public class PrintingService : IPrintingService, IDiscoveryHandler, IBluetoothDiscoverer, IDisposable
    {
        private static IConnection _connection;
        public IConnection GetConnection(me.ATDiscoveredPrinter atPrinter)
        {
            try
            {
                if (String.IsNullOrEmpty(atPrinter.Adress) || atPrinter.Adress == "BT:")
                    return null;
                if (_connection == null)
                    _connection = ConnectionBuilder.Current.Build(atPrinter.Adress);
                if (_connection.IsConnected)
                    return _connection;
                _connection.Open();
                return _connection;
            }
            catch (Exception ex)
            {
                PopupEvent.FireEvent(new EventArgs(),
                  new me.PopupEntity
                  {
                      ViewType = me.ViewType.Alert,
                      Status = me.PopupStatus.Failure,
                      Description = String.Format("Fehler. {0}", ex.Message)
                  });
                return null;
            }
        }
        //public void PrintTCP()
        //{
        //    IConnection connection = ConnectionBuilder.Current.Build("TCP:192.168.1.100:9100");
        //    Print(connection);
        //}
        //public void PrintBluetooth()
        //{
        //    IConnection connection = ConnectionBuilder.Current.Build("BT:00:22:33:44:55:66");
        //    Print(connection);
        //}
        public void PrintBarcode(me.Barcode barcode, me.ATDiscoveredPrinter atPrinter)
        {
            if (String.IsNullOrWhiteSpace(atPrinter.Adress)) return;
            string text = null;
            switch (barcode.ATBarcodeFormat)
            {
                case me.ATBarcodeFormat.CODE_128:
                    //resultPath = PrintingBarcodeHelper.ToImage(barcode.BarcodeNumber, barcode.Height);
                    //^XA
                    //^ FO100,100 ^ BY3
                    // ^ BCN,100,Y,N,N
                    //  ^ FD123456 ^ FS
                    //  ^ XZ
                    //^FO200,130
                    text = @"^XA
                            ^POI^PW1000^LL500                        
                            ^FO150,100                            
                            ^A0N,60,60
                            ^BCN,150,Y,N,A
                            ^FD"
                            + barcode.BarcodeNumber +
                            "^FS^XZ\r\n";
                    break;
                case me.ATBarcodeFormat.QR_CODE:
                    text = "^XA^FO100,100^BQN,2,10^FD" + barcode.BarcodeNumber + "^FS^XZ\r\n";
                    //resultPath = PrintingBarcodeHelper.ToImageQR(barcode.BarcodeNumber, barcode.Height);
                    break;
                case me.ATBarcodeFormat.AZTEC:
                case me.ATBarcodeFormat.CODABAR:
                case me.ATBarcodeFormat.CODE_39:
                case me.ATBarcodeFormat.CODE_93:
                case me.ATBarcodeFormat.DATA_MATRIX:
                case me.ATBarcodeFormat.EAN_8:
                case me.ATBarcodeFormat.EAN_13:
                case me.ATBarcodeFormat.ITF:
                case me.ATBarcodeFormat.MAXICODE:
                case me.ATBarcodeFormat.PDF_417:
                case me.ATBarcodeFormat.RSS_14:
                case me.ATBarcodeFormat.RSS_EXPANDED:
                case me.ATBarcodeFormat.UPC_A:
                case me.ATBarcodeFormat.UPC_E:
                case me.ATBarcodeFormat.All_1D:
                case me.ATBarcodeFormat.UPC_EAN_EXTENSION:
                case me.ATBarcodeFormat.MSI:
                case me.ATBarcodeFormat.PLESSEY:
                case me.ATBarcodeFormat.IMB:
                default:
                    PopupEvent.FireEvent(new EventArgs(),
                   new me.PopupEntity
                   {
                       ViewType = me.ViewType.Alert,
                       Status = me.PopupStatus.Failure,
                       Description = String.Format("Fehler. {0}", "Barcodetyp wird derzeit nicht unterstützt")
                   });
                    break;
            }
            Task.Factory.StartNew(() =>
            {
                try
                {
                    //IConnection _connection = ConnectionBuilder.Current.Build(atPrinter.Adress);
                    try
                    {
                        //_connection.Open();
                        IConnection _connection = GetConnection(atPrinter);
                        if (_connection == null)
                            return;
                        IZebraPrinter printer = ZebraPrinterFactory.Current.GetInstance(_connection);

                        if ((!CheckPrinterLanguage(_connection)) || (!PreCheckPrinterStatus(printer)))
                        {
                            return;
                        }

                        if (_connection.IsConnected)
                            _connection.Write(GetBytes(text));
                        PostPrintCheckStatus(printer);
                    }
                    catch (Exception e)
                    {
                        System.Diagnostics.Debug.WriteLine("Exception:" + e.Message);
                        PopupEvent.FireEvent(new EventArgs(),
                          new me.PopupEntity
                          {
                              ViewType = me.ViewType.Alert,
                              Status = me.PopupStatus.Failure,
                              Description = String.Format("Fehler. {0} ", e.Message)
                          });
                    }
                    finally
                    {
                        if (_connection?.IsConnected ?? false)
                            _connection?.Close();
                    }
                }
                catch (Exception ex)
                {
                    PopupEvent.FireEvent(new EventArgs(),
                   new me.PopupEntity
                   {
                       ViewType = me.ViewType.Alert,
                       Status = me.PopupStatus.Failure,
                       Description = String.Format("Fehler. {0}", ex.Message)
                   });
                }
            });
        }

        public void StartPrinterDiscovery()
        {
            try
            {
                IDiscoveryEventHandler handler = DiscoveryHandlerFactory.Current.GetInstance();
                handler.OnDiscoveryError += Handler_OnDiscoveryError;
                handler.OnDiscoveryFinished += Handler_OnDiscoveryFinished;
                handler.OnFoundPrinter += Handler_OnFoundPrinter;
                BluetoothDiscoverer.Current.FindPrinters(Android.App.Application.Context, handler);
            }
            catch { }
            //For Android 
            //BluetoothDiscoverer.Current.FindPrinters(MainActivity.Context, handler);
            //For iOS
            //BluetoothDiscoverer.Current.FindPrinters(null, handler);
            //new Task(new Action(() => {
            //    //NetworkDiscoverer.Current.FindPrinters(this);
            //    //NetworkDiscoverer.Current.LocalBroadcast(this);
            //    BluetoothDiscoverer.Current.FindPrinters(Android.App.Application.Context, handler);
            //})).Start();
        }

        private void Handler_OnFoundPrinter(IDiscoveryHandler handler, IDiscoveredPrinter discoveredPrinter)
        {
            System.Diagnostics.Debug.WriteLine($"Found printer: {discoveredPrinter.ToString()}");
            Device.BeginInvokeOnMainThread(() =>
            {
                PrinterFoundEvent.FireEvent(new EventArgs(), new me.ATDiscoveredPrinter { Adress = discoveredPrinter.Address, IsConnected = DiscoveredPrinter.Connection.IsConnected });
            });
        }

        private void Handler_OnDiscoveryFinished(IDiscoveryHandler handler)
        {
            Device.BeginInvokeOnMainThread(() =>
            {
                PrinterFoundEvent.FireEvent(new EventArgs(), new me.ATDiscoveredPrinter { Adress = "kein Drucker" });
            });
        }

        private void Handler_OnDiscoveryError(IDiscoveryHandler handler, string message)
        {
            Device.BeginInvokeOnMainThread(() =>
            {
                PrinterFoundEvent.FireEvent(new EventArgs(), new me.ATDiscoveredPrinter { Adress = "kein Drucker" });
                // System.Diagnostics.Debug.WriteLine($"Error discovering {Enum.GetName(typeof(ConnectionType), connectionType)} printers: {message}");
                PopupEvent.FireEvent(new EventArgs(),
                        new me.PopupEntity
                        {
                            ViewType = me.ViewType.Alert,
                            Status = me.PopupStatus.Failure,
                            Description = String.Format("Fehler. {0}", message)
                        });
            });
        }

        private void StartBluetoothDiscovery()
        {

            //IDiscoveryEventHandler bthandler = DiscoveryHandlerFactory.Current.GetInstance();
            //bthandler.OnDiscoveryError += DiscoveryHandler_OnDiscoveryError;
            //bthandler.OnDiscoveryFinished += DiscoveryHandler_OnDiscoveryFinished;
            //bthandler.OnFoundPrinter += DiscoveryHandler_OnFoundPrinter;
            //var connetionType = ConnectionType.BluetoothSsi;
            //System.Diagnostics.Debug.WriteLine("Starting Bluetooth Discovery");
            //DependencyService.Get<IPrinterDiscovery>().FindBluetoothPrinters(bthandler);
        }
        public void DiscoveryError(string message)
        {

            Device.BeginInvokeOnMainThread(() =>
            {
                PrinterFoundEvent.FireEvent(new EventArgs(), new me.ATDiscoveredPrinter { Adress = "kein Drucker" });
                // System.Diagnostics.Debug.WriteLine($"Error discovering {Enum.GetName(typeof(ConnectionType), connectionType)} printers: {message}");
                PopupEvent.FireEvent(new EventArgs(),
                        new me.PopupEntity
                        {
                            ViewType = me.ViewType.Alert,
                            Status = me.PopupStatus.Failure,
                            Description = String.Format("Fehler. {0}", message)
                        });
            });

        }

        public void DiscoveryFinished()
        {
            Device.BeginInvokeOnMainThread(() =>
            {
                PrinterFoundEvent.FireEvent(new EventArgs(), new me.ATDiscoveredPrinter { Adress = "kein Drucker" });
            });
        }

        public void FoundPrinter(IDiscoveredPrinter discoveredPrinter)
        {
            System.Diagnostics.Debug.WriteLine($"Found printer: {discoveredPrinter.ToString()}");
            Device.BeginInvokeOnMainThread(() =>
            {
                PrinterFoundEvent.FireEvent(new EventArgs(), new me.ATDiscoveredPrinter { Adress = discoveredPrinter.Address, IsConnected = DiscoveredPrinter.Connection.IsConnected });
            });
        }

        public void Print(me.CheckItem item)
        {

        }
        public IDiscoveredPrinter _discoveredPrinter;
        public IDiscoveredPrinter DiscoveredPrinter
        {
            get { return _discoveredPrinter; }
            set { _discoveredPrinter = value; }
        }

        public byte[] GetBytes(string str)
        {
            byte[] bytes = new byte[str.Length];
            bytes = Encoding.UTF8.GetBytes(str);
            return bytes;
        }
        public bool PostPrintCheckStatus(IZebraPrinter printer)
        {
            if (printer == null)
                return false;
            // Check the status again to verify print happened successfully
            IPrinterStatus status = printer.CurrentStatus;

            // Wait while the printer is printing
            while ((status.NumberOfFormatsInReceiveBuffer > 0) && (status.IsReadyToPrint))
            {
                status = printer.CurrentStatus;
            }

            // verify the print didn't have errors like running out of paper
            if (!status.IsReadyToPrint)
            {
                //ShowErrorAlert("Error durring print. Printer is " + status.Status);
                PopupEvent.FireEvent(new EventArgs(),
                new me.PopupEntity
                {
                    ViewType = me.ViewType.Alert,
                    Status = me.PopupStatus.Failure,
                    Description = String.Format("Fehler beim Drucken. Drucker ist {0}", status.Status)
                });
                return false;
            }
            return true;
        }

        public bool PreCheckPrinterStatus(IZebraPrinter printer)
        {
            if (printer == null)
                return false;
            // Check the printer status
            IPrinterStatus status = printer.CurrentStatus;
            if (!status.IsReadyToPrint)
            {
                //ShowErrorAlert("Unable to print. Printer is " + status.Status);
                PopupEvent.FireEvent(new EventArgs(),
                      new me.PopupEntity
                      {
                          ViewType = me.ViewType.Alert,
                          Status = me.PopupStatus.Failure,
                          Description = String.Format("Drucken nicht möglich. Drucker ist {0}", status.Status)
                      });
                return false;
            }
            return true;
        }
        public bool CheckPrinterLanguage(IConnection connection)
        {
            try
            {
                if (connection == null)
                    return false;
                if (!connection.IsConnected)
                    connection.Open();

                //  Check the current printer language
                byte[] response = connection.SendAndWaitForResponse(GetBytes("! U1 getvar \"device.languages\"\r\n"), 500, 100);
                string language = Encoding.UTF8.GetString(response, 0, response.Length);
                if (language.Contains("line_print"))
                {
                    //ShowAlert("Switching printer to ZPL Control Language.", "Notification");
                    PopupEvent.FireEvent(new EventArgs(),
                        new me.PopupEntity
                        {
                            ViewType = me.ViewType.Alert,
                            Status = me.PopupStatus.Failure,
                            Description = String.Format("Einstellung {0} ist aktiviert. Korrektur wird viorgenommen", "<line_print>")
                        });
                }
                // printer is already in zpl mode
                else if (language.Contains("zpl"))
                {
                    return true;
                }

                //  Set the printer command languege
                connection.Write(GetBytes("! U1 setvar \"device.languages\" \"zpl\"\r\n"));
                response = connection.SendAndWaitForResponse(GetBytes("! U1 getvar \"device.languages\"\r\n"), 500, 100);
                language = Encoding.UTF8.GetString(response, 0, response.Length);
                if (!language.Contains("zpl"))
                {
                    // ShowErrorAlert("Printer language not set. Not a ZPL printer.");
                    PopupEvent.FireEvent(new EventArgs(),
                     new me.PopupEntity
                     {
                         ViewType = me.ViewType.Alert,
                         Status = me.PopupStatus.Failure,
                         Description = String.Format("Fehler. {0} ist nicht gesetzt. Kein ZPL Drucker.", "<ZPL>")
                     });
                    return false;
                }
                return true;
            }
            catch { return false; }
        }

        public void FindPrinters(object androidContext, IDiscoveryHandler handler)
        {

        }

        public void Dispose()
        {
            try
            {
                if (_connection != null && _connection.IsConnected)
                    _connection.Close();
            }
            catch { }
        }
    }