using Newtonsoft.Json;
using System.Buffers.Text;

namespace YLErp.Converter
{
    public class QuotedInt64Converter_Nullable : JsonConverter<Int64?>
    {
        private const Int64 defaultValue = default(Int64);

        public override Int64? ReadJson(JsonReader reader, Type objectType, Int64? existingValue, bool hasExistingValue, JsonSerializer serializer)
        {
            if (reader.TokenType == JsonToken.String)
            {
                if (string.IsNullOrWhiteSpace(reader.ReadAsString()))
                {
                    if (Nullable.GetUnderlyingType(objectType) != null)
                    {
                        return null;
                    }
                    return defaultValue;
                }

                if (Int64.TryParse(reader.ReadAsString(), out Int64 number))
                    return number;
            }

            return (Int64?)reader.Value;
        }

        public override void WriteJson(JsonWriter writer, Int64? value, JsonSerializer serializer)
        {
            if (!value.HasValue)
            {
                writer.WriteNull();
            }
            else
            {
                writer.WriteValueAsync(value);
            }
        }
    }
}