/*
 * 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:
 *     * 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
 * 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;
using System.Collections.Generic;
using System.Reflection;
using System.Net;
using System.Threading;
using OpenMetaverse;
using log4net;
using Nini.Config;
using Nwc.XmlRpc;
using OpenSim.Framework;
using OpenSim.Framework.Client;
using OpenSim.Region.Interfaces;
using OpenSim.Region.Environment.Interfaces;
using OpenSim.Region.Environment.Scenes;

namespace OpenSim.Region.Environment.Modules.Avatar.InstantMessage
{
    public class PresenceModule : IRegionModule, IPresenceModule
    {
        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        private bool m_Enabled = false;
        private bool m_Gridmode = false;

        // some default scene for doing things that aren't connected to a specific scene. Avoids locking.
        private Scene m_initialScene;

        private List<Scene> m_Scenes = new List<Scene>();

        private Dictionary<UUID, Scene> m_RootAgents =
                new Dictionary<UUID, Scene>();

        public event PresenceChange OnPresenceChange;
        public event BulkPresenceData OnBulkPresenceData;

        public void Initialise(Scene scene, IConfigSource config)
        {
            lock (m_Scenes)
            {
                // This is a shared module; Initialise will be called for every region on this server.
                // Only check config once for the first region.
                if (m_Scenes.Count == 0)
                {
                    IConfig cnf = config.Configs["Messaging"];
                    if (cnf != null && cnf.GetString(
                            "PresenceModule", "PresenceModule") !=
                            "PresenceModule")
                        return;

                    cnf = config.Configs["Startup"];
                    if (cnf != null)
                        m_Gridmode = cnf.GetBoolean("gridmode", false);

                    m_Enabled = true;

                    m_initialScene = scene;
                }

                if (m_Gridmode)
                    NotifyMessageServerOfStartup(scene);

                scene.RegisterModuleInterface<IPresenceModule>(this);

                scene.EventManager.OnNewClient += OnNewClient;
                scene.EventManager.OnSetRootAgentScene += OnSetRootAgentScene;
                //scene.EventManager.OnMakeChildAgent += OnMakeChildAgent;

                m_Scenes.Add(scene);
            }
        }

        public void PostInitialise()
        {
        }

        public void Close()
        {
            if (!m_Gridmode || !m_Enabled)
                return;

            lock (m_Scenes)
            {
                foreach (Scene scene in m_Scenes)
                    NotifyMessageServerOfShutdown(scene);
            }
        }

        public string Name
        {
            get { return "PresenceModule"; }
        }

        public bool IsSharedModule
        {
            get { return true; }
        }

        public void RequestBulkPresenceData(UUID[] users)
        {
            if (OnBulkPresenceData != null)
            {
                PresenceInfo[] result = new PresenceInfo[users.Length];
                if (m_Gridmode)
                {
                    // TODO process local info first and only do a server lookup if necessary.
                    // TODO fix m_RootAgents contents. Currently, they won't work right in a
                    // non standalone server. Consider two servers, with one sim each in a
                    // 2x1 grid. Clients will never be closed, just the root moves from
                    // server to server. But it stays in m_RootAgents on both servers.
                    Dictionary<UUID, FriendRegionInfo> infos = m_initialScene.GetFriendRegionInfos(new List<UUID>(users));
                    for (int i = 0; i < users.Length; ++i)
                    {
                        FriendRegionInfo info;
                        if (infos.TryGetValue(users[i], out info) && info.isOnline)
                        {
                            UUID regionID = info.regionID;
                            if (regionID == UUID.Zero)
                            {
                                // TODO this is the old messaging-server protocol; only the regionHandle is available.
                                // Fetch region-info to get the id
                                RegionInfo regionInfo = m_initialScene.RequestNeighbouringRegionInfo(info.regionHandle);
                                regionID = regionInfo.RegionID;
                            }
                            result[i] = new PresenceInfo(users[i], regionID);
                        }
                        else result[i] = new PresenceInfo(users[i], UUID.Zero);
                    }
                }
                else
                {
                    // in standalone mode, we have all the info locally available.
                    lock (m_RootAgents)
                    {
                        for (int i = 0; i < users.Length; ++i)
                        {
                            Scene scene;
                            if (m_RootAgents.TryGetValue(users[i], out scene))
                            {
                                result[i] = new PresenceInfo(users[i], scene.RegionInfo.RegionID);
                            }
                            else
                            {
                                result[i] = new PresenceInfo(users[i], UUID.Zero);
                            }
                        }
                    }
                }

                // tell everyone
                OnBulkPresenceData(result);
            }
        }

        public void OnNewClient(IClientAPI client)
        {
            client.OnConnectionClosed += OnConnectionClosed;
            client.OnLogout += OnConnectionClosed;
        }

        public void OnConnectionClosed(IClientAPI client)
        {
            if (!(client.Scene is Scene))
                return;

            Scene scene = (Scene)client.Scene;

            // OnConnectionClosed can be called from several threads at once (with different client, of course)
            // Concurrent access to m_RootAgents is prone to failure on multi-core/-processor systems without
            // correct locking).
            lock (m_RootAgents)
            {
                Scene rootScene;
                if (!(m_RootAgents.TryGetValue(client.AgentId, out rootScene)) || scene != rootScene)
                    return;

                m_RootAgents.Remove(client.AgentId);
            }
            NotifyMessageServerOfAgentLeaving(client.AgentId, scene.RegionInfo.RegionID, scene.RegionInfo.RegionHandle);
        }

        public void OnSetRootAgentScene(UUID agentID, Scene scene)
        {
            // OnSetRootAgentScene can be called from several threads at once (with different agentID).
            // Concurrent access to m_RootAgents is prone to failure on multi-core/-processor systems without
            // correct locking).
            lock (m_RootAgents)
            {
                Scene rootScene;
                if (m_RootAgents.TryGetValue(agentID, out rootScene) && scene == rootScene)
                {
                    return;
                }
                m_RootAgents[agentID] = scene;
            }
            NotifyMessageServerOfAgentLocation(agentID, scene.RegionInfo.RegionID, scene.RegionInfo.RegionHandle);
        }

// TODO not sure about that yet
//        public void OnMakeChildAgent(ScenePresence agent)
//        {
//            // OnMakeChildAgent can be called from several threads at once (with different agent).
//            // Concurrent access to m_RootAgents is prone to failure on multi-core/-processor systems without
//            // correct locking).
//            lock (m_RootAgents)
//            {
//                Scene rootScene;
//                if (m_RootAgents.TryGetValue(agentID, out rootScene) && agent.Scene == rootScene)
//                {
//                    m_RootAgents[agentID] = scene;
//                }
//            }
//            // don't notify the messaging-server; either this is just downgraded and another one will be upgraded
//            // to root momentarily (which will notify the messaging-server), or possibly it will be closed in a moment,
//            // which will update the messaging-server, too.
//        }

        private void NotifyMessageServerOfStartup(Scene scene)
        {
            Hashtable xmlrpcdata = new Hashtable();
            xmlrpcdata["RegionUUID"] = scene.RegionInfo.RegionID.ToString();
            ArrayList SendParams = new ArrayList();
            SendParams.Add(xmlrpcdata);
            try
            {
                XmlRpcRequest UpRequest = new XmlRpcRequest("region_startup", SendParams);
                XmlRpcResponse resp = UpRequest.Send(scene.CommsManager.NetworkServersInfo.MessagingURL, 5000);

                Hashtable responseData = (Hashtable)resp.Value;
                if (responseData == null || (!responseData.ContainsKey("success")) || (string)responseData["success"] != "TRUE")
                {
                    m_log.ErrorFormat("[PRESENCE] Failed to notify message server of region startup for region {0}", scene.RegionInfo.RegionName);
                }
            }
            catch (System.Net.WebException)
            {
                m_log.ErrorFormat("[PRESENCE] Failed to notify message server of region startup for region {0}", scene.RegionInfo.RegionName);
            }
        }

        private void NotifyMessageServerOfShutdown(Scene scene)
        {
            Hashtable xmlrpcdata = new Hashtable();
            xmlrpcdata["RegionUUID"] = scene.RegionInfo.RegionID.ToString();
            ArrayList SendParams = new ArrayList();
            SendParams.Add(xmlrpcdata);
            try
            {
                XmlRpcRequest DownRequest = new XmlRpcRequest("region_shutdown", SendParams);
                XmlRpcResponse resp = DownRequest.Send(scene.CommsManager.NetworkServersInfo.MessagingURL, 5000);

                Hashtable responseData = (Hashtable)resp.Value;
                if ((!responseData.ContainsKey("success")) || (string)responseData["success"] != "TRUE")
                {
                    m_log.ErrorFormat("[PRESENCE] Failed to notify message server of region shutdown for region {0}", scene.RegionInfo.RegionName);
                }
            }
            catch (System.Net.WebException)
            {
                m_log.ErrorFormat("[PRESENCE] Failed to notify message server of region shutdown for region {0}", scene.RegionInfo.RegionName);
            }
        }

        private void NotifyMessageServerOfAgentLocation(UUID agentID, UUID region, ulong regionHandle)
        {
            Hashtable xmlrpcdata = new Hashtable();
            xmlrpcdata["AgentID"] = agentID.ToString();
            xmlrpcdata["RegionUUID"] = region.ToString();
            xmlrpcdata["RegionHandle"] = regionHandle.ToString();
            ArrayList SendParams = new ArrayList();
            SendParams.Add(xmlrpcdata);
            try
            {
                XmlRpcRequest LocationRequest = new XmlRpcRequest("agent_location", SendParams);
                XmlRpcResponse resp = LocationRequest.Send(m_Scenes[0].CommsManager.NetworkServersInfo.MessagingURL, 5000);

                Hashtable responseData = (Hashtable)resp.Value;
                if ((!responseData.ContainsKey("success")) || (string)responseData["success"] != "TRUE")
                {
                    m_log.ErrorFormat("[PRESENCE] Failed to notify message server of agent location for {0}", agentID.ToString());
                }
            }
            catch (System.Net.WebException)
            {
                m_log.ErrorFormat("[PRESENCE] Failed to notify message server of agent location for {0}", agentID.ToString());
            }
        }

        private void NotifyMessageServerOfAgentLeaving(UUID agentID, UUID region, ulong regionHandle)
        {
            Hashtable xmlrpcdata = new Hashtable();
            xmlrpcdata["AgentID"] = agentID.ToString();
            xmlrpcdata["RegionUUID"] = region.ToString();
            xmlrpcdata["RegionHandle"] = regionHandle.ToString();
            ArrayList SendParams = new ArrayList();
            SendParams.Add(xmlrpcdata);
            try
            {
                XmlRpcRequest LeavingRequest = new XmlRpcRequest("agent_leaving", SendParams);
                XmlRpcResponse resp = LeavingRequest.Send(m_Scenes[0].CommsManager.NetworkServersInfo.MessagingURL, 5000);

                Hashtable responseData = (Hashtable)resp.Value;
                if ((!responseData.ContainsKey("success")) || (string)responseData["success"] != "TRUE")
                {
                    m_log.ErrorFormat("[PRESENCE] Failed to notify message server of agent leaving for {0}", agentID.ToString());
                }
            }
            catch (System.Net.WebException)
            {
                m_log.ErrorFormat("[PRESENCE] Failed to notify message server of agent leaving for {0}", agentID.ToString());
            }
        }
    }
}