managing-apps/src/Managing.Core/MiscExtensions.cs

namespace Managing.Core
{
    public static class MiscExtensions
    {
        // Ex: collection.TakeLast(5);
        //public static IEnumerable<T> TakeLast<T>(this IEnumerable<T> source, int N)
        //{
        //    return source.Skip(Math.Max(0, source.Count() - N));
        //}

        // foreach(IEnumerable<User> batch in users.Batch(1000))
        public static IEnumerable<IEnumerable<T>> Batch<T>(
            this IEnumerable<T> source, int size)
        {
            T[] bucket = null;
            var count = 0;

            foreach (var item in source)
            {
                if (bucket == null)
                    bucket = new T[size];

                bucket[count++] = item;

                if (count != size)
                    continue;

                yield return bucket.Select(x => x);

                bucket = null;
                count = 0;
            }

            // Return the last bucket with all remaining elements
            if (bucket != null && count > 0)
            {
                Array.Resize(ref bucket, count);
                yield return bucket.Select(x => x);
            }
        }

        public static void AddItem<T>(this List<T> list, T item)
        {
            if (!list.Contains(item))
            {
                list.Add(item);
            }
        }

        public static T ParseEnum<T>(string value)
        {
            return (T)Enum.Parse(typeof(T), value, true);
        }

        public static string Base64Encode(string plainText)
        {
            var plainTextBytes = System.Text.Encoding.UTF8.GetBytes(plainText);
            return System.Convert.ToBase64String(plainTextBytes);
        }
        public static string Base64Decode(string base64EncodedData)
        {
            var base64EncodedBytes = System.Convert.FromBase64String(base64EncodedData);
            return System.Text.Encoding.UTF8.GetString(base64EncodedBytes);
        }
    }
}