/*
 * 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 OpenSimulator 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;
 * 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.Collections;
using System.Collections.Generic;
using System.Net;
using System.Reflection;
using log4net;
using Nini.Config;
using Nwc.XmlRpc;
using Mono.Addins;
using OpenMetaverse;
using OpenSim.Framework;
using OpenSim.Framework.Servers;
using OpenSim.Region.Framework.Interfaces;
using OpenSim.Region.Framework.Scenes;
using GridRegion = OpenSim.Services.Interfaces.GridRegion;
using PresenceInfo = OpenSim.Services.Interfaces.PresenceInfo;
using OpenSim.Services.Interfaces;
using OpenSim.Services.Connectors.InstantMessage;
using OpenSim.Services.Connectors.Hypergrid;
using OpenSim.Server.Handlers.Hypergrid;

namespace OpenSim.Region.CoreModules.Avatar.InstantMessage
{
    [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule", Id = "HGMessageTransferModule")]
    public class HGMessageTransferModule : ISharedRegionModule, IMessageTransferModule, IInstantMessageSimConnector
    {
        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        protected bool m_Enabled = false;
        protected List<Scene> m_Scenes = new List<Scene>();

        protected IInstantMessage m_IMService;
        protected Dictionary<UUID, object> m_UserLocationMap = new Dictionary<UUID, object>();

        public event UndeliveredMessage OnUndeliveredMessage;

        IUserManagement m_uMan;
        IUserManagement UserManagementModule
        {
            get
            {
                if (m_uMan == null)
                    m_uMan = m_Scenes[0].RequestModuleInterface<IUserManagement>();
                return m_uMan;
            }
        }

        public virtual void Initialise(IConfigSource config)
        {
            IConfig cnf = config.Configs["Messaging"];
            if (cnf != null && cnf.GetString("MessageTransferModule", "MessageTransferModule") != Name)
            {
                m_log.Debug("[HG MESSAGE TRANSFER]: Disabled by configuration");
                return;
            }

            InstantMessageServerConnector imServer = new InstantMessageServerConnector(config, MainServer.Instance, this);
            m_IMService = imServer.GetService();
            m_Enabled = true;
        }

        public virtual void AddRegion(Scene scene)
        {
            if (!m_Enabled)
                return;

            lock (m_Scenes)
            {
                m_log.DebugFormat("[HG MESSAGE TRANSFER]: Message transfer module {0} active", Name);
                scene.RegisterModuleInterface<IMessageTransferModule>(this);
                m_Scenes.Add(scene);
            }
        }

        public virtual void PostInitialise()
        {
            if (!m_Enabled)
                return;

        }

        public virtual void RegionLoaded(Scene scene)
        {
        }

        public virtual void RemoveRegion(Scene scene)
        {
            if (!m_Enabled)
                return;

            lock (m_Scenes)
            {
                m_Scenes.Remove(scene);
            }
        }

        public virtual void Close()
        {
        }

        public virtual string Name
        {
            get { return "HGMessageTransferModule"; }
        }

        public virtual Type ReplaceableInterface
        {
            get { return null; }
        }

        public void SendInstantMessage(GridInstantMessage im, MessageResultNotification result)
        {
            UUID toAgentID = new UUID(im.toAgentID);
            if (toAgentID.IsZero())
                return;

            ScenePresence achildsp = null;
            // Try root avatar first
            foreach (Scene scene in m_Scenes)
            {
                //m_log.DebugFormat(
                //    "[HG INSTANT MESSAGE]: Looking for root agent {0} in {1}",
                //     toAgentID.ToString(), scene.RegionInfo.RegionName);
                ScenePresence sp = scene.GetScenePresence(toAgentID);
                if (sp != null && !sp.IsDeleted)
                {
                    if(sp.IsChildAgent)
                        achildsp = sp;
                    else
                    {
                        // m_log.DebugFormat("[HG INSTANT MESSAGE]: Delivering IM to root agent {0} {1}", user.Name, toAgentID);
                        sp.ControllingClient.SendInstantMessage(im);
                        result(true);
                        return;
                    }
                }
            }
            if(achildsp != null)
            {
                // m_log.DebugFormat("[HG INSTANT MESSAGE]: Delivering IM to child agent {0} {1}", user.Name, toAgentID);
                achildsp.ControllingClient.SendInstantMessage(im);
                result(true);
                return;
            }

            // m_log.DebugFormat("[HG INSTANT MESSAGE]: Delivering IM to {0} via XMLRPC", im.toAgentID);
            // Is the user a local user?
            string url = string.Empty;
            bool foreigner = false;
            if (UserManagementModule != null) // foreign user
            {
                foreigner = !UserManagementModule.IsLocalGridUser(toAgentID);
                if(foreigner)
                    url = UserManagementModule.GetUserServerURL(toAgentID, "IMServerURI");
            }
            Util.FireAndForget(delegate
                {
                    UUID toDelAgentID = new UUID(im.toAgentID);
                    bool success = false;
                    if (foreigner && url.Length == 0) // we don't know about this user
                    {
                        string recipientUUI = TryGetRecipientUUI(new UUID(im.fromAgentID), toDelAgentID);
                        //m_log.DebugFormat("[HG MESSAGE TRANSFER]: Got UUI {0}", recipientUUI);
                        if (recipientUUI.Length > 0)
                        {
                            if (Util.ParseFullUniversalUserIdentifier(recipientUUI, out UUID id, out string tourl,
                                    out string first, out string last) && !string.IsNullOrEmpty(tourl))
                            {
                                success = m_IMService.OutgoingInstantMessage(im, tourl, true);
                                if (success)
                                    UserManagementModule.AddUser(toDelAgentID, first, last, tourl);
                            }
                        }                 
                    }
                    else
                        success = m_IMService.OutgoingInstantMessage(im, url, foreigner);

                    if (!success && !foreigner)
                        HandleUndeliverableMessage(im, result);
                    else
                        result(success);
                }, null, "HGMessageTransferModule.SendInstantMessage");
        }

        protected bool SendIMToScene(GridInstantMessage gim, UUID toAgentID)
        {
            Scene childScene = null;
            foreach (Scene scene in m_Scenes)
            {
                ScenePresence sp = scene.GetScenePresence(toAgentID);
                if(sp != null && !sp.IsDeleted)
                {
                    if(sp.IsChildAgent)
                        childScene = scene;
                    else
                    {
                        scene.EventManager.TriggerIncomingInstantMessage(gim);
                        return true;
                    }
                }
            }

            if(childScene != null)
            {
                childScene.EventManager.TriggerIncomingInstantMessage(gim);
                return true;
            }

            // If the message can't be delivered to an agent, it
            // is likely to be a group IM. On a group IM, the
            // imSessionID = toAgentID = group id. Raise the
            // unhandled IM event to give the groups module
            // a chance to pick it up. We raise that in a random
            // scene, since the groups module is shared.
            //
            m_Scenes[0].EventManager.TriggerUnhandledInstantMessage(gim);
            return false;
        }

        public void HandleUndeliverableMessage(GridInstantMessage im, MessageResultNotification result)
        {
            UndeliveredMessage handlerUndeliveredMessage = OnUndeliveredMessage;

            // If this event has handlers, then an IM from an agent will be
            // considered delivered. This will suppress the error message.
            //
            if (handlerUndeliveredMessage != null)
            {
                handlerUndeliveredMessage(im);
                if (im.dialog == (byte)InstantMessageDialog.MessageFromAgent)
                    result(true);
                else
                    result(false);
                return;
            }

            //m_log.DebugFormat("[INSTANT MESSAGE]: Undeliverable");
            result(false);
        }

        private string TryGetRecipientUUI(UUID fromAgent, UUID toAgent)
        {
            // Let's call back the fromAgent's user agent service
            // Maybe that service knows about the toAgent

            AgentCircuitData circuit = m_Scenes[0].AuthenticateHandler.GetAgentCircuitData(fromAgent);
            if (circuit != null)
            {
                if (circuit.ServiceURLs.ContainsKey("HomeURI"))
                {
                    string uasURL = circuit.ServiceURLs["HomeURI"].ToString();
                    m_log.DebugFormat("[HG MESSAGE TRANSFER]: getting UUI of user {0} from {1}", toAgent, uasURL);
                    UserAgentServiceConnector uasConn = new UserAgentServiceConnector(uasURL);

                    string agentUUI = string.Empty;
                    try
                    {
                        agentUUI = uasConn.GetUUI(fromAgent, toAgent);
                    }
                    catch (Exception e) {
                        m_log.Debug("[HG MESSAGE TRANSFER]: GetUUI call failed ", e);
                    }

                    return agentUUI;
                }
            }

            return string.Empty;
        }

        /// <summary>
        /// Find the root client for a ID
        /// </summary>
        public IClientAPI LocateClientObject(UUID agentID)
        {
            lock (m_Scenes)
            {
                foreach (Scene scene in m_Scenes)
                {
                    ScenePresence presence = scene.GetScenePresence(agentID);
                    if (presence != null && !presence.IsChildAgent && !presence.IsDeleted)
                        return presence.ControllingClient;
                }
            }

            return null;
        }

        #region IInstantMessageSimConnector
        public bool SendInstantMessage(GridInstantMessage im)
        {
            //m_log.DebugFormat("[XXX] Hook SendInstantMessage {0}", im.message);
            UUID agentID = new UUID(im.toAgentID);
            return SendIMToScene(im, agentID);
        }
        #endregion


    }
}