using DominionBase.Enums;
using System;
using System.ComponentModel;
using System.Diagnostics.Contracts;

namespace DominionBase.Enums
{
	public static class EnumUtility
	{
		public static string GetEnumDescription(Enum value)
		{
			Contract.Requires(value != null, "value cannot be null");
			var fi = value.GetType().GetField(value.ToString());

			var attributes =
				(DescriptionAttribute[])fi.GetCustomAttributes(
				typeof(DescriptionAttribute),
				false);

			return attributes.Length > 0 ? attributes[0].Description : value.ToString();
		}

		internal static UInt32 Count(this Categories category)
		{
			var v = (UInt32)category;
			v = v - ((v >> 1) & 0x55555555); // reuse input as temporary
			v = (v & 0x33333333) + ((v >> 2) & 0x33333333); // temp
			var c = ((v + (v >> 4) & 0xF0F0F0F) * 0x1010101) >> 24; // count
			return c;
		}
	}
}