jellyfin/src/Jellyfin.Extensions/DictionaryExtensions.cs

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>
        /// <param name="key2">The second checked key.</param>
        /// <param name="key3">The third checked key.</param>
        /// <param name="key4">The fourth checked key.</param>
        /// <returns>System.String.</returns>
        public static string? GetFirstNotNullNorWhiteSpaceValue(this IReadOnlyDictionary<string, string> dictionary, string key1, string? key2 = null, string? key3 = null, string? key4 = null)
        {
            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;
            }

            if (!string.IsNullOrEmpty(key4) && dictionary.TryGetValue(key4, out val) && !string.IsNullOrWhiteSpace(val))
            {
                return val;
            }

            return null;
        }
    }
}