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

namespace Common
{
    /// <summary>
    /// 枚举扩展方法
    /// </summary>
    public static class EnumExtension
    {
        /// <summary>
        /// 返回枚举项的描述信息。
        /// </summary>
        /// <param name="value">要获取描述信息的枚举项。</param>
        /// <returns>枚举想的描述信息。</returns>
        public static string GetEnumDescription(this Enum value)
        {
            Type enumType = value.GetType();
            // 获取枚举常数名称。
            string name = Enum.GetName(enumType, value);
            if (name != null)
            {
                // 获取枚举字段。
                FieldInfo fieldInfo = enumType.GetField(name);
                if (fieldInfo != null)
                {
                    // 获取描述的属性。
                    DescriptionAttribute attr = Attribute.GetCustomAttribute(fieldInfo,
                        typeof(DescriptionAttribute), false) as DescriptionAttribute;
                    if (attr != null)
                    {
                        return attr.Description;
                    }
                }
            }
            return null;
        }

        /// <summary>
        /// 获取彩种对应数据库表名称
        /// </summary>
        /// <param name="value">彩种枚举类型</param>
        /// <returns></returns>
        public static string GetLotteryTableName(this Enum value)
        {
            if (value == null)
            {
                throw new ArgumentException("value");
            }

            string tableName = String.Empty;

            var fieldInfo = value.GetType().GetField(value.ToString());
            var attributes = (CustomAttribute.TableNameAttribute[])fieldInfo.GetCustomAttributes(typeof(CustomAttribute.TableNameAttribute), false);
            if (attributes.Length > 0)
            {
                tableName = attributes[0].TableName;
            }
            return tableName;
        }
    }
}