using System;

using System.Collections;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Runtime.Serialization.Formatters;

using System.IO;

using System.Data;

using System.ComponentModel.DataAnnotations;

using System.Globalization;

using System.Reflection;

using System.Collections.ObjectModel;

​

using System.Text.Json;

using System.Text.Json.Serialization;

using System.Text.Json.Nodes;

​

using System.Security.Cryptography;

using System.Web;

​

using NUnit.Framework; // Throws NUnit.Framework.AssertionException

​

//https://stackoverflow.com/questions/72592246/how-do-i-add-lexicographical-sort-in-this-system-text-json-serialization-way?noredirect=1#comment128232022_72592246

​

#nullable enable

​

    internal class MexcSubPersonalPayload

    {

        private readonly string _apiSecret;

​

        public MexcSubPersonalPayload(string apiKey, string apiSecret)

        {

            ApiKey = apiKey;

            _apiSecret = apiSecret;

        }

​

        [JsonPropertyName("op")]

        [JsonPropertyOrder(1)]

        public string Operation => "sub.personal";

​

        [JsonPropertyName("api_key")]

        [JsonPropertyOrder(2)]

        public string ApiKey { get; }

​

        [JsonPropertyName("sign")]

        [JsonPropertyOrder(3)]

        public string Signature => Sign(ToString());

​

        [JsonPropertyName("req_time")]

        [JsonPropertyOrder(4)]

        public long RequestTime => DateTimeOffset.UtcNow.ToUnixTimeMilliseconds();

​

        private string Sign(string payload)

        {

            if (string.IsNullOrWhiteSpace(payload))

            {

                return string.Empty;

            }

​

            using var md5 = MD5.Create();

            var sourceBytes = Encoding.UTF8.GetBytes(payload);

            var hash = md5.ComputeHash(sourceBytes);

            return Convert.ToHexString(hash);

        }

​

        public override string ToString()

        {

            return $"api_key={HttpUtility.UrlEncode(ApiKey)}&req_time={RequestTime}&op={Operation}&api_secret={HttpUtility.UrlEncode(_apiSecret)}";

        }

    }

​

    class MexcSubPersonalPayloadConverter : JsonConverter<MexcSubPersonalPayload>

    {

        record MexcSubPersonalPayloadDTO(

            [property:JsonPropertyName("api_key"), JsonPropertyOrder(1)] string ApiKey, 

            [property:JsonPropertyName("op"), JsonPropertyOrder(2)] string Operation, 

            [property:JsonPropertyName("req_time"), JsonPropertyOrder(3)]long RequestTime, 

            [property:JsonPropertyName("sign"), JsonPropertyOrder(4)]string Signature);

        public override void Write(Utf8JsonWriter writer, MexcSubPersonalPayload value, JsonSerializerOptions options) =>

            JsonSerializer.Serialize(writer, new MexcSubPersonalPayloadDTO(value.ApiKey, value.Operation, value.RequestTime, value.Signature), options);

        public override MexcSubPersonalPayload Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options) => throw new NotImplementedException();

    }

​

    class TestClass

    {

        static readonly string _apiKey = "foo";

        static readonly string _apiSecret = "bar";

        public string GenerateRequest() => JsonSerializer.Serialize(new MexcSubPersonalPayload(_apiKey, _apiSecret), new JsonSerializerOptions { Converters = { new MexcSubPersonalPayloadConverter() }});

        public static void Test()

        {

            var request = new TestClass().GenerateRequest();

            Console.WriteLine(request);

            var keys = JsonNode.Parse(request)!.AsObject().AsDictionary().Keys;

            Assert.That(keys.SequenceEqual(keys.OrderBy(n => n, StringComparer.Ordinal)));

        }   

    }

​

    public static partial class JsonExtensions

    {

        public static IDictionary<String, JsonNode?> AsDictionary(this JsonObject obj) => obj;

    }

​

    public class Program

    {

        public static void Main()

        {

            Console.WriteLine("Environment version: {0} ({1}), {2}", System.Runtime.InteropServices.RuntimeInformation.FrameworkDescription , Environment.Version, Environment.OSVersion);

            Console.WriteLine("System.Text.Json version: " + typeof(JsonSerializer).Assembly.FullName);

            Console.WriteLine();

​

            try

            {

                TestClass.Test();

            }

            catch (Exception ex)

            {

                Console.WriteLine("Failed with unhandled exception: ");

                Console.WriteLine(ex);

                throw;

            }

        }

    }

​