splitter/splitter-cli/FlexibleLongConverter.cs

using System.Globalization;
using System.Text.Json;
using System.Text.Json.Serialization;

namespace splitter;

public sealed class FlexibleLongConverter : JsonConverter<long?>
{
    public override long? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
    {
        if (reader.TokenType == JsonTokenType.Number)
            return reader.GetInt64();

        if (reader.TokenType == JsonTokenType.String)
        {
            var s = reader.GetString();
            if (long.TryParse(s, NumberStyles.Integer, CultureInfo.InvariantCulture, out var v))
                return v;
        }

        return null;
    }

    public override void Write(Utf8JsonWriter writer, long? value, JsonSerializerOptions options)
    {
        if (value.HasValue)
            writer.WriteNumberValue(value.Value);
        else
            writer.WriteNullValue();
    }
}