using MediaBrowser.Common.Extensions;
using MediaBrowser.Controller.Configuration;
using MediaBrowser.Controller.Net;
using MediaBrowser.Model.Logging;
using System;
using System.Collections.Generic;
using System.Globalization;
using System.IO;
using System.Linq;
using System.Reflection;
using System.Security.Cryptography.X509Certificates;
using System.Text;
using System.Threading;
using System.Threading.Tasks;
using Emby.Server.Implementations.HttpServer.SocketSharp;
using Emby.Server.Implementations.Services;
using MediaBrowser.Common.Net;
using MediaBrowser.Common.Security;
using MediaBrowser.Controller;
using MediaBrowser.Model.Cryptography;
using MediaBrowser.Model.Extensions;
using MediaBrowser.Model.IO;
using MediaBrowser.Model.Net;
using MediaBrowser.Model.Serialization;
using MediaBrowser.Model.Services;
using MediaBrowser.Model.System;
using MediaBrowser.Model.Text;

namespace Emby.Server.Implementations.HttpServer
{
    public class HttpListenerHost : IHttpServer, IDisposable
    {
        private string DefaultRedirectPath { get; set; }

        private readonly ILogger _logger;
        public string[] UrlPrefixes { get; private set; }

        private readonly List<IService> _restServices = new List<IService>();

        private IHttpListener _listener;

        public event EventHandler<WebSocketConnectEventArgs> WebSocketConnected;
        public event EventHandler<WebSocketConnectingEventArgs> WebSocketConnecting;

        private readonly IServerConfigurationManager _config;
        private readonly INetworkManager _networkManager;
        private readonly IMemoryStreamFactory _memoryStreamProvider;

        private readonly IServerApplicationHost _appHost;

        private readonly ITextEncoding _textEncoding;
        private readonly ISocketFactory _socketFactory;
        private readonly ICryptoProvider _cryptoProvider;

        private readonly IFileSystem _fileSystem;
        private readonly IJsonSerializer _jsonSerializer;
        private readonly IXmlSerializer _xmlSerializer;
        private readonly X509Certificate _certificate;
        private readonly IEnvironmentInfo _environment;
        private readonly Func<Type, Func<string, object>> _funcParseFn;
        private readonly bool _enableDualModeSockets;

        public Action<IRequest, IResponse, object>[] RequestFilters { get; set; }
        public Action<IRequest, IResponse, object>[] ResponseFilters { get; set; }

        private readonly Dictionary<Type, Type> ServiceOperationsMap = new Dictionary<Type, Type>();
        public static HttpListenerHost Instance { get; protected set; }

        public HttpListenerHost(IServerApplicationHost applicationHost,
            ILogger logger,
            IServerConfigurationManager config,
            string serviceName,
            string defaultRedirectPath, INetworkManager networkManager, IMemoryStreamFactory memoryStreamProvider, ITextEncoding textEncoding, ISocketFactory socketFactory, ICryptoProvider cryptoProvider, IJsonSerializer jsonSerializer, IXmlSerializer xmlSerializer, IEnvironmentInfo environment, X509Certificate certificate, Func<Type, Func<string, object>> funcParseFn, bool enableDualModeSockets, IFileSystem fileSystem)
        {
            Instance = this;

            _appHost = applicationHost;
            DefaultRedirectPath = defaultRedirectPath;
            _networkManager = networkManager;
            _memoryStreamProvider = memoryStreamProvider;
            _textEncoding = textEncoding;
            _socketFactory = socketFactory;
            _cryptoProvider = cryptoProvider;
            _jsonSerializer = jsonSerializer;
            _xmlSerializer = xmlSerializer;
            _environment = environment;
            _certificate = certificate;
            _funcParseFn = funcParseFn;
            _enableDualModeSockets = enableDualModeSockets;
            _fileSystem = fileSystem;
            _config = config;

            _logger = logger;

            RequestFilters = new Action<IRequest, IResponse, object>[] { };
            ResponseFilters = new Action<IRequest, IResponse, object>[] { };
        }

        public string GlobalResponse { get; set; }

        readonly Dictionary<Type, int> _mapExceptionToStatusCode = new Dictionary<Type, int>
            {
                {typeof (ResourceNotFoundException), 404},
                {typeof (RemoteServiceUnavailableException), 502},
                {typeof (FileNotFoundException), 404},
                //{typeof (DirectoryNotFoundException), 404},
                {typeof (SecurityException), 401},
                {typeof (PaymentRequiredException), 402},
                {typeof (ArgumentException), 400}
            };

        protected ILogger Logger
        {
            get
            {
                return _logger;
            }
        }

        public object CreateInstance(Type type)
        {
            return _appHost.CreateInstance(type);
        }

        /// <summary>
        /// Applies the request filters. Returns whether or not the request has been handled 
        /// and no more processing should be done.
        /// </summary>
        /// <returns></returns>
        public void ApplyRequestFilters(IRequest req, IResponse res, object requestDto)
        {
            //Exec all RequestFilter attributes with Priority < 0
            var attributes = GetRequestFilterAttributes(requestDto.GetType());
            var i = 0;
            var count = attributes.Count;

            for (; i < count && attributes[i].Priority < 0; i++)
            {
                var attribute = attributes[i];
                attribute.RequestFilter(req, res, requestDto);
            }

            //Exec global filters
            foreach (var requestFilter in RequestFilters)
            {
                requestFilter(req, res, requestDto);
            }

            //Exec remaining RequestFilter attributes with Priority >= 0
            for (; i < count && attributes[i].Priority >= 0; i++)
            {
                var attribute = attributes[i];
                attribute.RequestFilter(req, res, requestDto);
            }
        }

        public Type GetServiceTypeByRequest(Type requestType)
        {
            Type serviceType;
            ServiceOperationsMap.TryGetValue(requestType, out serviceType);
            return serviceType;
        }

        public void AddServiceInfo(Type serviceType, Type requestType)
        {
            ServiceOperationsMap[requestType] = serviceType;
        }

        private List<IHasRequestFilter> GetRequestFilterAttributes(Type requestDtoType)
        {
            var attributes = requestDtoType.GetTypeInfo().GetCustomAttributes(true).OfType<IHasRequestFilter>().ToList();

            var serviceType = GetServiceTypeByRequest(requestDtoType);
            if (serviceType != null)
            {
                attributes.AddRange(serviceType.GetTypeInfo().GetCustomAttributes(true).OfType<IHasRequestFilter>());
            }

            attributes.Sort((x, y) => x.Priority - y.Priority);

            return attributes;
        }

        private IHttpListener GetListener()
        {
            //return new KestrelHost.KestrelListener(_logger, _environment, _fileSystem);

            return new WebSocketSharpListener(_logger,
                _certificate,
                _memoryStreamProvider,
                _textEncoding,
                _networkManager,
                _socketFactory,
                _cryptoProvider,
                _enableDualModeSockets,
                _fileSystem,
                _environment);
        }

        private void OnWebSocketConnecting(WebSocketConnectingEventArgs args)
        {
            if (_disposed)
            {
                return;
            }

            if (WebSocketConnecting != null)
            {
                WebSocketConnecting(this, args);
            }
        }

        private void OnWebSocketConnected(WebSocketConnectEventArgs args)
        {
            if (_disposed)
            {
                return;
            }

            if (WebSocketConnected != null)
            {
                WebSocketConnected(this, args);
            }
        }

        private Exception GetActualException(Exception ex)
        {
            var agg = ex as AggregateException;
            if (agg != null)
            {
                var inner = agg.InnerException;
                if (inner != null)
                {
                    return GetActualException(inner);
                }
                else
                {
                    var inners = agg.InnerExceptions;
                    if (inners != null && inners.Count > 0)
                    {
                        return GetActualException(inners[0]);
                    }
                }
            }

            return ex;
        }

        private int GetStatusCode(Exception ex)
        {
            if (ex is ArgumentException)
            {
                return 400;
            }

            var exceptionType = ex.GetType();

            int statusCode;
            if (!_mapExceptionToStatusCode.TryGetValue(exceptionType, out statusCode))
            {
                if (ex is DirectoryNotFoundException)
                {
                    statusCode = 404;
                }
                else
                {
                    statusCode = 500;
                }
            }

            return statusCode;
        }

        private void ErrorHandler(Exception ex, IRequest httpReq, bool logException = true)
        {
            try
            {
                ex = GetActualException(ex);

                if (logException)
                {
                    _logger.ErrorException("Error processing request", ex);
                }

                var httpRes = httpReq.Response;

                if (httpRes.IsClosed)
                {
                    return;
                }

                var statusCode = GetStatusCode(ex);
                httpRes.StatusCode = statusCode;

                httpRes.ContentType = "text/html";
                Write(httpRes, ex.Message);
            }
            catch
            {
                //_logger.ErrorException("Error this.ProcessRequest(context)(Exception while writing error to the response)", errorEx);
            }
        }

        /// <summary>
        /// Shut down the Web Service
        /// </summary>
        public void Stop()
        {
            if (_listener != null)
            {
                _logger.Info("Stopping HttpListener...");
                var task = _listener.Stop();
                Task.WaitAll(task);
                _logger.Info("HttpListener stopped");
            }
        }

        private readonly Dictionary<string, int> _skipLogExtensions = new Dictionary<string, int>(StringComparer.OrdinalIgnoreCase)
        {
            {".js", 0},
            {".css", 0},
            {".woff", 0},
            {".woff2", 0},
            {".ttf", 0},
            {".html", 0}
        };

        private bool EnableLogging(string url, string localPath)
        {
            var extension = GetExtension(url);

            if (string.IsNullOrWhiteSpace(extension) || !_skipLogExtensions.ContainsKey(extension))
            {
                if (string.IsNullOrWhiteSpace(localPath) || localPath.IndexOf("system/ping", StringComparison.OrdinalIgnoreCase) == -1)
                {
                    return true;
                }
            }

            return false;
        }

        private string GetExtension(string url)
        {
            var parts = url.Split(new[] { '?' }, 2);

            return Path.GetExtension(parts[0]);
        }

        public static string RemoveQueryStringByKey(string url, string key)
        {
            var uri = new Uri(url);

            // this gets all the query string key value pairs as a collection
            var newQueryString = MyHttpUtility.ParseQueryString(uri.Query);

            var originalCount = newQueryString.Count;

            if (originalCount == 0)
            {
                return url;
            }

            // this removes the key if exists
            newQueryString.Remove(key);

            if (originalCount == newQueryString.Count)
            {
                return url;
            }

            // this gets the page path from root without QueryString
            string pagePathWithoutQueryString = url.Split(new[] { '?' }, StringSplitOptions.RemoveEmptyEntries)[0];

            return newQueryString.Count > 0
                ? String.Format("{0}?{1}", pagePathWithoutQueryString, newQueryString)
                : pagePathWithoutQueryString;
        }

        private string GetUrlToLog(string url)
        {
            url = RemoveQueryStringByKey(url, "api_key");

            return url;
        }

        private string NormalizeConfiguredLocalAddress(string address)
        {
            var index = address.Trim('/').IndexOf('/');

            if (index != -1)
            {
                address = address.Substring(index + 1);
            }

            return address.Trim('/');
        }

        private bool ValidateHost(string host)
        {
            var hosts = _config
                .Configuration
                .LocalNetworkAddresses
                .Select(NormalizeConfiguredLocalAddress)
                .ToList();

            if (hosts.Count == 0)
            {
                return true;
            }

            host = host ?? string.Empty;

            _logger.Debug("Validating host {0}", host);

            if (_networkManager.IsInPrivateAddressSpace(host))
            {
                hosts.Add("localhost");
                hosts.Add("127.0.0.1");

                return hosts.Any(i => host.IndexOf(i, StringComparison.OrdinalIgnoreCase) != -1);
            }

            return true;
        }

        private bool ValidateSsl(string remoteIp, string urlString)
        {
            if (_config.Configuration.RequireHttps && _appHost.EnableHttps)
            {
                if (urlString.IndexOf("https://", StringComparison.OrdinalIgnoreCase) == -1)
                {
                    if (!_networkManager.IsInLocalNetwork(remoteIp))
                    {
                        return false;
                    }
                }
            }

            return true;
        }

        /// <summary>
        /// Overridable method that can be used to implement a custom hnandler
        /// </summary>
        protected async Task RequestHandler(IHttpRequest httpReq, string urlString, string host, string localPath, CancellationToken cancellationToken)
        {
            var date = DateTime.Now;
            var httpRes = httpReq.Response;
            bool enableLog = false;
            bool logHeaders = false;
            string urlToLog = null;
            string remoteIp = null;

            try
            {
                if (_disposed)
                {
                    httpRes.StatusCode = 503;
                    httpRes.ContentType = "text/plain";
                    Write(httpRes, "Server shutting down");
                    return;
                }

                if (!ValidateHost(host))
                {
                    httpRes.StatusCode = 400;
                    httpRes.ContentType = "text/plain";
                    Write(httpRes, "Invalid host");
                    return;
                }

                if (!ValidateSsl(httpReq.RemoteIp, urlString))
                {
                    var httpsUrl = urlString
                        .Replace("http://", "https://", StringComparison.OrdinalIgnoreCase)
                        .Replace(":" + _config.Configuration.PublicPort.ToString(CultureInfo.InvariantCulture), ":" + _config.Configuration.PublicHttpsPort.ToString(CultureInfo.InvariantCulture), StringComparison.OrdinalIgnoreCase);

                    RedirectToUrl(httpRes, httpsUrl);
                    return;
                }

                if (string.Equals(httpReq.Verb, "OPTIONS", StringComparison.OrdinalIgnoreCase))
                {
                    httpRes.StatusCode = 200;
                    httpRes.AddHeader("Access-Control-Allow-Origin", "*");
                    httpRes.AddHeader("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, PATCH, OPTIONS");
                    httpRes.AddHeader("Access-Control-Allow-Headers", "Content-Type, Authorization, Range, X-MediaBrowser-Token, X-Emby-Authorization");
                    httpRes.ContentType = "text/plain";
                    Write(httpRes, string.Empty);
                    return;
                }

                var operationName = httpReq.OperationName;

                enableLog = EnableLogging(urlString, localPath);
                urlToLog = urlString;
                logHeaders = enableLog && urlToLog.IndexOf("/videos/", StringComparison.OrdinalIgnoreCase) != -1;

                if (enableLog)
                {
                    urlToLog = GetUrlToLog(urlString);
                    remoteIp = httpReq.RemoteIp;

                    LoggerUtils.LogRequest(_logger, urlToLog, httpReq.HttpMethod, httpReq.UserAgent, logHeaders ? httpReq.Headers : null);
                }

                if (string.Equals(localPath, "/emby/", StringComparison.OrdinalIgnoreCase) ||
                    string.Equals(localPath, "/mediabrowser/", StringComparison.OrdinalIgnoreCase))
                {
                    RedirectToUrl(httpRes, DefaultRedirectPath);
                    return;
                }
                if (string.Equals(localPath, "/emby", StringComparison.OrdinalIgnoreCase) ||
                    string.Equals(localPath, "/mediabrowser", StringComparison.OrdinalIgnoreCase))
                {
                    RedirectToUrl(httpRes, "emby/" + DefaultRedirectPath);
                    return;
                }

                if (string.Equals(localPath, "/mediabrowser/", StringComparison.OrdinalIgnoreCase) ||
                    string.Equals(localPath, "/mediabrowser", StringComparison.OrdinalIgnoreCase) ||
                    localPath.IndexOf("mediabrowser/web", StringComparison.OrdinalIgnoreCase) != -1)
                {
                    httpRes.StatusCode = 200;
                    httpRes.ContentType = "text/html";
                    var newUrl = urlString.Replace("mediabrowser", "emby", StringComparison.OrdinalIgnoreCase)
                        .Replace("/dashboard/", "/web/", StringComparison.OrdinalIgnoreCase);

                    if (!string.Equals(newUrl, urlString, StringComparison.OrdinalIgnoreCase))
                    {
                        Write(httpRes,
                            "<!doctype html><html><head><title>Emby</title></head><body>Please update your Emby bookmark to <a href=\"" +
                            newUrl + "\">" + newUrl + "</a></body></html>");
                        return;
                    }
                }

                if (localPath.IndexOf("dashboard/", StringComparison.OrdinalIgnoreCase) != -1 &&
                    localPath.IndexOf("web/dashboard", StringComparison.OrdinalIgnoreCase) == -1)
                {
                    httpRes.StatusCode = 200;
                    httpRes.ContentType = "text/html";
                    var newUrl = urlString.Replace("mediabrowser", "emby", StringComparison.OrdinalIgnoreCase)
                        .Replace("/dashboard/", "/web/", StringComparison.OrdinalIgnoreCase);

                    if (!string.Equals(newUrl, urlString, StringComparison.OrdinalIgnoreCase))
                    {
                        Write(httpRes,
                            "<!doctype html><html><head><title>Emby</title></head><body>Please update your Emby bookmark to <a href=\"" +
                            newUrl + "\">" + newUrl + "</a></body></html>");
                        return;
                    }
                }

                if (string.Equals(localPath, "/web", StringComparison.OrdinalIgnoreCase))
                {
                    RedirectToUrl(httpRes, DefaultRedirectPath);
                    return;
                }
                if (string.Equals(localPath, "/web/", StringComparison.OrdinalIgnoreCase))
                {
                    RedirectToUrl(httpRes, "../" + DefaultRedirectPath);
                    return;
                }
                if (string.Equals(localPath, "/", StringComparison.OrdinalIgnoreCase))
                {
                    RedirectToUrl(httpRes, DefaultRedirectPath);
                    return;
                }
                if (string.IsNullOrEmpty(localPath))
                {
                    RedirectToUrl(httpRes, "/" + DefaultRedirectPath);
                    return;
                }

                if (string.Equals(localPath, "/emby/pin", StringComparison.OrdinalIgnoreCase))
                {
                    RedirectToUrl(httpRes, "web/pin.html");
                    return;
                }

                if (!string.IsNullOrWhiteSpace(GlobalResponse))
                {
                    httpRes.StatusCode = 503;
                    httpRes.ContentType = "text/html";
                    Write(httpRes, GlobalResponse);
                    return;
                }

                var handler = GetServiceHandler(httpReq);

                if (handler != null)
                {
                    await handler.ProcessRequestAsync(this, httpReq, httpRes, Logger, operationName, cancellationToken).ConfigureAwait(false);
                }
                else
                {
                    ErrorHandler(new FileNotFoundException(), httpReq, false);
                }
            }
            catch (OperationCanceledException ex)
            {
                ErrorHandler(ex, httpReq, false);
            }

            catch (Exception ex)
            {
                var logException = !string.Equals(ex.GetType().Name, "SocketException", StringComparison.OrdinalIgnoreCase);

#if DEBUG
                logException = true;
#endif

                ErrorHandler(ex, httpReq, logException);
            }
            finally
            {
                httpRes.Close();

                if (enableLog)
                {
                    var statusCode = httpRes.StatusCode;

                    var duration = DateTime.Now - date;

                    LoggerUtils.LogResponse(_logger, statusCode, urlToLog, remoteIp, duration, logHeaders ? httpRes.Headers : null);
                }
            }
        }

        // Entry point for HttpListener
        public ServiceHandler GetServiceHandler(IHttpRequest httpReq)
        {
            var pathInfo = httpReq.PathInfo;

            var pathParts = pathInfo.TrimStart('/').Split('/');
            if (pathParts.Length == 0)
            {
                _logger.Error("Path parts empty for PathInfo: {0}, Url: {1}", pathInfo, httpReq.RawUrl);
                return null;
            }

            string contentType;
            var restPath = ServiceHandler.FindMatchingRestPath(httpReq.HttpMethod, pathInfo, _logger, out contentType);

            if (restPath != null)
            {
                return new ServiceHandler
                {
                    RestPath = restPath,
                    ResponseContentType = contentType
                };
            }

            _logger.Error("Could not find handler for {0}", pathInfo);
            return null;
        }

        private void Write(IResponse response, string text)
        {
            var bOutput = Encoding.UTF8.GetBytes(text);
            response.SetContentLength(bOutput.Length);

            var outputStream = response.OutputStream;
            outputStream.Write(bOutput, 0, bOutput.Length);
        }

        public static void RedirectToUrl(IResponse httpRes, string url)
        {
            httpRes.StatusCode = 302;
            httpRes.AddHeader("Location", url);
        }

        public ServiceController ServiceController { get; private set; }

        /// <summary>
        /// Adds the rest handlers.
        /// </summary>
        /// <param name="services">The services.</param>
        public void Init(IEnumerable<IService> services)
        {
            _restServices.AddRange(services);

            ServiceController = new ServiceController();

            _logger.Info("Calling ServiceStack AppHost.Init");

            var types = _restServices.Select(r => r.GetType()).ToArray();

            ServiceController.Init(this, types);

            var list = new List<Action<IRequest, IResponse, object>>();
            foreach (var filter in _appHost.GetExports<IRequestFilter>())
            {
                list.Add(filter.Filter);
            }

            RequestFilters = list.ToArray();

            ResponseFilters = new Action<IRequest, IResponse, object>[]
            {
                new ResponseFilter(_logger).FilterResponse
            };
        }

        public RouteAttribute[] GetRouteAttributes(Type requestType)
        {
            var routes = requestType.GetTypeInfo().GetCustomAttributes<RouteAttribute>(true).ToList();
            var clone = routes.ToList();

            foreach (var route in clone)
            {
                routes.Add(new RouteAttribute(NormalizeEmbyRoutePath(route.Path), route.Verbs)
                {
                    Notes = route.Notes,
                    Priority = route.Priority,
                    Summary = route.Summary
                });

                routes.Add(new RouteAttribute(NormalizeMediaBrowserRoutePath(route.Path), route.Verbs)
                {
                    Notes = route.Notes,
                    Priority = route.Priority,
                    Summary = route.Summary
                });

                // needed because apps add /emby, and some users also add /emby, thereby double prefixing
                routes.Add(new RouteAttribute(DoubleNormalizeEmbyRoutePath(route.Path), route.Verbs)
                {
                    Notes = route.Notes,
                    Priority = route.Priority,
                    Summary = route.Summary
                });
            }

            return routes.ToArray(routes.Count);
        }

        public Func<string, object> GetParseFn(Type propertyType)
        {
            return _funcParseFn(propertyType);
        }

        public void SerializeToJson(object o, Stream stream)
        {
            _jsonSerializer.SerializeToStream(o, stream);
        }

        public void SerializeToXml(object o, Stream stream)
        {
            _xmlSerializer.SerializeToStream(o, stream);
        }

        public object DeserializeXml(Type type, Stream stream)
        {
            return _xmlSerializer.DeserializeFromStream(type, stream);
        }

        public object DeserializeJson(Type type, Stream stream)
        {
            //using (var reader = new StreamReader(stream))
            //{
            //    var json = reader.ReadToEnd();
            //    Logger.Info(json);
            //    return _jsonSerializer.DeserializeFromString(json, type);
            //}
            return _jsonSerializer.DeserializeFromStream(stream, type);
        }

        private string NormalizeEmbyRoutePath(string path)
        {
            if (path.StartsWith("/", StringComparison.OrdinalIgnoreCase))
            {
                return "/emby" + path;
            }

            return "emby/" + path;
        }

        private string NormalizeMediaBrowserRoutePath(string path)
        {
            if (path.StartsWith("/", StringComparison.OrdinalIgnoreCase))
            {
                return "/mediabrowser" + path;
            }

            return "mediabrowser/" + path;
        }

        private string DoubleNormalizeEmbyRoutePath(string path)
        {
            if (path.StartsWith("/", StringComparison.OrdinalIgnoreCase))
            {
                return "/emby/emby" + path;
            }

            return "emby/emby/" + path;
        }

        private bool _disposed;
        private readonly object _disposeLock = new object();
        protected virtual void Dispose(bool disposing)
        {
            if (_disposed) return;

            lock (_disposeLock)
            {
                if (_disposed) return;

                _disposed = true;

                if (disposing)
                {
                    Stop();
                }
            }
        }

        public void Dispose()
        {
            Dispose(true);
            GC.SuppressFinalize(this);
        }

        public void StartServer(string[] urlPrefixes)
        {
            UrlPrefixes = urlPrefixes;

            _listener = GetListener();

            _listener.WebSocketConnected = OnWebSocketConnected;
            _listener.WebSocketConnecting = OnWebSocketConnecting;
            _listener.ErrorHandler = ErrorHandler;
            _listener.RequestHandler = RequestHandler;

            _listener.Start(UrlPrefixes);
        }
    }
}