//                           UNCLASSIFIED
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using System;
using System.IO.Ports;
using System.Text;
using System.Threading;
using NLog;
using Raytheon.Common;

namespace Raytheon.Instruments
{
   /// <summary>
   /// A class the provides an interface for read/write to registers on an FPGA that implement a custom ascii serial interface
   /// </summary>
   public class CommFpgaCustomAsciiSerial : IFpgaComm, IDisposable
   {
      #region PrivateClassMembers
      private SerialPort _serialPort;
      private byte[] _readBuf;
      private static object _syncObj = new Object();
      private uint _delayBeforeReadMs;
      private string _readFormat;
      private string _writeFormat;
      private SelfTestResult _selfTestResult;
      private State _state;
      private string _name;

      private readonly ILogger _logger;

      private readonly IConfigurationManager _configurationManager;
      private readonly IConfiguration _configuration;

      #endregion

      #region PrivateFuctions

      /// <summary>
      /// The Finalizer
      /// </summary>
      ~CommFpgaCustomAsciiSerial()
      {
         Dispose(false);
      }


      /// <summary>
      /// Reads the serial port until it is empty
      /// </summary>
      private void ClearBuffer()
      {
         lock (_syncObj)
         {
            bool isClearComplete = false;

            while (isClearComplete == false)
            {
               try
               {
                  int numBytesRead = _serialPort.Read(_readBuf, 0, _readBuf.Length);

                  if (numBytesRead < _readBuf.Length)
                  {
                     isClearComplete = true;
                  }
               }
               catch (Exception)
               {
                  //expected if buffer is already cleared
                  isClearComplete = true;
               }
            }
         }
      }


      /// <summary>
      /// Dispose of this object
      /// </summary>
      /// <param name="disposing"></param>
      protected virtual void Dispose(bool disposing)
      {
         if (disposing)
         {
            if (_state == State.Ready)
            {
               _serialPort.Dispose();
               _state = State.Uninitialized;
            }
         }
      }

      #endregion

      #region PublicFuctions

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

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

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

         const int READ_BUF_SIZE = 1024;

         try
         {
            _selfTestResult = SelfTestResult.Unknown;

            _state = State.Uninitialized;

            string comPortName = _configuration.GetConfigurationValue("CommFpgaCustomAsciiSerial", "ComPortName", "COM1");
            int baudRate = _configuration.GetConfigurationValue("CommFpgaCustomAsciiSerial", "BaudRate", 9600);
            Parity parity = _configuration.GetConfigurationValue("CommFpgaCustomAsciiSerial", "Parity", Parity.None);
            int dataBits = _configuration.GetConfigurationValue("CommFpgaCustomAsciiSerial", "DataBits", 8);
            StopBits stopBits = _configuration.GetConfigurationValue("CommFpgaCustomAsciiSerial", "StopBits", StopBits.None);

            _serialPort = new SerialPort(comPortName, baudRate, parity, dataBits, stopBits);
            _readFormat = _configuration.GetConfigurationValue("CommFpgaCustomAsciiSerial", "ReadFormat", "");
            _writeFormat = _configuration.GetConfigurationValue("CommFpgaCustomAsciiSerial", "WriteFormat", "");
            _serialPort.ReadTimeout = _configuration.GetConfigurationValue("CommFpgaCustomAsciiSerial", "ReadTimeout", 100);
            _delayBeforeReadMs = _configuration.GetConfigurationValue<uint>("CommFpgaCustomAsciiSerial", "DelayBeforeReadMs", 0);

            _readBuf = new byte[READ_BUF_SIZE];

            //check format of readFormat and writeFormat
            if (!_readFormat.Contains("<ADDRESS>"))
            {
               throw new Exception("the read format input for card " + _name + " does not contain the <ADDRESS> tag");
            }

            if (!_writeFormat.Contains("<ADDRESS>"))
            {
               throw new Exception("the write format input for card " + _name + "  does not contain the <ADDRESS> tag");
            }

            if (!_writeFormat.Contains("<DATA>"))
            {
               throw new Exception("the write format input for card " + _name + "  does not contain the <DATA> tag");
            }
         }
         catch (Exception ex)
         {
            _logger.Error(ex);

            if (_serialPort.IsOpen == true)
            {
               _serialPort.Close();
            }

            throw;
         }
      }

      /// <summary>
      /// The constructor which opens up a serial port
      /// </summary>
      /// <param name="comPortName">The port name. "Com1' for example</param>
      /// <param name="delayBeforeReadMs">The num of ms to wait before a read</param>
      /// <param name="baudRate">The baud rate</param>
      /// <param name="parity">The parity</param>
      /// <param name="dataBits">Number of data bits</param>
      /// <param name="stopBits">Number of Stop Bits</param>
      public CommFpgaCustomAsciiSerial(string deviceName, string comPortName, uint delayBeforeReadMs, string readFormat, string writeFormat, int baudRate = 115200, Parity parity = Parity.None, int dataBits = 8, StopBits stopBits = StopBits.One)
      {
         const int READ_BUF_SIZE = 1024;

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

         try
         {
            _name = deviceName;

            _selfTestResult = SelfTestResult.Unknown;

            _state = State.Uninitialized;

            _serialPort = new SerialPort(comPortName, baudRate, parity, dataBits, stopBits);

            _readFormat = readFormat;

            _writeFormat = writeFormat;

            _serialPort.ReadTimeout = 100;

            _delayBeforeReadMs = delayBeforeReadMs;

            _readBuf = new byte[READ_BUF_SIZE];

            Array.Clear(_readBuf, 0, _readBuf.Length);

            //check format of readFormat and writeFormat
            if (readFormat.Contains("<ADDRESS>") == false)
            {
               throw new Exception("the read format input for card " + _name + " does not contain the <ADDRESS> tag");
            }

            if (writeFormat.Contains("<ADDRESS>") == false)
            {
               throw new Exception("the write format input for card " + _name + "  does not contain the <ADDRESS> tag");
            }

            if (writeFormat.Contains("<DATA>") == false)
            {
               throw new Exception("the write format input for card " + _name + "  does not contain the <DATA> tag");
            }
         }
         catch (Exception ex)
         {
            _logger.Error(ex);

            if (_serialPort.IsOpen == true)
            {
               _serialPort.Close();
            }

            throw;
         }
      }

      /// <summary>
      /// 
      /// </summary>
      /// <returns></returns>
      public bool ClearErrors()
      {
         return false;
      }

      /// <summary>
      /// 
      /// </summary>
      public string DetailedStatus
      {
         get
         {
            return "This is a FPGA Custom Ascii called " + _name;
         }
      }

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

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

         GC.SuppressFinalize(this);
      }

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

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

      /// <summary>
      /// 
      /// </summary>
      public void Initialize()
      {
         Initialize(string.Empty);
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="fpga"></param>
      public void Initialize(string fpga)
      {
         lock (_syncObj)
         {
            if (_state == State.Uninitialized)
            {
               if (_serialPort.IsOpen == false)
               {
                  _serialPort.Open();
               }

               //ClearBuffer();

               _state = State.Ready;
            }
            else
            {
               throw new Exception("expected the state to be Uninitialized, state was: " + _state.ToString() + " on card " + _name);
            }
         }
      }

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

      /// <summary>
      /// 
      /// </summary>
      /// <returns></returns>
      public SelfTestResult PerformSelfTest()
      {
         _selfTestResult = SelfTestResult.Unknown;
         return _selfTestResult;
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="fpga"></param>
      /// <param name="address"></param>
      /// <returns></returns>
      public uint Read(string fpga, uint address)
      {
         // lock up the FPGA resource
         lock (_syncObj)
         {

            string hexAddress = "0x" + address.ToString("X8");

            string commandToSend = _readFormat.Replace("<ADDRESS>", hexAddress);

            commandToSend = commandToSend.Trim();

            _serialPort.Write(commandToSend);

            Thread.Sleep((int)_delayBeforeReadMs);

            int numBytesRead = _serialPort.Read(_readBuf, 0, _readBuf.Length);

            string data = Encoding.UTF8.GetString(_readBuf, 0, _readBuf.Length);

            // get rid of new lines
            data = data.Replace("\r", " ");
            data = data.Replace("\n", " ");
            data = data.Trim();

            uint dataToReturn = Convert.ToUInt32(data, 16);

            return dataToReturn;
         }
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="fpgaName"></param>
      /// <param name="address"></param>
      /// <param name="numberOfWordsToRead"></param>
      /// <param name="shallWeIncrementAddress"></param>
      /// <param name="dataRead"></param>
      public void ReadBlock(string fpgaName, uint address, uint numberOfWordsToRead, bool shallWeIncrementAddress, ref uint[] dataRead)
      {
         // lock up the FPGA resource
         lock (_syncObj)
         {
            Thread.Sleep((int)_delayBeforeReadMs);

            int bytesRead = _serialPort.Read(_readBuf, 0, _readBuf.Length);

            int bytesToCopy = Math.Min(bytesRead, dataRead.Length);

            Array.Copy(_readBuf, dataRead, bytesToCopy);

            Array.Clear(_readBuf, 0, _readBuf.Length);
         }
      }

      /// <summary>
      /// 
      /// </summary>
      public void Reset()
      {
         Shutdown();

         Initialize();
      }

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

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

      /// <summary>
      /// 
      /// </summary>
      public void Shutdown()
      {
         // lock up the FPGA resource
         lock (_syncObj)
         {
            if (_state == State.Ready)
            {
               _serialPort.Dispose();
               _state = State.Uninitialized;
            }
         }
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="fpga"></param>
      /// <param name="address"></param>
      /// <param name="data"></param>
      public void Write(string fpga, uint address, uint data)
      {
         // lock up the FPGA resource
         lock (_syncObj)
         {
            string hexAddress = "0x" + address.ToString("X8");

            string hexData = "0x" + data.ToString("X8");

            string commandToSend = _writeFormat.Replace("<ADDRESS>", hexAddress);

            commandToSend = commandToSend.Replace("<DATA>", hexData);

            commandToSend = commandToSend.Trim();

            _serialPort.Write(commandToSend);
         }
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="fpgaName"></param>
      /// <param name="address"></param>
      /// <param name="numberOfWordsToWrite"></param>
      /// <param name="data"></param>
      /// <param name="shallWeIncrementAddress"></param>
      public void WriteBlock(string fpgaName, uint address, uint numberOfWordsToWrite, uint[] data, bool shallWeIncrementAddress)
      {
         // lock up the FPGA resource
         lock (_syncObj)
         {
            throw new Exception("Not Implemented");
         }
      }

      /// <summary>
      /// Loads firmware
      /// </summary>
      /// <param name="fpgaName"></param>
      public void LoadFirmware(string fpgaName)
      {
         Initialize(fpgaName);
      }

      #endregion
   }
}