//                           UNCLASSIFIED
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  PROPRIETARY TO RAYTHEON COMPANY AND IS RESTRICTED TO USE ONLY BY PERSONS
  AUTHORIZED BY RAYTHEON COMPANY IN WRITING TO USE IT. DISCLOSURE TO
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  OUTSIDE RAYTHEON COMPANY WITHOUT THE EXPRESS WRITTEN APPROVAL OF RAYTHEON
  COMPANY.

  THIS PROPRIETARY NOTICE IS NOT APPLICABLE IF DELIVERED TO THE U.S.
  GOVERNMENT.

  UNPUBLISHED WORK - COPYRIGHT RAYTHEON COMPANY.
  -------------------------------------------------------------------------*/

using System;
using System.Net.Sockets;
using System.Text;
using NLog;
using Raytheon.Common;
using Raytheon.Instruments.Dmm;
using Raytheon.Units;

namespace Raytheon.Instruments
{
   /// <summary>
   /// A keysight implementation of the DMM interface
   /// </summary>
   public class DMMKeysightScpi : IDmm
   {
      #region PrivateMemberVariables

      private const string READ_ERROR_STATUS_CMD = "SYST:ERR?";
      private const string _SELFTESTCMD = "*TST?";
      private const string _RESETCMD = "*RST";
      private const string _MEASUREFRES = "MEAS:FRES? "; //Resistance 4-wire
      private const string _MEASURERES = "MEAS:RES? "; //Resistance 2-wire
      private const string _MEASUREDCVOLT = "MEAS:VOLT:DC? ";
      private const string _MEASUREACVOLT = "MEAS:VOLT:AC? ";

      //Frequency
      private const string _FREQ_SETUP1 = "CONF:FREQ ";
      private const string _FREQ_SETUP2 = "SENS:FREQ:VOLT:RANGE:AUTO OFF";
      private const string _FREQ_SETUP3 = "FREQ:VOLT:RANG ";
      private const string _FREQ_SETUP4 = "SAMPLE:COUNT ";
      private const string _MEASUREFREQ = "READ? ";

      private const string _AUTO = "AUTO";
      private const string _DEFAULT = "DEF";

      private const int _PORT = 5025;
      private const int _READ_TIMEOUT = 5000;
      private byte[] _readBuffer;
      private NetworkStream _tcpStream;
      private string _name;
      private readonly string _address;
      private MeasurementFunction _lastType;
      private double _lastRange;
      private double _lastResolution;
      private State _state;
      private SelfTestResult _selfTestResult;

      private readonly ILogger _logger;

      private readonly IConfigurationManager _configurationManager;
      private readonly IConfiguration _configuration;

      #endregion

      #region PrivateFunctions

      /// <summary>
      /// Dispose of this objects resources
      /// </summary>
      /// <param name="disposing"></param>
      [System.Diagnostics.CodeAnalysis.SuppressMessage("Microsoft.Usage", "CA2213:DisposableFieldsShouldBeDisposed", MessageId = "_34461A")]
      protected virtual void Dispose(bool disposing)
      {
         if (disposing)
         {
            if (_state == State.Ready)
            {
               Reset();

               _tcpStream.Dispose();

               _state = State.Uninitialized;
            }
         }
      }

      /// <summary>
      /// Reads frequency from the dmm
      /// </summary>
      /// <param name="range">The range to use on the DMM</param>
      /// <param name="resolution">The resolution to use on the DMM</param>
      /// <param name="voltRange">The voltage range for the measurement</param>
      /// <param name="numReads">The number of reads to make</param>
      /// <returns>The frequency or average of frequencies read</returns>
      private double ReadFrequency(double range, double resolution, double voltRange, double numReads)
      {
         //Setup the frequency measurement
         string command = _FREQ_SETUP1;

         if (range == -1)
         {
            command += _DEFAULT + ", " + _DEFAULT;
         }
         else
         {
            command += range + ", " + resolution;
         }

         command += ";:" + _FREQ_SETUP2 + ";:" + _FREQ_SETUP3 + voltRange;

         //want to read frequency more than once
         if (numReads > 1)
         {
            command += ";:" + _FREQ_SETUP4 + "\n";
         }
         else
         {
            command += "\n";
         }

         // send the command
         IOWrite(command);

         //read the frequency
         command = _MEASUREFREQ + "\n";
         string rspStr = IOQuery(command);

         double frequency = 0.0;

         if (rspStr.IndexOf(',') > -1)
         {
            frequency = GetFrequencyAvg(rspStr);
         }
         else
         {
            frequency = Util.ConvertStringToDouble(rspStr);
         }

         return frequency;
      }

      /// <summary>
      /// Reads resistance
      /// </summary>
      /// <param name="range">The range to use on the DMM</param>
      /// <param name="resolution">The resolution to use on the DMM</param>\
      /// <param name="dmmResistanceType"></param>
      /// <returns>The resistance</returns>
      private double ReadResistance(double range, double resolution, MeasurementFunction resistanceType)
      {
         string command = "";

         if (resistanceType == MeasurementFunction.FourWireResistance)
         {
            command = _MEASUREFRES;
         }
         else if (resistanceType == MeasurementFunction.TwoWireResistance)
         {
            command = _MEASURERES;
         }
         else
         {
            throw new Exception("only 4 or 2 write resistance is acceptable for param type: " + resistanceType.ToString());
         }

         if (range == -1)
         {
            command += _AUTO + ", " + _DEFAULT;
         }
         else
         {
            command += range + ", " + resolution;
         }

         command += "\n";

         string rspStr = IOQuery(command);

         double resistance = Util.ConvertStringToDouble(rspStr);

         return resistance;
      }

      /// <summary>
      /// Reads voltage
      /// </summary>
      /// <param name="range">The range to use on the DMM</param>
      /// <param name="resolution">The resolution to use on the DMM</param>
      /// <returns></returns>
      private double ReadVoltage(double range, double resolution, MeasurementFunction voltageType)
      {
         string command = "";

         if (voltageType == MeasurementFunction.ACVolts)
         {
            command = _MEASUREACVOLT;
         }
         else if (voltageType == MeasurementFunction.DCVolts)
         {
            command = _MEASUREDCVOLT;
         }
         else
         {
            throw new Exception("only ac or dc volt is acceptable for param type: " + voltageType.ToString());
         }

         if (range == -1)
         {
            command += _AUTO + ", " + _DEFAULT;
         }
         else
         {
            command += range + ", " + resolution;
         }

         command += "\n";
         string rspStr = IOQuery(command);

         double dcVoltage = Util.ConvertStringToDouble(rspStr);
         return dcVoltage;
      }

      /// <summary>
      /// Convert scpi data to string
      /// </summary>
      /// <param name="data"></param>
      /// <returns></returns>
      private string ConvertToString(ref byte[] data)
      {
         string rsp = System.Text.Encoding.ASCII.GetString(data);
         return rsp;
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="numbers"></param>
      /// <returns></returns>
      private double GetFrequencyAvg(string numbers)
      {
         string[] numArr = numbers.Split(',');
         double retVal = 0;

         foreach (string val in numArr)
         {
            retVal += Util.ConvertStringToDouble(val);
         }

         retVal = retVal / numArr.Length;

         return retVal;
      }


      /// <summary>
      /// Get the error code.
      /// </summary>
      /// <returns>The error code (number).</returns>
      private int GetErrorCode()
      {
         // not calling IOQuery() here so IOQuery() can call GetErrorCode() after each query

         string command = READ_ERROR_STATUS_CMD + "\n";

         // convert to a byte array
         byte[] commandBuffer = Encoding.ASCII.GetBytes(command);

         // send the data out
         _tcpStream.Write(commandBuffer, 0, commandBuffer.Length);

         // clear our buffer
         Array.Clear(_readBuffer, 0, _readBuffer.Length);

         // read the response
         int numBytesRead = _tcpStream.Read(_readBuffer, 0, _readBuffer.Length);

         // convert to a string
         string rspStr = ConvertToString(ref _readBuffer);

         // parse the response
         string[] tokens = rspStr.Split(',');

         int ret = Util.ConvertStringToInt32(tokens[0]);

         return ret;
      }

      /// <summary>
      /// Send a command to the DMM and get the response
      /// </summary>
      /// <param name="commandString">The command to send</param>
      /// <returns>The DMM response</returns>
      private string IOQuery(string commandString)
      {
         // send the command
         IOWrite(commandString, false);

         // clear our buffer
         Array.Clear(_readBuffer, 0, _readBuffer.Length);

         // read from the response
         int numBytesRead = _tcpStream.Read(_readBuffer, 0, _readBuffer.Length);

         if (numBytesRead == 0)
         {
            throw new Exception($"DMMKeysightScpi:IOQuery() - Number of bytes read from stream was {numBytesRead}");
         }

         // convert response to a string
         string rspStr = ConvertToString(ref _readBuffer);

         // check for errors
         int err = GetErrorCode();
         if (err != 0)
         {
            throw new Exception("DMMKeysightScpi:IOQuery() - returned error code: " + err.ToString());
         }

         return rspStr;
      }

      /// <summary>
      /// Sends a SCPI Command to the instrument.
      /// </summary>
      /// <param name="commandString">The SCPI Command to be sent to the instrument.</param>
      private void IOWrite(string commandString, bool checkForError = true)
      {
         // convert to a byte array
         byte[] commandBuffer = Encoding.ASCII.GetBytes(commandString);

         // send the data out
         _tcpStream.Write(commandBuffer, 0, commandBuffer.Length);

         if (checkForError)
         {
            // check for errors
            int err = GetErrorCode();
            if (err != 0)
            {
               throw new Exception("DMMKeysightScpi:IOWrite() - returned error code: " + err.ToString());
            }
         }
      }

      #endregion

      #region PublicFunctions

      /// <summary>
      /// DMMKeysightScpi factory constructor
      /// </summary>
      /// <param name="deviceName"></param>
      /// <param name="configurationManager"></param>
      public DMMKeysightScpi(string deviceName, IConfigurationManager configurationManager)
      {
         Name = deviceName;

         _logger = LogManager.GetLogger($"{this.GetType().Name} - {deviceName}");

         _configurationManager = configurationManager;
         _configuration = _configurationManager.GetConfiguration(Name);

         _address = _configuration.GetConfigurationValue(Name, Dmm.ConfigXml.IP_ADDRESS.ToString());

         _lastType = 0;
         _lastRange = 0;
         _lastResolution = 0;

         const int READ_BUFFER_SIZE = 512;
         _readBuffer = new byte[READ_BUFFER_SIZE];

         // created in initialize
         _tcpStream = null;
         _state = State.Uninitialized;
         _selfTestResult = SelfTestResult.Unknown;
      }

      /// <summary>
      /// The constructor which opens the handle to the DMM and performs a self test on the instrument
      /// </summary>
      /// <param name="deviceName">The name of this dmm</param>
      /// <param name="address">The address of the DMM</param>
      public DMMKeysightScpi(string deviceName, string address)
      {
         const int READ_BUFFER_SIZE = 512;

         _name = deviceName;
         _address = address;
         _lastType = 0;
         _lastRange = 0;
         _lastResolution = 0;

         _readBuffer = new byte[READ_BUFFER_SIZE];

         _logger = LogManager.GetLogger($"{this.GetType().Name} - {deviceName}");

         // created in initialize
         _tcpStream = null;
         _state = State.Uninitialized;
         _selfTestResult = SelfTestResult.Unknown;
      }

      /// <summary>
      /// The Finalizer which will release resources if required
      /// </summary>
      ~DMMKeysightScpi()
      {
         Dispose(false);
      }

      /// <summary>
      /// 
      /// </summary>
      /// <returns></returns>
      public bool ClearErrors()
      {
         throw new NotImplementedException();
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="type"></param>
      /// <param name="range"></param>
      /// <param name="resolution"></param>
      public void ConfigureCurrentMeasurement(MeasurementFunction type, Current range, Current resolution)
      {
         throw new NotImplementedException();
         /*_lastType = type;
			  _lastRange = range.Amps;
			  _lastResolution = resolution.Amps;*/
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="type"></param>
      /// <param name="range"></param>
      /// <param name="resolution"></param>
      public void ConfigureVoltageMeasurement(MeasurementFunction type, Voltage range, Voltage resolution)
      {
         if (type != MeasurementFunction.DCVolts && type != MeasurementFunction.ACVolts)
         {
            throw new Exception("only ac or dc volt is acceptable for param type: " + type.ToString());
         }

         _lastType = type;
         _lastRange = range.Volts;
         _lastResolution = resolution.Volts;
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="type"></param>
      /// <param name="range"></param>
      /// <param name="resolution"></param>
      public void ConfigureResistanceMeasurement(MeasurementFunction type, Resistance range, Resistance resolution)
      {
         if (type != MeasurementFunction.FourWireResistance && type != MeasurementFunction.TwoWireResistance)
         {
            throw new Exception("only FourWireResistance or TwoWireResistance is acceptable for param type: " + _lastType.ToString());
         }

         _lastType = type;
         _lastRange = range.Ohms;
         _lastResolution = resolution.Ohms;
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="type"></param>
      /// <param name="range"></param>
      /// <param name="resolution"></param>
      public void ConfigureFrequencyMeasurement(MeasurementFunction type, Frequency range, Frequency resolution)
      {
         if (type != MeasurementFunction.Frequency)
         {
            throw new Exception("only frequency is acceptable for param type: " + _lastType.ToString());
         }

         _lastType = type;
         _lastRange = range.Hertz;
         _lastResolution = resolution.Hertz;
      }

      /// <summary>
      /// Dispose of this objects resources
      /// </summary>
      public void Dispose()
      {
         Dispose(true);

         GC.SuppressFinalize(this);
      }

      /// <summary>
      /// 
      /// </summary>
      public string DetailedStatus
      {
         get
         {
            return "This is a Keysight Dmm";
         }
      }

      /// <summary>
      /// 
      /// </summary>
      public bool DisplayEnabled
      {
         get
         {
            throw new NotImplementedException();
         }

         set
         {
            throw new NotImplementedException();
         }
      }

      /// <summary>
      /// 
      /// </summary>
      public bool FrontPanelEnabled
      {
         get
         {
            throw new NotImplementedException();
         }

         set
         {
            throw new NotImplementedException();
         }
      }

      /// <summary>
      /// 
      /// </summary>
      public InstrumentMetadata Info
      {
         get
         {
            throw new NotImplementedException();
         }
      }

      /// <summary>
      /// 
      /// </summary>
      public void Initialize()
      {
         if (_state == State.Uninitialized)
         {
            TcpClient dmmSocketConn = new TcpClient(_address, _PORT);
            _tcpStream = dmmSocketConn.GetStream();
            _tcpStream.ReadTimeout = _READ_TIMEOUT;
            _selfTestResult = PerformSelfTest();
            _state = State.Ready;
         }
         else
         {
            throw new Exception("expected the state to be Uninitialized, state was: " + _state.ToString());
         }
      }

      /// <summary>
      /// 
      /// </summary>
      public MeasurementFunction MeasurementType
      {
         get
         {
            throw new NotImplementedException();
         }
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="timeout"></param>
      /// <returns></returns>
      public Current MeasureCurrent(int timeout)
      {
         throw new NotImplementedException();

         /*
			   if (_lastType != MeasurementFunction.DCVolts && _lastType != MeasurementFunction.ACVolts)
			   {
			   throw new Exception("only ac or dc volt is acceptable for param type: " + type.ToString());
			   }

			   return Current.FromAmps(ReadCurrent();*/
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="timeout"></param>
      /// <returns></returns>
      public Frequency MeasureFrequency(int timeout)
      {
         if (_lastType != MeasurementFunction.Frequency)
         {
            throw new Exception("only frequency is acceptable for param type: " + _lastType.ToString());
         }

         return Frequency.FromHertz(ReadFrequency(_lastRange, _lastResolution, _lastRange, 1));
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="timeout"></param>
      /// <returns></returns>
      public Resistance MeasureResistance(int timeout)
      {
         if (_lastType != MeasurementFunction.FourWireResistance && _lastType != MeasurementFunction.TwoWireResistance)
         {
            throw new Exception("only FourWireResistance or TwoWireResistance is acceptable for param type: " + _lastType.ToString());
         }

         return Resistance.FromOhms(ReadResistance(_lastRange, _lastResolution, _lastType));
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="timeout"></param>
      /// <returns></returns>
      public Voltage MeasureVoltage(int timeout)
      {
         if (_lastType != MeasurementFunction.DCVolts && _lastType != MeasurementFunction.ACVolts)
         {
            throw new Exception("only ac or dc volt is acceptable for param type: " + _lastType.ToString());
         }

         return Voltage.FromVolts(ReadVoltage(_lastRange, _lastResolution, _lastType));
      }

      /// <summary>
      /// 
      /// </summary>
      public string Name
      {
         get { return _name; }
         set { _name = value; }
      }

      /// <summary>
      /// 
      /// </summary>
      /// <returns></returns>
      public SelfTestResult PerformSelfTest()
      {
         try
         {
            // change the timeout to account for the long self test
            _tcpStream.ReadTimeout = 30000;

            // send the command and get the response
            string command = _SELFTESTCMD + "\n";
            string rspStr = IOQuery(command);

            // parse the response
            string[] tokens = rspStr.Split('\n');

            int rsp = Util.ConvertStringToInt32(tokens[0].Replace("+", "").Split(',')[0]);


            if (rsp != 0)
            {
               string errorMsg = "returned an error: " + rspStr;
               _selfTestResult = SelfTestResult.Fail;
               throw new Exception(errorMsg);
            }
            _selfTestResult = SelfTestResult.Pass;
         }
         catch (Exception)
         {
            throw;
         }
         finally
         {
            // restore the timeout
            _tcpStream.ReadTimeout = _READ_TIMEOUT;
         }

         return SelfTestResult;
      }

      /// <summary>
      /// 
      /// </summary>
      public void Reset()
      {
         IOWrite(_RESETCMD + "\n");
      }

      /// <summary>
      /// 
      /// </summary>
      public SelfTestResult SelfTestResult
      {
         get
         {
            return _selfTestResult;
         }
      }

      /// <summary>
      /// 
      /// </summary>
      public State Status
      {
         get
         {
            return _state;
         }
      }

      /// <summary>
      /// 
      /// </summary>
      public void Shutdown()
      {
         if (_state == State.Ready)
         {
            Reset();

            _tcpStream.Dispose();

            _state = State.Uninitialized;
         }
      }

      #endregion
   }
}