using System;
using System.Collections;
using System.Collections.Generic;
using System.ComponentModel;
using System.Linq;
using System.Reflection;
using System.Text;

/// <summary>
/// 枚举拓展
/// </summary>
namespace Common
{
   /// <summary>
   /// 枚举拓展
   /// </summary>
  public static class EnumExtensions
    {
        private static Dictionary<string, Dictionary<string, string>> enumCache;

        private static Dictionary<string, Dictionary<string, string>> EnumCache
        {
            get
            {
                if (enumCache == null)
                {
                    enumCache = new Dictionary<string, Dictionary<string, string>>();
                }
                return enumCache;
            }
            set { enumCache = value; }
        }

        /// <summary>
        ///根据枚举Name获取枚举value
        /// </summary>
        /// <param name="enumType"></param>
        /// <param name="enumName"></param>
        /// <returns></returns>
        public static int GetEnumValue(Type enumType, string enumName)
        {
            try
            {
                if (!enumType.IsEnum)
                    throw new ArgumentException("enumType必须是枚举类型");
                var values = Enum.GetValues(enumType);
                var ht = new Hashtable();
                foreach (var val in values)
                {
                    ht.Add(Enum.GetName(enumType, val), val);
                }
                return (int)ht[enumName];
            }
            catch (Exception e)
            {
                throw e;
            }
        }

        /// <summary>
        /// 获得枚举提示文本
        /// </summary>
        /// <param name="en"></param>
        /// <returns></returns>
        public static string GetEnumText(this Enum en)
        {
            string enString = string.Empty;
            if (null == en) return enString;
            var type = en.GetType();
            
            enString = en.ToString();
            if (!EnumCache.ContainsKey(type.FullName))
            {
                var fields = type.GetFields();
                Dictionary<string, string> temp = new Dictionary<string, string>();
                foreach (var item in fields)
                {
                    var attrs = item.GetCustomAttributes(typeof(EnumTextAttribute), false);
                    if (attrs.Length == 1)
                    {
                        var v = ((EnumTextAttribute)attrs[0]).Value;
                        temp.Add(item.Name, v);
                    }
                }
                try
                {
                    EnumCache.Add(type.FullName, temp);
                }
                catch { }
            }
            if (EnumCache[type.FullName].ContainsKey(enString))
            {
                return EnumCache[type.FullName][enString];
            }
            return enString;
        }



    }

    /// <summary>
    /// 枚举描述 
    /// </summary>
    public class EnumTextAttribute : Attribute
    {
        /// <summary>
        /// 
        /// </summary>
        /// <param name="value"></param>
        public EnumTextAttribute(string value)
        {
            Value = value;
        }
        /// <summary>
        /// 
        /// </summary>
        public string Value { get; set; }
    }
}