using System;

using System.ComponentModel;


namespace Epost.Common
{
   public static class EnumHelper
    {
        #region 枚举描述输出
        /// <summary>
        /// 枚举描述输出
        /// </summary>
        /// <param name="e"></param>
        /// <returns></returns>
        public static string EMToDescriptionString(this System.Enum e)
        {
            Type enumType = e.GetType();
            if (!enumType.IsEnum)
            {
                throw new ArgumentException("enumItem requires a Enum ");
            }

            string name = System.Enum.GetName(enumType, e);
            if (name == null)
                return string.Empty;
            object[] objs = enumType.GetField(name).GetCustomAttributes(typeof(DescriptionAttribute), false);
            if (objs == null || objs.Length == 0)
            {
                return string.Empty;
            }
            else
            {
                DescriptionAttribute attr = objs[0] as DescriptionAttribute;
                return attr.Description;
            }
        }
        #endregion

        #region 枚举值输出描述
        /// <summary>
        /// 枚举值输出描述
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="i"></param>
        /// <returns></returns>
        public static string EMToEnumDescriptionString<T>(this Nullable<int> i)
        {
            if (!(i > 0))
            {
                return string.Empty;
            }
            Type enumType = typeof(T);
            if (!enumType.IsEnum)
            {
                throw new ArgumentException("enumItem requires a Enum ");
            }

            string name = System.Enum.GetName(enumType, i);
            if (name == null)
                return string.Empty;
            object[] objs = enumType.GetField(name).GetCustomAttributes(typeof(DescriptionAttribute), false);
            if (objs == null || objs.Length == 0)
            {
                return string.Empty;
            }
            else
            {
                DescriptionAttribute attr = objs[0] as DescriptionAttribute;
                return attr.Description;
            }
        }
        #endregion

        #region 枚举值输出描述
        /// <summary>
        /// 枚举值输出描述
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="i"></param>
        /// <returns></returns>
        public static string EMToEnumDescriptionString<T>(this int i)
        {
            //if (!(i > 0))
            //{
            //    return string.Empty;
            //}
            Type enumType = typeof(T);
            if (!enumType.IsEnum)
            {
                throw new ArgumentException("enumItem requires a Enum ");
            }

            string name = System.Enum.GetName(enumType, i);
            if (name == null)
                return string.Empty;
            object[] objs = enumType.GetField(name).GetCustomAttributes(typeof(DescriptionAttribute), false);
            if (objs == null || objs.Length == 0)
            {
                return string.Empty;
            }
            else
            {
                DescriptionAttribute attr = objs[0] as DescriptionAttribute;
                return attr.Description;
            }
        }
        #endregion

        #region 枚举值输出描述
        /// <summary>
        /// 枚举值输出描述
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="i"></param>
        /// <returns></returns>
        public static string EMToEnumDescriptionString<T>(this string i)
        {
            //if (!(i > 0))
            //{
            //    return string.Empty;
            //}
            Type enumType = typeof(T);
            if (!enumType.IsEnum)
            {
                throw new ArgumentException("enumItem requires a Enum ");
            }

            try
            {
                string name = i;
                if (name == null)
                    return string.Empty;
                object[] objs = enumType.GetField(name).GetCustomAttributes(typeof(DescriptionAttribute), false);
                if (objs == null || objs.Length == 0)
                {
                    return string.Empty;
                }
                else
                {
                    DescriptionAttribute attr = objs[0] as DescriptionAttribute;
                    return attr.Description;
                }
            }
            catch
            {
                return string.Empty;
            }
        }
        #endregion

        #region 枚举值输出带标签描述
        /// <summary>
        /// 枚举值输出带标签描述
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="i"></param>
        /// <returns></returns>
        public static string EMToEnumDescriptionWithLabelString<T>(this Nullable<int> i)
        {
            if (!(i > 0))
            {
                return string.Empty;
            }
            Type enumType = typeof(T);
            if (!enumType.IsEnum)
            {
                throw new ArgumentException("enumItem requires a Enum ");
            }
            string name = System.Enum.GetName(enumType, i);
            return string.Format("<span class=\"label label-{0}\">{1}</span> ", name.ToLower(), i.EMToEnumDescriptionString<T>());
        }
        #endregion

        #region 枚举值输出带标签描述
        /// <summary>
        /// 枚举值输出带标签描述
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="i"></param>
        /// <returns></returns>
        public static string EMToEnumDescriptionWithLabelString<T>(this int i)
        {
            return ((int?)i).EMToEnumDescriptionWithLabelString<T>();
        }
        #endregion

        #region 字符串转枚举
        /// <summary>
        /// 字符串转枚举
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <param name="i"></param>
        /// <returns></returns>
        public static T EMToEnum<T>(this string i)
        {
            if (string.IsNullOrWhiteSpace(i))
            {
                return default(T);
            }
            Type enumType = typeof(T);
            if (!enumType.IsEnum)
            {
                throw new ArgumentException("enumItem requires a Enum ");
            }
            try
            {
                return (T)Enum.Parse(enumType, i);
            }
            catch
            {
                return default(T);
            }
        }
        #endregion

        #region 枚举值输出
        /// <summary>
        /// 枚举值输出
        /// </summary>
        /// <param name="e"></param>
        /// <returns></returns>
        public static string EMToEnumValueString(this System.Enum e)
        {
            Type enumType = e.GetType();
            if (!enumType.IsEnum)
            {
                throw new ArgumentException("enumItem requires a Enum ");
            }

            string name = System.Enum.GetName(enumType, e);
            if (name == null)
                return string.Empty;
            object[] objs = enumType.GetField(name).GetCustomAttributes(typeof(DescriptionAttribute), false);
            if (objs == null || objs.Length == 0)
            {
                return string.Empty;
            }
            else
            {
                return ((int)Enum.Parse(enumType, e.ToString())).ToString();
            }
        }
        #endregion

    }
}