// 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.IO.Pipelines;
using System.Text;
using System.Threading.Tasks;
using Microsoft.Extensions.Logging;
using Microsoft.Extensions.WebSockets.Internal;
using Microsoft.Extensions.WebSockets.Internal.Tests;
using Xunit;

namespace Microsoft.AspNetCore.Sockets.Tests
{
    public class WebSocketsTests
    {
        [Fact]
        public async Task ReceivedFramesAreWrittenToPipeline()
        {
            using (var factory = new PipelineFactory())
            using (var pair = WebSocketPair.Create(factory))
            {
                var connection = new Connection();
                connection.ConnectionId = Guid.NewGuid().ToString();
                var httpConnection = new HttpConnection(factory);
                connection.Channel = httpConnection;
                var ws = new WebSockets(connection, Format.Text, new LoggerFactory());

                // Give the server socket to the transport and run it
                var transport = ws.ProcessSocketAsync(pair.ServerSocket);

                // Run the client socket
                var client = pair.ClientSocket.ExecuteAndCaptureFramesAsync();

                // Send a frame, then close
                await pair.ClientSocket.SendAsync(new WebSocketFrame(
                    endOfMessage: true,
                    opcode: WebSocketOpcode.Text,
                    payload: ReadableBuffer.Create(Encoding.UTF8.GetBytes("Hello"))));
                await pair.ClientSocket.CloseAsync(WebSocketCloseStatus.NormalClosure);

                // Capture everything out of the input channel and then complete the writer (to do our end of the close)
                var buffer = (await connection.Channel.Input.ReadToEndAsync()).ToArray();
                httpConnection.Output.CompleteWriter();

                // 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;

                // Read from the connection pipeline
                Assert.Equal("Hello", Encoding.UTF8.GetString(buffer));
                Assert.Equal(WebSocketCloseStatus.NormalClosure, clientSummary.CloseResult.Status);
            }
        }

        [Theory]
        [InlineData(Format.Text, WebSocketOpcode.Text)]
        [InlineData(Format.Binary, WebSocketOpcode.Binary)]
        public async Task DataWrittenToOutputPipelineAreSentAsFrames(Format format, WebSocketOpcode expectedOpcode)
        {
            using (var factory = new PipelineFactory())
            using (var pair = WebSocketPair.Create(factory))
            {
                var connection = new Connection();
                connection.ConnectionId = Guid.NewGuid().ToString();
                var httpConnection = new HttpConnection(factory);
                connection.Channel = httpConnection;
                var ws = new WebSockets(connection, format, new LoggerFactory());

                // Give the server socket to the transport and run it
                var transport = ws.ProcessSocketAsync(pair.ServerSocket);

                // Run the client socket
                var client = pair.ClientSocket.ExecuteAndCaptureFramesAsync();

                // Write to the output channel, and then complete it
                await httpConnection.Output.WriteAsync(Encoding.UTF8.GetBytes("Hello"));
                httpConnection.Output.CompleteWriter();

                // The client should finish now, as should the server
                var clientSummary = await client;
                await pair.ClientSocket.CloseAsync(WebSocketCloseStatus.NormalClosure);
                await transport;

                Assert.Equal(1, clientSummary.Received.Count);
                Assert.True(clientSummary.Received[0].EndOfMessage);
                Assert.Equal(expectedOpcode, clientSummary.Received[0].Opcode);
                Assert.Equal("Hello", Encoding.UTF8.GetString(clientSummary.Received[0].Payload.ToArray()));
            }
        }

        [Fact]
        public async Task FrameReceivedAfterServerCloseSent()
        {
            using (var factory = new PipelineFactory())
            using (var pair = WebSocketPair.Create(factory))
            {
                var connection = new Connection();
                connection.ConnectionId = Guid.NewGuid().ToString();
                var httpConnection = new HttpConnection(factory);
                connection.Channel = httpConnection;
                var ws = new WebSockets(connection, Format.Binary, new LoggerFactory());

                // Give the server socket to the transport and run it
                var transport = ws.ProcessSocketAsync(pair.ServerSocket);

                // Run the client socket
                var client = pair.ClientSocket.ExecuteAndCaptureFramesAsync();

                // Close the output and wait for the close frame
                httpConnection.Output.CompleteWriter();
                await client;

                // Send another frame. Then close
                await pair.ClientSocket.SendAsync(new WebSocketFrame(
                    endOfMessage: true,
                    opcode: WebSocketOpcode.Text,
                    payload: ReadableBuffer.Create(Encoding.UTF8.GetBytes("Hello"))));
                await pair.ClientSocket.CloseAsync(WebSocketCloseStatus.NormalClosure);

                // Read that frame from the input
                var result = (await httpConnection.Input.ReadToEndAsync()).ToArray();
                Assert.Equal("Hello", Encoding.UTF8.GetString(result));

                await transport;
            }
        }

        [Fact]
        public async Task TransportFailsWhenClientDisconnectsAbnormally()
        {
            using (var factory = new PipelineFactory())
            using (var pair = WebSocketPair.Create(factory))
            {
                var connection = new Connection();
                connection.ConnectionId = Guid.NewGuid().ToString();
                var httpConnection = new HttpConnection(factory);
                connection.Channel = httpConnection;
                var ws = new WebSockets(connection, Format.Binary, new LoggerFactory());

                // Give the server socket to the transport and run it
                var transport = ws.ProcessSocketAsync(pair.ServerSocket);

                // Run the client socket
                var client = pair.ClientSocket.ExecuteAndCaptureFramesAsync();

                // Terminate the client to server channel with an exception
                pair.TerminateFromClient(new InvalidOperationException());

                // Wait for the transport
                await Assert.ThrowsAsync<InvalidOperationException>(() => transport);
            }
        }

        [Fact]
        public async Task ClientReceivesInternalServerErrorWhenTheApplicationFails()
        {
            using (var factory = new PipelineFactory())
            using (var pair = WebSocketPair.Create(factory))
            {
                var connection = new Connection();
                connection.ConnectionId = Guid.NewGuid().ToString();
                var httpConnection = new HttpConnection(factory);
                connection.Channel = httpConnection;
                var ws = new WebSockets(connection, Format.Binary, new LoggerFactory());

                // Give the server socket to the transport and run it
                var transport = ws.ProcessSocketAsync(pair.ServerSocket);

                // Run the client socket
                var client = pair.ClientSocket.ExecuteAndCaptureFramesAsync();

                // Fail in the app
                httpConnection.Output.CompleteWriter(new InvalidOperationException());
                var clientSummary = await client;
                Assert.Equal(WebSocketCloseStatus.InternalServerError, clientSummary.CloseResult.Status);

                // Close from the client
                await pair.ClientSocket.CloseAsync(WebSocketCloseStatus.NormalClosure);
            }
        }
    }
}