/*
* Copyright (c) Contributors, http://www.openmetaverse.org/
* See CONTRIBUTORS.TXT for a full list of copyright holders.
*
* 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.
*     * Redistributions in binary form must reproduce the above copyright
*       notice, this list of conditions and the following disclaimer in the
*       documentation and/or other materials provided with the distribution.
*     * Neither the name of the OpenSim Project 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 DEVELOPERS ``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
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
* (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
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* 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.Generic;
using System.Net;
using System.Net.Sockets;
using libsecondlife.Packets;
using OpenSim.Assets;
using OpenSim.Framework;
using OpenSim.Framework.Console;
using OpenSim.Framework.Interfaces;
using OpenSim.Region.Caches;

namespace OpenSim.Region.ClientStack
{

    public class UDPServer : ClientStackNetworkHandler
    {
        protected Dictionary<EndPoint, uint> clientCircuits = new Dictionary<EndPoint, uint>();
        public Socket Server;
        protected IPEndPoint ServerIncoming;
        protected byte[] RecvBuffer = new byte[4096];
        protected byte[] ZeroBuffer = new byte[8192];
        protected IPEndPoint ipeSender;
        protected EndPoint epSender;
        protected AsyncCallback ReceivedData;
        protected PacketServer _packetServer;

        protected int listenPort;
        protected IWorld m_localWorld;
        protected AssetCache m_assetCache;
        protected InventoryCache m_inventoryCache;
        protected LogBase m_log;
        protected AuthenticateSessionsBase m_authenticateSessionsClass;

        public PacketServer PacketServer
        {
            get
            {
                return _packetServer;
            }
            set
            {
                _packetServer = value;
            }
        }

        public IWorld LocalWorld
        {
            set
            {
                this.m_localWorld = value;
                this._packetServer.LocalWorld = this.m_localWorld;
            }
        }

        public UDPServer()
        {
        }

        public UDPServer(int port, AssetCache assetCache, InventoryCache inventoryCache, LogBase console, AuthenticateSessionsBase authenticateClass)
        {
            listenPort = port;
            this.m_assetCache = assetCache;
            this.m_inventoryCache = inventoryCache;
            this.m_log = console;
            this.m_authenticateSessionsClass = authenticateClass;
            this.CreatePacketServer();

        }

        protected virtual void CreatePacketServer()
        {
            PacketServer packetServer = new PacketServer(this);
        }

        protected virtual void OnReceivedData(IAsyncResult result)
        {
            ipeSender = new IPEndPoint(IPAddress.Parse("0.0.0.0"), 0);
            epSender = (EndPoint)ipeSender;
            Packet packet = null;
            int numBytes = Server.EndReceiveFrom(result, ref epSender);
            int packetEnd = numBytes - 1;

            packet = Packet.BuildPacket(RecvBuffer, ref packetEnd, ZeroBuffer);

            // do we already have a circuit for this endpoint
            if (this.clientCircuits.ContainsKey(epSender))
            {
                //if so then send packet to the packetserver
                this._packetServer.ClientInPacket(this.clientCircuits[epSender], packet);
            }
            else if (packet.Type == PacketType.UseCircuitCode)
            {
                // new client
                this.AddNewClient(packet);
            }
            else
            { // invalid client
                m_log.Warn("UDPServer.cs:OnReceivedData() - WARNING: Got a packet from an invalid client - " + epSender.ToString());
            }

            Server.BeginReceiveFrom(RecvBuffer, 0, RecvBuffer.Length, SocketFlags.None, ref epSender, ReceivedData, null);
        }

        protected virtual void AddNewClient(Packet packet)
        {
            UseCircuitCodePacket useCircuit = (UseCircuitCodePacket)packet;
            this.clientCircuits.Add(epSender, useCircuit.CircuitCode.Code);

            this.PacketServer.AddNewClient(epSender, useCircuit, m_assetCache, m_inventoryCache, m_authenticateSessionsClass); 
        }

        public void ServerListener()
        {
            m_log.Status("UDPServer.cs:ServerListener() - Opening UDP socket on " + listenPort);

            ServerIncoming = new IPEndPoint(IPAddress.Parse("0.0.0.0"), listenPort);
            Server = new Socket(AddressFamily.InterNetwork, SocketType.Dgram, ProtocolType.Udp);
            Server.Bind(ServerIncoming);
 
            m_log.Verbose("UDPServer.cs:ServerListener() - UDP socket bound, getting ready to listen");

            ipeSender = new IPEndPoint(IPAddress.Parse("0.0.0.0"), 0);
            epSender = (EndPoint)ipeSender;
            ReceivedData = new AsyncCallback(this.OnReceivedData);
            Server.BeginReceiveFrom(RecvBuffer, 0, RecvBuffer.Length, SocketFlags.None, ref epSender, ReceivedData, null);

            m_log.Verbose("UDPServer.cs:ServerListener() - Listening...");

        }

        public virtual void RegisterPacketServer(PacketServer server)
        {
            this._packetServer = server;
        }

        public virtual void SendPacketTo(byte[] buffer, int size, SocketFlags flags, uint circuitcode)//EndPoint packetSender)
        {
            // find the endpoint for this circuit
            EndPoint sendto = null;
            foreach (KeyValuePair<EndPoint, uint> p in this.clientCircuits)
            {
                if (p.Value == circuitcode)
                {
                    sendto = p.Key;
                    break;
                }
            }
            if (sendto != null)
            {
                //we found the endpoint so send the packet to it
                this.Server.SendTo(buffer, size, flags, sendto);
            }
        }

        public virtual void RemoveClientCircuit(uint circuitcode)
        {
            foreach (KeyValuePair<EndPoint, uint> p in this.clientCircuits)
            {
                if (p.Value == circuitcode)
                {
                    this.clientCircuits.Remove(p.Key);
                    break;
                }
            }
        }

      
    }
}