#region Copyright & License Information
/*
 * Copyright 2007,2009,2010 Chris Forbes, Robert Pepperell, Matthew Bowra-Dean, Paul Chote, Alli Witheford.
 * This file is part of OpenRA.
 * 
 *  OpenRA is free software: you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation, either version 3 of the License, or
 *  (at your option) any later version.
 * 
 *  OpenRA 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
 *  GNU General Public License for more details.
 * 
 *  You should have received a copy of the GNU General Public License
 *  along with OpenRA.  If not, see <http://www.gnu.org/licenses/>.
 */
#endregion

using System;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Net.Sockets;

namespace OpenRA.Server
{
	class Connection
	{
		public Socket socket;
		public List<byte> data = new List<byte>();
		public ReceiveState State = ReceiveState.Header;
		public int ExpectLength = 8;
		public int Frame = 0;

		/* client data */
		public int PlayerIndex;

		/* file server state */
		public int NextChunk = 0;
		public int NumChunks = 0;
		public int RemainingBytes = 0;
		public Stream Stream = null;

		public byte[] PopBytes(int n)
		{
			var result = data.GetRange(0, n);
			data.RemoveRange(0, n);
			return result.ToArray();
		}

		bool ReadDataInner()
		{
			var rx = new byte[1024];
			var len = 0;

			for (; ; )
			{
				try
				{
					if (0 < (len = socket.Receive(rx)))
						data.AddRange(rx.Take(len));
					else
					{
						if (len == 0)
							Server.DropClient(this, null);
						break;
					}
						
				}
				catch (SocketException e)
				{
					if (e.SocketErrorCode == SocketError.WouldBlock) break;
					Server.DropClient(this, e); 
					return false; 
				}
			}

			return true;
		}

		public void ReadData()
		{
			if (ReadDataInner())
				while (data.Count >= ExpectLength)
				{
					var bytes = PopBytes(ExpectLength);
					switch (State)
					{
						case ReceiveState.Header:
							{
								ExpectLength = BitConverter.ToInt32(bytes, 0) - 4;
								Frame = BitConverter.ToInt32(bytes, 4);
								State = ReceiveState.Data;
							} break;

						case ReceiveState.Data:
							{
								Server.DispatchOrders(this, Frame, bytes);
								ExpectLength = 8;
								State = ReceiveState.Header;

								Server.UpdateInFlightFrames(this);
							} break;
					}
				}
		}}

	enum ReceiveState { Header, Data };
}