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

namespace Waste.Web.Core
{
    ///<summary>
    /// long类型处理
    /// </summary>
    //public class CustomContractResolver : CamelCasePropertyNamesContractResolver //默认为驼峰样式
    public class CustomContractResolver : DefaultContractResolver //保持默认值
    {
        protected override string ResolvePropertyName(string propertyName)
        {
            //所有字母小写
            return propertyName.ToLower();
            //  return base.ResolvePropertyName(propertyName);
        }

        /// <summary>
        /// 对长整型做处理
        /// </summary>
        /// <param name="objectType"></param>
        /// <returns></returns>
        protected override JsonConverter ResolveContractConverter(Type objectType)
        {
            if (objectType == typeof(long))
            {
                return new JsonConverterLong();
            }
            return base.ResolveContractConverter(objectType);
        }
        /// <summary>
        /// 创建属性
        /// </summary>
        /// <param name="type">类型</param>
        /// <param name="memberSerialization">序列化成员</param>
        /// <returns></returns>
        protected override IList<JsonProperty> CreateProperties(Type type, MemberSerialization memberSerialization)
        {
            return type.GetProperties().Select(c =>
            {
                var jsonProperty = base.CreateProperty(c, memberSerialization);
                jsonProperty.ValueProvider = new NullToEmptyStringValueProvider(c);
                return jsonProperty;
            }).ToList();
        }
    }
    /// <summary>
    /// 对null类型的处理
    /// </summary>
    public class NullToEmptyStringValueProvider : IValueProvider
    {
        private readonly PropertyInfo _memberInfo;
        /// <summary>
        /// 构造函数
        /// </summary>
        /// <param name="memberInfo"></param>
        public NullToEmptyStringValueProvider(PropertyInfo memberInfo)
        {
            _memberInfo = memberInfo;
        }
        /// <summary>
        /// 获取value
        /// </summary>
        /// <param name="target"></param>
        /// <returns></returns>
        public object GetValue(object target)
        {
            var result = _memberInfo.GetValue(target);
            if (_memberInfo.PropertyType == typeof(string) && result == null)
                result = string.Empty;
            return result;
        }
        /// <summary>
        /// 设置value
        /// </summary>
        /// <param name="target"></param>
        /// <param name="value"></param>
        public void SetValue(object target, object value)
        {
            _memberInfo.SetValue(target, value);
        }
    }
    /// <summary>
    /// 对于LONG类型的转换
    /// </summary>
    public class JsonConverterLong : JsonConverter
    {
        /// <summary>
        /// 判断是否为Long类型
        /// </summary>
        /// <param name="objectType">类型</param>
        /// <returns>为long类型则可以进行转换</returns>
        public override bool CanConvert(Type objectType)
        {
            if (objectType == typeof(long))
                return true;
            return false;
        }

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

        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)
            //{
            //    return null;
            //}
            //if (reader.TokenType == JsonToken.Integer)
            //{
            //    return reader.Value.ToString();
            //}
            //return null;
            if ((reader.ValueType == null || reader.ValueType == typeof(long?)) && reader.Value == null)
            {
                return null;
            }
            else
            {
                long.TryParse(reader.Value != null ? reader.Value.ToString() : "", out long value);
                return value;
            }
        }
    }
}