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.Web;

using System.Collections.Specialized;

using System.Dynamic;

​

using Newtonsoft.Json;

using Newtonsoft.Json.Linq;

using Newtonsoft.Json.Converters;

using Newtonsoft.Json.Serialization;    

​

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

​

//https://stackoverflow.com/questions/29710688/how-can-i-convert-a-json-string-to-url-parameters-get-request

​

    public static partial class JsonExtensions

    {

        public static string ToUrlEncodedQueryString(this JContainer container)

        {

            return container.ToQueryStringKeyValuePairs().ToUrlEncodedQueryString();

        }

        public static IEnumerable<KeyValuePair<string, string>> ToQueryStringKeyValuePairs(this JContainer container)

        {

            return container.Descendants()

                .OfType<JValue>()

                .Select(v => new KeyValuePair<string, string>(v.ToQueryStringParameterName(), (string)v));

        }

        public static string ToUrlEncodedQueryString(this IEnumerable<KeyValuePair<string, string>> pairs)

        {

            return string.Join("&", pairs.Select(p => HttpUtility.UrlEncode(p.Key) + "=" + HttpUtility.UrlEncode(p.Value)));

            //The following works but it seems heavy to construct and await a task just to built a string:

            //return new System.Net.Http.FormUrlEncodedContent(pairs).ReadAsStringAsync().Result;

            //The following works and eliminates allocation of one intermediate string per pair, but requires more code:

            //return pairs.Aggregate(new StringBuilder(), (sb, p) => (sb.Length > 0 ? sb.Append("&") : sb).Append(HttpUtility.UrlEncode(p.Key)).Append("=").Append(HttpUtility.UrlEncode(p.Value))).ToString();

            //Answers from https://stackoverflow.com/questions/3865975/namevaluecollection-to-url-query that use HttpUtility.ParseQueryString() are wrong because that class doesn't correctly escape the keys names.

        }

        public static string ToQueryStringParameterName(this JToken token)

        {

            // Loosely modeled on JToken.Path

            // https://github.com/JamesNK/Newtonsoft.Json/blob/master/Src/Newtonsoft.Json/Linq/JToken.cs#L184

            // By https://github.com/JamesNK

            if (token == null || token.Parent == null)

                return string.Empty;

            var positions = new List<string>();

            for (JToken previous = null, current = token; current != null; previous = current, current = current.Parent)

            {

                switch (current)

                {

                    case JProperty property:

                        positions.Add(property.Name);

                        break;

                    case JArray array:

                    case JConstructor constructor:

                        if (previous != null)

                            positions.Add(((IList<JToken>)current).IndexOf(previous).ToString(CultureInfo.InvariantCulture)); // Don't localize the indices!

                        break;

                }

            }

            var sb = new StringBuilder();

            for (var i = positions.Count - 1; i >= 0; i--)

            {

                var name = positions[i];

                // TODO: decide what should happen if the name contains the characters `[` or `]`.

                if (sb.Length == 0)

                    sb.Append(name);

                else

                    sb.Append('[').Append(name).Append(']');

            }

            return sb.ToString();

        }

    }

​

    class TestClass

    {

        public static void Test()

        {

            var jsonString = GetJson();

​

            TestJsonString(jsonString);

​

            var model = JsonConvert.DeserializeObject<ExpandoObject>(jsonString);

​

            TestDataModel(model);

            Console.WriteLine("Desired query string:");

            Console.WriteLine(GetDesiredFormUrlEncodedString());            

            PrintKeysAndValues2(HttpUtility.ParseQueryString(GetDesiredFormUrlEncodedString()));

        }   

​

        static void TestJsonString(string jsonString)

        {

            Console.WriteLine("\nTesting JSON string...");

            var obj = JObject.Parse(jsonString);

            var queryString = obj.ToUrlEncodedQueryString();

​

            Console.WriteLine("Generated query string: ");

            Console.WriteLine(queryString);

            PrintKeysAndValues2(HttpUtility.ParseQueryString(queryString));

            Assert.IsTrue(GetDesiredFormUrlEncodedString().Equals(queryString, StringComparison.OrdinalIgnoreCase));

        }

        static void TestDataModel<T>(T myModel)

        {

            Console.WriteLine("\nTesting model {0}...", myModel);

            var obj = JObject.FromObject(myModel);

            var queryString = obj.ToUrlEncodedQueryString();

​

            Console.WriteLine("Generated query string: ");

            Console.WriteLine(queryString);

            PrintKeysAndValues2(HttpUtility.ParseQueryString(queryString));

            Assert.IsTrue(GetDesiredFormUrlEncodedString().Equals(queryString, StringComparison.OrdinalIgnoreCase));

        }

        public static void PrintKeysAndValues2( NameValueCollection myCol )  

        {

            // Modified from https://docs.microsoft.com/en-us/dotnet/api/system.collections.specialized.namevaluecollection?view=netcore-3.1#examples

            Console.WriteLine("{");

            for ( int i = 0; i < myCol.Count; i++ )

                Console.WriteLine("    {{ {0}, {1} }} ", JsonConvert.SerializeObject(myCol.GetKey(i)), JsonConvert.SerializeObject(myCol.Get(i)));

            Console.WriteLine("}\n");

       }        

        static string GetDesiredFormUrlEncodedString()

        {

            return @"foo=bar&purchase_invoice%5Bdate%5D=14%2F04%2F2015&purchase_invoice%5Bdue_date%5D=14%2F04%2F2015&purchase_invoice%5Bcontact_id%5D=500&purchase_invoice%5Bcontact_name%5D=TestContact&purchase_invoice%5Breference%5D=TestReference&purchase_invoice%5Bline_items_attributes%5D%5B0%5D%5Bunit_price%5D=10&purchase_invoice%5Bline_items_attributes%5D%5B0%5D%5Bquantity%5D=1&purchase_invoice%5Bline_items_attributes%5D%5B0%5D%5Bdescription%5D=TestLineItemAttDesc&purchase_invoice%5Bline_items_attributes%5D%5B0%5D%5Btax_code_id%5D=1&purchase_invoice%5Bline_items_attributes%5D%5B0%5D%5Bledger_account_id%5D=501&purchase_invoice%5Bline_items_attributes%5D%5B0%5D%5Btax_rate_percentage%5D=19&purchase_invoice%5Bline_items_attributes%5D%5B0%5D%5Btax_amount%5D=1.6";

        }

        static string GetJson()

        {

            return @"{

    ""foo"":""bar"",

    ""purchase_invoice"":

    {

        ""date"":""14/04/2015"",

        ""due_date"":""14/04/2015"",

        ""contact_id"":500,

        ""contact_name"":""TestContact"",

        ""reference"":""TestReference"",

        ""line_items_attributes"":[

            {

                ""unit_price"":10.00,

                ""quantity"":1,

                ""description"":""TestLineItemAttDesc"",

                ""tax_code_id"":1,

                ""ledger_account_id"":501,

                ""tax_rate_percentage"":19.0,

                ""tax_amount"":1.60

​

            }]

    }

}";

        }

    }

​

    public class Program

    {

        public static void Main()

        {

            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

            {

                TestClass.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.CodeBase.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;

        }

    }

​