refactor(Extensions): move to common

EnvelopeGenerator.Application/Common/Extensions/MemoryCacheExtensions.cs

@@ -0,0 +1,30 @@
+using EnvelopeGenerator.Application.Extensions;
+using Microsoft.Extensions.Caching.Memory;
+
+namespace EnvelopeGenerator.Application.Common.Extensions;
+
+public static class MemoryCacheExtensions
+{
+    private static readonly Guid BaseId = Guid.NewGuid();
+
+    public static IDictionary<string, int> GetEnumAsDictionary<TEnum>(this IMemoryCache memoryCache, string key = "", params object[] ignores)
+        where TEnum : Enum
+        => memoryCache.GetOrCreate(BaseId + typeof(TEnum).FullName + key, _ =>
+        {
+            var mergedIgnores = new List<TEnum>();
+
+            foreach (var ignore in ignores)
+            {
+                if (ignore is IEnumerable<TEnum> ignoreList)
+                    mergedIgnores.AddRange(ignoreList);
+                else if (ignore is TEnum ignoreVal)
+                    mergedIgnores.Add(ignoreVal);
+            }
+
+            return Enum.GetValues(typeof(TEnum))
+                   .Cast<TEnum>()
+                   .Where(e => !mergedIgnores.Contains(e))
+                   .ToDictionary(e => e.ToString(), e => Convert.ToInt32(e));
+        })
+           ?? throw new InvalidOperationException($"Failed to cache or retrieve enum dictionary for type '{typeof(TEnum).FullName}'.");
+}