/*
 * Copyright (c) 2006, Second Life Reverse Engineering Team
 * All rights reserved.
 *
 * - Redistribution and use in source and binary forms, with or without 
 *   modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice, this
 *   list of conditions and the following disclaimer.
 * - Neither the name of the Second Life Reverse Engineering Team nor the names 
 *   of its contributors may be used to endorse or promote products derived from
 *   this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" 
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 
 * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE 
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR 
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF 
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS 
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN 
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) 
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE 
 * POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using System.Collections;
using System.Threading;

namespace libsecondlife
{
	/// <summary>
	/// Main class to expose Second Life functionality to clients. All of the 
	/// classes are accessible through this class.
	/// </summary>
	public class SecondLife
	{
		public ProtocolManager Protocol;
		public NetworkManager Network;
		public ParcelManager Parcels;
		public MainAvatar Avatar;
		public Inventory Inventory;
		public ArrayList Regions;
		public Mutex RegionsMutex;
		public Region CurrentRegion;
		public byte[] CurrentParcelOverlay;
		public uint ParcelOverlaysReceived;

		public SecondLife(string keywordFile, string mapFile)
		{
			Protocol = new ProtocolManager(keywordFile, mapFile);
			Network = new NetworkManager(this, Protocol);
			Parcels = new ParcelManager(this);
			Avatar = new MainAvatar(this);
			Inventory = new Inventory(this);
			Regions = new ArrayList();
			RegionsMutex = new Mutex(false, "RegionsMutex");
			CurrentRegion = null;
			CurrentParcelOverlay = new byte[4096];
			ParcelOverlaysReceived = 0;
		}

		public override string ToString()
		{
			return Avatar.FirstName + " " + Avatar.LastName;
		}

		public void Tick()
		{
			System.Threading.Thread.Sleep(0);
		}

		public Region FindRegion(string name)
		{
			RegionsMutex.WaitOne();

			foreach (Region region in Regions)
			{
				if (region.Name == name)
				{
					RegionsMutex.ReleaseMutex();
					return region;
				}
			}

			RegionsMutex.ReleaseMutex();
			return null;
		}
	}

	/// <summary>
	/// Static helper functions and global variables
	/// </summary>
	public class Helpers
	{
		public readonly static string VERSION = "libsecondlife-cs 0.0.5";

		public const byte MSG_APPENDED_ACKS = 0x10;
		public const byte MSG_RESENT = 0x20;
		public const byte MSG_RELIABLE = 0x40;
		public const byte MSG_ZEROCODED = 0x80;
		public const ushort MSG_FREQ_HIGH = 0x0000;
		public const ushort MSG_FREQ_MED = 0xFF00;
		public const ushort MSG_FREQ_LOW = 0xFFFF;

		public enum LogLevel
		{
			Info,
			Warning,
			Error
		};

		/// <summary>
		/// Send a log message to the debugging output system
		/// </summary>
		/// <param name="message">The log message</param>
		/// <param name="level">From the LogLevel enum, either Info, Warning, or Error</param>
		public static void Log(string message, LogLevel level)
		{
			Console.WriteLine(level.ToString() + ": " + message);
		}

		/// <summary>
		/// Converting a variable length field (byte array) to a string
		/// </summary>
		/// <param name="data">The Data member of the Field class you are converting</param>
		public static string FieldToString(object data)
		{
			byte[] byteArray;

			try
			{
				byteArray = (byte[])data;
			}
			catch (Exception e)
			{
				Helpers.Log(e.ToString(), Helpers.LogLevel.Warning);
				return "";
			}

			return System.Text.Encoding.ASCII.GetString(byteArray).Replace("\0", "");
		}

		/// <summary>
		/// Decode a zerocoded byte array. Used to decompress packets marked 
		/// with the zerocoded flag. Any time a zero is encountered, the 
		/// next byte is a count of how many zeroes to expand. One zero is 
		/// encoded with 0x00 0x01, two zeroes is 0x00 0x02, three zeroes is 
		/// 0x00 0x03, etc. The first four bytes are copied directly to the 
		/// output buffer.
		/// </summary>
		/// <param name="src">The byte array to decode</param>
		/// <param name="srclen">The length of the byte array to decode</param>
		/// <param name="dest">The output byte array to decode to</param>
		/// <returns>The length of the output buffer</returns>
		public static int ZeroDecode(byte[] src, int srclen, byte[] dest)
		{
			uint zerolen = 0;

			try
			{
				Array.Copy(src, 0, dest, 0, 4);
				zerolen += 4;

				for (uint i = zerolen; i < srclen; i++) 
				{
					if (src[i] == 0x00) 
					{
						for (byte j = 0; j < src[i + 1]; j++) 
						{
							dest[zerolen++] = 0x00;
						}

						i++;
					} 
					else 
					{
						dest[zerolen++] = src[i];
					}
				}
			}
			catch (Exception e)
			{
				Helpers.Log(e.ToString(), Helpers.LogLevel.Error);
			}

			return (int)zerolen;
		}

		/// <summary>
		/// Encode a byte array with zerocoding. Used to compress packets marked
		/// with the zerocoded flag. Any zeroes in the array are compressed down 
		/// to a single zero byte followed by a count of how many zeroes to expand 
		/// out. A single zero becomes 0x00 0x01, two zeroes becomes 0x00 0x02, 
		/// three zeroes becomes 0x00 0x03, etc. The first four bytes are copied 
		/// directly to the output buffer.
		/// </summary>
		/// <param name="src">The byte array to encode</param>
		/// <param name="srclen">The length of the byte array to encode</param>
		/// <param name="dest">The output byte array to encode to</param>
		/// <returns>The length of the output buffer</returns>
		public static int ZeroEncode(byte[] src, int srclen, byte[] dest)
		{
			uint zerolen = 0;
			byte zerocount = 0;

			Array.Copy(src, 0, dest, 0, 4);
			zerolen += 4;

			for (uint i = zerolen; i < srclen; i++) 
			{
				if (src[i] == 0x00) 
				{
					zerocount++;

					if (zerocount == 0) 
					{
						dest[zerolen++] = 0x00;
						dest[zerolen++] = 0xff;
						zerocount++;
					}
				}
				else 
				{
					if (zerocount != 0) 
					{
						dest[zerolen++] = 0x00;
						dest[zerolen++] = (byte)zerocount;
						zerocount = 0;
					}

					dest[zerolen++] = src[i];
				}
			}

			if (zerocount != 0) 
			{
				dest[zerolen++] = 0x00;
				dest[zerolen++] = (byte)zerocount;
			}

			return (int)zerolen;
		}
	}
}