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

namespace HighWayIot.Common
{
    /// <summary>
    /// 通用工具类
    /// </summary>
    public class GeneralUtils
    {
        /// <summary>
        /// 获取枚举类值的description元数据(没有Des返回名字)
        /// </summary>
        /// <returns></returns>
        public static string GetEnumStringDescription(Enum enumValue)
        {
            string value = enumValue.ToString();
            FieldInfo field = enumValue.GetType().GetField(value);
            object[] objs = field.GetCustomAttributes(typeof(DescriptionAttribute), false);    //获取描述属性
            if (objs.Length == 0)    //当描述属性没有时，直接返回名称
                return value;
            DescriptionAttribute descriptionAttribute = (DescriptionAttribute)objs[0];
            return descriptionAttribute.Description;
        }

        /// <summary>
        /// 获取枚举类的键值对
        /// </summary>
        /// <typeparam name="T"></typeparam>
        /// <returns></returns>
        public static IEnumerable<KeyValuePair<string, int>> GetEnumKeyValuePairs<T>() where T : Enum
        {
            var enumType = typeof(T);
            var fields = enumType.GetFields();

            foreach (var fi in fields)
            {
                if (fi.FieldType != enumType || !fi.IsLiteral)
                    continue;

                var name = fi.Name;
                var value = (int)enumType.GetField(name).GetValue(null);
                yield return new KeyValuePair<string, int>(name, value);
            }
        }
    }
}