/*
 * 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;
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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.Threading;
using log4net;
using Nini.Config;
using Mono.Addins;
using OpenMetaverse;
using OpenSim.Framework;
using OpenSim.Framework.Servers;
using OpenSim.Framework.Servers.HttpServer;
using OpenSim.Region.Framework.Interfaces;
using OpenSim.Region.Framework.Scenes;
using OpenSim.Services.Interfaces;
using Caps = OpenSim.Framework.Capabilities.Caps;
using OpenSim.Capabilities.Handlers;
using OpenSim.Framework.Monitoring;

namespace OpenSim.Region.ClientStack.Linden
{
    /// <summary>
    /// This module implements both WebFetchInventoryDescendents and FetchInventoryDescendents2 capabilities.
    /// </summary>
    [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule")]
    public class WebFetchInvDescModule : INonSharedRegionModule
    {
        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        private Scene m_scene;

        private IInventoryService m_InventoryService;
        private ILibraryService m_LibraryService;

        private static WebFetchInvDescHandler m_webFetchHandler;

        private Dictionary<UUID, string> m_capsDict = new Dictionary<UUID, string>();
        private static Thread[] m_workerThreads = null;

        private static OpenMetaverse.BlockingQueue<PollServiceInventoryEventArgs> m_queue =
                new OpenMetaverse.BlockingQueue<PollServiceInventoryEventArgs>();

        #region ISharedRegionModule Members

        public void Initialise(IConfigSource source)
        {
        }

        public void AddRegion(Scene s)
        {
            m_scene = s;
        }

        public void RemoveRegion(Scene s)
        {
            m_scene.EventManager.OnRegisterCaps -= RegisterCaps;
            m_scene.EventManager.OnDeregisterCaps -= DeregisterCaps;
            m_scene = null;
        }

        public void RegionLoaded(Scene s)
        {
            m_InventoryService = m_scene.InventoryService;
            m_LibraryService = m_scene.LibraryService;

            // We'll reuse the same handler for all requests.
            m_webFetchHandler = new WebFetchInvDescHandler(m_InventoryService, m_LibraryService);

            m_scene.EventManager.OnRegisterCaps += RegisterCaps;
            m_scene.EventManager.OnDeregisterCaps += DeregisterCaps;

            if (m_workerThreads == null)
            {
                m_workerThreads = new Thread[2];

                for (uint i = 0; i < 2; i++)
                {
                    m_workerThreads[i] = Watchdog.StartThread(DoInventoryRequests,
                            String.Format("InventoryWorkerThread{0}", i),
                            ThreadPriority.Normal,
                            false,
                            true,
                            null,
                            int.MaxValue);
                }
            }
        }

        public void PostInitialise()
        {
        }

        public void Close() { }

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

        public Type ReplaceableInterface
        {
            get { return null; }
        }

        #endregion

        ~WebFetchInvDescModule()
        {
            foreach (Thread t in m_workerThreads)
                t.Abort();
        }

        private class PollServiceInventoryEventArgs : PollServiceEventArgs
        {
            private List<Hashtable> requests =
                    new List<Hashtable>();
            private Dictionary<UUID, Hashtable> responses =
                    new Dictionary<UUID, Hashtable>();

            public PollServiceInventoryEventArgs(UUID pId) :
                    base(null, null, null, null, pId, 30000)
            {
                HasEvents = (x, y) => { return this.responses.ContainsKey(x); };
                GetEvents = (x, y, s) =>
                {
                    try
                    {
                        return this.responses[x];
                    }
                    finally
                    {
                        responses.Remove(x);
                    }
                };

                Request = (x, y) =>
                {
                    y["RequestID"] = x.ToString();
                    lock (this.requests)
                        this.requests.Add(y);

                    m_queue.Enqueue(this);
                };

                NoEvents = (x, y) =>
                {
                    lock (this.requests)
                    {
                        Hashtable request = requests.Find(id => id["RequestID"].ToString() == x.ToString());
                        requests.Remove(request);
                    }

                    Hashtable response = new Hashtable();

                    response["int_response_code"] = 500;
                    response["str_response_string"] = "Script timeout";
                    response["content_type"] = "text/plain";
                    response["keepalive"] = false;
                    response["reusecontext"] = false;

                    return response;
                };
            }

            public void Process()
            {
                Hashtable request = null;

                try
                {
                    lock (this.requests)
                    {
                        request = requests[0];
                        requests.RemoveAt(0);
                    }
                }
                catch
                {
                    return;
                }

                UUID requestID = new UUID(request["RequestID"].ToString());

                Hashtable response = new Hashtable();

                response["int_response_code"] = 200;
                response["content_type"] = "text/plain";
                response["keepalive"] = false;
                response["reusecontext"] = false;

                response["str_response_string"] = m_webFetchHandler.FetchInventoryDescendentsRequest(request["body"].ToString(), String.Empty, String.Empty, null, null);

                responses[requestID] = response; 
            }
        }

        private void RegisterCaps(UUID agentID, Caps caps)
        {
            string capUrl = "/CAPS/" + UUID.Random() + "/";

            // Register this as a poll service
            // absurd large timeout to tune later to make a bit less than viewer
            PollServiceInventoryEventArgs args = new PollServiceInventoryEventArgs(agentID);
            
            args.Type = PollServiceEventArgs.EventType.Inventory;
            MainServer.Instance.AddPollServiceHTTPHandler(capUrl, args);

            string hostName = m_scene.RegionInfo.ExternalHostName;
            uint port = (MainServer.Instance == null) ? 0 : MainServer.Instance.Port;
            string protocol = "http";
            
            if (MainServer.Instance.UseSSL)
            {
                hostName = MainServer.Instance.SSLCommonName;
                port = MainServer.Instance.SSLPort;
                protocol = "https";
            }
            caps.RegisterHandler("FetchInventoryDescendents2", String.Format("{0}://{1}:{2}{3}", protocol, hostName, port, capUrl));

            m_capsDict[agentID] = capUrl;
        }

        private void DeregisterCaps(UUID agentID, Caps caps)
        {
            string capUrl;

            if (m_capsDict.TryGetValue(agentID, out capUrl))
            {
                MainServer.Instance.RemoveHTTPHandler("", capUrl);
                m_capsDict.Remove(agentID);
            }
        }

        private void DoInventoryRequests()
        {
            while (true)
            {
                PollServiceInventoryEventArgs args = m_queue.Dequeue();

                args.Process();
            }
        }
    }
}