using System;

using System.Text.Json;

using System.Text.Json.Serialization;

using System.Collections.Generic;

using FluentAssertions;

public class Program

{

    public static void Main()

    {

        var json = """

            {

                "emailZakelijk": {

                    "email": {

                        "value":"foo@bar.com"

                    }

                }

            }

            """;

​

        var options = new JsonSerializerOptions()

        {

            PropertyNamingPolicy = JsonNamingPolicy.CamelCase,

            //PropertyNameCaseInsensitive = true

        };

        Console.WriteLine("PropertyNamingPolicy: " + options.PropertyNamingPolicy);

        //options.Converters.Clear();

        options.Converters.Add(new EmailadressenConverter());

        //options.Converters.Add(new EmailsConverterFactory());

​

        var dmc = JsonSerializer.Deserialize<DummyMailClass>(json, options);

​

        dmc.Should().NotBeNull();

        dmc!.EmailZakelijk.Should().NotBeNull();

        dmc.EmailZakelijk!.Email.Value.Should().Be("foo@bar.com");

        Console.WriteLine(JsonSerializer.Serialize(dmc, options));

    }

}

​

public class EmailadressenConverter : JsonConverter<Emails>

{

    public override bool CanConvert(Type typeToConvert)

    {

        //Console.WriteLine("CanConvert");

        return base.CanConvert(typeToConvert);

    }

​

    public override Emails? Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)

    {

        Console.WriteLine("Read");

        var ctorEmail = "";

        var optionalEmails = new List<string>();

        var currentPropertyName = "";

​

        while (reader.Read())

        {           

            if (reader.TokenType == JsonTokenType.StartObject)

            {

                continue;

            }

            else if (reader.TokenType == JsonTokenType.EndObject)

            {

                break;

            }

            else if (reader.TokenType == JsonTokenType.PropertyName)

            {

                currentPropertyName = reader.GetString()!;

                if (string.Equals(currentPropertyName, "email", StringComparison.CurrentCultureIgnoreCase))

                {

                    Emailadres emailadres = JsonSerializer.Deserialize<Emailadres>(ref reader, options);

                    ctorEmail = emailadres.Value;

                    reader.Skip();

                }

                continue;

            }

            else if (reader.TokenType == JsonTokenType.String)

            {

                ctorEmail = reader.GetString()!;

                break;

            }

        }

​

        if (string.IsNullOrEmpty(ctorEmail))

            return null;

​

        return new Emails(ctorEmail); 

    }

​

    public override void Write(Utf8JsonWriter writer, Emails value, JsonSerializerOptions options)

    {

​

        writer.WriteStartObject();

​

        writer.WriteString(nameof(Emails.Email), value.Email.Value);

        writer.WriteEndObject();

​

        return;

    }

}

​

public class Emails

{

    public Emails(string primairEmailadres)

    {

        Email = new Emailadres(primairEmailadres);

    }

    public Emailadres Email { get; set; }

}

​

public class DummyMailClass

{

    public Emails? EmailZakelijk { get; set; }

​

}

​

public partial record Emailadres

{

    public Emailadres(string value)

    {

        Value = value;

​

    }

​

    public string Value { get; private set; }

}