using Newtonsoft.Json;
using System.Text;

namespace AmrControl.ADS
{
    /// <summary>
    /// TcModel的JSON转换器
    /// 这个是把byte[]与ASCII字符串互转
    /// </summary>
    public class TcModelArrayConverter : JsonConverter
    {
        public override bool CanConvert(Type objectType)
        {
            return objectType == typeof(byte[]);
        }

        /// <summary>
        /// 把json字符串转对象
        /// </summary>
        /// <param name="reader"></param>
        /// <param name="objectType"></param>
        /// <param name="existingValue"></param>
        /// <param name="serializer"></param>
        /// <returns></returns>
        /// <exception cref="NotImplementedException"></exception>
        public override object? ReadJson(JsonReader reader, Type objectType, object? existingValue, JsonSerializer serializer)
        {
            
            //todo,需要评估一下长度有没有影响，在结构体中限定了长度
            string str = (string)reader.Value;
            if(str == null)
            {
                //返回一个空数组
                //return new byte[12];
                return null;
            }
            else
            {
                //byte[] chars = Encoding.ASCII.GetBytes(str);
                //byte[] bytes = new byte[12];
                //if(chars.Length <= 12)
                //{
                //    Array.Copy(chars, bytes, chars.Length);
                //}
                //else
                //{
                //    Array.Copy(chars, bytes, 12);
                //}

                //return bytes;
                return Encoding.ASCII.GetBytes(str);
            }
        }

        /// <summary>
        /// 把对象转json字符串
        /// </summary>
        /// <param name="writer"></param>
        /// <param name="Data"></param>
        /// <param name="serializer"></param>
        /// <exception cref="NotImplementedException"></exception>
        public override void WriteJson(JsonWriter writer, object? Data, JsonSerializer serializer)
        {
            if(Data is byte[] bytes)
            {
                //判断非0的长度,0是字符串结尾
                int index = 0;
                for (int i = 0; i < bytes.Length; i++)
                {
                    if (bytes[index++] == 0)
                    {
                        break;
                    }
                }
                writer.WriteValue(Encoding.ASCII.GetString(bytes,0,index).Trim());
            }

        }
    }
}