using System.ComponentModel;
using System.Reflection;

namespace NewLife;

/// <summary>枚举类型助手类</summary>
[EditorBrowsable(EditorBrowsableState.Never)]
public static class EnumHelper
{
    /// <summary>枚举变量是否包含指定标识</summary>
    /// <param name="value">枚举变量</param>
    /// <param name="flag">要判断的标识</param>
    /// <returns></returns>
    public static Boolean Has(this Enum value, Enum flag)
    {
        if (value.GetType() != flag.GetType()) throw new ArgumentException("flag", "Enumeration identification judgment must be of the same type");

        var num = Convert.ToUInt64(flag);
        return (Convert.ToUInt64(value) & num) == num;
    }

    /// <summary>设置标识位</summary>
    /// <typeparam name="T"></typeparam>
    /// <param name="source"></param>
    /// <param name="flag"></param>
    /// <param name="value">数值</param>
    /// <returns></returns>
    public static T Set<T>(this Enum source, T flag, Boolean value)
    {
        if (source is not T) throw new ArgumentException("source", "Enumeration identification judgment must be of the same type");

        var s = Convert.ToUInt64(source);
        var f = Convert.ToUInt64(flag);

        if (value)
        {
            s |= f;
        }
        else
        {
            s &= ~f;
        }

        return (T)Enum.ToObject(typeof(T), s);
    }

    /// <summary>获取枚举字段的注释</summary>
    /// <param name="value">数值</param>
    /// <returns></returns>
    public static String? GetDescription(this Enum value)
    {
        if (value == null) return null;

        var type = value.GetType();
        var item = type.GetField(value.ToString(), BindingFlags.Public | BindingFlags.Static);
        //云飞扬 2017-07-06 传的枚举值可能并不存在，需要判断是否为null
        if (item == null) return null;
        //var att = AttributeX.GetCustomAttribute<DescriptionAttribute>(item, false);
        var att = item.GetCustomAttribute<DescriptionAttribute>(false);
        if (att != null && !String.IsNullOrEmpty(att.Description)) return att.Description;

        return null;
    }

    /// <summary>获取枚举类型的所有字段注释</summary>
    /// <typeparam name="TEnum"></typeparam>
    /// <returns></returns>
    public static Dictionary<TEnum, String> GetDescriptions<TEnum>() where TEnum : notnull
    {
        var dic = new Dictionary<TEnum, String>();

        foreach (var item in GetDescriptions(typeof(TEnum)))
        {
            dic.Add((TEnum)Enum.ToObject(typeof(TEnum), item.Key), item.Value);
        }

        return dic;
    }

    /// <summary>获取枚举类型的所有字段注释</summary>
    /// <param name="enumType"></param>
    /// <returns></returns>
    public static Dictionary<Int32, String> GetDescriptions(Type enumType)
    {
        var dic = new Dictionary<Int32, String>();
        foreach (var item in enumType.GetFields(BindingFlags.Public | BindingFlags.Static))
        {
            if (!item.IsStatic) continue;

            // 这里的快速访问方法会报错
            //FieldInfoX fix = FieldInfoX.Create(item);
            //PermissionFlags value = (PermissionFlags)fix.GetValue(null);
            var value = Convert.ToInt32(item.GetValue(null));

            var des = item.Name;

            //var dna = AttributeX.GetCustomAttribute<DisplayNameAttribute>(item, false);
            var dna = item.GetCustomAttribute<DisplayNameAttribute>(false);
            if (dna != null && !String.IsNullOrEmpty(dna.DisplayName)) des = dna.DisplayName;

            //var att = AttributeX.GetCustomAttribute<DescriptionAttribute>(item, false);
            var att = item.GetCustomAttribute<DescriptionAttribute>(false);
            if (att != null && !String.IsNullOrEmpty(att.Description)) des = att.Description;
            //dic.Add(value, des);
            // 有些枚举可能不同名称有相同的值
            dic[value] = des;
        }

        return dic;
    }
}