From ee670487ddc19cc184c94dada87f02f6c73cda46 Mon Sep 17 00:00:00 2001
From: Austin Noska <austin.noska@profound-tech.com>
Date: Wed, 17 Jun 2020 14:05:54 -0400
Subject: [PATCH] feat: Added AggregateOrDefault extension method

---
 CHANGELOG.md                                  |  1 +
 .../Extensions/EnumerableExtensions.cs        | 77 +++++++++++++------
 2 files changed, 53 insertions(+), 25 deletions(-)

diff --git a/CHANGELOG.md b/CHANGELOG.md
index e603e83..37d2802 100644
--- a/CHANGELOG.md
+++ b/CHANGELOG.md
@@ -8,6 +8,7 @@ and this project adheres to [Semantic Versioning](http://semver.org/spec/v2.0.0.
 
 ### Added
  - Added attributes for controlling obfuscation
+ - Added AggregateOrDefault extension method for applying an accumulator function over a sequence that returns a default value if the sequence is empty
 
 ## [12.0.0] - 2020-06-18
 ### Added
diff --git a/ICD.Common.Utils/Extensions/EnumerableExtensions.cs b/ICD.Common.Utils/Extensions/EnumerableExtensions.cs
index c6eec3e..4a541e6 100644
--- a/ICD.Common.Utils/Extensions/EnumerableExtensions.cs
+++ b/ICD.Common.Utils/Extensions/EnumerableExtensions.cs
@@ -1407,24 +1407,7 @@ namespace ICD.Common.Utils.Extensions
 			if (extends == null)
 				throw new ArgumentNullException("extends");
 
-			Comparer<T> comparer = Comparer<T>.Default;
-			T value = default(T);
-			bool first = true;
-
-			foreach (T x in extends)
-			{
-				if (first)
-				{
-					first = false;
-					value = x;
-					continue;
-				}
-
-				if (comparer.Compare(x, value) < 0)
-					value = x;
-			}
-
-			return value;
+			return extends.AggregateOrDefault((a, b) => Comparer<T>.Default.Compare(a, b) < 0 ? a : b);
 		}
 
 		/// <summary>
@@ -1438,16 +1421,60 @@ namespace ICD.Common.Utils.Extensions
 			if (extends == null)
 				throw new ArgumentNullException("extends");
 
-			Comparer<T> comparer = Comparer<T>.Default;
-			T value = default(T);
+			return extends.AggregateOrDefault((a, b) => Comparer<T>.Default.Compare(a, b) > 0 ? a : b);
+		}
 
-			foreach (T x in extends)
+		/// <summary>
+		/// Applies an accumulator function over a sequence.
+		/// </summary>
+		/// <typeparam name="TSource"></typeparam>
+		/// <param name="extends"></param>
+		/// <param name="func"></param>
+		/// <returns>The final accumulator value.</returns>
+		[CanBeNull]
+		public static TSource AggregateOrDefault<TSource>([NotNull] this IEnumerable<TSource> extends,
+		                                                  [NotNull] Func<TSource, TSource, TSource> func)
+		{
+			if (extends == null)
+				throw new ArgumentNullException("extends");
+
+			if (func == null)
+				throw new ArgumentNullException("func");
+
+			return extends.AggregateOrDefault(func, default(TSource));
+		}
+
+		/// <summary>
+		/// Applies an accumulator function over a sequence.
+		/// </summary>
+		/// <typeparam name="TSource"></typeparam>
+		/// <param name="extends"></param>
+		/// <param name="func"></param>
+		/// <param name="defaultValue"></param>
+		/// <returns>The final accumulator value.</returns>
+		[CanBeNull]
+		public static TSource AggregateOrDefault<TSource>([NotNull] this IEnumerable<TSource> extends,
+		                                                  [NotNull] Func<TSource, TSource, TSource> func,
+		                                                  TSource defaultValue)
+		{
+			if (extends == null)
+				throw new ArgumentNullException("extends");
+
+			if (func == null)
+				throw new ArgumentNullException("func");
+
+			using (IEnumerator<TSource> enumerator = extends.GetEnumerator())
 			{
-				if (comparer.Compare(x, value) > 0)
-					value = x;
-			}
+				if (!enumerator.MoveNext())
+					return defaultValue;
 
-			return value;
+				TSource result = enumerator.Current;
+
+				while (enumerator.MoveNext())
+					result = func(result, enumerator.Current);
+
+				return result;
+			}
 		}
 
 		/// <summary>