//                           UNCLASSIFIED
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using System;
using System.Net;
using System.Net.Sockets;
using System.Runtime.InteropServices;
using FpgaMeasurementInstrumentsLib;
using NLog;
using Raytheon.Common;

namespace Raytheon.Instruments
{
   /// <summary>
   /// This class serves as an interface to FPGAs that implement a UDP interface.
   /// It allows for the ability to read and write to registers.
   /// </summary>
   public class CommFpgaEthernet : IFpgaComm, IDisposable
   {
      #region PrivateClassMembers
      private UdpClient _udpClient;
      private readonly int _localPort;
      private readonly int _remotePort;
      private readonly string _remoteAddress;
      private static object _syncObj = new Object();
      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>
      ~CommFpgaEthernet()
      {
         Dispose(false);
      }

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

               _state = State.Uninitialized;
            }
         }
      }

      /// <summary>
      /// Read data off of the socket
      /// </summary>
      /// <param name="dataRead">The data that was read</param>
      /// <returns>The number of bytes read</returns>
      private int ReadData(ref byte[] dataRead)
      {
         IPEndPoint remoteIPEndPoint = new IPEndPoint(IPAddress.Any, _localPort);

         dataRead = _udpClient.Receive(ref remoteIPEndPoint);

         int numBytesRead = dataRead.Length;

         return numBytesRead;
      }

      /// <summary>
      /// Send a command message and get a response message
      /// </summary>
      /// <param name="commandMsg">The message to send</param>
      /// <param name="rspMsg">The response</param>
      private void SendCommandGetResponse(FPGACmdMessage commandMsg, ref FPGARspMessage rspMsg)
      {
         uint rxBufferSize = rspMsg.GetEntireMsgLength();
         uint rxNumBytesExpected = rxBufferSize;

         uint dataToSendNumBytes = commandMsg.GetEntireMsgLength();

         // send the command
         byte[] dataToSend = new byte[dataToSendNumBytes];

         // get a pointer to the data
         GCHandle sendPinnedArray = GCHandle.Alloc(dataToSend, GCHandleType.Pinned);
         IntPtr pByte = sendPinnedArray.AddrOfPinnedObject();
         commandMsg.Format(pByte);
         sendPinnedArray.Free();

         // send the data
         int numBytesSent = SendData(dataToSend);

         if (dataToSendNumBytes != numBytesSent)
         {
            throw new Exception("wanted to send: " + dataToSendNumBytes.ToString() + " bytes,  SendData() reported that it sent: " + numBytesSent.ToString());
         }

         // read the response
         byte[] rspBuffer = new byte[rxBufferSize];
         int numBytesRead = ReadData(ref rspBuffer);

         if (numBytesRead != rxNumBytesExpected)
         {
            throw new Exception("received " + numBytesRead.ToString() + " bytes, expected " + rxNumBytesExpected.ToString());
         }

         // populate the rspMsg object
         GCHandle rxPinnedArray = GCHandle.Alloc(rspBuffer, GCHandleType.Pinned);
         IntPtr pBytePtr = rxPinnedArray.AddrOfPinnedObject();
         rspMsg.Parse(pBytePtr);
         rxPinnedArray.Free();
      }

      /// <summary>
      /// Send data out of the socket
      /// </summary>
      /// <param name="dataToSend">The data to send</param>
      /// <returns>The number of bytes sent</returns>
      private int SendData(byte[] dataToSend)
      {
         IPAddress addy = IPAddress.Parse(_remoteAddress);

         IPEndPoint ipEndPoint = new IPEndPoint(addy, _remotePort);

         int numBytesSent = _udpClient.Send(dataToSend, dataToSend.Length, ipEndPoint);

         return numBytesSent;
      }
      #endregion

      #region PublicFuctions

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

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

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

         _selfTestResult = SelfTestResult.Unknown;
         _state = State.Uninitialized;

         _localPort = _configuration.GetConfigurationValue("CommFpgaEthernet", "LocalPort", 0);
         _remotePort = _configuration.GetConfigurationValue("CommFpgaEthernet", "RemotePort", 0);
         _remoteAddress = _configuration.GetConfigurationValue("CommFpgaEthernet", "RemoteAddress", "127.0.0.1");
      }


      /// <summary>
      /// 
      /// </summary>
      /// <param name="fpgaName"></param>
      /// <param name="localPort">The port on the local computer</param>
      /// <param name="remotePort">The port that the FPGA is using</param>
      /// <param name="remoteAddress">The address that the FPGA is using</param>
      public CommFpgaEthernet(string deviceName, int localPort, int remotePort, string remoteAddress)
      {
         _name = deviceName;
         _logger = LogManager.GetLogger($"{this.GetType().Name} - {deviceName}");
         _selfTestResult = SelfTestResult.Unknown;
         _state = State.Uninitialized;

         _localPort = localPort;
         _remotePort = remotePort;
         _remoteAddress = remoteAddress;
      }

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

      /// <summary>
      /// 
      /// </summary>
      public string DetailedStatus
      {
         get
         {
            return "This is a FPGA Ethernet 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)
      {
         //5 second timeout
         const int TIMEOUT = 5000;

         lock (_syncObj)
         {
            if (_state == State.Uninitialized)
            {
               _udpClient = new UdpClient(_localPort);

               _udpClient.Client.ReceiveBufferSize = int.MaxValue;

               _udpClient.Client.SendBufferSize = int.MaxValue;

               _udpClient.Client.SendTimeout = TIMEOUT;

               _udpClient.Client.ReceiveTimeout = TIMEOUT;

               _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>
      /// Reads a single register
      /// </summary>
      /// <param name="page">The page of the register to read from</param>
      /// <param name="address">The register address to read from</param>
      /// <returns>The data at the address</returns>
      public uint Read(string fpgaName, uint address)
      {
         // lock up the FPGA resource
         lock (_syncObj)
         {
            FPGACmdMessage cmd = new FPGAReadRegisterCmdMessage((FPGACmdMessage.Page)0, address);

            // this get populated in SendCommandGetResponse()
            FPGARspMessage rsp = new FPGAReadRegisterRspMessage(0, 0);

            SendCommandGetResponse(cmd, ref rsp);

            return rsp.GetData();
         }
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="fpgaName"></param>
      /// <param name="address"></param>
      /// <param name="numberOfWordsToRead"></param>
      /// <param name="dataRead"></param>
      /// <param name="shallWeIncrementAddress"></param>
      public void ReadBlock(string fpgaName, uint address, uint numberOfWordsToRead, bool shallWeIncrementAddress, ref uint[] dataRead)
      {
         // lock up the FPGA resource
         lock (_syncObj)
         {
            if (shallWeIncrementAddress)
            {
               FPGACmdMessage cmd = new FPGAReadRegisterCmdBlockIncrMessage((FPGACmdMessage.Page)0, address, numberOfWordsToRead, false);

               // this get populated in SendCommandGetResponse()
               FPGARspMessage rsp = new FPGAReadRegisterBlockIncrRspMessage(0, ref dataRead);

               SendCommandGetResponse(cmd, ref rsp);
            }
            else
            {
               throw new Exception("Not Implemented");
            }
         }
      }

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

         Initialize();
      }

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

      /// <summary>
      /// 
      /// </summary>
      public void Shutdown()
      {
         // lock up the FPGA resource
         lock (_syncObj)
         {
            if (_state == State.Ready)
            {
               _udpClient.Close();

               _state = State.Uninitialized;
            }
         }
      }

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

      /// <summary>
      /// Write to a single register
      /// </summary>
      /// <param name="page">The page of the register to read from</param>
      /// <param name="address">The address to write to</param>
      /// <param name="value">The data to write</param>
      public void Write(string fpgaName, uint address, uint value)
      {
         // lock up the FPGA resource
         lock (_syncObj)
         {
            FPGACmdMessage cmd = new FPGAWriteRegisterCmdMessage((FPGACmdMessage.Page)0, address, value);

            // this get populated in SendCommandGetResponse()
            FPGARspMessage rsp = new FPGAWriteRegisterRspMessage(0, 0);

            SendCommandGetResponse(cmd, ref rsp);

            if (rsp.GetAddress() != address)
            {
               throw new Exception("Command write on address: " + address.ToString("X8") + ", received address: " + rsp.GetAddress().ToString("X8"));
            }
            else if (rsp.GetData() != 0xace0beef)
            {
               throw new Exception("Command write on address: " + address.ToString("X8") + " returned value: " + rsp.GetData().ToString("X8"));
            }
         }
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="fpgaName"></param>
      /// <param name="address"></param>
      /// <param name="numberOfBytes"></param>
      /// <param name="data"></param>
      public void WriteBlock(string fpgaName, uint address, uint numberOfWordsToWrite, uint[] data, bool shallWeIncrementAddress)
      {
         // lock up the FPGA resource
         lock (_syncObj)
         {
            FPGACmdMessage cmd = null;

            if (shallWeIncrementAddress)
            {
               cmd = new FPGAWriteRegisterCmdBlockIncrMessage((FPGACmdMessage.Page)0, address, data, false);
            }
            else
            {
               cmd = new FPGAWriteRegisterCmdBlockMessage((FPGACmdMessage.Page)0, address, data, false);
            }

            // this get populated in SendCommandGetResponse()
            FPGARspMessage rsp = new FPGAWriteRegisterRspMessage(0, 0);

            SendCommandGetResponse(cmd, ref rsp);

            if (rsp.GetAddress() != address)
            {
               throw new Exception("Command write on address: " + address.ToString("X8") + ", received address: " + rsp.GetAddress().ToString("X8"));
            }
            else if (rsp.GetData() != 0xace0beef)
            {
               throw new Exception("Command write on address: " + address.ToString("X8") + " returned value: " + rsp.GetData().ToString("X8"));
            }
         }
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="page"></param>
      /// <param name="address"></param>
      /// <param name="data"></param>
      /// <param name="incrementAddress"></param>
      /// <param name="byteSwap"></param>
      public void WriteRegister(uint page, uint address, uint[] data, bool incrementAddress = true, bool byteSwap = true)
      {
         // lock up the FPGA resource
         lock (_syncObj)
         {
            if (page > (uint)FPGACmdMessage.Page.PAGE3)
            {
               throw new Exception("input parameter 'page' is out of range: " + page.ToString());
            }

            FPGACmdMessage cmd;

            if (incrementAddress)
            {
               cmd = new FPGAWriteRegisterCmdBlockIncrMessage((FPGACmdMessage.Page)page, address, data, byteSwap);
            }
            else
            {
               cmd = new FPGAWriteRegisterCmdBlockMessage((FPGACmdMessage.Page)page, address, data, byteSwap);
            }


            // this get populated in SendCommandGetResponse()
            FPGARspMessage rsp = new FPGAWriteRegisterRspMessage(0, 0);

            SendCommandGetResponse(cmd, ref rsp);

            if (rsp.GetAddress() != address)
            {
               throw new Exception("Command write on address: " + address.ToString("X8") + ", received address: " + rsp.GetAddress().ToString("X8"));
            }
            else if (rsp.GetData() != 0xace0beef)
            {
               throw new Exception("Command write on address: " + address.ToString("X8") + " returned value: " + rsp.GetData().ToString("X8"));
            }
         }
      }

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