Refactor ProbeResultNormalizer

Improve code structure and readability

src/Jellyfin.Extensions/DictionaryExtensions.cs

@@ -0,0 +1,65 @@
+using System;
+using System.Collections.Generic;
+
+namespace Jellyfin.Extensions
+{
+    /// <summary>
+    /// Static extensions for the <see cref="IReadOnlyDictionary{TKey,TValue}"/> interface.
+    /// </summary>
+    public static class DictionaryExtensions
+    {
+        /// <summary>
+        /// Gets a string from a string dictionary, checking all keys sequentially,
+        /// stopping at the first key that returns a result that's neither null nor blank.
+        /// </summary>
+        /// <param name="dictionary">The dictionary.</param>
+        /// <param name="key1">The first checked key.</param>
+        /// <returns>System.String.</returns>
+        public static string? GetFirstNotNullNorWhiteSpaceValue(this IReadOnlyDictionary<string, string> dictionary, string key1)
+        {
+            return dictionary.GetFirstNotNullNorWhiteSpaceValue(key1, string.Empty, string.Empty);
+        }
+
+        /// <summary>
+        /// Gets a string from a string dictionary, checking all keys sequentially,
+        /// stopping at the first key that returns a result that's neither null nor blank.
+        /// </summary>
+        /// <param name="dictionary">The dictionary.</param>
+        /// <param name="key1">The first checked key.</param>
+        /// <param name="key2">The second checked key.</param>
+        /// <returns>System.String.</returns>
+        public static string? GetFirstNotNullNorWhiteSpaceValue(this IReadOnlyDictionary<string, string> dictionary, string key1, string key2)
+        {
+            return dictionary.GetFirstNotNullNorWhiteSpaceValue(key1, key2, string.Empty);
+        }
+
+        /// <summary>
+        /// Gets a string from a string dictionary, checking all keys sequentially,
+        /// stopping at the first key that returns a result that's neither null nor blank.
+        /// </summary>
+        /// <param name="dictionary">The dictionary.</param>
+        /// <param name="key1">The first checked key.</param>
+        /// <param name="key2">The second checked key.</param>
+        /// <param name="key3">The third checked key.</param>
+        /// <returns>System.String.</returns>
+        public static string? GetFirstNotNullNorWhiteSpaceValue(this IReadOnlyDictionary<string, string> dictionary, string key1, string key2, string key3)
+        {
+            if (dictionary.TryGetValue(key1, out var val) && !string.IsNullOrWhiteSpace(val))
+            {
+                return val;
+            }
+
+            if (!string.IsNullOrEmpty(key2) && dictionary.TryGetValue(key2, out val) && !string.IsNullOrWhiteSpace(val))
+            {
+                return val;
+            }
+
+            if (!string.IsNullOrEmpty(key3) && dictionary.TryGetValue(key3, out val) && !string.IsNullOrWhiteSpace(val))
+            {
+                return val;
+            }
+
+            return null;
+        }
+    }
+}