// 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;
using System.Net.WebSockets;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using System.Threading.Channels;
using Microsoft.AspNetCore.SignalR.Internal;
using Microsoft.AspNetCore.SignalR.Tests.Common;
using Microsoft.AspNetCore.Sockets.Internal;
using Microsoft.AspNetCore.Sockets.Internal.Transports;
using Microsoft.Extensions.Logging.Testing;
using Xunit;
using Xunit.Abstractions;

namespace Microsoft.AspNetCore.Sockets.Tests
{
    public class WebSocketsTests : LoggedTest
    {
        public WebSocketsTests(ITestOutputHelper output)
            : base(output)
        {
        }

        [Theory]
        [InlineData(WebSocketMessageType.Text)]
        [InlineData(WebSocketMessageType.Binary)]
        public async Task ReceivedFramesAreWrittenToChannel(WebSocketMessageType webSocketMessageType)
        {
            using (StartLog(out var loggerFactory))
            {
                var transportToApplication = Channel.CreateUnbounded<byte[]>();
                var applicationToTransport = Channel.CreateUnbounded<byte[]>();

                using (var transportSide = ChannelConnection.Create<byte[]>(applicationToTransport, transportToApplication))
                using (var applicationSide = ChannelConnection.Create<byte[]>(transportToApplication, applicationToTransport))
                using (var feature = new TestWebSocketConnectionFeature())
                {
                    var connectionContext = new DefaultConnectionContext(string.Empty, null, null);
                    var ws = new WebSocketsTransport(new WebSocketOptions(), transportSide, connectionContext, loggerFactory);

                    // Give the server socket to the transport and run it
                    var transport = ws.ProcessSocketAsync(await feature.AcceptAsync());

                    // Run the client socket
                    var client = feature.Client.ExecuteAndCaptureFramesAsync();

                    // Send a frame, then close
                    await feature.Client.SendAsync(
                        buffer: new ArraySegment<byte>(Encoding.UTF8.GetBytes("Hello")),
                        messageType: webSocketMessageType,
                        endOfMessage: true,
                        cancellationToken: CancellationToken.None);
                    await feature.Client.CloseAsync(WebSocketCloseStatus.NormalClosure, "", CancellationToken.None);

                    var buffer = await applicationSide.Reader.ReadAsync();
                    Assert.Equal("Hello", Encoding.UTF8.GetString(buffer));

                    Assert.True(applicationSide.Writer.TryComplete());

                    // The transport should finish now
                    await transport;

                    // The connection should close after this, which means the client will get a close frame.
                    var clientSummary = await client;

                    Assert.Equal(WebSocketCloseStatus.NormalClosure, clientSummary.CloseResult.CloseStatus);
                }
            }
        }

        [Theory]
        [InlineData(TransferMode.Text, WebSocketMessageType.Text)]
        [InlineData(TransferMode.Binary, WebSocketMessageType.Binary)]
        public async Task WebSocketTransportSetsMessageTypeBasedOnTransferModeFeature(TransferMode transferMode, WebSocketMessageType expectedMessageType)
        {
            using (StartLog(out var loggerFactory))
            {
                var transportToApplication = Channel.CreateUnbounded<byte[]>();
                var applicationToTransport = Channel.CreateUnbounded<byte[]>();

                using (var transportSide = ChannelConnection.Create<byte[]>(applicationToTransport, transportToApplication))
                using (var applicationSide = ChannelConnection.Create<byte[]>(transportToApplication, applicationToTransport))
                using (var feature = new TestWebSocketConnectionFeature())
                {
                    var connectionContext = new DefaultConnectionContext(string.Empty, null, null) { TransferMode = transferMode };
                    var ws = new WebSocketsTransport(new WebSocketOptions(), transportSide, connectionContext, loggerFactory);

                    // Give the server socket to the transport and run it
                    var transport = ws.ProcessSocketAsync(await feature.AcceptAsync());

                    // Run the client socket
                    var client = feature.Client.ExecuteAndCaptureFramesAsync();

                    // Write to the output channel, and then complete it
                    await applicationSide.Writer.WriteAsync(Encoding.UTF8.GetBytes("Hello"));
                    Assert.True(applicationSide.Writer.TryComplete());

                    // The client should finish now, as should the server
                    var clientSummary = await client;
                    await feature.Client.CloseAsync(WebSocketCloseStatus.NormalClosure, "", CancellationToken.None);
                    await transport;

                    Assert.Equal(1, clientSummary.Received.Count);
                    Assert.True(clientSummary.Received[0].EndOfMessage);
                    Assert.Equal(expectedMessageType, clientSummary.Received[0].MessageType);
                    Assert.Equal("Hello", Encoding.UTF8.GetString(clientSummary.Received[0].Buffer));
                }
            }
        }

        [Fact]
        public async Task TransportFailsWhenClientDisconnectsAbnormally()
        {
            using (StartLog(out var loggerFactory))
            {
                var transportToApplication = Channel.CreateUnbounded<byte[]>();
                var applicationToTransport = Channel.CreateUnbounded<byte[]>();

                using (var transportSide = ChannelConnection.Create<byte[]>(applicationToTransport, transportToApplication))
                using (var applicationSide = ChannelConnection.Create<byte[]>(transportToApplication, applicationToTransport))
                using (var feature = new TestWebSocketConnectionFeature())
                {
                    async Task CompleteApplicationAfterTransportCompletes()
                    {
                        // Wait until the transport completes so that we can end the application
                        await applicationSide.Reader.WaitToReadAsync();

                        // Complete the application so that the connection unwinds without aborting
                        applicationSide.Writer.TryComplete();
                    }

                    var connectionContext = new DefaultConnectionContext(string.Empty, null, null);
                    var ws = new WebSocketsTransport(new WebSocketOptions(), transportSide, connectionContext, loggerFactory);

                    // Give the server socket to the transport and run it
                    var transport = ws.ProcessSocketAsync(await feature.AcceptAsync());

                    // Run the client socket
                    var client = feature.Client.ExecuteAndCaptureFramesAsync();

                    // When the close frame is received, we complete the application so the send
                    // loop unwinds
                    _ = CompleteApplicationAfterTransportCompletes();

                    // Terminate the client to server channel with an exception
                    feature.Client.SendAbort();

                    // Wait for the transport
                    await Assert.ThrowsAsync<WebSocketException>(() => transport).OrTimeout();

                    var summary = await client.OrTimeout();
                    Assert.Equal(WebSocketCloseStatus.InternalServerError, summary.CloseResult.CloseStatus);
                }
            }
        }

        [Fact]
        public async Task ClientReceivesInternalServerErrorWhenTheApplicationFails()
        {
            using (StartLog(out var loggerFactory))
            {
                var transportToApplication = Channel.CreateUnbounded<byte[]>();
                var applicationToTransport = Channel.CreateUnbounded<byte[]>();

                using (var transportSide = ChannelConnection.Create<byte[]>(applicationToTransport, transportToApplication))
                using (var applicationSide = ChannelConnection.Create<byte[]>(transportToApplication, applicationToTransport))
                using (var feature = new TestWebSocketConnectionFeature())
                {
                    var connectionContext = new DefaultConnectionContext(string.Empty, null, null);
                    var ws = new WebSocketsTransport(new WebSocketOptions(), transportSide, connectionContext, loggerFactory);

                    // Give the server socket to the transport and run it
                    var transport = ws.ProcessSocketAsync(await feature.AcceptAsync());

                    // Run the client socket
                    var client = feature.Client.ExecuteAndCaptureFramesAsync();

                    // Fail in the app
                    Assert.True(applicationSide.Writer.TryComplete(new InvalidOperationException("Catastrophic failure.")));
                    var clientSummary = await client.OrTimeout();
                    Assert.Equal(WebSocketCloseStatus.InternalServerError, clientSummary.CloseResult.CloseStatus);

                    // Close from the client
                    await feature.Client.CloseAsync(WebSocketCloseStatus.NormalClosure, "", CancellationToken.None);

                    var ex = await Assert.ThrowsAsync<InvalidOperationException>(() => transport.OrTimeout());
                    Assert.Equal("Catastrophic failure.", ex.Message);
                }
            }
        }

        [Fact]
        public async Task TransportClosesOnCloseTimeoutIfClientDoesNotSendCloseFrame()
        {
            using (StartLog(out var loggerFactory))
            {
                var transportToApplication = Channel.CreateUnbounded<byte[]>();
                var applicationToTransport = Channel.CreateUnbounded<byte[]>();

                using (var transportSide = ChannelConnection.Create<byte[]>(applicationToTransport, transportToApplication))
                using (var applicationSide = ChannelConnection.Create<byte[]>(transportToApplication, applicationToTransport))
                using (var feature = new TestWebSocketConnectionFeature())
                {
                    var options = new WebSocketOptions()
                    {
                        CloseTimeout = TimeSpan.FromSeconds(1)
                    };

                    var connectionContext = new DefaultConnectionContext(string.Empty, null, null);
                    var ws = new WebSocketsTransport(options, transportSide, connectionContext, loggerFactory);

                    var serverSocket = await feature.AcceptAsync();
                    // Give the server socket to the transport and run it
                    var transport = ws.ProcessSocketAsync(serverSocket);

                    // End the app
                    applicationSide.Dispose();

                    await transport.OrTimeout(TimeSpan.FromSeconds(10));

                    // Now we're closed
                    Assert.Equal(WebSocketState.Aborted, serverSocket.State);

                    serverSocket.Dispose();
                }
            }
        }

        [Fact]
        public async Task TransportFailsOnTimeoutWithErrorWhenApplicationFailsAndClientDoesNotSendCloseFrame()
        {
            using (StartLog(out var loggerFactory))
            {
                var transportToApplication = Channel.CreateUnbounded<byte[]>();
                var applicationToTransport = Channel.CreateUnbounded<byte[]>();

                using (var transportSide = ChannelConnection.Create<byte[]>(applicationToTransport, transportToApplication))
                using (var applicationSide = ChannelConnection.Create<byte[]>(transportToApplication, applicationToTransport))
                using (var feature = new TestWebSocketConnectionFeature())
                {
                    var options = new WebSocketOptions
                    {
                        CloseTimeout = TimeSpan.FromSeconds(1)
                    };

                    var connectionContext = new DefaultConnectionContext(string.Empty, null, null);
                    var ws = new WebSocketsTransport(options, transportSide, connectionContext, loggerFactory);

                    var serverSocket = await feature.AcceptAsync();
                    // Give the server socket to the transport and run it
                    var transport = ws.ProcessSocketAsync(serverSocket);

                    // Run the client socket
                    var client = feature.Client.ExecuteAndCaptureFramesAsync();

                    // fail the client to server channel
                    applicationToTransport.Writer.TryComplete(new Exception());

                    await Assert.ThrowsAsync<Exception>(() => transport).OrTimeout();

                    Assert.Equal(WebSocketState.Aborted, serverSocket.State);
                }
            }
        }

        [Fact]
        public async Task ServerGracefullyClosesWhenApplicationEndsThenClientSendsCloseFrame()
        {
            using (StartLog(out var loggerFactory))
            {
                var transportToApplication = Channel.CreateUnbounded<byte[]>();
                var applicationToTransport = Channel.CreateUnbounded<byte[]>();

                using (var transportSide = ChannelConnection.Create<byte[]>(applicationToTransport, transportToApplication))
                using (var applicationSide = ChannelConnection.Create<byte[]>(transportToApplication, applicationToTransport))
                using (var feature = new TestWebSocketConnectionFeature())
                {
                    var options = new WebSocketOptions
                    {
                        // We want to verify behavior without timeout affecting it
                        CloseTimeout = TimeSpan.FromSeconds(20)
                    };

                    var connectionContext = new DefaultConnectionContext(string.Empty, null, null);
                    var ws = new WebSocketsTransport(options, transportSide, connectionContext, loggerFactory);

                    var serverSocket = await feature.AcceptAsync();
                    // Give the server socket to the transport and run it
                    var transport = ws.ProcessSocketAsync(serverSocket);

                    // Run the client socket
                    var client = feature.Client.ExecuteAndCaptureFramesAsync();

                    // close the client to server channel
                    applicationToTransport.Writer.TryComplete();

                    _ = await client.OrTimeout();

                    await feature.Client.CloseOutputAsync(WebSocketCloseStatus.NormalClosure, null, CancellationToken.None).OrTimeout();

                    await transport.OrTimeout();

                    Assert.Equal(WebSocketCloseStatus.NormalClosure, serverSocket.CloseStatus);
                }
            }
        }

        [Fact]
        public async Task ServerGracefullyClosesWhenClientSendsCloseFrameThenApplicationEnds()
        {
            using (StartLog(out var loggerFactory))
            {
                var transportToApplication = Channel.CreateUnbounded<byte[]>();
                var applicationToTransport = Channel.CreateUnbounded<byte[]>();

                using (var transportSide = ChannelConnection.Create<byte[]>(applicationToTransport, transportToApplication))
                using (var applicationSide = ChannelConnection.Create<byte[]>(transportToApplication, applicationToTransport))
                using (var feature = new TestWebSocketConnectionFeature())
                {
                    var options = new WebSocketOptions
                    {
                        // We want to verify behavior without timeout affecting it
                        CloseTimeout = TimeSpan.FromSeconds(20)
                    };
                    var connectionContext = new DefaultConnectionContext(string.Empty, null, null);
                    var ws = new WebSocketsTransport(options, transportSide, connectionContext, loggerFactory);

                    var serverSocket = await feature.AcceptAsync();
                    // Give the server socket to the transport and run it
                    var transport = ws.ProcessSocketAsync(serverSocket);

                    // Run the client socket
                    var client = feature.Client.ExecuteAndCaptureFramesAsync();

                    await feature.Client.CloseOutputAsync(WebSocketCloseStatus.NormalClosure, null, CancellationToken.None).OrTimeout();

                    // close the client to server channel
                    applicationToTransport.Writer.TryComplete();

                    _ = await client.OrTimeout();

                    await transport.OrTimeout();

                    Assert.Equal(WebSocketCloseStatus.NormalClosure, serverSocket.CloseStatus);
                }
            }
        }
    }
}