// Licensed to the .NET Foundation under one or more agreements.
// The .NET Foundation licenses this file to you under the MIT license.
 
using System;
using System.Net;
using System.Text;
using System.Threading.Tasks;
using Microsoft.AspNetCore.Server.Kestrel.Core;
using Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http2;
using Microsoft.AspNetCore.Server.Kestrel.InMemory.FunctionalTests.TestTransport;
using Microsoft.AspNetCore.InternalTesting;
using Microsoft.Extensions.Logging;
using Xunit;
 
namespace Microsoft.AspNetCore.Server.Kestrel.InMemory.FunctionalTests;
 
public class HttpProtocolSelectionTests : TestApplicationErrorLoggerLoggedTest
{
    [Fact]
    public Task Server_NoProtocols_Error()
    {
        return TestError<InvalidOperationException>(HttpProtocols.None, CoreStrings.EndPointRequiresAtLeastOneProtocol);
    }
 
    [Fact]
    public Task Server_Http1AndHttp2_Cleartext_Http1Default()
    {
        return TestSuccess(HttpProtocols.Http1AndHttp2, "GET / HTTP/1.1\r\nHost:\r\n\r\n", "HTTP/1.1 200 OK");
    }
 
    [Fact]
    public Task Server_Http1Only_Cleartext_Success()
    {
        return TestSuccess(HttpProtocols.Http1, "GET / HTTP/1.1\r\nHost:\r\n\r\n", "HTTP/1.1 200 OK");
    }
 
    [Fact]
    public Task Server_Http2Only_Cleartext_Success()
    {
        // Expect a SETTINGS frame with default settings then a connection-level WINDOW_UPDATE frame.
        var expected = new byte[]
        {
                0x00, 0x00, 0x18, // Payload Length (6 * settings count)
                0x04, 0x00, 0x00, 0x00, 0x00, 0x00, // SETTINGS frame (type 0x04)
                0x00, 0x03, 0x00, 0x00, 0x00, 0x64, // Connection limit (100)
                0x00, 0x04, 0x00, 0x0C, 0x00, 0x00, // Initial stream window size (768 KiB)
                0x00, 0x06, 0x00, 0x00, 0x80, 0x00, // Header size limit (32 KiB)
                0x00, 0x08, 0x00, 0x00, 0x00, 0x01, // CONNECT enabled
                0x00, 0x00, 0x04, // Payload Length (4)
                0x08, 0x00, 0x00, 0x00, 0x00, 0x00, // WINDOW_UPDATE frame (type 0x08)
                0x00, 0x0F, 0x00, 0x01, // Diff between configured and protocol default (1 MiB - 0XFFFF)
        };
 
        return TestSuccess(HttpProtocols.Http2,
            Encoding.ASCII.GetString(Http2Connection.ClientPreface),
            Encoding.ASCII.GetString(expected));
    }
 
    private async Task TestSuccess(HttpProtocols serverProtocols, string request, string expectedResponse)
    {
        var testContext = new TestServiceContext(LoggerFactory);
        var listenOptions = new ListenOptions(new IPEndPoint(IPAddress.Loopback, 0))
        {
            Protocols = serverProtocols
        };
 
        await using (var server = new TestServer(context => Task.CompletedTask, testContext, listenOptions))
        {
            using (var connection = server.CreateConnection())
            {
                await connection.Send(request);
                await connection.Receive(expectedResponse);
            }
        }
    }
 
    private async Task TestError<TException>(HttpProtocols serverProtocols, string expectedErrorMessage)
        where TException : Exception
    {
        var testContext = new TestServiceContext(LoggerFactory);
        var listenOptions = new ListenOptions(new IPEndPoint(IPAddress.Loopback, 0))
        {
            Protocols = serverProtocols
        };
 
        await using (var server = new TestServer(context => Task.CompletedTask, testContext, listenOptions))
        {
            using (var connection = server.CreateConnection())
            {
                await connection.WaitForConnectionClose();
            }
        }
 
        Assert.Single(LogMessages, message => message.LogLevel == LogLevel.Error
            && message.EventId.Id == 0
            && message.Message == expectedErrorMessage);
    }
}