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

namespace YLErp.Converter
{
    public class QuotedInt32Converter_Nullable : JsonConverter<Int32?>
    {
        private const Int32 defaultValue = default(Int32);

        public override Int32? ReadJson(JsonReader reader, Type objectType, Int32? existingValue, bool hasExistingValue, JsonSerializer serializer)
        {
            if (reader.TokenType == JsonToken.String)
            {
                if (string.IsNullOrWhiteSpace(reader.Value?.ToString()))
                {
                    if (Nullable.GetUnderlyingType(objectType) != null)
                    {
                        return null;
                    }
                    return defaultValue;
                }

                if (Int32.TryParse(reader.ReadAsString(), out Int32 number))
                    return number;
            }

            return (Int32?)reader.Value;
        }

        public override void WriteJson(JsonWriter writer, Int32? value, JsonSerializer serializer)
        {
            if (!value.HasValue)
            {
                writer.WriteNull();
            }
            else
            {
                writer.WriteValueAsync(value);
            }
        }
    }
}