using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Connections;
using Microsoft.AspNetCore.Hosting;
using Microsoft.Extensions.DependencyInjection;
using Microsoft.VisualStudio.TestTools.UnitTesting;

using System;
using System.Linq;
using System.Threading;
using System.Threading.Tasks;
using MQTTnet.Adapter;
using MQTTnet.AspNetCore.Tests.Mockups;
using MQTTnet.Client.Options;
using MQTTnet.Exceptions;
using MQTTnet.Formatter;
using MQTTnet.Packets;
using System.Net;
using MQTTnet.AspNetCore.Extensions;
using MQTTnet.Protocol;

namespace MQTTnet.AspNetCore.Tests
{
    [TestClass]
    public class MqttConnectionContextTest
    {
        [TestMethod]
        public async Task TestReceivePacketAsyncThrowsWhenReaderCompleted()
        {
            var serializer = new MqttPacketFormatterAdapter(MqttProtocolVersion.V311);
            var pipe = new DuplexPipeMockup();
            var connection = new DefaultConnectionContext();
            connection.Transport = pipe;
            var ctx = new MqttConnectionContext(serializer, connection);

            pipe.Receive.Writer.Complete();

            await Assert.ThrowsExceptionAsync<MqttCommunicationException>(() => ctx.ReceivePacketAsync(TimeSpan.Zero, CancellationToken.None));
        }

        [TestMethod]
        public async Task TestCorruptedConnectPacket()
        {
            var writer = new MqttPacketWriter();
            var serializer = new MqttPacketFormatterAdapter(writer);
            var pipe = new DuplexPipeMockup();
            var connection = new DefaultConnectionContext();
            connection.Transport = pipe;
            var ctx = new MqttConnectionContext(serializer, connection);
            
            await pipe.Receive.Writer.WriteAsync(writer.AddMqttHeader(MqttControlPacketType.Connect, new byte[0]));

            await Assert.ThrowsExceptionAsync<MqttProtocolViolationException>(() => ctx.ReceivePacketAsync(TimeSpan.Zero, CancellationToken.None));

            // the first exception should complete the pipes so if someone tries to use the connection after that it should throw immidiatly
            await Assert.ThrowsExceptionAsync<InvalidOperationException>(() =>  ctx.ReceivePacketAsync(TimeSpan.Zero, CancellationToken.None));
        }

        // COMMENTED OUT DUE TO DEAD LOCK? OR VERY VERY SLOW PERFORMANCE ON LOCAL DEV MACHINE. TEST WAS STILL RUNNING AFTER SEVERAL MINUTES!
        //[TestMethod]
        //public async Task TestParallelWrites()
        //{
        //    var serializer = new MqttPacketFormatterAdapter(MqttProtocolVersion.V311);
        //    var pipe = new DuplexPipeMockup();
        //    var connection = new DefaultConnectionContext();
        //    connection.Transport = pipe;
        //    var ctx = new MqttConnectionContext(serializer, connection);

        //    var tasks = Enumerable.Range(1, 100).Select(_ => Task.Run(async () => 
        //    {
        //        for (int i = 0; i < 100; i++)
        //        {
        //            await ctx.SendPacketAsync(new MqttPublishPacket(), TimeSpan.Zero, CancellationToken.None).ConfigureAwait(false);
        //        }
        //    }));

        //    await Task.WhenAll(tasks).ConfigureAwait(false);
        //}
        
        [TestMethod]
        public async Task TestLargePacket()
        {
            var serializer = new MqttPacketFormatterAdapter(MqttProtocolVersion.V311);
            var pipe = new DuplexPipeMockup();
            var connection = new DefaultConnectionContext();
            connection.Transport = pipe;
            var ctx = new MqttConnectionContext(serializer, connection);

            await ctx.SendPacketAsync(new MqttPublishPacket() { Payload = new byte[20_000] }, TimeSpan.Zero, CancellationToken.None).ConfigureAwait(false);

            var readResult = await pipe.Send.Reader.ReadAsync();
            Assert.IsTrue(readResult.Buffer.Length > 20000);
        }

        private class Startup 
        {
            public void Configure(IApplicationBuilder app)
            { 
            }
        }

        [TestMethod]
        public async Task TestEndpoint()
        {
            var mockup = new ConnectionHandlerMockup();


            using (var host = new WebHostBuilder()
                .UseKestrel(kestrel => kestrel.ListenLocalhost(1883, listener => listener.Use((ctx, next) => mockup.OnConnectedAsync(ctx))))
                .UseStartup<Startup>()
                .ConfigureServices((hostContext, services) =>
                {
                    services.AddHostedMqttServer(o => o.WithoutDefaultEndpoint());
                    services.AddSingleton<IMqttServerAdapter>(mockup);
                })
                .Build())
            using (var client = new MqttFactory().CreateMqttClient())
            {
                host.Start();
                await client.ConnectAsync(new MqttClientOptionsBuilder()
                    .WithTcpServer("localhost")
                    .Build(), CancellationToken.None);

                var ctx = await mockup.Context.Task;
#if NETCOREAPP3_1
                var ep = IPEndPoint.Parse(ctx.Endpoint);
                Assert.IsNotNull(ep);
#endif
                Assert.IsNotNull(ctx);
            }               
        }
    }
}