using Newtonsoft.Json;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Text;
using System.Threading.Tasks;

namespace Misc
{
    public class IPEndPointJsonConverter : JsonConverter
    {
        //
        /// <summary>
        /// 是否开启自定义反序列化，值为true时，反序列化时会走ReadJson方法，值为false时，不走ReadJson方法，而是默认的反序列化
        /// </summary>
        public override bool CanRead => true;

        /// <summary>
        /// 是否开启自定义序列化，值为true时，序列化时会走WriteJson方法，值为false时，不走WriteJson方法，而是默认的序列化
        /// </summary>
        public override bool CanWrite => true;

        /// <summary>
        /// 判断是否为IPEndPoint类型
        /// </summary>
        /// <param name="objectType"></param>
        /// <returns></returns>
        public override bool CanConvert(Type objectType)
        {
            return typeof(IPEndPoint) == objectType;
        }

        public override object ReadJson(JsonReader reader, Type objectType, object existingValue, JsonSerializer serializer)
        {
            bool isNullable = IsNullableType(objectType);
            Type t = isNullable ? Nullable.GetUnderlyingType(objectType) : objectType;

            if (reader.TokenType == JsonToken.Null)
            {
                if (!IsNullableType(objectType))
                {
                    throw new Exception(string.Format("不能转换null value to {0}.", objectType));
                }

                return null;
            }

            try
            {
                if (reader.TokenType == JsonToken.String)
                {
                    string epText = reader.Value.ToString();
                    return Misc.StringConverter.ToIPEndPoint(epText);
                }
            }
            catch (Exception ex)
            {
                throw new Exception(string.Format("Error converting value {0} to type '{1}'", reader.Value, objectType));
            }
            throw new Exception(string.Format("Unexpected token {0} when parsing enum", reader.TokenType));
        }

        public bool IsNullableType(Type t)
        {
            if (t == null)
            {
                throw new ArgumentNullException("t");
            }
            return (t.BaseType.FullName == "System.ValueType" && t.GetGenericTypeDefinition() == typeof(Nullable<>));
        }

        public override void WriteJson(JsonWriter writer, object value, JsonSerializer serializer)
        {
            if (value == null)
            {
                writer.WriteNull();
                return;
            }

            IPEndPoint ep = (IPEndPoint)value;

            writer.WriteValue(ep.ToString());
        }
    }
}