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.Threading.Tasks;

using System.Net.Http;

using System.Threading;

using System.Buffers;

​

using System.Text.Json;

using System.Text.Json.Serialization;

​

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

​

#nullable enable

​

//https://stackoverflow.com/questions/69572189/jsonelement-getrawtext-method-throws-operation-is-not-valid-exception-on-empty

​

    public static partial class JsonExtensions

    {

        public static async Task<T?> DeserializeResponse<T>(Stream str, string? property, CancellationToken ct = default)

        {

            if (property is null) // some calls to the API do return data at root-level

            {

                return await JsonSerializer.DeserializeAsync<T>(str, cancellationToken: ct).ConfigureAwait(false);

            }

​

            using var jsonDocument = await JsonDocument.ParseAsync(str, default, ct).ConfigureAwait(false);

​

            if (!jsonDocument.RootElement.TryGetProperty(property, out JsonElement parsed))

                throw new InvalidDataException($"The specified lookup property \"{property}\" could not be found.");

​

            return typeof(T).IsSerializedAsArray() 

                ? parsed.Deserialize<T>()

                : parsed.EnumerateArray().Select(i => i.Deserialize<T>()).FirstOrDefault();

        }       

        static bool IsSerializedAsArray(this Type type) =>

            type != typeof(string)

            && typeof(IEnumerable).IsAssignableFrom(type)

            && type != typeof(byte []) // byte arrays are serialized as Base64 strings.

            && !type.IsDictionary();

​

        static bool IsDictionary(this Type type) =>

            typeof(IDictionary).IsAssignableFrom(type)

            || type.GetInterfacesAndSelf().Any(t => t.IsGenericType && t.GetGenericTypeDefinition() == typeof(IDictionary<,>));

​

        static IEnumerable<Type> GetInterfacesAndSelf(this Type type) =>

            (type ?? throw new ArgumentNullException()).IsInterface 

            ? new[] { type }.Concat(type.GetInterfaces())

            : type.GetInterfaces();

    }

​

    public class JobFunctionCombination

    {

        /// <summary>

        /// Gets or sets the combined identifier of the main function group, the function group and the sub function group.

        /// </summary>

        /// <example>01_0101_010101</example>

        [JsonPropertyName("job_function_combination_id")]

        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]

        public string Id { get; set; } = string.Empty;

​

        /// <summary>

        /// Gets or sets the combined names of the function groups.

        /// </summary>

        /// <example>Management | Human Resources | Finance controller</example>

        [JsonPropertyName("description")]

        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]

        public string Description { get; set; } = string.Empty;

​

        /// <summary>

        /// Gets or sets the identifier of the main function group.

        /// </summary>

        [JsonPropertyName("job_main_function_group_id")]

        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]

        public string MainFunctionGroupId { get; set; } = string.Empty;

​

        /// <summary>

        /// Gets or sets the identifier of the function group.

        /// </summary>

        [JsonPropertyName("job_function_group_id")]

        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]

        public string FunctionGroupId { get; set; } = string.Empty;

​

        /// <summary>

        /// Gets or sets the identifier of the sub function group.

        /// </summary>

        [JsonPropertyName("job_sub_function_group_id")]

        [JsonIgnore(Condition = JsonIgnoreCondition.WhenWritingDefault)]

        public string SubFunctionGroupId { get; set; } = string.Empty;

    }

​

    public class Program

    {

        public static async Task Test()

        {

            Console.WriteLine(JsonSerializer.Serialize(new byte [] { 1, 2, 3 }));

            await Test<JobFunctionCombination>();

            await Test<int>();

            await Test<string>();

            await Test<Dictionary<string, string>>();

            await Test<byte []>();

            await TestArray<JobFunctionCombination []>();

            await TestArray<List<int>>();

            await TestArray<HashSet<string>>();

            await TestArray<List<Dictionary<string, string>>>();

        }

​

        public static async Task Test<T>()

        {

            using var stream = new MemoryStream(Encoding.UTF8.GetBytes(GetJson()));

            var item = await JsonExtensions.DeserializeResponse<T>(stream, "value");

​

            Assert.AreEqual(item, default(T));

        }

​

        public static async Task TestArray<T>() where T : IEnumerable

        {

            using var stream = new MemoryStream(Encoding.UTF8.GetBytes(GetJson()));

            var item = await JsonExtensions.DeserializeResponse<T>(stream, "value");

​

            Assert.IsNotNull(item, $"item of type {typeof(T)} is null");

            Assert.AreEqual(0, ((IEnumerable)item!).Cast<object>().Count(), $"item of type {typeof(T)} has nonzero count");

        }

​

        static string GetJson() => @"{

    ""context"": ""SomeUnusedContextValue"",

    ""value"": []

}

";

​

        public static async Task Main(string[] args)

        {

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

            Console.WriteLine("{0} version: {1}", typeof(JsonSerializer).Assembly.GetName().Name,  typeof(JsonSerializer).Assembly.FullName);

            Console.WriteLine();

​

            try

            {

                await Test();

            }

            catch (Exception ex)

            {

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

                Console.WriteLine(ex);

                throw;

            }

        }

        public static string GetNetCoreVersion()

        {

            //https://techblog.dorogin.com/how-to-detect-net-core-version-in-runtime-ecd65ad695be

            //

            var assembly = typeof(System.Runtime.GCSettings).GetTypeInfo().Assembly;

            var assemblyPath = assembly.Location.Split(new[] { '/', '\\' }, StringSplitOptions.RemoveEmptyEntries);

            int netCoreAppIndex = Array.IndexOf(assemblyPath, "Microsoft.NETCore.App");

            if (netCoreAppIndex > 0 && netCoreAppIndex < assemblyPath.Length - 2)

                return assemblyPath[netCoreAppIndex + 1];

            return null;

        }

    }

​