#if !WINDOWS_UWP && (NET48_OR_GREATER || NET5_0_OR_GREATER)
using Microsoft.VisualStudio.TestTools.UnitTesting;
using MQTTnet.Certificates;
using MQTTnet.Client;
using MQTTnet.Server;
using MQTTnet.Tests.Mockups;
using System;
using System.Linq;
using System.Net;
using System.Security.Authentication;
using System.Security.Cryptography;
using System.Security.Cryptography.X509Certificates;
using System.Threading;
using System.Threading.Tasks;

namespace MQTTnet.Tests.Server
{

    [TestClass]
    
    public class Tls_Tests : BaseTestClass
    {

        public X509Certificate2 CreateCertificate(string oid)
        {
            var sanBuilder = new SubjectAlternativeNameBuilder();
            sanBuilder.AddIpAddress(IPAddress.Loopback);
            sanBuilder.AddIpAddress(IPAddress.IPv6Loopback);
            sanBuilder.AddDnsName("localhost");
            var rsa = RSA.Create();

            var certRequest = new CertificateRequest("CN=localhost", rsa, HashAlgorithmName.SHA512, RSASignaturePadding.Pkcs1);

            certRequest.CertificateExtensions.Add(
                new X509KeyUsageExtension(X509KeyUsageFlags.DataEncipherment | X509KeyUsageFlags.KeyEncipherment | X509KeyUsageFlags.DigitalSignature, false));

            certRequest.CertificateExtensions.Add(
                new X509EnhancedKeyUsageExtension(
                    new OidCollection { new Oid(oid) }, false));

            certRequest.CertificateExtensions.Add(sanBuilder.Build());

            var certificate = certRequest.CreateSelfSigned(DateTimeOffset.Now.AddMinutes(-10), DateTimeOffset.Now.AddMinutes(10));
            var pfxCertificate = new X509Certificate2(certificate.Export(X509ContentType.Pfx), (string)null, X509KeyStorageFlags.MachineKeySet | X509KeyStorageFlags.Exportable);
            
            return pfxCertificate;
        }

        private async Task<IMqttClient> ConnectClientAsync(TestEnvironment testEnvironment, Func<MqttClientCertificateValidationEventArgs, bool> certValidator)
        {
            var clientOptionsBuilder = testEnvironment.Factory.CreateClientOptionsBuilder();
            clientOptionsBuilder
                .WithClientId(Guid.NewGuid().ToString())
                .WithTcpServer("localhost", 8883)
                .WithTls(tls =>
                {
                    tls.UseTls = true;
                    tls.SslProtocol = SslProtocols.Tls12;
                    tls.CertificateValidationHandler = certValidator;
                });

            var clientOptions = clientOptionsBuilder.Build();
            return await testEnvironment.ConnectClient(clientOptions);
        }

        [TestMethod]
        public async Task Tls_Swap_Test()
        {
            var testEnvironment = CreateTestEnvironment(MQTTnet.Formatter.MqttProtocolVersion.V500);
            var serverOptionsBuilder = testEnvironment.Factory.CreateServerOptionsBuilder();

            var firstOid = "1.3.6.1.5.5.7.3.1";
            var secondOid = "1.3.6.1.5.5.7.3.2";

            var certificateProvider = new CertificateProvider
            {
                CurrentCertificate = CreateCertificate(firstOid)
            };

            serverOptionsBuilder
                .WithoutDefaultEndpoint()
                .WithEncryptedEndpoint()
                .WithEncryptionSslProtocol(SslProtocols.Tls12)
                .WithEncryptionCertificate(certificateProvider);

            var serverOptions = serverOptionsBuilder.Build();

            var server = testEnvironment.CreateServer(serverOptions);

            var publishedCount = 0;
            server.InterceptingPublishAsync += args =>
            {
                Interlocked.Increment(ref publishedCount);

                return Task.CompletedTask;
            };

            await server.StartAsync();
     
            var firstClient = await ConnectClientAsync(testEnvironment, args =>
            {
                Assert.AreEqual(firstOid, ((X509Certificate2)args.Certificate).Extensions.OfType<X509EnhancedKeyUsageExtension>().First().EnhancedKeyUsages[0].Value);
                return true;
            });

            var firstClientReceivedCount = 0;
            firstClient.ApplicationMessageReceivedAsync += args =>
            {
                Interlocked.Increment(ref firstClientReceivedCount);

                return Task.CompletedTask;
            };

            await firstClient.SubscribeAsync("TestTopic1");

            await firstClient.PublishAsync(new MqttApplicationMessage
                {
                    Topic = "TestTopic1",
                    Payload = new byte[] { 1, 2, 3, 4}
                });

            await testEnvironment.Server.InjectApplicationMessage(new InjectedMqttApplicationMessage(
                new MqttApplicationMessage
                {
                    Topic = "TestTopic1",
                    Payload = new byte[] { 1, 2, 3, 4 }
                }));

            certificateProvider.CurrentCertificate = CreateCertificate(secondOid);

            // Validate that the certificate was switched
            var secondClient = await ConnectClientAsync(testEnvironment, args =>
            {
                Assert.AreEqual(secondOid, ((X509Certificate2)args.Certificate).Extensions.OfType<X509EnhancedKeyUsageExtension>().First().EnhancedKeyUsages[0].Value);
                return true;
            });

            var secondClientReceivedCount = 0;
            secondClient.ApplicationMessageReceivedAsync += args =>
            {
                Interlocked.Increment(ref secondClientReceivedCount);

                return Task.CompletedTask;
            };

            await secondClient.SubscribeAsync("TestTopic2");

            await firstClient.PublishAsync(new MqttApplicationMessage
                {
                    Topic = "TestTopic2",
                    Payload = new byte[] { 1, 2, 3, 4 }
                });

            await testEnvironment.Server.InjectApplicationMessage(new InjectedMqttApplicationMessage(
                new MqttApplicationMessage
                {
                    Topic = "TestTopic2",
                    Payload = new byte[] { 1, 2, 3, 4 }
                }));

            // Ensure first client still works
            await firstClient.PublishAsync(new MqttApplicationMessage
            {
                Topic = "TestTopic1",
                Payload = new byte[] { 1, 2, 3, 4 }
            });

            await testEnvironment.Server.InjectApplicationMessage(new InjectedMqttApplicationMessage(
                new MqttApplicationMessage
                {
                    Topic = "TestTopic1",
                    Payload = new byte[] { 1, 2, 3, 4 }
                }));

            await Task.Delay(1000);

            Assert.AreEqual(6, publishedCount);
            Assert.AreEqual(4, firstClientReceivedCount);
            Assert.AreEqual(2, secondClientReceivedCount);

            await server.StopAsync();
        }


        private class CertificateProvider : ICertificateProvider
        {

            public X509Certificate2 CurrentCertificate { get; set; }

            public X509Certificate2 GetCertificate()
                => CurrentCertificate;

        }

    }
}
#endif