight = 0;
@@ -41,8 +42,8 @@ namespace MLEM.Extensions {
             throw new IndexOutOfRangeException();
         }
 
-        /// <inheritdoc cref="GetRandomWeightedEntry{T}(System.Random,System.Collections.Generic.IList{T},System.Func{T,int})"/>
-        public static T GetRandomWeightedEntry<T>(this Random random, IList<T> entries, Func<T, float> weightFunc) {
+        /// <inheritdoc cref="GetRandomWeightedEntry{T}(System.Random,System.Collections.Generic.ICollection{T},System.Func{T,int})"/>
+        public static T GetRandomWeightedEntry<T>(this Random random, ICollection<T> entries, Func<T, float> weightFunc) {
             var totalWeight = entries.Sum(weightFunc);
             var goalWeight = random.NextDouble() * totalWeight;
             var currWeight = 0F;