using System;
using System.Collections.Generic;
 using System.Net;
using System.Net.WebSockets;
using System.Threading;
using System.Threading.Tasks;
using Emby.Server.Implementations.HttpServer;
using Emby.Server.Implementations.Net;
using MediaBrowser.Controller.Net;
using MediaBrowser.Model.Services;
using Microsoft.AspNetCore.Http;
using Microsoft.AspNetCore.Http.Extensions;
using Microsoft.Extensions.Logging;

 namespace Emby.Server.Implementations.SocketSharp
{
    public class WebSocketSharpListener : IHttpListener
    {
        private HttpListener _listener;

        private readonly ILogger _logger;

        private CancellationTokenSource _disposeCancellationTokenSource = new CancellationTokenSource();
        private CancellationToken _disposeCancellationToken;

        public WebSocketSharpListener(
            ILogger logger)
        {
            _logger = logger;

            _disposeCancellationToken = _disposeCancellationTokenSource.Token;
        }

        public Func<Exception, IRequest, bool, bool, Task> ErrorHandler { get; set; }
        public Func<IHttpRequest, string, string, string, CancellationToken, Task> RequestHandler { get; set; }

        public Action<WebSocketConnectingEventArgs> WebSocketConnecting { get; set; }

        public Action<WebSocketConnectEventArgs> WebSocketConnected { get; set; }

//        public void Start(IEnumerable<string> urlPrefixes)
//        {
//            // TODO
//            //if (_listener == null)
//            //{
//            //    _listener = new HttpListener(_logger, _cryptoProvider, _socketFactory, _streamHelper, _fileSystem, _environment);
//            //}
//
//            //_listener.EnableDualMode = _enableDualMode;
//
//            //if (_certificate != null)
//            //{
//            //    _listener.LoadCert(_certificate);
//            //}
//
//            //_logger.LogInformation("Adding HttpListener prefixes {Prefixes}", urlPrefixes);
//            //_listener.Prefixes.AddRange(urlPrefixes);
//
//            //_listener.OnContext = async c => await InitTask(c, _disposeCancellationToken).ConfigureAwait(false);
//
//            //_listener.Start();
//
//            if (_listener == null)
//            {
//                _listener = new HttpListener();
//            }
//
//            _logger.LogInformation("Adding HttpListener prefixes {Prefixes}", urlPrefixes);
//
//            //foreach (var urlPrefix in urlPrefixes)
//            //{
//            //    _listener.Prefixes.Add(urlPrefix);
//            //}
//            _listener.Prefixes.Add("http://localhost:8096/");
//
//            _listener.Start();
//
//            // TODO how to do this in netcore?
//            _listener.BeginGetContext(async c => await InitTask(c, _disposeCancellationToken).ConfigureAwait(false),
//                null);
//        }

        private static void LogRequest(ILogger logger, HttpListenerRequest request)
        {
            var url = request.Url.ToString();

            logger.LogInformation(
                "{0} {1}. UserAgent: {2}",
                request.IsWebSocketRequest ? "WS" : "HTTP " + request.HttpMethod,
                url,
                request.UserAgent ?? string.Empty);
        }
//
//        private Task InitTask(IAsyncResult asyncResult, CancellationToken cancellationToken)
//        {
//            var context = _listener.EndGetContext(asyncResult);
//            _listener.BeginGetContext(async c => await InitTask(c, _disposeCancellationToken).ConfigureAwait(false), null);
//            IHttpRequest httpReq = null;
//            var request = context.Request;
//
//            try
//            {
//                if (request.IsWebSocketRequest)
//                {
//                    LogRequest(_logger, request);
//
//                    return ProcessWebSocketRequest(context);
//                }
//
//                httpReq = GetRequest(context);
//            }
//            catch (Exception ex)
//            {
//                _logger.LogError(ex, "Error processing request");
//
//                httpReq = httpReq ?? GetRequest(context);
//                return ErrorHandler(ex, httpReq, true, true);
//            }
//
//            var uri = request.Url;
//
//            return RequestHandler(httpReq, uri.OriginalString, uri.Host, uri.LocalPath, cancellationToken);
//        }

        public async Task ProcessWebSocketRequest(HttpContext ctx)
        {
            try
            {
                var endpoint = ctx.Connection.RemoteIpAddress.ToString();
                var url = ctx.Request.GetDisplayUrl();

                var queryString = new QueryParamCollection(ctx.Request.Query);

                var connectingArgs = new WebSocketConnectingEventArgs
                {
                    Url = url,
                    QueryString = queryString,
                    Endpoint = endpoint
                };

                WebSocketConnecting?.Invoke(connectingArgs);

                if (connectingArgs.AllowConnection)
                {
                    _logger.LogDebug("Web socket connection allowed");

                    var webSocketContext = await ctx.WebSockets.AcceptWebSocketAsync(null).ConfigureAwait(false);
                    var socket = new SharpWebSocket(webSocketContext, _logger);
                    await socket.ConnectAsServerAsync().ConfigureAwait(false);

                    WebSocketConnected(new WebSocketConnectEventArgs
                    {
                        Url = url,
                        QueryString = queryString,
                        WebSocket = socket,
                        Endpoint = endpoint
                    });

                    //await ReceiveWebSocketAsync(ctx, socket).ConfigureAwait(false);
                    var buffer = WebSocket.CreateClientBuffer(1024 * 4, 1024 * 4);
                    WebSocketReceiveResult result = await webSocketContext.ReceiveAsync(buffer, CancellationToken.None);
                    socket.OnReceiveBytes(buffer.Array);
                    //while (!result.CloseStatus.HasValue)
                    //{
                    //    await webSocketContext.SendAsync(new ArraySegment<byte>(buffer, 0, result.Count), result.MessageType, result.EndOfMessage, CancellationToken.None);

                    //    result = await webSocketContext.ReceiveAsync(new ArraySegment<byte>(buffer), CancellationToken.None);
                    //}
                    //WebSocketConnected?.Invoke(new WebSocketConnectEventArgs
                    //{
                    //    Url = url,
                    //    QueryString = queryString,
                    //    WebSocket = webSocketContext,
                    //    Endpoint = endpoint
                    //});
                    await webSocketContext.CloseAsync(result.CloseStatus.Value, result.CloseStatusDescription, CancellationToken.None);
                    //SharpWebSocket socket = new SharpWebSocket(webSocketContext, _logger);
                    //await socket.ConnectAsServerAsync().ConfigureAwait(false);

                    

                    //await ReceiveWebSocketAsync(ctx, socket).ConfigureAwait(false);
                }
                else
                {
                    _logger.LogWarning("Web socket connection not allowed");
                    ctx.Response.StatusCode = 401;
                    //ctx.Response.Close();
                }
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "AcceptWebSocketAsync error");
                ctx.Response.StatusCode = 500;
                //ctx.Response.Close();
            }
        }

        private async Task ReceiveWebSocketAsync(HttpContext ctx, SharpWebSocket socket)
        {
            try
            {
                await socket.StartReceive().ConfigureAwait(false);
            }
            finally
            {
                TryClose(ctx, 200);
            }
        }

        private void TryClose(HttpContext ctx, int statusCode)
        {
            try
            {
                ctx.Response.StatusCode = statusCode;
            }
            catch (ObjectDisposedException)
            {
                // TODO: Investigate and properly fix.
            }
            catch (Exception ex)
            {
                _logger.LogError(ex, "Error closing web socket response");
            }
        }

        private IHttpRequest GetRequest(HttpRequest httpContext)
        {
            var urlSegments = httpContext.Path;

            var operationName = urlSegments;

            var req = new WebSocketSharpRequest(httpContext, httpContext.HttpContext.Response, operationName, _logger);

            return req;
        }

        public void Start(IEnumerable<string> urlPrefixes)
        {
            throw new NotImplementedException();
        }

        public Task Stop()
        {
            _disposeCancellationTokenSource.Cancel();
            _listener?.Close();

            return Task.CompletedTask;
        }

        /// <summary>
        /// Releases the unmanaged resources and disposes of the managed resources used.
        /// </summary>
        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        private bool _disposed;

        /// <summary>
        /// Releases the unmanaged resources and disposes of the managed resources used.
        /// </summary>
        /// <param name="disposing">Whether or not the managed resources should be disposed</param>
        protected virtual void Dispose(bool disposing)
        {
            if (_disposed)
            {
                return;
            }

            if (disposing)
            {
                Stop().GetAwaiter().GetResult();
            }

            _disposed = true;
        }
    }
}