// Ignore Spelling: Geu Sdlc

using System;
using System.Threading;
using NLog;
using Raytheon.Common;
using Raytheon.GuidedElectronicsUnit;

namespace Raytheon.Instruments
{
   public class CommDeviceGeuSdlc : ICommDevice, IDisposable
   {
      #region PrivateClassMembers

      private GuidedElectronicsUnit.GuidedElectronicsUnit _guidanceElectronicsUnit;
      private readonly bool _idQuery = false;
      private readonly bool _reset = false;
      private readonly SelfTestResult _selfTestResult;
      private State _state;
      private readonly string _instrumentDriverSetup;
      private readonly int _pollingRate;
      private static readonly object _syncObj = new object();

      private readonly ILogger _logger;

      private readonly IConfigurationManager _configurationManager;
      private readonly IConfiguration _configuration;

      #endregion

      #region PrivatelassFunctions

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

      /// <summary>
      /// Dispose of the resources contained by this object
      /// </summary>
      /// <param name="disposing"></param>
      protected virtual void Dispose(bool disposing)
      {
         if (disposing)
         {
            // close resources
            try
            {
               if (_state == State.Ready)
               {
                  _guidanceElectronicsUnit.Close();
                  _guidanceElectronicsUnit.Dispose();
                  _state = State.Uninitialized;
               }
            }
            catch (Exception)
            {
               try
               {
               }
               catch (Exception)
               {
                  //Do not rethrow. Exception from error logger that has already been garbage collected
               }
            }
         }
      }

      /// <summary>
      /// Some HSS corrections
      /// </summary>
      /// <param name="data"></param>
      /// <param name="numDWords"></param>
      private static unsafe void PerformHssSwirl(ref byte[] data, uint numDWords)
      {
         fixed (byte* pBytePtr = &data[0])
         {
            for (int i = 0; i < numDWords; i++)
            {
               // swap the first word
               ushort* pWord1 = (ushort*)pBytePtr + (i * 2);
               *pWord1 = Util.Swap(*pWord1);

               //swap the second word
               ushort* pWord2 = (ushort*)pBytePtr + ((i * 2) + 1);
               *pWord2 = Util.Swap(*pWord2);

               // now swap the dword
               uint* pDWord = (uint*)pBytePtr + i;
               *pDWord = Util.SwapHighAndLowBytes(*pDWord);
            }
         }
      }

      #endregion

      #region PublicClassFunctions

      bool IInstrument.DisplayEnabled { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
      bool IInstrument.FrontPanelEnabled { get => throw new NotImplementedException(); set => throw new NotImplementedException(); }
      InstrumentMetadata IInstrument.Info => throw new NotImplementedException();

      /// <summary>
      /// CommDevice factory constructor
      /// </summary>
      /// <param name="deviceName"></param>
      /// <param name="configurationManager"></param>
      public CommDeviceGeuSdlc(string deviceName, IConfigurationManager configurationManager)
      {
         Name = deviceName;
         _guidanceElectronicsUnit = null;
         _selfTestResult = SelfTestResult.Unknown;
         _state = State.Uninitialized;

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

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

         _idQuery = _configuration.GetConfigurationValue("CommDeviceGeuSdlc", "IdQuery", true);
         _reset = _configuration.GetConfigurationValue("CommDeviceGeuSdlc", "Reset", true);
         _instrumentDriverSetup = _configuration.GetConfigurationValue("CommDeviceGeuSdlc", "InstrumentDriverSetup", "");
         _pollingRate = _configuration.GetConfigurationValue("CommDeviceGeuSdlc", "PollingRate", 10);
      }

      /// <summary>
      /// The constructor. Does not initialize anything. Use Initialize() to create the handle to the hardware
      /// </summary>
      /// <param name="deviceName"></param>
      /// <param name="idQuery"></param>
      /// <param name="reset"></param>
      public CommDeviceGeuSdlc(string deviceName, bool idQuery, bool reset, string instrumentDriverSetup = "", int pollingRate = 10)
      {
         Name = deviceName;
         _idQuery = idQuery;
         _reset = reset;
         _guidanceElectronicsUnit = null;
         _selfTestResult = SelfTestResult.Unknown;
         _state = State.Uninitialized;
         _instrumentDriverSetup = instrumentDriverSetup;
         _pollingRate = pollingRate;
         _logger = LogManager.GetLogger($"{this.GetType().Name} - {deviceName}");
      }

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

      /// <summary>
      /// 
      /// </summary>
      public string DetailedStatus
      {
         get
         {
            return "This is a HSS GEU SDLC Device called " + Name;
         }
      }

      /// <summary>
      /// Dispose of the resources contained by this object
      /// </summary>
      public void Dispose()
      {
         try
         {
            Dispose(true);

            GC.SuppressFinalize(this);
         }
         catch (Exception err)
         {
            _logger.Error(err.Message + "\r\n" + err.StackTrace);
         }
      }

      /// <summary>
      /// Create a handle to the hardware
      /// </summary>
      public void Initialize()
      {
         const uint AUTO_FWDING_ADDR = 0x00080100;
         const uint WRITE_OFFSET = 0x00200000;
         const uint ENABLE_AUTO_FWDING = 0b0000_0001;
         const uint ENABLE_TLP_HDR = 0b0000_0010;
         //const uint INSERT_MSG_CNT = 0b0000_0100;

         _guidanceElectronicsUnit = new GuidedElectronicsUnit.GuidedElectronicsUnit(Name, _idQuery, _reset,
            $"QueryInstrStatus=true, Simulate=false, DriverSetup= {_instrumentDriverSetup}, PollingInterval={_pollingRate}");

         _guidanceElectronicsUnit.LowLevel.HSSub9100.EnableIO = ControlState.Enabled;

         _guidanceElectronicsUnit.LowLevel.HSSub9100.WriteRegister(AUTO_FWDING_ADDR + WRITE_OFFSET, ENABLE_AUTO_FWDING | ENABLE_TLP_HDR);

         _state = State.Ready;
      }

      /// <summary>
      /// 
      /// </summary>
      public string Name { get; protected set; }

      /// <summary>
      /// 
      /// </summary>
      /// <returns></returns>
      SelfTestResult IInstrument.PerformSelfTest()
      {
         throw new NotImplementedException();
      }

      /// <summary>
      /// 
      /// </summary>
      /// <param name="dataRead"></param>
      /// <returns></returns>
      uint ICommDevice.Read(ref byte[] dataRead)
      {

         if (_guidanceElectronicsUnit == null)
         {
            return 0;
         }

         byte[] sdlcMsgs = new byte[0];
         lock (_syncObj)
         {
            // read all of the data that is available
            sdlcMsgs = _guidanceElectronicsUnit.GsKwSyncronousDataLinkControl.FetchMessageData();
         }

         if (sdlcMsgs.Length > dataRead.Length)
         {
            throw new Exception("The data buffer that the host provided is: " + dataRead.Length + " bytes, there are: " + sdlcMsgs.Length + " bytes of SDLC data. Need to increase the host buffer size");
         }

         Buffer.BlockCopy(sdlcMsgs, 0, dataRead, 0, sdlcMsgs.Length);

         return (uint)sdlcMsgs.Length;
      }

      /// <summary>
      /// 
      /// </summary>
      void IInstrument.Reset()
      {
         lock (_syncObj)
         {
            _guidanceElectronicsUnit.Close();
            _state = State.Uninitialized;
            Thread.Sleep(500);
            Initialize();
         }
      }

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

      /// <summary>
      /// 
      /// </summary>
      /// <param name="timeoutMs"></param>
      void ICommDevice.SetReadTimeout(uint timeoutMs)
      {
         throw new NotImplementedException();
      }

      /// <summary>
      /// 
      /// </summary>
      void IInstrument.Shutdown()
      {
         lock (_syncObj)
         {
            if (_guidanceElectronicsUnit != null)
            {
               _guidanceElectronicsUnit.LowLevel.HSSub9100.EnableIO = ControlState.Disabled;

               _guidanceElectronicsUnit.Close();
               _guidanceElectronicsUnit.Dispose();
               _state = State.Uninitialized;
            }
         }
      }

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

      /// <summary>
      /// 
      /// </summary>
      /// <param name="data"></param>
      /// <param name="numBytesToWrite"></param>
      /// <returns></returns>
      uint ICommDevice.Write(byte[] data, uint numBytesToWrite)
      {
         lock (_syncObj)
         {
            if (numBytesToWrite % 4 != 0)
            {
               throw new Exception("Data is not dword aligned");
            }

            // do all of the HSS Tx only byte order corrections
            PerformHssSwirl(ref data, numBytesToWrite / 4);

            var tempArr = new uint[data.Length / 4];
            Buffer.BlockCopy(data, 0, tempArr, 0, (int)numBytesToWrite);
            _guidanceElectronicsUnit.GsKwSyncronousDataLinkControl.SendMessage(tempArr);
         }
         return numBytesToWrite;
      }

      public void Close()
      {
      }

      public void Open()
      {
      }

      #endregion
   }
}