//==========================================================================================
//
//		OpenNETCF.IO.Serial.Port
//		Copyright (c) 2003, OpenNETCF.org
//
//		This library is free software; you can redistribute it and/or modify it under
//		the terms of the OpenNETCF.org Shared Source License.
//
//		This library is distributed in the hope that it will be useful, but
//		WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
//		FITNESS FOR A PARTICULAR PURPOSE. See the OpenNETCF.org Shared Source License
//		for more details.
//
//		You should have received a copy of the OpenNETCF.org Shared Source License
//		along with this library; if not, email licensing@opennetcf.org to request a copy.
//
//		If you wish to contact the OpenNETCF Advisory Board to discuss licensing, please
//		email licensing@opennetcf.org.
//
//		For general enquiries, email enquiries@opennetcf.org or visit our website at:
//		http://www.opennetcf.org
//
//==========================================================================================

//
// Dec 04:	Yuri Astrakhan (YuriAstrakhan at gmail dot com)
//			Changed access modificers from private to internal on 
//			hPort, rxBufferSize, rxFIFO, txBufferSize, ptxBuffer, rxBufferBusy, and m_CommAPI.
//

using System;
using System.Runtime.InteropServices;
using System.Threading;
using System.Text;
using System.Collections;

namespace OpenNETCF.IO.Serial
{
	/// <summary>
	/// Exceptions throw by the OpenNETCF.IO.Serial class
	/// </summary>
	public class CommPortException : Exception
	{
		/// <summary>
		/// Default CommPortException
		/// </summary>
		/// <param name="desc"></param>
		public CommPortException(string desc) : base(desc) {}
	}

	/// <summary>
	/// A class wrapper for serial port communications
	/// </summary>
	public class Port : IDisposable
	{
		[DllImport("kernel32", EntryPoint="LocalAlloc", SetLastError=true)]
		internal static extern IntPtr LocalAlloc(int uFlags, int uBytes);

		[DllImport("kernel32", EntryPoint="LocalFree", SetLastError=true)]
		internal static extern IntPtr LocalFree(IntPtr hMem);

		#region delegates and events
		/// <summary>
		/// Raised on all enabled communication events
		/// </summary>
		public delegate void CommEvent();
		/// <summary>
		/// Raised when the communication state changes
		/// </summary>
		public delegate void CommChangeEvent(bool NewState);
		/// <summary>
		/// Raised during any communication error
		/// </summary>
		public delegate void CommErrorEvent(string Description);
		/// <summary>
		///  A communication error has occurred
		/// </summary>
		public event CommErrorEvent OnError;
		/// <summary>
		/// Serial data has been received
		/// </summary>
		public event CommEvent DataReceived;
//		/// <summary>
//		/// Overrun of the transmit buffer
//		/// </summary>
//		public event CommEvent RxOverrun;
		/// <summary>
		/// Transmit complete
		/// </summary>
		public event CommEvent TxDone;
		/// <summary>
		/// Set flag character was in the receive stream
		/// </summary>
		public event CommEvent FlagCharReceived;
		/// <summary>
		/// Power change event has occurred
		/// </summary>
		public event CommEvent PowerEvent;
		/// <summary>
		/// Serial buffer's high-water level has been exceeded
		/// </summary>
		public event CommEvent HighWater;
		/// <summary>
		/// DSR state has changed
		/// </summary>
		public event CommChangeEvent DSRChange;
		/// <summary>
		/// Ring signal has been detected
		/// </summary>
		public event CommChangeEvent RingChange;
		/// <summary>
		/// CTS state has changed
		/// </summary>
		public event CommChangeEvent CTSChange;
		/// <summary>
		/// RLSD state has changed
		/// </summary>
		public event CommChangeEvent RLSDChange;
		#endregion

		#region ##### variable declarations #####
		private string portName;
		internal IntPtr hPort = (IntPtr)CommAPI.INVALID_HANDLE_VALUE;

		// default Rx buffer is 1024 bytes
		internal int rxBufferSize = 1024;
		internal Queue rxFIFO;
		private int rthreshold = 1;

		// default Tx buffer is 1024 bytes
		internal int txBufferSize = 1024;
		private byte[] txBuffer;
		internal int ptxBuffer	= 0;
		private int sthreshold = 1;

		internal Mutex rxBufferBusy = new Mutex();
		private int inputLength;

		private DCB dcb = new DCB();
		private DetailedPortSettings portSettings;

		private Thread eventThread;
		private ManualResetEvent threadStarted = new ManualResetEvent(false);

		private IntPtr closeEvent;
		private string closeEventName = "CloseEvent";

		private int		rts			= 0;
		private bool	rtsavail	= false;
		private int		dtr			= 0;
		private bool	dtravail	= false;
		private int		brk			= 0;
		private int		setir		= 0;
		private bool	isOpen		= false;

		private IntPtr txOverlapped = IntPtr.Zero;
		private IntPtr rxOverlapped = IntPtr.Zero;

		internal CommAPI m_CommAPI;
		/// <summary>
		/// stores port's capabilities - capabilities can only be retreived not set
		/// </summary>
		public readonly CommCapabilities Capabilities = new CommCapabilities();

		#endregion

		private void Init()
		{
			// create the API class based on the target
			if (System.Environment.OSVersion.Platform != PlatformID.WinCE)
				m_CommAPI=new IO.Serial.WinCommAPI();
			else
				m_CommAPI=new IO.Serial.CECommAPI();

			// create a system event for synchronizing Closing
			closeEvent = m_CommAPI.CreateEvent(true, false, closeEventName);

			rxFIFO = new Queue(rxBufferSize);
			txBuffer = new byte[txBufferSize];
			portSettings = new DetailedPortSettings();
		}

		#region constructors
		/// <summary>
		/// Create a serial port class.  The port will be created with defualt settings.
		/// </summary>
		/// <param name="PortName">The port to open (i.e. "COM1:")</param>
		public Port(string PortName)
		{
			this.PortName = PortName;
			Init();
		}

		/// <summary>
		/// Create a serial port class.
		/// </summary>
		/// <param name="PortName">The port to open (i.e. "COM1:")</param>
		/// <param name="InitialSettings">BasicPortSettings to apply to the new Port</param>
		public Port(string PortName, BasicPortSettings InitialSettings)
		{
			this.PortName = PortName;
			Init();

			//override default ettings
			portSettings.BasicSettings = InitialSettings;
		}

		/// <summary>
		/// Create a serial port class.
		/// </summary>
		/// <param name="PortName">The port to open (i.e. "COM1:")</param>
		/// <param name="InitialSettings">DetailedPortSettings to apply to the new Port</param>
		public Port(string PortName, DetailedPortSettings InitialSettings)
		{
			this.PortName = PortName;
			Init();

			//override default ettings
			portSettings = InitialSettings;
		}

		/// <summary>
		/// Create a serial port class.
		/// </summary>
		/// <param name="PortName">The port to open (i.e. "COM1:")</param>
		/// <param name="RxBufferSize">Receive buffer size, in bytes</param>
		/// <param name="TxBufferSize">Transmit buffer size, in bytes</param>
		public Port(string PortName, int RxBufferSize, int TxBufferSize)
		{
			rxBufferSize = RxBufferSize;
			txBufferSize = TxBufferSize;
			this.PortName = PortName;
			Init();
		}

		/// <summary>
		/// Create a serial port class.
		/// </summary>
		/// <param name="PortName">The port to open (i.e. "COM1:")</param>
		/// <param name="InitialSettings">BasicPortSettings to apply to the new Port</param>
		/// <param name="RxBufferSize">Receive buffer size, in bytes</param>
		/// <param name="TxBufferSize">Transmit buffer size, in bytes</param>
		public Port(string PortName, BasicPortSettings InitialSettings, int RxBufferSize, int TxBufferSize)
		{
			rxBufferSize = RxBufferSize;
			txBufferSize = TxBufferSize;
			this.PortName = PortName;
			Init();

			//override default ettings
			portSettings.BasicSettings = InitialSettings;
		}

		/// <summary>
		/// Create a serial port class.
		/// </summary>
		/// <param name="PortName">The port to open (i.e. "COM1:")</param>
		/// <param name="InitialSettings">DetailedPortSettings to apply to the new Port</param>
		/// <param name="RxBufferSize">Receive buffer size, in bytes</param>
		/// <param name="TxBufferSize">Transmit buffer size, in bytes</param>
		public Port(string PortName, DetailedPortSettings InitialSettings, int RxBufferSize, int TxBufferSize)
		{
			rxBufferSize = RxBufferSize;
			txBufferSize = TxBufferSize;
			this.PortName = PortName;
			Init();

			//override default ettings
			portSettings = InitialSettings;
		}
		#endregion

		// since the event thread blocks until the port handle is closed
		// implement both a Dispose and destrucor to make sure that we
		// clean up as soon as possible
		/// <summary>
		/// Dispose the object's resources
		/// </summary>
		public void Dispose()
		{
			if(isOpen)
				this.Close();
		}

		/// <summary>
		/// Class destructor
		/// </summary>
		~Port()
		{
			if(isOpen)
				this.Close();
		}

		/// <summary>
		/// The name of the Port (i.e. "COM1:")
		/// </summary>
		public string PortName
		{
			get
			{
				return portName;
			}
			set
			{
				if(! CommAPI.FullFramework)
				{
					// for CE, ensure the port name is colon terminated "COMx:"
					if(! value.EndsWith(":"))
					{
						portName = value + ":";
						return;
					}
				}

				portName = value;
			}
		}

		/// <summary>
		/// Returns whether or not the port is currently open
		/// </summary>
		public bool IsOpen
		{
			get
			{
				return isOpen;
			}
		}

		/// <summary>
		/// Open the current port
		/// </summary>
		/// <returns>true if successful, false if it fails</returns>
		public bool Open()
		{
			if(isOpen) return false;

			if(CommAPI.FullFramework)
			{
				// set up the overlapped tx IO
				//				AutoResetEvent are = new AutoResetEvent(false);
				OVERLAPPED o = new OVERLAPPED();
				txOverlapped = LocalAlloc(0x40, Marshal.SizeOf(o));
				o.Offset = 0;
				o.OffsetHigh = 0;
				o.hEvent = IntPtr.Zero;
				Marshal.StructureToPtr(o, txOverlapped, true);
			}

			hPort = m_CommAPI.CreateFile(portName);

			if(hPort == (IntPtr)CommAPI.INVALID_HANDLE_VALUE)
			{
				int e = Marshal.GetLastWin32Error();

				if(e == (int)APIErrors.ERROR_ACCESS_DENIED)
				{
					// port is unavailable
					return false;
				}

				// ClearCommError failed!
				string error = String.Format("CreateFile Failed: {0}", e);
				throw new CommPortException(error);
			}


			isOpen = true;

			// set queue sizes
			m_CommAPI.SetupComm(hPort, rxBufferSize, txBufferSize);

			// transfer the port settings to a DCB structure
			dcb.BaudRate = (uint)portSettings.BasicSettings.BaudRate;
			dcb.ByteSize = portSettings.BasicSettings.ByteSize;
			dcb.EofChar = (sbyte)portSettings.EOFChar;
			dcb.ErrorChar = (sbyte)portSettings.ErrorChar;
			dcb.EvtChar = (sbyte)portSettings.EVTChar;
			dcb.fAbortOnError = portSettings.AbortOnError;
			dcb.fBinary = true;
			dcb.fDsrSensitivity = portSettings.DSRSensitive;
			dcb.fDtrControl = (DCB.DtrControlFlags)portSettings.DTRControl;