/*
* Copyright (c) Contributors, http://opensimulator.org/
* See CONTRIBUTORS.TXT for a full list of copyright holders.
*
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* modification, are permitted provided that the following conditions are met:
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*       derived from this software without specific prior written permission.
*
* THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS AND ANY
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*/
using System;
using System.Collections.Generic;
using System.Net;
using System.Text;
using System.Threading;
using System.Timers;
using libsecondlife;
using libsecondlife.Packets;
using OpenSim.Framework;
using OpenSim.Framework.Communications.Cache;
using OpenSim.Framework.Console;
using Timer=System.Timers.Timer;

namespace OpenSim.Region.ClientStack
{
    public delegate bool PacketMethod(IClientAPI simClient, Packet packet);

    /// <summary>
    /// Handles new client connections
    /// Constructor takes a single Packet and authenticates everything
    /// </summary>
    public partial class ClientView : IClientAPI
    {
        public static TerrainManager TerrainManager;

        protected static Dictionary<PacketType, PacketMethod> PacketHandlers =
            new Dictionary<PacketType, PacketMethod>(); //Global/static handlers for all clients

        protected Dictionary<PacketType, PacketMethod> m_packetHandlers = new Dictionary<PacketType, PacketMethod>();
        //local handlers for this instance 

        private LLUUID m_sessionId;
        public LLUUID SecureSessionID = LLUUID.Zero;
        public string firstName;
        public string lastName;
        private UseCircuitCodePacket cirpack;
        public Thread ClientThread;
        public LLVector3 startpos;

        //private AgentAssetUpload UploadAssets;
        private LLUUID newAssetFolder = LLUUID.Zero;
        private int debug = 0;

        protected IScene m_scene;

        public IScene Scene
        {
            get { return m_scene; }
        }

        private ClientManager m_clientManager;
        private AssetCache m_assetCache;
        // private InventoryCache m_inventoryCache;
        private int cachedtextureserial = 0;
        protected AgentCircuitManager m_authenticateSessionsHandler;
        private Encoding enc = Encoding.ASCII;
        // Dead client detection vars
        private Timer clientPingTimer;
        private int packetsReceived = 0;
        private int probesWithNoIngressPackets = 0;
        private int lastPacketsReceived = 0;


        private int throttleOutbound = 262144; // Number of bytes allowed to go out per second. (256kbps per client) 
                                              // TODO: Make this variable. Lower throttle on un-ack. Raise over time?
        private int throttleSentPeriod = 0;   // Number of bytes sent this period

        private Timer throttleTimer;

        public ClientView(EndPoint remoteEP, UseCircuitCodePacket initialcirpack, ClientManager clientManager,
                          IScene scene, AssetCache assetCache, PacketServer packServer,
                          AgentCircuitManager authenSessions)
        {
            m_moneyBalance = 1000;

            m_scene = scene;
            m_clientManager = clientManager;
            m_assetCache = assetCache;

            m_networkServer = packServer;
            // m_inventoryCache = inventoryCache;
            m_authenticateSessionsHandler = authenSessions;

            MainLog.Instance.Verbose("CLIENT", "Started up new client thread to handle incoming request");
            cirpack = initialcirpack;
            userEP = remoteEP;

            startpos = m_authenticateSessionsHandler.GetPosition(initialcirpack.CircuitCode.Code);

            PacketQueue = new BlockingQueue<QueItem>();

            //this.UploadAssets = new AgentAssetUpload(this, m_assetCache, m_inventoryCache);
            AckTimer = new Timer(750);
            AckTimer.Elapsed += new ElapsedEventHandler(AckTimer_Elapsed);
            AckTimer.Start();

            throttleTimer = new Timer(1000);
            throttleTimer.Elapsed += new ElapsedEventHandler(throttleTimer_Elapsed);
            throttleTimer.Start();

            RegisterLocalPacketHandlers();

            ClientThread = new Thread(new ThreadStart(AuthUser));
            ClientThread.IsBackground = true;
            ClientThread.Start();
        }

        void throttleTimer_Elapsed(object sender, ElapsedEventArgs e)
        {
            throttleSentPeriod = 0;
        }

        public LLUUID SessionId
        {
            get { return m_sessionId; }
        }

        public void SetDebug(int newDebug)
        {
            debug = newDebug;
        }

        # region Client Methods

        public void Close()
        {
            clientPingTimer.Stop();

            m_scene.RemoveClient(AgentId);

            ClientThread.Abort();
        }

        #endregion

        # region Packet Handling

        public static bool AddPacketHandler(PacketType packetType, PacketMethod handler)
        {
            bool result = false;
            lock (PacketHandlers)
            {
                if (!PacketHandlers.ContainsKey(packetType))
                {
                    PacketHandlers.Add(packetType, handler);
                    result = true;
                }
            }
            return result;
        }

        public bool AddLocalPacketHandler(PacketType packetType, PacketMethod handler)
        {
            bool result = false;
            lock (m_packetHandlers)
            {
                if (!m_packetHandlers.ContainsKey(packetType))
                {
                    m_packetHandlers.Add(packetType, handler);
                    result = true;
                }
            }
            return result;
        }

        protected virtual bool ProcessPacketMethod(Packet packet)
        {
            bool result = false;
            bool found = false;
            PacketMethod method;
            if (m_packetHandlers.TryGetValue(packet.Type, out method))
            {
                //there is a local handler for this packet type
                result = method(this, packet);
            }
            else
            {
                //there is not a local handler so see if there is a Global handler
                lock (PacketHandlers)
                {
                    found = PacketHandlers.TryGetValue(packet.Type, out method);
                }
                if (found)
                {
                    result = method(this, packet);
                }
            }
            return result;
        }

        protected void DebugPacket(string direction, Packet packet)
        {
            if (debug > 0)
            {
                string info = "";
                if (debug < 255 && packet.Type == PacketType.AgentUpdate)
                    return;
                if (debug < 254 && packet.Type == PacketType.ViewerEffect)
                    return;
                if (debug < 253 && (
                                       packet.Type == PacketType.CompletePingCheck ||
                                       packet.Type == PacketType.StartPingCheck
                                   ))
                    return;
                if (debug < 252 && packet.Type == PacketType.PacketAck)
                    return;

                if (debug > 1)
                {
                    info = packet.ToString();
                }
                else
                {
                    info = packet.Type.ToString();
                }
                Console.WriteLine(m_circuitCode + ":" + direction + ": " + info);
            }
        }

        protected virtual void ClientLoop()
        {
            MainLog.Instance.Verbose("CLIENT", "Entered loop");
            while (true)
            {
                QueItem nextPacket = PacketQueue.Dequeue();
                if (nextPacket.Incoming)
                {
                    //is a incoming packet
                    if (nextPacket.Packet.Type != PacketType.AgentUpdate)
                    {
                        packetsReceived++;
                    }
                    DebugPacket("IN", nextPacket.Packet);
                    ProcessInPacket(nextPacket.Packet);
                }
                else
                {
                    // Throw it back on the queue if it's going to cause us to flood the client
                    if (throttleSentPeriod > throttleOutbound)
                    {
                        PacketQueue.Enqueue(nextPacket);
                        Thread.Sleep(100); // Wait a little while, should prevent a CPU spike during high transmission periods
                    }
                    else
                    {
                        // TODO: May be a bit expensive doing this twice.
                        throttleSentPeriod += nextPacket.Packet.ToBytes().Length;

                        //is a out going packet
                        DebugPacket("OUT", nextPacket.Packet);
                        ProcessOutPacket(nextPacket.Packet);
                    }
                }
            }
        }

        # endregion

        protected void CheckClientConnectivity(object sender, ElapsedEventArgs e)
        {
            if (packetsReceived == lastPacketsReceived)
            {
                probesWithNoIngressPackets++;
                if (probesWithNoIngressPackets > 30)
                {
                    if (OnConnectionClosed != null)
                    {
                        OnConnectionClosed(this);
                    }
                }
                else
                {
                    // this will normally trigger at least one packet (ping response)
                    SendStartPingCheck(0);
                }
            }
            else
            {
                // Something received in the meantime - we can reset the counters
                probesWithNoIngressPackets = 0;
                lastPacketsReceived = packetsReceived;
            }
        }

        # region Setup

        protected virtual void InitNewClient()
        {
            clientPingTimer = new Timer(5000);
            clientPingTimer.Elapsed += new ElapsedEventHandler(CheckClientConnectivity);
            clientPingTimer.Enabled = true;

            MainLog.Instance.Verbose("CLIENT", "Adding viewer agent to scene");
            m_scene.AddNewClient(this, true);
        }

        protected virtual void AuthUser()
        {
            // AuthenticateResponse sessionInfo = m_gridServer.AuthenticateSession(cirpack.m_circuitCode.m_sessionId, cirpack.m_circuitCode.ID, cirpack.m_circuitCode.Code);
            AuthenticateResponse sessionInfo =
                m_authenticateSessionsHandler.AuthenticateSession(cirpack.CircuitCode.SessionID, cirpack.CircuitCode.ID,
                                                                  cirpack.CircuitCode.Code);
            if (!sessionInfo.Authorised)
            {
                //session/circuit not authorised
                MainLog.Instance.Notice("CLIENT", "New user request denied to " + userEP.ToString());
                ClientThread.Abort();
            }
            else
            {
                MainLog.Instance.Notice("CLIENT", "Got authenticated connection from " + userEP.ToString());
                //session is authorised
                m_agentId = cirpack.CircuitCode.ID;
                m_sessionId = cirpack.CircuitCode.SessionID;
                m_circuitCode = cirpack.CircuitCode.Code;
                firstName = sessionInfo.LoginInfo.First;
                lastName = sessionInfo.LoginInfo.Last;

                if (sessionInfo.LoginInfo.SecureSession != LLUUID.Zero)
                {
                    SecureSessionID = sessionInfo.LoginInfo.SecureSession;
                }
                InitNewClient();

                ClientLoop();
            }
        }

        # endregion

        protected void KillThread()
        {
            ClientThread.Abort();
        }
    }
}