// Copyright (c) .NET Foundation. All rights reserved.
// Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.

using System.Globalization;
using System.Net;
using System.Net.Http;
using System.Net.Sockets;
using System.Text;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Builder;
using Microsoft.AspNetCore.Hosting;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Testing.xunit;
using Newtonsoft.Json;
using Newtonsoft.Json.Linq;
using Xunit;

namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
{
    public class RequestTests
    {
        [Theory]
        [InlineData(10 * 1024 * 1024, true)]
        // In the following dataset, send at least 2GB.
        // Never change to a lower value, otherwise regression testing for
        // https://github.com/aspnet/KestrelHttpServer/issues/520#issuecomment-188591242
        // will be lost.
        [InlineData((long)int.MaxValue + 1, false)]
        public void LargeUpload(long contentLength, bool checkBytes)
        {
            const int bufferLength = 1024 * 1024;
            Assert.True(contentLength % bufferLength == 0, $"{nameof(contentLength)} sent must be evenly divisible by {bufferLength}.");
            Assert.True(bufferLength % 256 == 0, $"{nameof(bufferLength)} must be evenly divisible by 256");

            var builder = new WebHostBuilder()
                .UseKestrel()
                .UseUrls("http://127.0.0.1:0/")
                .Configure(app =>
                {
                    app.Run(async context =>
                    {
                        // Read the full request body
                        long total = 0;
                        var receivedBytes = new byte[bufferLength];
                        var received = 0;
                        while ((received = await context.Request.Body.ReadAsync(receivedBytes, 0, receivedBytes.Length)) > 0)
                        {
                            if (checkBytes)
                            {
                                for (var i = 0; i < received; i++)
                                {
                                    Assert.Equal((byte)((total + i) % 256), receivedBytes[i]);
                                }
                            }

                            total += received;
                        }

                        await context.Response.WriteAsync(total.ToString(CultureInfo.InvariantCulture));
                    });
                });

            using (var host = builder.Build())
            {
                host.Start();

                using (var socket = new Socket(AddressFamily.InterNetwork, SocketType.Stream, ProtocolType.Tcp))
                {
                    socket.Connect(new IPEndPoint(IPAddress.Loopback, host.GetPort()));
                    socket.Send(Encoding.ASCII.GetBytes($"POST / HTTP/1.0\r\nContent-Length: {contentLength}\r\n\r\n"));

                    var contentBytes = new byte[bufferLength];

                    if (checkBytes)
                    {
                        for (var i = 0; i < contentBytes.Length; i++)
                        {
                            contentBytes[i] = (byte)i;
                        }
                    }

                    for (var i = 0; i < contentLength / contentBytes.Length; i++)
                    {
                        socket.Send(contentBytes);
                    }

                    var response = new StringBuilder();
                    var responseBytes = new byte[4096];
                    var received = 0;
                    while ((received = socket.Receive(responseBytes)) > 0)
                    {
                        response.Append(Encoding.ASCII.GetString(responseBytes, 0, received));
                    }

                    Assert.Contains(contentLength.ToString(CultureInfo.InvariantCulture), response.ToString());
                }
            }
        }

        [Fact]
        public Task RemoteIPv4Address()
        {
            return TestRemoteIPAddress("127.0.0.1", "127.0.0.1", "127.0.0.1");
        }

        [ConditionalFact]
        [IPv6SupportedCondition]
        public Task RemoteIPv6Address()
        {
            return TestRemoteIPAddress("[::1]", "[::1]", "::1");
        }

        [Fact]
        public async Task DoesNotHangOnConnectionCloseRequest()
        {
            var builder = new WebHostBuilder()
                .UseKestrel()
                .UseUrls($"http://127.0.0.1:0")
                .Configure(app =>
                {
                    app.Run(async context =>
                    {
                        await context.Response.WriteAsync("hello, world");
                    });
                });

            using (var host = builder.Build())
            using (var client = new HttpClient())
            {
                host.Start();

                client.DefaultRequestHeaders.Connection.Clear();
                client.DefaultRequestHeaders.Connection.Add("close");

                var response = await client.GetAsync($"http://localhost:{host.GetPort()}/");
                response.EnsureSuccessStatusCode();
            }
        }

        private async Task TestRemoteIPAddress(string registerAddress, string requestAddress, string expectAddress)
        {
            var builder = new WebHostBuilder()
                .UseKestrel()
                .UseUrls($"http://{registerAddress}:0")
                .Configure(app =>
                {
                    app.Run(async context =>
                    {
                        var connection = context.Connection;
                        await context.Response.WriteAsync(JsonConvert.SerializeObject(new
                        {
                            RemoteIPAddress = connection.RemoteIpAddress?.ToString(),
                            RemotePort = connection.RemotePort,
                            LocalIPAddress = connection.LocalIpAddress?.ToString(),
                            LocalPort = connection.LocalPort
                        }));
                    });
                });

            using (var host = builder.Build())
            using (var client = new HttpClient())
            {
                host.Start();

                var response = await client.GetAsync($"http://{requestAddress}:{host.GetPort()}/");
                response.EnsureSuccessStatusCode();

                var connectionFacts = await response.Content.ReadAsStringAsync();
                Assert.NotEmpty(connectionFacts);

                var facts = JsonConvert.DeserializeObject<JObject>(connectionFacts);
                Assert.Equal(expectAddress, facts["RemoteIPAddress"].Value<string>());
                Assert.NotEmpty(facts["RemotePort"].Value<string>());
            }
        }
    }
}