/*
* Copyright (c) Contributors, http://opensimulator.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:
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*       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
* DISCLAIMED. IN NO EVENT SHALL THE CONTRIBUTORS BE LIABLE FOR ANY
* 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 libsecondlife;
using OpenSim.Framework;
using OpenSim.Framework.Communications;
using OpenSim.Framework.Console;

namespace OpenSim.Region.Environment.Scenes
{
    public delegate void KillObjectDelegate(uint localID);

    public class SceneCommunicationService //one instance per region
    {
        protected CommunicationsManager m_commsProvider;
        protected RegionInfo m_regionInfo;

        protected RegionCommsListener regionCommsHost;

        public event AgentCrossing OnAvatarCrossingIntoRegion;
        public event ExpectUserDelegate OnExpectUser;
        public event CloseAgentConnection OnCloseAgentConnection;
        public event PrimCrossing OnPrimCrossingIntoRegion;
        public event RegionUp OnRegionUp;
        public event ChildAgentUpdate OnChildAgentUpdate;
        


        public KillObjectDelegate KillObject;
        public string _debugRegionName = String.Empty;

        public string debugRegionName
        {
            get { return _debugRegionName; }
            set { _debugRegionName = value; }
        }

        public SceneCommunicationService(CommunicationsManager commsMan)
        {
            m_commsProvider = commsMan;
            m_commsProvider.GridService.gdebugRegionName = _debugRegionName;
            m_commsProvider.InterRegion.rdebugRegionName = _debugRegionName;
        }

        public void RegisterRegion(RegionInfo regionInfos)
        {
            m_regionInfo = regionInfos;
            regionCommsHost = m_commsProvider.GridService.RegisterRegion(m_regionInfo);

            if (regionCommsHost != null)
            {
                //MainLog.Instance.Verbose("INTER", debugRegionName + ": SceneCommunicationService: registered with gridservice and got" + regionCommsHost.ToString());

                regionCommsHost.debugRegionName = _debugRegionName;

                regionCommsHost.OnExpectUser += NewUserConnection;
                regionCommsHost.OnAvatarCrossingIntoRegion += AgentCrossing;
                regionCommsHost.OnPrimCrossingIntoRegion += PrimCrossing;
                regionCommsHost.OnCloseAgentConnection += CloseConnection;
                regionCommsHost.OnRegionUp += newRegionUp;
                regionCommsHost.OnChildAgentUpdate += ChildAgentUpdate;
                
            }
            else
            {
                //MainLog.Instance.Verbose("INTER", debugRegionName + ": SceneCommunicationService: registered with gridservice and got null");
            }
        }

        public void Close()
        {
            if (regionCommsHost != null)
            {
                regionCommsHost.OnChildAgentUpdate -= ChildAgentUpdate;
                regionCommsHost.OnRegionUp -= newRegionUp;
                regionCommsHost.OnExpectUser -= NewUserConnection;
                regionCommsHost.OnAvatarCrossingIntoRegion -= AgentCrossing;
                regionCommsHost.OnPrimCrossingIntoRegion -= PrimCrossing;
                regionCommsHost.OnCloseAgentConnection -= CloseConnection;
                m_commsProvider.GridService.DeregisterRegion(m_regionInfo);
                regionCommsHost = null;
            }
        }

        #region CommsManager Event handlers

        /// <summary>
        /// 
        /// </summary>
        /// <param name="regionHandle"></param>
        /// <param name="agent"></param>
        ///
        protected void NewUserConnection(ulong regionHandle, AgentCircuitData agent)
        {
            if (OnExpectUser != null)
            {
                //MainLog.Instance.Verbose("INTER", debugRegionName + ": SceneCommunicationService: OnExpectUser Fired for User:" + agent.firstname + " " + agent.lastname);
                OnExpectUser(regionHandle, agent);
            }
        }

        protected bool newRegionUp(RegionInfo region)
        {
            if (OnRegionUp != null)
            {
                //MainLog.Instance.Verbose("INTER", debugRegionName + ": SceneCommunicationService: newRegionUp Fired for User:" + region.RegionName);
                OnRegionUp(region);
            }
            return true;
        }

        protected bool ChildAgentUpdate(ulong regionHandle, ChildAgentDataUpdate cAgentData)
        {
            if (OnChildAgentUpdate != null)
                OnChildAgentUpdate(regionHandle, cAgentData);


            return true;
        }

        protected void AgentCrossing(ulong regionHandle, LLUUID agentID, LLVector3 position, bool isFlying)
        {
            if (OnAvatarCrossingIntoRegion != null)
            {
                OnAvatarCrossingIntoRegion(regionHandle, agentID, position, isFlying);
            }
        }

        protected void PrimCrossing(ulong regionHandle, LLUUID primID, LLVector3 position, bool isPhysical)
        {
            if (OnPrimCrossingIntoRegion != null)
            {
                OnPrimCrossingIntoRegion(regionHandle, primID, position, isPhysical);
            }
        }

        protected bool CloseConnection(ulong regionHandle, LLUUID agentID)
        {
            MainLog.Instance.Verbose("INTERREGION", "Incoming Agent Close Request for agent: " + agentID.ToString());
            
            if (OnCloseAgentConnection != null)
            {
                return OnCloseAgentConnection(regionHandle, agentID);
            }
            return false;
        }

        #endregion

        #region Inform Client of Neighbours

        private delegate void InformClientOfNeighbourDelegate(
            ScenePresence avatar, AgentCircuitData a, ulong regionHandle, IPEndPoint endPoint);

        private void InformClientOfNeighbourCompleted(IAsyncResult iar)
        {
            InformClientOfNeighbourDelegate icon = (InformClientOfNeighbourDelegate) iar.AsyncState;
            icon.EndInvoke(iar);
        }

        /// <summary>
        /// Async compnent for informing client of which neighbours exists
        /// </summary>
        /// <remarks>
        /// This needs to run asynchronesously, as a network timeout may block the thread for a long while
        /// </remarks>
        /// <param name="remoteClient"></param>
        /// <param name="a"></param>
        /// <param name="regionHandle"></param>
        /// <param name="endPoint"></param>
        private void InformClientOfNeighbourAsync(ScenePresence avatar, AgentCircuitData a, ulong regionHandle,
                                                  IPEndPoint endPoint)
        {
            MainLog.Instance.Notice("INTERGRID", "Starting to inform client about neighbours");
            bool regionAccepted = m_commsProvider.InterRegion.InformRegionOfChildAgent(regionHandle, a);

            if (regionAccepted)
            {
                avatar.ControllingClient.InformClientOfNeighbour(regionHandle, endPoint);
                avatar.AddNeighbourRegion(regionHandle);
                MainLog.Instance.Notice("INTERGRID", "Completed inform client about neighbours");
            }
        }

        public void RequestNeighbors(RegionInfo region)
        {
            List<SimpleRegionInfo> neighbours =
                m_commsProvider.GridService.RequestNeighbours(m_regionInfo.RegionLocX, m_regionInfo.RegionLocY);
            //IPEndPoint blah = new IPEndPoint();

            //blah.Address = region.RemotingAddress;
            //blah.Port = region.RemotingPort;
        }

        /// <summary>
        /// This informs all neighboring regions about agent "avatar".
        /// Calls an asynchronous method to do so..  so it doesn't lag the sim.
        /// </summary>
        public void EnableNeighbourChildAgents(ScenePresence avatar, List<RegionInfo> lstneighbours)
        {
            List<SimpleRegionInfo> neighbours = new List<SimpleRegionInfo>();

            //m_commsProvider.GridService.RequestNeighbours(m_regionInfo.RegionLocX, m_regionInfo.RegionLocY);
            for (int i = 0; i < lstneighbours.Count; i++)
            {
                // We don't want to keep sending to regions that consistently fail on comms.
                if (!(lstneighbours[i].commFailTF))
                {
                    neighbours.Add(new SimpleRegionInfo(lstneighbours[i]));
                }
            }
            // we're going to be using the above code once neighbour cache is correct.  Currently it doesn't appear to be
            // So we're temporarily going back to the old method of grabbing it from the Grid Server Every time :/
            neighbours =
                m_commsProvider.GridService.RequestNeighbours(m_regionInfo.RegionLocX, m_regionInfo.RegionLocY);

            if (neighbours != null)
            {
                for (int i = 0; i < neighbours.Count; i++)
                {
                    AgentCircuitData agent = avatar.ControllingClient.RequestClientInfo();
                    agent.BaseFolder = LLUUID.Zero;
                    agent.InventoryFolder = LLUUID.Zero;
                    agent.startpos = new LLVector3(128, 128, 70);
                    agent.child = true;

                    InformClientOfNeighbourDelegate d = InformClientOfNeighbourAsync;
                    d.BeginInvoke(avatar, agent, neighbours[i].RegionHandle, neighbours[i].ExternalEndPoint,
                                  InformClientOfNeighbourCompleted,
                                  d);
                }
            }
        }

        /// <summary>
        /// This informs a single neighboring region about agent "avatar".
        /// Calls an asynchronous method to do so..  so it doesn't lag the sim.
        /// </summary>
        public void InformNeighborChildAgent(ScenePresence avatar, RegionInfo region, List<RegionInfo> neighbours)
        {
            AgentCircuitData agent = avatar.ControllingClient.RequestClientInfo();
            agent.BaseFolder = LLUUID.Zero;
            agent.InventoryFolder = LLUUID.Zero;
            agent.startpos = new LLVector3(128, 128, 70);
            agent.child = true;

            InformClientOfNeighbourDelegate d = InformClientOfNeighbourAsync;
            d.BeginInvoke(avatar, agent, region.RegionHandle, region.ExternalEndPoint,
                          InformClientOfNeighbourCompleted,
                          d);
        }

        #endregion

        public delegate void InformNeighbourThatRegionUpDelegate(RegionInfo region, ulong regionhandle);

        private void InformNeighborsThatRegionisUpCompleted(IAsyncResult iar)
        {
            InformNeighbourThatRegionUpDelegate icon = (InformNeighbourThatRegionUpDelegate) iar.AsyncState;
            icon.EndInvoke(iar);
        }


        private void InformNeighboursThatRegionIsUpAsync(RegionInfo region, ulong regionhandle)
        {
            MainLog.Instance.Notice("INTERGRID", "Starting to inform neighbors that I'm here");
            bool regionAccepted =
                m_commsProvider.InterRegion.RegionUp((new SearializableRegionInfo(region)), regionhandle);

            if (regionAccepted)
            {
                MainLog.Instance.Notice("INTERGRID", "Completed informing neighbors that I'm here");
            }
            else
            {
                MainLog.Instance.Notice("INTERGRID", "Failed to inform neighbors that I'm here");
            }
        }

        /// <summary>
        /// Called by scene when region is initialized (not always when it's listening for agents)
        /// This is an inter-region message that informs the surrounding neighbors that the sim is up.
        /// </summary>
        public void InformNeighborsThatRegionisUp(RegionInfo region)
        {
            //MainLog.Instance.Verbose("INTER", debugRegionName + ": SceneCommunicationService: Sending InterRegion Notification that region is up " + region.RegionName);


            List<SimpleRegionInfo> neighbours = new List<SimpleRegionInfo>();
            // This stays uncached because we don't already know about our neighbors at this point.
            neighbours = m_commsProvider.GridService.RequestNeighbours(m_regionInfo.RegionLocX, m_regionInfo.RegionLocY);
            if (neighbours != null)
            {
                for (int i = 0; i < neighbours.Count; i++)
                {
                    InformNeighbourThatRegionUpDelegate d = InformNeighboursThatRegionIsUpAsync;

                    d.BeginInvoke(region, neighbours[i].RegionHandle,
                                  InformNeighborsThatRegionisUpCompleted,
                                  d);
                }
            }

            //bool val = m_commsProvider.InterRegion.RegionUp(new SearializableRegionInfo(region));
        }

        public delegate void SendChildAgentDataUpdateDelegate(ChildAgentDataUpdate cAgentData, ScenePresence presence);

        /// <summary>
        /// This informs all neighboring regions about the settings of it's child agent.
        /// Calls an asynchronous method to do so..  so it doesn't lag the sim.
        /// 
        /// This contains information, such as, Draw Distance, Camera location, Current Position, Current throttle settings, etc.
        /// 
        /// </summary>
        private void SendChildAgentDataUpdateAsync(ChildAgentDataUpdate cAgentData, ScenePresence presence)
        {
            //MainLog.Instance.Notice("INTERGRID", "Informing neighbors about my agent.");
            try
            {
                foreach (ulong regionHandle in presence.KnownChildRegions)
                {
                    bool regionAccepted = m_commsProvider.InterRegion.ChildAgentUpdate(regionHandle, cAgentData);

                    if (regionAccepted)
                    {
                        //MainLog.Instance.Notice("INTERGRID", "Completed sending a neighbor an update about my agent");
                    }
                    else
                    {
                        //MainLog.Instance.Notice("INTERGRID", "Failed sending a neighbor an update about my agent");
                    }
                }
            }
            catch (System.InvalidOperationException)
            {
                // We're ignoring a collection was modified error because this data gets old and outdated fast.
            }

        }

        private void SendChildAgentDataUpdateCompleted(IAsyncResult iar)
        {
            SendChildAgentDataUpdateDelegate icon = (SendChildAgentDataUpdateDelegate) iar.AsyncState;
            icon.EndInvoke(iar);
        }

        public void SendChildAgentDataUpdate(ChildAgentDataUpdate cAgentData, ScenePresence presence)
        {
            // This assumes that we know what our neighbors are.
            SendChildAgentDataUpdateDelegate d = SendChildAgentDataUpdateAsync;
            d.BeginInvoke(cAgentData,presence,
                          SendChildAgentDataUpdateCompleted,
                          d);
        }

        public delegate void SendCloseChildAgentDelegate( ScenePresence presence);

        /// <summary>
        /// This Closes child agents on neighboring regions
        /// Calls an asynchronous method to do so..  so it doesn't lag the sim.
        /// </summary>
        private void SendCloseChildAgentAsync(ScenePresence presence)
        {

            foreach (ulong regionHandle in presence.KnownChildRegions)
            {
                bool regionAccepted = m_commsProvider.InterRegion.TellRegionToCloseChildConnection(regionHandle, presence.ControllingClient.AgentId);

                if (regionAccepted)
                {
                    MainLog.Instance.Notice("INTERGRID", "Completed sending agent Close agent Request to neighbor");
                    presence.RemoveNeighbourRegion(regionHandle);
                }
                else
                {
                    MainLog.Instance.Notice("INTERGRID", "Failed sending agent Close agent Request to neighbor");
                    
                }
                
            }
        }

        private void SendCloseChildAgentCompleted(IAsyncResult iar)
        {
            SendCloseChildAgentDelegate icon = (SendCloseChildAgentDelegate)iar.AsyncState;
            icon.EndInvoke(iar);
        }

        public void SendCloseChildAgentConnections(ScenePresence presence)
        {
            // This assumes that we know what our neighbors are.
            SendCloseChildAgentDelegate d = SendCloseChildAgentAsync;
            d.BeginInvoke(presence,
                          SendCloseChildAgentCompleted,
                          d);
        }

        /// <summary>
        /// Helper function to request neighbors from grid-comms
        /// </summary>
        /// <param name="regionHandle"></param>
        /// <returns></returns>
        public virtual RegionInfo RequestNeighbouringRegionInfo(ulong regionHandle)
        {
            //MainLog.Instance.Verbose("INTER", debugRegionName + ": SceneCommunicationService: Sending Grid Services Request about neighbor " + regionHandle.ToString());
            return m_commsProvider.GridService.RequestNeighbourInfo(regionHandle);
        }

        /// <summary>
        /// Requests map blocks in area of minX, maxX, minY, MaxY in world cordinates
        /// </summary>
        /// <param name="minX"></param>
        /// <param name="minY"></param>
        /// <param name="maxX"></param>
        /// <param name="maxY"></param>
        public virtual void RequestMapBlocks(IClientAPI remoteClient, int minX, int minY, int maxX, int maxY)
        {
            List<MapBlockData> mapBlocks;
            mapBlocks = m_commsProvider.GridService.RequestNeighbourMapBlocks(minX - 4, minY - 4, minX + 4, minY + 4);
            remoteClient.SendMapBlock(mapBlocks);
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="remoteClient"></param>
        /// <param name="RegionHandle"></param>
        /// <param name="position"></param>
        /// <param name="lookAt"></param>
        /// <param name="flags"></param>
        public virtual void RequestTeleportToLocation(ScenePresence avatar, ulong regionHandle, LLVector3 position,
                                                      LLVector3 lookAt, uint flags)
        {
            bool destRegionUp = false;
            if (regionHandle == m_regionInfo.RegionHandle)
            {
                avatar.ControllingClient.SendTeleportLocationStart();
                avatar.ControllingClient.SendLocalTeleport(position, lookAt, flags);
                avatar.Teleport(position);
            }
            else
            {
                RegionInfo reg = RequestNeighbouringRegionInfo(regionHandle);
                if (reg != null)
                {
                    avatar.ControllingClient.SendTeleportLocationStart();
                    AgentCircuitData agent = avatar.ControllingClient.RequestClientInfo();
                    agent.BaseFolder = LLUUID.Zero;
                    agent.InventoryFolder = LLUUID.Zero;
                    agent.startpos = position;
                    agent.child = true;

                    if (reg.RemotingAddress != "" && reg.RemotingPort != 0)
                    {
                        // region is remote. see if it is up
                        m_commsProvider.InterRegion.CheckRegion(reg.RemotingAddress, reg.RemotingPort);
                        destRegionUp = m_commsProvider.InterRegion.Available;
                    }
                    else
                    {
                        // assume local regions are always up
                        destRegionUp = true;
                    }
                    if(destRegionUp)
                    {
                        avatar.Close();
                        m_commsProvider.InterRegion.InformRegionOfChildAgent(regionHandle, agent);
                        m_commsProvider.InterRegion.ExpectAvatarCrossing(regionHandle, avatar.ControllingClient.AgentId,
                                                                     position, false);
                        AgentCircuitData circuitdata = avatar.ControllingClient.RequestClientInfo();
                        string capsPath = Util.GetCapsURL(avatar.ControllingClient.AgentId);
                        avatar.ControllingClient.SendRegionTeleport(regionHandle, 13, reg.ExternalEndPoint, 4, (1 << 4),
                                                                    capsPath);
                        avatar.MakeChildAgent();
                        if (KillObject != null)
                        {
                            KillObject(avatar.LocalId);
                        }
                        uint newRegionX = (uint)(regionHandle >> 40);
                        uint newRegionY = (((uint)(regionHandle)) >> 8);
                        uint oldRegionX = (uint)(m_regionInfo.RegionHandle >> 40);
                        uint oldRegionY = (((uint)(m_regionInfo.RegionHandle)) >> 8);
                        if (Util.fast_distance2d((int)(newRegionX - oldRegionX), (int)(newRegionY - oldRegionY)) > 3)
                        {
                            SendCloseChildAgentConnections(avatar);
                        }
                    }
                    else
                    {
                        avatar.ControllingClient.SendTeleportFailed("Remote Region appears to be down");
                    }
                }
            }
        }

        /// <summary>
        /// 
        /// </summary>
        /// <param name="regionhandle"></param>
        /// <param name="agentID"></param>
        /// <param name="position"></param>
        public bool CrossToNeighbouringRegion(ulong regionhandle, LLUUID agentID, LLVector3 position, bool isFlying)
        {
            return m_commsProvider.InterRegion.ExpectAvatarCrossing(regionhandle, agentID, position, isFlying);
        }

        public bool PrimCrossToNeighboringRegion(ulong regionhandle, LLUUID primID, LLVector3 position, bool isPhysical)
        {
            return m_commsProvider.InterRegion.ExpectPrimCrossing(regionhandle, primID, position, isPhysical);
        }


        public Dictionary<string, string> GetGridSettings()
        {
            return m_commsProvider.GridService.GetGridSettings();
        }
    }
}