/*
 * 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.Timers;
using System.Threading;
using System.Collections;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Net;
using System.Net.Sockets;
using System.Globalization;
using System.IO;
using Nwc.XmlRpc;
using Nii.JSON;
using libsecondlife.Packets;

namespace libsecondlife
{
    /// <summary>
    /// This exception is thrown whenever a network operation is attempted 
    /// without a network connection.
    /// </summary>
    public class NotConnectedException : ApplicationException { }

    /// <summary>
    /// Capabilities is the name of the bi-directional HTTP REST protocol that
    /// Second Life uses to communicate transactions such as teleporting or
    /// asset transfers
    /// </summary>
    public class Caps
    {
        /// <summary>
        /// Triggered when an event is received via the EventQueueGet capability;
        /// </summary>
        /// <param name="message"></param>
        /// <param name="body"></param>
        public delegate void EventQueueCallback(string message, object body);

        /// <summary>Reference to the SecondLife client this system is connected to</summary>
        public SecondLife Client;
        /// <summary>Reference to the region this system is connected to</summary>
        public Region Region;

        internal bool Dead = false;

        private string Seedcaps;
        private StringDictionary Capabilities = new StringDictionary();
        private Thread EventThread;
        private List<EventQueueCallback> Callbacks;

        /// <summary>
        /// Default constructor
        /// </summary>
        /// <param name="client"></param>
        /// <param name="region"></param>
        /// <param name="seedcaps"></param>
        /// <param name="callbacks"></param>
        public Caps(SecondLife client, Region region, string seedcaps, List<EventQueueCallback> callbacks)
        {
            Client = client; Region = region;
            this.Seedcaps = seedcaps; Callbacks = callbacks;
            ArrayList req = new ArrayList();
            req.Add("MapLayer");
            req.Add("MapLayerGod");
            req.Add("NewAgentInventory");
            req.Add("EventQueueGet");
            Hashtable resp = (Hashtable)LLSDRequest(seedcaps, req);

            foreach (string cap in resp.Keys)
            {
                Client.Log("Got cap " + cap + ": " + (string)resp[cap], Helpers.LogLevel.Info);
                Capabilities[cap] = (string)resp[cap];
            }

            if (Capabilities.ContainsKey("EventQueueGet"))
            {
                Client.Log("Running event queue", Helpers.LogLevel.Info);
                EventThread = new Thread(new ThreadStart(EventQueue));
                EventThread.Start();
            }
        }

        private void EventQueue()
        {
            bool gotresp = false; long ack = 0;
            string cap = Capabilities["EventQueueGet"];

            while (!Dead)
            {
                try
                {
                    Hashtable req = new Hashtable();

                    if (gotresp)
                        req["ack"] = ack;
                    else
                        req["ack"] = null;

                    req["done"] = false;

                    Hashtable resp = (Hashtable)LLSDRequest(cap, req);
                    ack = (long)resp["id"];
                    gotresp = true;
                    ArrayList events = (ArrayList)resp["events"];

                    foreach (Hashtable evt in events)
                    {
                        string msg = (string)evt["message"];
                        object body = (object)evt["body"];

                        Client.DebugLog("Event " + msg + ":" + Environment.NewLine + LLSD.LLSDDump(body, 0));

                        if (!Dead)
                        {
                            foreach (EventQueueCallback callback in Callbacks)
                            {
                                try { callback(msg, body); }
                                catch (Exception e) { Client.Log(e.ToString(), Helpers.LogLevel.Error); }
                            }
                        }
                    }
                }
                catch (WebException e)
                {
                    // Perfectly normal
                    Client.DebugLog("EventQueueGet: " + e.Message);
                }
            }
        }

        private static object LLSDRequest(string uri, object req)
        {
            byte[] data = LLSD.LLSDSerialize(req);
            WebRequest wreq = WebRequest.Create(uri);
            wreq.Method = "POST";
            wreq.ContentLength = data.Length;
            Stream reqStream = wreq.GetRequestStream();
            reqStream.Write(data, 0, data.Length);
            reqStream.Close();
            HttpWebResponse wresp = (HttpWebResponse)wreq.GetResponse();
            Stream respStream = wresp.GetResponseStream();
            int read; int length = 0;
            byte[] respBuf = new byte[256];

            do
            {
                read = respStream.Read(respBuf, length, 256);

                if (read > 0)
                {
                    length += read;
                    Array.Resize(ref respBuf, length + 256);
                }
            } while (read > 0);

            Array.Resize(ref respBuf, length);
            return LLSD.LLSDDeserialize(respBuf);
        }

        public void Disconnect()
        {
            Dead = true;
        }
    }

    /// <summary>
    /// Simulator is a wrapper for a network connection to a simulator and the
    /// Region class representing the block of land in the metaverse
    /// </summary>
    public class Simulator
    {
        /// <summary>A public reference to the client that this Simulator object
        /// is attached to</summary>
        public SecondLife Client;

        /// <summary>The Region class that this Simulator wraps</summary>
        public Region Region;

        /// <summary>
        /// Used internally to track sim disconnections, do not modify this 
        /// variable
        /// </summary>
        public bool DisconnectCandidate = false;

        /// <summary>
        /// The ID number associated with this particular connection to the 
        /// simulator, used to emulate TCP connections. This is used 
        /// internally for packets that have a CircuitCode field
        /// </summary>
        public uint CircuitCode
        {
            get { return circuitCode; }
            set { circuitCode = value; }
        }

        /// <summary>
        /// The IP address and port of the server
        /// </summary>
        public IPEndPoint IPEndPoint
        {
            get { return ipEndPoint; }
        }

        /// <summary>
        /// A boolean representing whether there is a working connection to the
        /// simulator or not
        /// </summary>
        public bool Connected
        {
            get { return connected; }
        }

        private NetworkManager Network;
        private Dictionary<PacketType, List<NetworkManager.PacketCallback>> Callbacks;
        private uint Sequence = 0;
        private object SequenceLock = new object();
        private byte[] RecvBuffer = new byte[4096];
        private byte[] ZeroBuffer = new byte[8192];
        private byte[] ZeroOutBuffer = new byte[4096];
        private Socket Connection = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
        private AsyncCallback ReceivedData;
        // Packets we sent out that need ACKs from the simulator
        private Dictionary<uint, Packet> NeedAck = new Dictionary<uint, Packet>();
        // Sequence numbers of packets we've received from the simulator
        private Queue<uint> Inbox;
        // ACKs that are queued up to be sent to the simulator
        private Dictionary<uint, uint> PendingAcks = new Dictionary<uint, uint>();
        private bool connected = false;
        private uint circuitCode;
        private IPEndPoint ipEndPoint;
        private EndPoint endPoint;
        private System.Timers.Timer AckTimer;

        /// <summary>
        /// Constructor for Simulator
        /// </summary>
        /// <param name="client"></param>
        /// <param name="callbacks"></param>
        /// <param name="circuit"></param>
        /// <param name="ip"></param>
        /// <param name="port"></param>
        public Simulator(SecondLife client, Dictionary<PacketType, List<NetworkManager.PacketCallback>> callbacks,
            uint circuit, IPAddress ip, int port)
        {
            Client = client;
            Network = client.Network;
            Callbacks = callbacks;
            Region = new Region(client);
            circuitCode = circuit;
            Inbox = new Queue<uint>(Client.Settings.INBOX_SIZE);
            AckTimer = new System.Timers.Timer(Client.Settings.NETWORK_TICK_LENGTH);
            AckTimer.Elapsed += new ElapsedEventHandler(AckTimer_Elapsed);

            // Initialize the callback for receiving a new packet
            ReceivedData = new AsyncCallback(OnReceivedData);

            Client.Log("Connecting to " + ip.ToString() + ":" + port, Helpers.LogLevel.Info);

            try
            {
                // Create an endpoint that we will be communicating with (need it in two 
                // types due to .NET weirdness)
                ipEndPoint = new IPEndPoint(ip, port);
                endPoint = (EndPoint)ipEndPoint;

                // Associate this simulator's socket with the given ip/port and start listening
                Connection.Connect(endPoint);
                Connection.BeginReceiveFrom(RecvBuffer, 0, RecvBuffer.Length, SocketFlags.None, ref endPoint, ReceivedData, null);

                // Send the UseCircuitCode packet to initiate the connection
                UseCircuitCodePacket use = new UseCircuitCodePacket();
                use.CircuitCode.Code = circuitCode;
                use.CircuitCode.ID = Network.AgentID;
                use.CircuitCode.SessionID = Network.SessionID;

                // Start the ACK timer
                AckTimer.Start();

                // Send the initial packet out
                SendPacket(use, true);

                // Track the current time for timeout purposes
                int start = Environment.TickCount;

                while (true)
                {
                    if (connected || Environment.TickCount - start > Client.Settings.SIMULATOR_TIMEOUT)
                    {
                        return;
                    }
                    System.Threading.Thread.Sleep(10);
                }
            }
            catch (Exception e)
            {
                Client.Log(e.ToString(), Helpers.LogLevel.Error);
            }
        }

        /// <summary>
        /// Disconnect a Simulator
        /// </summary>
        public void Disconnect()
        {
            if (connected)
            {
                connected = false;
                AckTimer.Stop();

                // Send the CloseCircuit notice
                CloseCircuitPacket close = new CloseCircuitPacket();

                if (Connection.Connected)
                {
                    try
                    {
                        Connection.Send(close.ToBytes());
                    }
                    catch (SocketException)
                    {
                        // There's a high probability of this failing if the network is
                        // disconnecting, so don't even bother logging the error
                    }
                }

                try
                {
                    // Shut the socket communication down
                    Connection.Shutdown(SocketShutdown.Both);
                }
                catch (SocketException)
                {
                }
            }
        }

        /// <summary>
        /// Sends a packet
        /// </summary>
        /// <param name="packet">Packet to be sent</param>
        /// <param name="incrementSequence">Increment sequence number?</param>
        public void SendPacket(Packet packet, bool incrementSequence)
        {
            byte[] buffer;
            int bytes;

            if (!connected && packet.Type != PacketType.UseCircuitCode)
            {
                Client.Log("Trying to send a " + packet.Type.ToString() + " packet when the socket is closed",
                    Helpers.LogLevel.Info);

                return;
            }

            if (packet.Header.AckList.Length > 0)
            {
                // Scrub any appended ACKs since all of the ACK handling is done here
                packet.Header.AckList = new uint[0];
            }
            packet.Header.AppendedAcks = false;

            // Keep track of when this packet was sent out
            packet.TickCount = Environment.TickCount;

            if (incrementSequence)
            {
                // Set the sequence number
                lock (SequenceLock)
                {
                    if (Sequence > Client.Settings.MAX_SEQUENCE)
                        Sequence = 1;
                    else
                        Sequence++;
                    packet.Header.Sequence = Sequence;
                }

                if (packet.Header.Reliable)
                {
                    lock (NeedAck)
                    {
                        if (!NeedAck.ContainsKey(packet.Header.Sequence))
                        {
                            NeedAck.Add(packet.Header.Sequence, packet);
                        }
                        else
                        {
                            Client.Log("Attempted to add a duplicate sequence number (" +
                                packet.Header.Sequence + ") to the NeedAck dictionary for packet type " +
                                packet.Type.ToString(), Helpers.LogLevel.Warning);
                        }
                    }

                    // Don't append ACKs to resent packets, in case that's what was causing the
                    // delivery to fail
                    if (!packet.Header.Resent)
                    {
                        // Append any ACKs that need to be sent out to this packet
                        lock (PendingAcks)
                        {
                            if (PendingAcks.Count > 0 && PendingAcks.Count < Client.Settings.MAX_APPENDED_ACKS &&
                                packet.Type != PacketType.PacketAck &&
                                packet.Type != PacketType.LogoutRequest)
                            {
                                packet.Header.AckList = new uint[PendingAcks.Count];

                                int i = 0;

                                foreach (uint ack in PendingAcks.Values)
                                {
                                    packet.Header.AckList[i] = ack;
                                    i++;
                                }

                                PendingAcks.Clear();
                                packet.Header.AppendedAcks = true;
                            }
                        }
                    }
                }
            }

            // Serialize the packet
            buffer = packet.ToBytes();
            bytes = buffer.Length;

            try
            {
                // Zerocode if needed
                if (packet.Header.Zerocoded)
                {
                    lock (ZeroOutBuffer)
                    {
                        bytes = Helpers.ZeroEncode(buffer, bytes, ZeroOutBuffer);
                        Connection.Send(ZeroOutBuffer, bytes, SocketFlags.None);
                    }
                }
                else
                {
                    Connection.Send(buffer, bytes, SocketFlags.None);
                }
            }
            catch (SocketException)
            {
                Client.Log("Tried to send a " + packet.Type.ToString() + " on a closed socket",
                    Helpers.LogLevel.Warning);

                Disconnect();
            }
        }

        /// <summary>
        /// Send a raw byte array payload as a packet
        /// </summary>
        /// <param name="payload">The packet payload</param>
        /// <param name="setSequence">Whether the second, third, and fourth bytes
        /// should be modified to the current stream sequence number</param>
        public void SendPacket(byte[] payload, bool setSequence)
        {
            if (connected)
            {
                try
                {
                    if (setSequence && payload.Length > 3)
                    {
                        lock (SequenceLock)
                        {
                            payload[1] = (byte)(Sequence >> 16);
                            payload[2] = (byte)(Sequence >> 8);
                            payload[3] = (byte)(Sequence % 256);
                            Sequence++;
                        }
                    }

                    Connection.Send(payload, payload.Length, SocketFlags.None);
                }
                catch (SocketException e)
                {
                    Client.Log(e.ToString(), Helpers.LogLevel.Error);
                }
            }
            else
            {
                Client.Log("Attempted to send a " + payload.Length + " byte payload when " +
                    "we are disconnected", Helpers.LogLevel.Warning);
            }
        }

        /// <summary>
        /// Returns Simulator Name as a String
        /// </summary>
        /// <returns></returns>
        public override string ToString()
        {
            return Region.Name + " (" + ipEndPoint.ToString() + ")";
        }

        /// <summary>
        /// Sends out pending acknowledgements
        /// </summary>
        private void SendAcks()
        {
            lock (PendingAcks)
            {
                if (connected && PendingAcks.Count > 0)
                {
                    if (PendingAcks.Count > 250)
                    {
                        // FIXME: Handle the odd case where we have too many pending ACKs queued up
                        Client.Log("Too many ACKs queued up!", Helpers.LogLevel.Error);
                        return;
                    }

                    int i = 0;
                    PacketAckPacket acks = new PacketAckPacket();
                    acks.Packets = new PacketAckPacket.PacketsBlock[PendingAcks.Count];

                    foreach (uint ack in PendingAcks.Values)
                    {
                        acks.Packets[i] = new PacketAckPacket.PacketsBlock();
                        acks.Packets[i].ID = ack;
                        i++;
                    }

                    acks.Header.Reliable = false;
                    SendPacket(acks, true);

                    PendingAcks.Clear();
                }
            }
        }
        /// <summary>
        /// Resend unacknowledged packets
        /// </summary>
        private void ResendUnacked()
        {
            if (connected)
            {
                int now = Environment.TickCount;

                lock (NeedAck)
                {
                    foreach (Packet packet in NeedAck.Values)
                    {
                        if (now - packet.TickCount > Client.Settings.RESEND_TIMEOUT)
                        {
                            Client.Log("Resending " + packet.Type.ToString() + " packet, " +
                                (now - packet.TickCount) + "ms have passed", Helpers.LogLevel.Info);

                            packet.Header.Resent = true;
                            SendPacket(packet, false);
                        }
                    }
                }
            }
        }
        /// <summary>
        /// Callback handler for incomming data
        /// </summary>
        /// <param name="result"></param>
        private void OnReceivedData(IAsyncResult result)
        {
            Packet packet = null;
            int numBytes;

            // If we're receiving data the sim connection is open
            connected = true;

            // Update the disconnect flag so this sim doesn't time out
            DisconnectCandidate = false;

            lock (RecvBuffer)
            {
                // Retrieve the incoming packet
                try
                {
                    numBytes = Connection.EndReceiveFrom(result, ref endPoint);

                    int packetEnd = numBytes - 1;
                    packet = Packet.BuildPacket(RecvBuffer, ref packetEnd, ZeroBuffer);

                    Connection.BeginReceiveFrom(RecvBuffer, 0, RecvBuffer.Length, SocketFlags.None, ref endPoint, ReceivedData, null);
                }
                catch (SocketException)
                {
                    Client.Log(endPoint.ToString() + " socket is closed, shutting down " + this.Region.Name,
                        Helpers.LogLevel.Info);

                    connected = false;
                    Network.DisconnectSim(this);
                    return;
                }
            }

            // Fail-safe check
            if (packet == null)
            {
                Client.Log("Couldn't build a message from the incoming data", Helpers.LogLevel.Warning);
                return;
            }

            // Track the sequence number for this packet if it's marked as reliable
            if (packet.Header.Reliable)
            {
                if (PendingAcks.Count > Client.Settings.MAX_PENDING_ACKS)
                {
                    SendAcks();
                }

                // Check if we already received this packet
                if (Inbox.Contains(packet.Header.Sequence))
                {
                    Client.Log("Received a duplicate " + packet.Type.ToString() + ", sequence=" +
                        packet.Header.Sequence + ", resent=" + ((packet.Header.Resent) ? "Yes" : "No") +
                        ", Inbox.Count=" + Inbox.Count + ", NeedAck.Count=" + NeedAck.Count,
                        Helpers.LogLevel.Info);

                    // Send an ACK for this packet immediately
                    //SendAck(packet.Header.Sequence);

                    // TESTING: Try just queuing up ACKs for resent packets instead of immediately triggering an ACK
                    lock (PendingAcks)
                    {
                        uint sequence = (uint)packet.Header.Sequence;
                        if (!PendingAcks.ContainsKey(sequence)) { PendingAcks[sequence] = sequence; }
                    }

                    // Avoid firing a callback twice for the same packet
                    return;
                }
                else
                {
                    lock (PendingAcks)
                    {
                        uint sequence = (uint)packet.Header.Sequence;
                        if (!PendingAcks.ContainsKey(sequence)) { PendingAcks[sequence] = sequence; }
                    }
                }
            }

            // Add this packet to our inbox
            lock (Inbox)
            {
                while (Inbox.Count >= Client.Settings.INBOX_SIZE)
                {
                    Inbox.Dequeue();
                }
                Inbox.Enqueue(packet.Header.Sequence);
            }

            // Handle appended ACKs
            if (packet.Header.AppendedAcks)
            {
                lock (NeedAck)
                {
                    foreach (uint ack in packet.Header.AckList)
                    {
                        NeedAck.Remove(ack);
                    }
                }
            }

            // Handle PacketAck packets
            if (packet.Type == PacketType.PacketAck)
            {
                PacketAckPacket ackPacket = (PacketAckPacket)packet;

                lock (NeedAck)
                {
                    foreach (PacketAckPacket.PacketsBlock block in ackPacket.Packets)
                    {
                        NeedAck.Remove(block.ID);
                    }
                }
            }

            // Fire the registered packet events
            #region FireCallbacks
            if (Callbacks.ContainsKey(packet.Type))
            {
                List<NetworkManager.PacketCallback> callbackArray = Callbacks[packet.Type];

                // Fire any registered callbacks
                foreach (NetworkManager.PacketCallback callback in callbackArray)
                {
                    if (callback != null)
                    {
                        try
                        {
                            callback(packet, this);
                        }
                        catch (Exception e)
                        {
                            Client.Log("Caught an exception in a packet callback: " + e.ToString(),
                                Helpers.LogLevel.Error);
                        }
                    }
                }
            }

            if (Callbacks.ContainsKey(PacketType.Default))
            {
                List<NetworkManager.PacketCallback> callbackArray = Callbacks[PacketType.Default];

                // Fire any registered callbacks
                foreach (NetworkManager.PacketCallback callback in callbackArray)
                {
                    if (callback != null)
                    {
                        try
                        {
                            callback(packet, this);
                        }
                        catch (Exception e)
                        {
                            Client.Log("Caught an exception in a packet callback: " + e.ToString(),
                                Helpers.LogLevel.Error);
                        }
                    }
                }
            }
            #endregion FireCallbacks
        }

        private void AckTimer_Elapsed(object sender, ElapsedEventArgs ea)
        {
            if (connected)
            {
                SendAcks();
                ResendUnacked();
            }
        }
    }

    /// <summary>
    /// NetworkManager is responsible for managing the network layer of 
    /// libsecondlife. It tracks all the server connections, serializes 
    /// outgoing traffic and deserializes incoming traffic, and provides
    /// instances of delegates for network-related events.
    /// </summary>
    public class NetworkManager
    {
        /// <summary>
        /// Coupled with RegisterCallback(), this is triggered whenever a packet
        /// of a registered type is received
        /// </summary>
        /// <param name="packet"></param>
        /// <param name="simulator"></param>
        public delegate void PacketCallback(Packet packet, Simulator simulator);
        /// <summary>
        /// Triggered when a simulator other than the simulator that is currently
        /// being occupied disconnects for whatever reason
        /// </summary>
        /// <param name="simulator">The simulator that disconnected, which will become a null
        /// reference after the callback is finished</param>
        /// <param name="reason">Enumeration explaining the reason for the disconnect</param>
        public delegate void SimDisconnectCallback(Simulator simulator, DisconnectType reason);
        /// <summary>
        /// Triggered when we are logged out of the grid due to a simulator request,
        /// client request, network timeout, or any other cause
        /// </summary>
        /// <param name="reason">Enumeration explaining the reason for the disconnect</param>
        /// <param name="message">If we were logged out by the simulator, this 
        /// is a message explaining why</param>
        public delegate void DisconnectCallback(DisconnectType reason, string message);
        /// <summary>
        /// Triggered when CurrentSim changes
        /// </summary>
        /// <param name="PreviousSimulator">A reference to the old value of CurrentSim</param>
        public delegate void CurrentSimChangedCallback(Simulator PreviousSimulator);

        /// <summary>
        /// Explains why a simulator or the grid disconnected from us
        /// </summary>
        public enum DisconnectType
        {
            /// <summary>The client requested the logout or simulator disconnect</summary>
            ClientInitiated,
            /// <summary>The server notified us that it is disconnecting</summary>
            ServerInitiated,
            /// <summary>Either a socket was closed or network traffic timed out</summary>
            NetworkTimeout
        }

        /// <summary>
        /// The permanent UUID for the logged in avatar
        /// </summary>
        public LLUUID AgentID;
        /// <summary>
        /// A temporary UUID assigned to this session, used for secure 
        /// transactions
        /// </summary>
        public LLUUID SessionID;
        /// <summary>
        /// A string holding a descriptive error on login failure, empty
        /// otherwise
        /// </summary>
        public string LoginError;
        /// <summary>
        /// The simulator that the logged in avatar is currently occupying
        /// </summary>
        public Simulator CurrentSim;
        /// <summary>
        /// The capabilities for the current simulator
        /// </summary>
        public Caps CurrentCaps;
        /// <summary>
        /// The complete dictionary of all the login values returned by the 
        /// RPC login server, converted to native data types wherever possible
        /// </summary>
        public Dictionary<string, object> LoginValues = new Dictionary<string, object>();
        /// <summary>
        /// Shows whether the network layer is logged in to the grid or not
        /// </summary>
        public bool Connected
        {
            get { return connected; }
        }

        /// <summary>
        /// An event for the connection to a simulator other than the currently
        /// occupied one disconnecting
        /// </summary>
        public event SimDisconnectCallback OnSimDisconnected;
        /// <summary>
        /// An event for being logged out either through client request, server
        /// forced, or network error
        /// </summary>
        public event DisconnectCallback OnDisconnected;
        /// <summary>
        /// An event for when CurrentSim changes
        /// </summary>
        public event CurrentSimChangedCallback OnCurrentSimChanged;

        private SecondLife Client;
        private Dictionary<PacketType, List<PacketCallback>> Callbacks = new Dictionary<PacketType, List<PacketCallback>>();
        private List<Simulator> Simulators = new List<Simulator>();
        private System.Timers.Timer DisconnectTimer;
        private System.Timers.Timer LogoutTimer;
        private bool connected;
        private List<Caps.EventQueueCallback> EventQueueCallbacks = new List<Caps.EventQueueCallback>();

        private const int NetworkTrafficTimeout = 15000;

        ManualResetEvent LogoutReplyEvent = new ManualResetEvent(false);

        /// <summary>
        /// 
        /// </summary>
        /// <param name="client"></param>
        public NetworkManager(SecondLife client)
        {
            Client = client;
            CurrentSim = null;

            // Register the internal callbacks
            RegisterCallback(PacketType.RegionHandshake, new PacketCallback(RegionHandshakeHandler));
            RegisterCallback(PacketType.StartPingCheck, new PacketCallback(StartPingCheckHandler));
            RegisterCallback(PacketType.ParcelOverlay, new PacketCallback(ParcelOverlayHandler));
            RegisterCallback(PacketType.EnableSimulator, new PacketCallback(EnableSimulatorHandler));
            RegisterCallback(PacketType.KickUser, new PacketCallback(KickUserHandler));
            RegisterCallback(PacketType.LogoutReply, new PacketCallback(LogoutReplyHandler));

            // Disconnect a sim if we exceed our threshold
            DisconnectTimer = new System.Timers.Timer(NetworkTrafficTimeout);
            DisconnectTimer.Elapsed += new ElapsedEventHandler(DisconnectTimer_Elapsed);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="type"></param>
        /// <param name="callback"></param>
        public void RegisterCallback(PacketType type, PacketCallback callback)
        {
            if (!Callbacks.ContainsKey(type))
            {
                Callbacks[type] = new List<PacketCallback>();
            }

            List<PacketCallback> callbackArray = Callbacks[type];
            callbackArray.Add(callback);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="type"></param>
        /// <param name="callback"></param>
        public void UnregisterCallback(PacketType type, PacketCallback callback)
        {
            if (!Callbacks.ContainsKey(type))
            {
                Client.Log("Trying to unregister a callback for packet " + type.ToString() +
                    " when no callbacks are setup for that packet", Helpers.LogLevel.Info);
                return;
            }

            List<PacketCallback> callbackArray = Callbacks[type];

            if (callbackArray.Contains(callback))
            {
                callbackArray.Remove(callback);
            }
            else
            {
                Client.Log("Trying to unregister a non-existant callback for packet " + type.ToString(),
                    Helpers.LogLevel.Info);
            }
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="callback"></param>
        public void RegisterEventCallback(Caps.EventQueueCallback callback)
        {
            EventQueueCallbacks.Add(callback);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="packet"></param>
        public void SendPacket(Packet packet)
        {
            if (CurrentSim != null && CurrentSim.Connected)
            {
                CurrentSim.SendPacket(packet, true);
            }
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="packet"></param>
        /// <param name="simulator"></param>
        public void SendPacket(Packet packet, Simulator simulator)
        {
            if (simulator != null && simulator.Connected)
            {
                simulator.SendPacket(packet, true);
            }
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="payload"></param>
        /// <param name="setSequence">Whether to set the second, third, and fourth
        /// bytes of the payload to the current sequence number</param>
        public void SendPacket(byte[] payload, bool setSequence)
        {
            if (connected && CurrentSim != null)
            {
                CurrentSim.SendPacket(payload, setSequence);
            }
            else
            {
                Client.Log("Trying to send a " + payload.Length + " payload " +
                    "when we're not connected", Helpers.LogLevel.Warning);
            }
        }

        /// <summary>
        /// Use this if you want to login to a specific location
        /// </summary>
        /// <param name="sim"></param>
        /// <param name="x"></param>
        /// <param name="y"></param>
        /// <param name="z"></param>
        /// <returns>string with a value that can be used in the start field in .DefaultLoginValues()</returns>
        public static string StartLocation(string sim, int x, int y, int z)
        {
            //uri:sim&x&y&z
            return "uri:" + sim.ToLower() + "&" + x + "&" + y + "&" + z;
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="firstName"></param>
        /// <param name="lastName"></param>
        /// <param name="password"></param>
        /// <param name="userAgent"></param>
        /// <param name="author"></param>
        /// <returns></returns>
        public Dictionary<string, object> DefaultLoginValues(string firstName, string lastName,
            string password, string userAgent, string author)
        {
            return DefaultLoginValues(firstName, lastName, password, "00:00:00:00:00:00", "last",
                1, 50, 50, 50, "Win", "0", userAgent, author, false);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="firstName"></param>
        /// <param name="lastName"></param>
        /// <param name="password"></param>
        /// <param name="userAgent"></param>
        /// <param name="author"></param>
        /// <returns></returns>
        public Dictionary<string, object> DefaultLoginValues(string firstName, string lastName,
            string password, string startLocation, string userAgent, string author, bool md5pass)
        {
            return DefaultLoginValues(firstName, lastName, password, "00:00:00:00:00:00", startLocation,
                1, 50, 50, 50, "Win", "0", userAgent, author, md5pass);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="firstName"></param>
        /// <param name="lastName"></param>
        /// <param name="password"></param>
        /// <param name="mac"></param>
        /// <param name="startLocation"></param>
        /// <param name="platform"></param>
        /// <param name="viewerDigest"></param>
        /// <param name="userAgent"></param>
        /// <param name="author"></param>
        /// <returns></returns>
        public Dictionary<string, object> DefaultLoginValues(string firstName, string lastName,
            string password, string mac, string startLocation, string platform,
            string viewerDigest, string userAgent, string author)
        {
            return DefaultLoginValues(firstName, lastName, password, mac, startLocation,
                1, 50, 50, 50, platform, viewerDigest, userAgent, author, false);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="firstName"></param>
        /// <param name="lastName"></param>
        /// <param name="password"></param>
        /// <param name="mac"></param>
        /// <param name="startLocation"></param>
        /// <param name="major"></param>
        /// <param name="minor"></param>
        /// <param name="patch"></param>
        /// <param name="build"></param>
        /// <param name="platform"></param>
        /// <param name="viewerDigest"></param>
        /// <param name="userAgent"></param>
        /// <param name="author"></param>
        /// <returns></returns>
        public Dictionary<string, object> DefaultLoginValues(string firstName, string lastName,
            string password, string mac, string startLocation, int major, int minor, int patch,
            int build, string platform, string viewerDigest, string userAgent, string author,
            bool md5pass)
        {
            Dictionary<string, object> values = new Dictionary<string, object>();

            values["first"] = firstName;
            values["last"] = lastName;
            values["passwd"] = md5pass ? password : Helpers.MD5(password);
            values["start"] = startLocation;
            values["major"] = major;
            values["minor"] = minor;
            values["patch"] = patch;
            values["build"] = build;
            values["platform"] = platform;
            values["mac"] = mac;
            values["agree_to_tos"] = "true";
            values["read_critical"] = "true";
            values["viewer_digest"] = viewerDigest;
            values["user-agent"] = userAgent + " (" + Client.Settings.VERSION + ")";
            values["author"] = author;

            // Build the options array
            List<object> optionsArray = new List<object>();
            optionsArray.Add("inventory-root");
            optionsArray.Add("inventory-skeleton");
            optionsArray.Add("inventory-lib-root");
            optionsArray.Add("inventory-lib-owner");
            optionsArray.Add("inventory-skel-lib");
            optionsArray.Add("initial-outfit");
            optionsArray.Add("gestures");
            optionsArray.Add("event_categories");
            optionsArray.Add("event_notifications");
            optionsArray.Add("classified_categories");
            optionsArray.Add("buddy-list");
            optionsArray.Add("ui-config");
            optionsArray.Add("login-flags");
            optionsArray.Add("global-textures");

            values["options"] = optionsArray;

            return values;
        }

        /// <summary>
        /// Assigned by the OnConnected event. Raised when login was a success
        /// </summary>
        /// <param name="sender">Reference to the SecondLife class that called the event</param>
        public delegate void ConnectedCallback(object sender);

        /// <summary>
        /// Event raised when the client was able to connected successfully.
        /// </summary>
        /// <remarks>Uses the ConnectedCallback delegate.</remarks>
        public event ConnectedCallback OnConnected;
        /// <summary>
        /// Assigned by the OnLogoutReply callback. Raised upone receipt of a LogoutReply packet during logout process.
        /// </summary>
        /// <param name="inventoryItems"></param>
        public delegate void LogoutCallback(List<LLUUID> inventoryItems);
        /// <summary>
        /// Event raised when a logout is confirmed by the simulator
        /// </summary>
        public event LogoutCallback OnLogoutReply;

        /// <summary>
        /// 
        /// </summary>
        /// <param name="firstName"></param>
        /// <param name="lastName"></param>
        /// <param name="password"></param>
        /// <param name="userAgent"></param>
        /// <param name="author"></param>
        /// <returns></returns>
        public bool Login(string firstName, string lastName, string password, string userAgent, string author)
        {
            Dictionary<string, object> loginParams = DefaultLoginValues(firstName, lastName,
                password, "last", userAgent, author, false);
            return Login(loginParams);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="firstName"></param>
        /// <param name="lastName"></param>
        /// <param name="password"></param>
        /// <param name="userAgent"></param>
        /// <param name="start"></param>
        /// <param name="author"></param>
        /// <param name="md5pass"></param>
        /// <returns></returns>
        public bool Login(string firstName, string lastName, string password, string userAgent, string start,
            string author, bool md5pass)
        {
            Dictionary<string, object> loginParams = DefaultLoginValues(firstName, lastName,
                password, start, userAgent, author, md5pass);
            return Login(loginParams);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="loginParams"></param>
        /// <returns></returns>
        public bool Login(Dictionary<string, object> loginParams)
        {
            return Login(loginParams, Client.Settings.LOGIN_SERVER);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="loginParams"></param>
        /// <param name="url"></param>
        /// <returns></returns>
        public bool Login(Dictionary<string, object> loginParams, string url)
        {
            // Rebuild the Dictionary<> in to a Hashtable for compatibility with XmlRpcCS
            Hashtable loginValues = new Hashtable(loginParams.Count);
            foreach (KeyValuePair<string, object> kvp in loginParams)
            {
                if (kvp.Value is IList)
                {
                    IList list = ((IList)kvp.Value);
                    ArrayList array = new ArrayList(list.Count);
                    foreach (object obj in list)
                    {
                        array.Add(obj);
                    }
                    loginValues[kvp.Key] = array;
                }
                else
                {
                    loginValues[kvp.Key] = kvp.Value;
                }
            }

            XmlRpcResponse result;
            XmlRpcRequest xmlrpc = new XmlRpcRequest();
            xmlrpc.MethodName = "login_to_simulator";
            xmlrpc.Params.Clear();
            xmlrpc.Params.Add(loginValues);

            try
            {
                result = (XmlRpcResponse)xmlrpc.Send(url, Client.Settings.LOGIN_TIMEOUT);
            }
            catch (Exception e)
            {
                LoginError = "XML-RPC Error: " + e.Message;
                LoginValues.Clear();
                return false;
            }

            if (result.IsFault)
            {
                Client.Log("Fault " + result.FaultCode + ": " + result.FaultString, Helpers.LogLevel.Error);
                LoginError = "XML-RPC Fault: " + result.FaultCode + ": " + result.FaultString;
                LoginValues.Clear();
                return false;
            }

            Hashtable values = (Hashtable)result.Value;
            foreach (DictionaryEntry entry in values)
            {
                LoginValues[(string)entry.Key] = entry.Value;
            }

            if ((string)LoginValues["login"] == "indeterminate")
            {
                //FIXME: We need to do another XML-RPC, handle this case
                LoginError = "Got a redirect, login with the official client to update";
                return false;
            }
            else if ((string)LoginValues["login"] == "false")
            {
                LoginError = LoginValues["reason"] + ": " + LoginValues["message"];
                return false;
            }
            else if ((string)LoginValues["login"] != "true")
            {
                LoginError = "Unknown error";
                return false;
            }

            System.Text.RegularExpressions.Regex LLSDtoJSON =
                new System.Text.RegularExpressions.Regex(@"('|r([0-9])|r(\-))");
            string json;
            Dictionary<string, object> jsonObject = null;
            LLVector3 vector = LLVector3.Zero;
            LLVector3 posVector = LLVector3.Zero;
            LLVector3 lookatVector = LLVector3.Zero;
            ulong regionHandle = 0;

            try
            {
                if (LoginValues.ContainsKey("look_at"))
                {
                    // Replace LLSD variables with object representations

                    // Convert LLSD string to JSON
                    json = "{vector:" + LLSDtoJSON.Replace((string)LoginValues["look_at"], "$2") + "}";

                    // Convert JSON string to a JSON object
                    jsonObject = JsonFacade.fromJSON(json);
                    JSONArray jsonVector = (JSONArray)jsonObject["vector"];

                    // Convert the JSON object to an LLVector3
                    vector = new LLVector3(Convert.ToSingle(jsonVector[0], CultureInfo.InvariantCulture),
                        Convert.ToSingle(jsonVector[1], CultureInfo.InvariantCulture), Convert.ToSingle(jsonVector[2], CultureInfo.InvariantCulture));

                    LoginValues["look_at"] = vector;
                }
            }
            catch (Exception e)
            {
                Client.Log(e.ToString(), Helpers.LogLevel.Warning);
                LoginValues["look_at"] = null;
            }

            try
            {
                if (LoginValues.ContainsKey("home"))
                {
                    Dictionary<string, object> home;

                    // Convert LLSD string to JSON
                    json = LLSDtoJSON.Replace((string)LoginValues["home"], "$2");

                    // Convert JSON string to an object
                    jsonObject = JsonFacade.fromJSON(json);

                    // Create the position vector
                    JSONArray array = (JSONArray)jsonObject["position"];
                    posVector = new LLVector3(Convert.ToSingle(array[0], CultureInfo.InvariantCulture), Convert.ToSingle(array[1], CultureInfo.InvariantCulture),
                        Convert.ToSingle(array[2], CultureInfo.InvariantCulture));

                    // Create the look_at vector
                    array = (JSONArray)jsonObject["look_at"];
                    lookatVector = new LLVector3(Convert.ToSingle(array[0], CultureInfo.InvariantCulture),
                        Convert.ToSingle(array[1], CultureInfo.InvariantCulture), Convert.ToSingle(array[2], CultureInfo.InvariantCulture));

                    // Create the regionhandle
                    array = (JSONArray)jsonObject["region_handle"];
                    regionHandle = Helpers.UIntsToLong((uint)(int)array[0], (uint)(int)array[1]);

                    Client.Self.Position = posVector;
                    Client.Self.LookAt = lookatVector;

                    // Create a dictionary to hold the home values
                    home = new Dictionary<string, object>();
                    home["position"] = posVector;
                    home["look_at"] = lookatVector;
                    home["region_handle"] = regionHandle;
                    LoginValues["home"] = home;
                }
            }
            catch (Exception e)
            {
                Client.Log(e.ToString(), Helpers.LogLevel.Warning);
                LoginValues["home"] = null;
            }

            try
            {
                this.AgentID = new LLUUID((string)LoginValues["agent_id"]);
                this.SessionID = new LLUUID((string)LoginValues["session_id"]);
                Client.Self.ID = this.AgentID;
                // Names are wrapped in quotes now, have to strip those
                Client.Self.FirstName = ((string)LoginValues["first_name"]).Trim(new char[] { '"' });
                Client.Self.LastName = ((string)LoginValues["last_name"]).Trim(new char[] { '"' });
                Client.Self.LookAt = vector;
                Client.Self.HomePosition = posVector;
                Client.Self.HomeLookAt = lookatVector;

                // Get Inventory Root Folder
                Client.Log("Pulling root folder UUID from login data.", Helpers.LogLevel.Debug);
                ArrayList alInventoryRoot = (ArrayList)LoginValues["inventory-root"];
                Hashtable htInventoryRoot = (Hashtable)alInventoryRoot[0];
                Client.Self.InventoryRootFolderUUID = new LLUUID((string)htInventoryRoot["folder_id"]);


                // Connect to the sim given in the login reply
                Simulator simulator = new Simulator(Client, this.Callbacks, (uint)(int)LoginValues["circuit_code"],
                    IPAddress.Parse((string)LoginValues["sim_ip"]), (int)LoginValues["sim_port"]);
                if (!simulator.Connected)
                {
                    LoginError = "Unable to connect to the simulator";
                    return false;
                }

                Simulator oldSim = CurrentSim;
                CurrentSim = simulator;

                // Simulator is successfully connected, add it to the list and set it as default
                Simulators.Add(simulator);

                // Mark that we are now officially connected to the grid
                connected = true;

                // Start a timer that checks if we've been disconnected
                DisconnectTimer.Start();

                if (LoginValues.ContainsKey("seed_capability") && (string)LoginValues["seed_capability"] != "")
                {
                    CurrentCaps = new Caps(Client, simulator.Region, (string)LoginValues["seed_capability"], EventQueueCallbacks);
                }

                // Move our agent in to the sim to complete the connection
                Client.Self.CompleteAgentMovement(simulator);

                // Send a couple packets that are useful right after login
                SendInitialPackets();

                // Fire an event for connecting to the grid
                if (OnConnected != null)
                {
                    try
                    {
                        OnConnected(this.Client);
                    }
                    catch (Exception e)
                    {
                        Client.Log("Caught an exception in the OnConnected() callback: " + e.ToString(),
                            Helpers.LogLevel.Error);
                    }
                }

                // Fire an event that the current simulator has changed
                if (OnCurrentSimChanged != null)
                {
                    try
                    {
                        OnCurrentSimChanged(oldSim);
                    }
                    catch (Exception e)
                    {
                        Client.Log("Caught an exception in OnCurrentSimChanged(): " + e.ToString(),
                            Helpers.LogLevel.Error);
                    }
                }

                return true;
            }
            catch (Exception e)
            {
                Client.Log("Login error: " + e.ToString(), Helpers.LogLevel.Error);
                return false;
            }
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="ip"></param>
        /// <param name="port"></param>
        /// <param name="circuitCode"></param>
        /// <param name="setDefault"></param>
        /// <returns></returns>
        public Simulator Connect(IPAddress ip, ushort port, uint circuitCode, bool setDefault, string seedcaps)
        {
            Simulator simulator = new Simulator(Client, this.Callbacks, circuitCode, ip, (int)port);

            if (!simulator.Connected)
            {
                simulator = null;
                return null;
            }

            lock (Simulators)
            {
                Simulators.Add(simulator);
            }

            // Mark that we are connected to the grid (in case we weren't before)
            connected = true;

            // Start a timer that checks if we've been disconnected
            DisconnectTimer.Start();

            if (setDefault)
            {
                Simulator oldSim = CurrentSim;
                CurrentSim = simulator;
                if (CurrentCaps != null) CurrentCaps.Disconnect();
                CurrentCaps = null;
                if (seedcaps != null && seedcaps != "")
                    CurrentCaps = new Caps(Client, simulator.Region, seedcaps, EventQueueCallbacks);
                if (OnCurrentSimChanged != null && simulator != oldSim) OnCurrentSimChanged(oldSim);
            }

            return simulator;
        }

        /// <summary>
        /// Initiate a blocking logout request. This will return when the logout
        /// handshake has completed or when Settings.LOGOUT_TIMEOUT has expired
        /// and a LogoutDemand packet has been sent
        /// </summary>
        public void Logout()
        {
            LogoutReplyEvent.Reset();
            RequestLogout();
            LogoutReplyEvent.WaitOne(Client.Settings.LOGOUT_TIMEOUT, false);
        }

        /// <summary>
        /// Initiate the logout process (three step process!)
        /// </summary>
        public void RequestLogout()
        {
            // This will catch a Logout when the client is not logged in
            if (CurrentSim == null || !connected)
            {
                LogoutReplyEvent.Set();
                return;
            }

            Client.Log("Logging out", Helpers.LogLevel.Info);

            DisconnectTimer.Stop();

            // Send a logout request to the current sim
            LogoutRequestPacket logout = new LogoutRequestPacket();
            logout.AgentData.AgentID = AgentID;
            logout.AgentData.SessionID = SessionID;
            CurrentSim.SendPacket(logout, true);

            LogoutTimer = new System.Timers.Timer(Client.Settings.LOGOUT_TIMEOUT);
            LogoutTimer.Elapsed += new ElapsedEventHandler(LogoutTimer_Elapsed);
            LogoutTimer.Start();
        }

        /// <summary>
        /// Triggered if a LogoutReply is not received
        /// </summary>
        /// <param name="sender"></param>
        /// <param name="ev"></param>
        public void LogoutTimer_Elapsed(object sender, ElapsedEventArgs ev)
        {
            Client.Log("Logout due to timeout on server acknowledgement", Helpers.LogLevel.Debug);
            ForceLogout();
        }

        /// <summary>
        /// Uses a LogoutDemand packet to force initiate a logout
        /// </summary>
        public void ForceLogout()
        {
            // Insist on shutdown
            LogoutDemandPacket logoutDemand = new LogoutDemandPacket();
            logoutDemand.LogoutBlock.SessionID = SessionID;
            CurrentSim.SendPacket(logoutDemand, true);

            FinalizeLogout();
        }

        /// <summary>
        /// Finalize the logout procedure. Close down sockets, etc.
        /// </summary>
        private void FinalizeLogout()
        {
            LogoutTimer.Stop();

            // Shutdown the network layer
            Shutdown();

            if (OnDisconnected != null)
            {
                try
                {
                    OnDisconnected(DisconnectType.ClientInitiated, "");
                }
                catch (Exception e)
                {
                    Client.Log("Caught an exception in OnDisconnected(): " + e.ToString(),
                        Helpers.LogLevel.Error);
                }
            }

            // In case we are blocking in Logout()
            LogoutReplyEvent.Set();
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="sim"></param>
        public void DisconnectSim(Simulator sim)
        {
            if (sim != null)
            {
                sim.Disconnect();

                // Fire the SimDisconnected event if a handler is registered
                if (OnSimDisconnected != null)
                {
                    try
                    {
                        OnSimDisconnected(sim, DisconnectType.NetworkTimeout);
                    }
                    catch (Exception e)
                    {
                        Client.Log("Caught an exception in OnSimDisconnected(): " + e.ToString(),
                            Helpers.LogLevel.Error);
                    }
                }

                lock (Simulators)
                {
                    Simulators.Remove(sim);
                }
            }
            else
            {
                Client.Log("DisconnectSim() called with a null Simulator reference", Helpers.LogLevel.Warning);
            }
        }

        /// <summary>
        /// Shutdown will disconnect all the sims except for the current sim
        /// first, and then kill the connection to CurrentSim.
        /// </summary>
        private void Shutdown()
        {
            Client.Log("NetworkManager shutdown initiated", Helpers.LogLevel.Info);

            lock (Simulators)
            {
                // Disconnect all simulators except the current one
                foreach (Simulator simulator in Simulators)
                {
                    // Don't disconnect the current sim, we'll use LogoutRequest for that
                    if (simulator != null && simulator != CurrentSim)
                    {
                        DisconnectSim(simulator);

                        // Fire the SimDisconnected event if a handler is registered
                        // FIXME: This is a recipe for disaster. Firing an event when we 
                        // are locking is just inviting someone to call a function that 
                        // locks in Simulators and deadlocks the library
                        if (OnSimDisconnected != null)
                        {
                            try
                            {
                                OnSimDisconnected(simulator, DisconnectType.NetworkTimeout);
                            }
                            catch (Exception e)
                            {
                                Client.Log("Caught an exception in OnSimDisconnected(): " + e.ToString(),
                                    Helpers.LogLevel.Error);
                            }
                        }
                    }
                }

                Simulators.Clear();
            }

            if (CurrentSim != null)
            {
                Simulator oldSim = CurrentSim;

                DisconnectSim(CurrentSim);
                CurrentSim = null;

                if (OnCurrentSimChanged != null)
                {
                    try { OnCurrentSimChanged(oldSim); }
                    catch (Exception e) { Client.Log(e.ToString(), Helpers.LogLevel.Error); }
                }
            }

            if (CurrentCaps != null)
            {
                CurrentCaps.Disconnect();
                CurrentCaps = null;
            }

            connected = false;
        }

        private void SendInitialPackets()
        {
            // Request the economy data
            SendPacket(new EconomyDataRequestPacket());

            // TODO: A movement class should be handling this
            Avatar.AgentUpdateFlags controlFlags = Avatar.AgentUpdateFlags.AGENT_CONTROL_FINISH_ANIM;
            LLVector3 position = new LLVector3(128, 128, 32);
            LLVector3 forwardAxis = new LLVector3(0, 0.999999f, 0);
            LLVector3 leftAxis = new LLVector3(0.999999f, 0, 0);
            LLVector3 upAxis = new LLVector3(0, 0, 0.999999f);
            Client.Self.UpdateCamera(controlFlags, position, forwardAxis, leftAxis, upAxis, LLQuaternion.Identity,
                LLQuaternion.Identity, 384.0f, true);

            // TODO: A movement class should be handling this
            Client.Self.SetAlwaysRun(false);
        }

        private void DisconnectTimer_Elapsed(object sender, ElapsedEventArgs ev)
        {
            if (connected)
            {
                if (CurrentSim == null)
                {
                    DisconnectTimer.Stop();
                    connected = false;
                    return;
                }

                // If the current simulator is disconnected, shutdown+callback+return
                if (CurrentSim.DisconnectCandidate)
                {
                    Client.Log("Network timeout for the current simulator (" +
                        CurrentSim.Region.Name + "), logging out", Helpers.LogLevel.Warning);

                    DisconnectTimer.Stop();
                    connected = false;

                    // Shutdown the network layer
                    Shutdown();

                    if (OnDisconnected != null)
                    {
                        try
                        {
                            OnDisconnected(DisconnectType.NetworkTimeout, "");
                        }
                        catch (Exception e)
                        {
                            Client.Log("Caught an exception in OnDisconnected(): " + e.ToString(),
                                Helpers.LogLevel.Error);
                        }
                    }

                    // We're completely logged out and shut down, leave this function
                    return;
                }

                List<Simulator> disconnectedSims = null;

                // Check all of the connected sims for disconnects
                lock (Simulators)
                {
                    foreach (Simulator sim in Simulators)
                    {
                        if (sim.DisconnectCandidate)
                        {
                            if (disconnectedSims == null)
                            {
                                disconnectedSims = new List<Simulator>();
                            }

                            disconnectedSims.Add(sim);
                        }
                        else
                        {
                            sim.DisconnectCandidate = true;
                        }
                    }
                }

                // Actually disconnect each sim we detected as disconnected
                if (disconnectedSims != null)
                {
                    foreach (Simulator sim in disconnectedSims)
                    {
                        if (sim != null)
                        {
                            // This sim hasn't received any network traffic since the 
                            // timer last elapsed, consider it disconnected
                            Client.Log("Network timeout for simulator " + sim.Region.Name +
                                ", disconnecting", Helpers.LogLevel.Warning);

                            DisconnectSim(sim);
                        }
                    }
                }
            }
        }

        /// <summary>
        /// Called to deal with LogoutReply packet and fires off callback
        /// </summary>
        /// <param name="packet">Full packet of type LogoutReplyPacket</param>
        /// <param name="simulator"></param>
        private void LogoutReplyHandler(Packet packet, Simulator simulator)
        {
            LogoutReplyPacket logout = (LogoutReplyPacket)packet;

            if ((logout.AgentData.SessionID == SessionID) && (logout.AgentData.AgentID == AgentID))
            {
                Client.Log("Logout negotiated with server", Helpers.LogLevel.Debug);

                // Deal with callbacks, if any
                if (OnLogoutReply != null)
                {
                    List<LLUUID> itemIDs = new List<LLUUID>();

                    foreach (LogoutReplyPacket.InventoryDataBlock InventoryData in logout.InventoryData)
                    {
                        itemIDs.Add(InventoryData.ItemID);
                    }

                    try { OnLogoutReply(itemIDs); }
                    catch (Exception e) { Client.Log(e.ToString(), Helpers.LogLevel.Error); }
                }

                FinalizeLogout();
            }
            else
            {
                Client.Log("Invalid Session or Agent ID received in Logout Reply... ignoring", Helpers.LogLevel.Warning);
            }
        }

        private void StartPingCheckHandler(Packet packet, Simulator simulator)
        {
            StartPingCheckPacket incomingPing = (StartPingCheckPacket)packet;
            CompletePingCheckPacket ping = new CompletePingCheckPacket();
            ping.PingID.PingID = incomingPing.PingID.PingID;

            // TODO: We can use OldestUnacked to correct transmission errors

            SendPacket((Packet)ping, simulator);
        }

        private void RegionHandshakeHandler(Packet packet, Simulator simulator)
        {
            // Send a RegionHandshakeReply
            RegionHandshakeReplyPacket reply = new RegionHandshakeReplyPacket();
            reply.AgentData.AgentID = AgentID;
            reply.AgentData.SessionID = SessionID;
            reply.RegionInfo.Flags = 0;
            SendPacket(reply, simulator);

            RegionHandshakePacket handshake = (RegionHandshakePacket)packet;

            simulator.Region.ID = handshake.RegionInfo.CacheID;

            // TODO: What do we need these for? RegionFlags probably contains good stuff
            //handshake.RegionInfo.BillableFactor;
            //handshake.RegionInfo.RegionFlags;
            //handshake.RegionInfo.SimAccess;

            simulator.Region.IsEstateManager = handshake.RegionInfo.IsEstateManager;
            simulator.Region.Name = Helpers.FieldToString(handshake.RegionInfo.SimName);
            simulator.Region.SimOwner = handshake.RegionInfo.SimOwner;
            simulator.Region.TerrainBase0 = handshake.RegionInfo.TerrainBase0;
            simulator.Region.TerrainBase1 = handshake.RegionInfo.TerrainBase1;
            simulator.Region.TerrainBase2 = handshake.RegionInfo.TerrainBase2;
            simulator.Region.TerrainBase3 = handshake.RegionInfo.TerrainBase3;
            simulator.Region.TerrainDetail0 = handshake.RegionInfo.TerrainDetail0;
            simulator.Region.TerrainDetail1 = handshake.RegionInfo.TerrainDetail1;
            simulator.Region.TerrainDetail2 = handshake.RegionInfo.TerrainDetail2;
            simulator.Region.TerrainDetail3 = handshake.RegionInfo.TerrainDetail3;
            simulator.Region.TerrainHeightRange00 = handshake.RegionInfo.TerrainHeightRange00;
            simulator.Region.TerrainHeightRange01 = handshake.RegionInfo.TerrainHeightRange01;
            simulator.Region.TerrainHeightRange10 = handshake.RegionInfo.TerrainHeightRange10;
            simulator.Region.TerrainHeightRange11 = handshake.RegionInfo.TerrainHeightRange11;
            simulator.Region.TerrainStartHeight00 = handshake.RegionInfo.TerrainStartHeight00;
            simulator.Region.TerrainStartHeight01 = handshake.RegionInfo.TerrainStartHeight01;
            simulator.Region.TerrainStartHeight10 = handshake.RegionInfo.TerrainStartHeight10;
            simulator.Region.TerrainStartHeight11 = handshake.RegionInfo.TerrainStartHeight11;
            simulator.Region.WaterHeight = handshake.RegionInfo.WaterHeight;

            Client.Log("Received a region handshake for " + simulator.Region.Name, Helpers.LogLevel.Info);
        }

        private void ParcelOverlayHandler(Packet packet, Simulator simulator)
        {
            ParcelOverlayPacket overlay = (ParcelOverlayPacket)packet;

            if (overlay.ParcelData.SequenceID >= 0 && overlay.ParcelData.SequenceID <= 3)
            {
                Array.Copy(overlay.ParcelData.Data, 0, simulator.Region.ParcelOverlay,
                    overlay.ParcelData.SequenceID * 1024, 1024);
                simulator.Region.ParcelOverlaysReceived++;

                if (simulator.Region.ParcelOverlaysReceived > 3)
                {
                    // TODO: ParcelOverlaysReceived should become internal, and reset to zero every 
                    // time it hits four. Also need a callback here
                }
            }
            else
            {
                Client.Log("Parcel overlay with sequence ID of " + overlay.ParcelData.SequenceID +
                    " received from " + simulator.Region.Name, Helpers.LogLevel.Warning);
            }
        }

        private void EnableSimulatorHandler(Packet packet, Simulator simulator)
        {
            // TODO: Actually connect to the simulator

            // TODO: Sending ConfirmEnableSimulator completely screws things up. :-?

            // Respond to the simulator connection request
            //Packet replyPacket = Packets.Network.ConfirmEnableSimulator(Protocol, AgentID, SessionID);
            //SendPacket(replyPacket, circuit);
        }

        private void KickUserHandler(Packet packet, Simulator simulator)
        {
            string message = Helpers.FieldToString(((KickUserPacket)packet).UserInfo.Reason);

            // Shutdown the network layer
            Shutdown();

            if (OnDisconnected != null)
            {
                try
                {
                    OnDisconnected(DisconnectType.ServerInitiated, message);
                }
                catch (Exception e)
                {
                    Client.Log("Caught an exception in OnDisconnected(): " + e.ToString(),
                        Helpers.LogLevel.Error);
                }
            }
        }
    }

    /// <summary>
    /// Throttles the network traffic for various different traffic types.
    /// Access this class through SecondLife.Throttle
    /// </summary>
    public class AgentThrottle
    {
        /// <summary>Maximum bytes per second for resending unacknowledged packets</summary>
        public float Resend;
        /// <summary>Maximum bytes per second for LayerData terrain</summary>
        public float Land;
        /// <summary>Maximum bytes per second for LayerData wind data</summary>
        public float Wind;
        /// <summary>Maximum bytes per second for LayerData clouds</summary>
        public float Cloud;
        /// <summary>Unknown, includes object data</summary>
        public float Task;
        /// <summary>Maximum bytes per second for textures</summary>
        public float Texture;
        /// <summary>Maximum bytes per second for downloaded assets</summary>
        public float Asset;

        /// <summary>Maximum bytes per second the entire connection, divided up
        /// between invidiual streams using default multipliers</summary>
        public float Total
        {
            get { return Resend + Land + Wind + Cloud + Task + Texture + Asset; }
            set
            {
                // These sane initial values were pulled from the Second Life client
                Resend = (value * 0.1f);
                Land = (float)(value * 0.52f / 3f);
                Wind = (float)(value * 0.05f);
                Cloud = (float)(value * 0.05f);
                Task = (float)(value * 0.704f / 3f);
                Texture = (float)(value * 0.704f / 3f);
                Asset = (float)(value * 0.484f / 3f);
            }
        }

        private SecondLife Client;

        /// <summary>
        /// Default constructor, uses a default high total of 1500 KBps (1536000)
        /// </summary>
        public AgentThrottle(SecondLife client)
        {
            Client = client;
            Total = 1536000.0f;
        }

        /// <summary>
        /// Sets the total KBps throttle
        /// <param name="total">The total kilobytes per second for the connection.
        /// This will be divided up between the various stream types using the 
        /// default multipliers</param>
        /// </summary>
        public AgentThrottle(SecondLife client, float total)
        {
            Client = client;
            // Note that the client itself never seems to go below 75k, even if you tell it to
            Total = total;
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="data"></param>
        /// <param name="pos"></param>
        public AgentThrottle(byte[] data, int pos)
        {
            int i;
            if (!BitConverter.IsLittleEndian)
                for (i = 0; i < 7; i++)
                    Array.Reverse(data, pos + i * 4, 4);

            Resend = BitConverter.ToSingle(data, pos); pos += 4;
            Land = BitConverter.ToSingle(data, pos); pos += 4;
            Wind = BitConverter.ToSingle(data, pos); pos += 4;
            Cloud = BitConverter.ToSingle(data, pos); pos += 4;
            Task = BitConverter.ToSingle(data, pos); pos += 4;
            Texture = BitConverter.ToSingle(data, pos); pos += 4;
            Asset = BitConverter.ToSingle(data, pos);
        }

        /// <summary>
        /// Send an AgentThrottle packet to the server using the current values
        /// </summary>
        public void Set()
        {
            AgentThrottlePacket throttle = new AgentThrottlePacket();
            throttle.AgentData.AgentID = Client.Network.AgentID;
            throttle.AgentData.SessionID = Client.Network.SessionID;
            throttle.AgentData.CircuitCode = Client.Network.CurrentSim.CircuitCode;
            throttle.Throttle.GenCounter = 0;
            throttle.Throttle.Throttles = this.ToBytes();

            Client.Network.SendPacket(throttle);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <returns></returns>
        public byte[] ToBytes()
        {
            byte[] data = new byte[7 * 4];
            int i = 0;

            BitConverter.GetBytes(Resend).CopyTo(data, i); i += 4;
            BitConverter.GetBytes(Land).CopyTo(data, i); i += 4;
            BitConverter.GetBytes(Wind).CopyTo(data, i); i += 4;
            BitConverter.GetBytes(Cloud).CopyTo(data, i); i += 4;
            BitConverter.GetBytes(Task).CopyTo(data, i); i += 4;
            BitConverter.GetBytes(Texture).CopyTo(data, i); i += 4;
            BitConverter.GetBytes(Asset).CopyTo(data, i); i += 4;

            if (!BitConverter.IsLittleEndian)
                for (i = 0; i < 7; i++)
                    Array.Reverse(data, i * 4, 4);

            return data;
        }
    }
}