using System.Collections.Concurrent;
using System.ComponentModel;
using System.Reflection;

namespace JNPF.Extras.CollectiveOAuth.Enums;

/// <summary>
/// 枚举拓展类.
/// </summary>
public static class EnumExtensions
{
    private static ConcurrentDictionary<Enum, string> _concurrentDictionary = new ConcurrentDictionary<Enum, string>();
    private static ConcurrentDictionary<Type, Dictionary<string, string>> _concurrentDicDictionary = new ConcurrentDictionary<Type, Dictionary<string, string>>();

    /// <summary>
    /// 锁对象.
    /// </summary>
    private static object objLock = new object();

    /// <summary>
    /// 获取枚举的Code信息(Code).
    /// </summary>
    public static int GetCode(this Enum @this)
    {
        return Convert.ToInt32(@this);
    }

    /// <summary>
    /// 获取枚举的描述信息(Descripion).
    /// 支持位域，如果是位域组合值，多个按分隔符组合.
    /// </summary>
    public static string GetDesc(this Enum @this)
    {
        return _concurrentDictionary.GetOrAdd(@this, (key) =>
        {
            var type = key.GetType();
            var field = type.GetField(key.ToString());

            // 如果field为null则应该是组合位域值，
            return field == null ? key.GetDescriptions() : GetDescription(field);
        });
    }

    /// <summary>
    /// 获取枚举的说明.
    /// </summary>
    /// <param name="em">枚举对象.</param>
    /// <param name="split">位枚举的分割符号（仅对位枚举有作用）.</param>
    public static string GetDescriptions(this Enum em, string split = ",")
    {
        var names = em.ToString().Split(',');
        string[] res = new string[names.Length];
        var type = em.GetType();
        for (int i = 0; i < names.Length; i++)
        {
            var field = type.GetField(names[i].Trim());
            if (field == null) continue;
            res[i] = GetDescription(field);
        }

        return string.Join(split, res);
    }

    private static string GetDescription(FieldInfo field)
    {
        var att = Attribute.GetCustomAttribute(field, typeof(DescriptionAttribute), false);
        return att == null ? field.Name : ((DescriptionAttribute)att).Description;
    }

    /// <summary>
    /// 把枚举转换成为列表.
    /// </summary>
    public static List<EnumObject> ToList(this Type type)
    {
        List<EnumObject> list = new List<EnumObject>();
        foreach (object obj in Enum.GetValues(type))
        {
            list.Add(new EnumObject((Enum)obj));
        }

        return list;
    }

    /// <summary>
    /// 构造UTable枚举json样式 eg.{"Resource":{"value":0,"name":"Resource","text":"自有资源"},"New":{"value":1,"name":"New","text":"业务费用"}}.
    /// </summary>
    /// <param name="type"></param>
    /// <returns></returns>
    public static Dictionary<string, EnumModel> GetEnumList(this Type type)
    {
        Dictionary<string, EnumModel> list = new Dictionary<string, EnumModel>();
        foreach (object obj in Enum.GetValues(type))
        {
            list.Add(((Enum)obj).ToString(), new EnumModel((Enum)obj));
        }
        return list;
    }

    /// <summary>
    /// 获取枚举值+描述.
    /// </summary>
    /// <param name="enumType">Type,该参数的格式为typeof(需要读的枚举类型).</param>
    /// <returns>键值对.</returns>
    public static Dictionary<string, string> GetEnumItemValueDesc(Type enumType)
    {
        Dictionary<string, string> dic = new Dictionary<string, string>();
        Type typeDescription = typeof(DescriptionAttribute);
        FieldInfo[] fields = enumType.GetFields();
        string strText = string.Empty;
        string strValue = string.Empty;
        foreach (FieldInfo field in fields)
        {
            if (field.FieldType.IsEnum)
            {
                strValue = ((int)enumType.InvokeMember(field.Name, BindingFlags.GetField, null, null, null)).ToString();
                object[] arr = field.GetCustomAttributes(typeDescription, true);
                if (arr.Length > 0)
                {
                    DescriptionAttribute aa = (DescriptionAttribute)arr[0];
                    strText = aa.Description;
                }
                else
                {
                    strText = field.Name;
                }
                dic.Add(strValue, strText);
            }
        }

        return dic;
    }

    /// <summary>
    /// 获取枚举类型键值对.
    /// </summary>
    /// <param name="em"></param>
    /// <returns></returns>
    public static Dictionary<string, string> GetEunItemValueAndDesc(Type em)
    {
        return _concurrentDicDictionary.GetOrAdd(em, (key) =>
        {
            var type = key.GetType();
            if (_concurrentDicDictionary.ContainsKey(key))
                return _concurrentDicDictionary[key];
            else
                return GetEnumItemValueDesc(em);
        });
    }

    /// <summary>
    /// 获取枚举项+描述.
    /// </summary>
    /// <param name="enumType">Type,该参数的格式为typeof(需要读的枚举类型).</param>
    /// <returns>键值对.</returns>
    public static Dictionary<string, string> GetEnumItemDesc(Type enumType)
    {
        Dictionary<string, string> dic = new Dictionary<string, string>();
        FieldInfo[] fieldinfos = enumType.GetFields();
        foreach (FieldInfo field in fieldinfos)
        {
            if (field.FieldType.IsEnum)
            {
                object[] objs = field.GetCustomAttributes(typeof(DescriptionAttribute), false);
                dic.Add(field.Name, ((DescriptionAttribute)objs[0]).Description);
            }
        }
        return dic;
    }

    /// <summary>
    /// 获取枚举项描述信息 例如GetEnumDesc(Days.Sunday)
    /// </summary>
    /// <param name="en">枚举项 如Days.Sunday</param>
    /// <returns></returns>
    public static string GetEnumDesc(this Enum en)
    {
        Type type = en.GetType();
        MemberInfo[] memInfo = type.GetMember(en.ToString());
        if (memInfo != null && memInfo.Length > 0)
        {
            object[] attrs = memInfo[0].GetCustomAttributes(typeof(DescriptionAttribute), false);
            if (attrs != null && attrs.Length > 0)
                return ((DescriptionAttribute)attrs[0]).Description;
        }

        return en.ToString();
    }

    /// <summary>
    /// 将注释转换成枚举值，匹配不上返回Null.
    /// </summary>
    /// <param name="type"></param>
    /// <param name="strDescription"></param>
    /// <returns></returns>
    public static int? GetEnumValByDescription(this Type type, string strDescription)
    {
        int? enumVal = null;
        foreach (object obj in Enum.GetValues(type))
        {
            Enum nEnum = (Enum)obj;
            if (nEnum.GetDesc() == strDescription)
            {
                enumVal = (int)Convert.ChangeType(nEnum, typeof(int));
            }
        }

        return enumVal;
    }
}