/*
 * 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.Generic;
using System.Collections.Specialized;
using System.Drawing;
using System.Drawing.Imaging;
using System.IO;
using System.Net;
using System.Reflection;
using log4net;
using Mono.Addins;
using Nini.Config;
using OpenSim.Framework;
using OpenSim.Region.Framework.Interfaces;
using OpenSim.Region.Framework.Scenes;
using OpenSim.Services.Interfaces;
using OpenMetaverse;
using OpenMetaverse.StructuredData;

using GridRegion = OpenSim.Services.Interfaces.GridRegion;

namespace OpenSim.Services.Connectors.SimianGrid
{
    /// <summary>
    /// Connects region registration and neighbor lookups to the SimianGrid
    /// backend
    /// </summary>
    [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule")]
    public class SimianGridServiceConnector : IGridService, ISharedRegionModule
    {
        private static readonly ILog m_log =
                LogManager.GetLogger(
                MethodBase.GetCurrentMethod().DeclaringType);

        private string m_serverUrl = String.Empty;

        #region ISharedRegionModule

        public Type ReplaceableInterface { get { return null; } }
        public void RegionLoaded(Scene scene) { if (!String.IsNullOrEmpty(m_serverUrl)) { UploadMapTile(scene); } }
        public void PostInitialise() { }
        public void Close() { }

        public SimianGridServiceConnector() { }
        public string Name { get { return "SimianGridServiceConnector"; } }
        public void AddRegion(Scene scene) { if (!String.IsNullOrEmpty(m_serverUrl)) { scene.RegisterModuleInterface<IGridService>(this); } }
        public void RemoveRegion(Scene scene) { if (!String.IsNullOrEmpty(m_serverUrl)) { scene.UnregisterModuleInterface<IGridService>(this); } }

        #endregion ISharedRegionModule

        public SimianGridServiceConnector(IConfigSource source)
        {
            Initialise(source);
        }

        public void Initialise(IConfigSource source)
        {
            if (Simian.IsSimianEnabled(source, "GridServices", this.Name))
            {
                IConfig gridConfig = source.Configs["GridService"];
                if (gridConfig == null)
                {
                    m_log.Error("[SIMIAN GRID CONNECTOR]: GridService missing from OpenSim.ini");
                    throw new Exception("Grid connector init error");
                }

                string serviceUrl = gridConfig.GetString("GridServerURI");
                if (String.IsNullOrEmpty(serviceUrl))
                {
                    m_log.Error("[SIMIAN GRID CONNECTOR]: No Server URI named in section GridService");
                    throw new Exception("Grid connector init error");
                }

                m_serverUrl = serviceUrl;
            }
        }

        #region IGridService

        public string RegisterRegion(UUID scopeID, GridRegion regionInfo)
        {
            IPEndPoint ext = regionInfo.ExternalEndPoint;
            if (ext == null) return "Region registration for " + regionInfo.RegionName + " failed: Could not resolve EndPoint";
            Vector3d minPosition = new Vector3d(regionInfo.RegionLocX, regionInfo.RegionLocY, 0.0);
            Vector3d maxPosition = minPosition + new Vector3d(Constants.RegionSize, Constants.RegionSize, 4096.0);

            string httpAddress = "http://" + regionInfo.ExternalHostName + ":" + regionInfo.HttpPort + "/";

            OSDMap extraData = new OSDMap
            {
                { "ServerURI", OSD.FromString(regionInfo.ServerURI) },
                { "InternalAddress", OSD.FromString(regionInfo.InternalEndPoint.Address.ToString()) },
                { "InternalPort", OSD.FromInteger(regionInfo.InternalEndPoint.Port) },
                { "ExternalAddress", OSD.FromString(ext.Address.ToString()) },
                { "ExternalPort", OSD.FromInteger(regionInfo.ExternalEndPoint.Port) },
                { "MapTexture", OSD.FromUUID(regionInfo.TerrainImage) },
                { "Access", OSD.FromInteger(regionInfo.Access) },
                { "RegionSecret", OSD.FromString(regionInfo.RegionSecret) },
                { "EstateOwner", OSD.FromUUID(regionInfo.EstateOwner) },
                { "Token", OSD.FromString(regionInfo.Token) }
            };

            NameValueCollection requestArgs = new NameValueCollection
            {
                { "RequestMethod", "AddScene" },
                { "SceneID", regionInfo.RegionID.ToString() },
                { "Name", regionInfo.RegionName },
                { "MinPosition", minPosition.ToString() },
                { "MaxPosition", maxPosition.ToString() },
                { "Address", httpAddress },
                { "Enabled", "1" },
                { "ExtraData", OSDParser.SerializeJsonString(extraData) }
            };

            OSDMap response = WebUtil.PostToService(m_serverUrl, requestArgs);
            if (response["Success"].AsBoolean())
                return String.Empty;
            else
                return "Region registration for " + regionInfo.RegionName + " failed: " + response["Message"].AsString();
        }

        public bool DeregisterRegion(UUID regionID)
        {
            NameValueCollection requestArgs = new NameValueCollection
            {
                { "RequestMethod", "AddScene" },
                { "SceneID", regionID.ToString() },
                { "Enabled", "0" }
            };

            OSDMap response = WebUtil.PostToService(m_serverUrl, requestArgs);
            bool success = response["Success"].AsBoolean();

            if (!success)
                m_log.Warn("[SIMIAN GRID CONNECTOR]: Region deregistration for " + regionID + " failed: " + response["Message"].AsString());

            return success;
        }

        public List<GridRegion> GetNeighbours(UUID scopeID, UUID regionID)
        {
            const int NEIGHBOR_RADIUS = 128;

            GridRegion region = GetRegionByUUID(scopeID, regionID);

            if (region != null)
            {
                List<GridRegion> regions = GetRegionRange(scopeID,
                    region.RegionLocX - NEIGHBOR_RADIUS, region.RegionLocX + (int)Constants.RegionSize + NEIGHBOR_RADIUS,
                    region.RegionLocY - NEIGHBOR_RADIUS, region.RegionLocY + (int)Constants.RegionSize + NEIGHBOR_RADIUS);

                for (int i = 0; i < regions.Count; i++)
                {
                    if (regions[i].RegionID == regionID)
                    {
                        regions.RemoveAt(i);
                        break;
                    }
                }

                m_log.Debug("[SIMIAN GRID CONNECTOR]: Found " + regions.Count + " neighbors for region " + regionID);
                return regions;
            }

            return new List<GridRegion>(0);
        }

        public GridRegion GetRegionByUUID(UUID scopeID, UUID regionID)
        {
            NameValueCollection requestArgs = new NameValueCollection
            {
                { "RequestMethod", "GetScene" },
                { "SceneID", regionID.ToString() }
            };

            OSDMap response = WebUtil.PostToService(m_serverUrl, requestArgs);
            if (response["Success"].AsBoolean())
            {
                return ResponseToGridRegion(response);
            }
            else
            {
                m_log.Warn("[SIMIAN GRID CONNECTOR]: Grid service did not find a match for region " + regionID);
                return null;
            }
        }

        public GridRegion GetRegionByPosition(UUID scopeID, int x, int y)
        {
            // Go one meter in from the requested x/y coords to avoid requesting a position
            // that falls on the border of two sims
            Vector3d position = new Vector3d(x + 1, y + 1, 0.0);

            NameValueCollection requestArgs = new NameValueCollection
            {
                { "RequestMethod", "GetScene" },
                { "Position", position.ToString() },
                { "Enabled", "1" }
            };

            OSDMap response = WebUtil.PostToService(m_serverUrl, requestArgs);
            if (response["Success"].AsBoolean())
            {
                return ResponseToGridRegion(response);
            }
            else
            {
                //m_log.InfoFormat("[SIMIAN GRID CONNECTOR]: Grid service did not find a match for region at {0},{1}",
                //    x / Constants.RegionSize, y / Constants.RegionSize);
                return null;
            }
        }

        public GridRegion GetRegionByName(UUID scopeID, string regionName)
        {
            List<GridRegion> regions = GetRegionsByName(scopeID, regionName, 1);

            m_log.Debug("[SIMIAN GRID CONNECTOR]: Got " + regions.Count + " matches for region name " + regionName);

            if (regions.Count > 0)
                return regions[0];

            return null;
        }

        public List<GridRegion> GetRegionsByName(UUID scopeID, string name, int maxNumber)
        {
            List<GridRegion> foundRegions = new List<GridRegion>();

            NameValueCollection requestArgs = new NameValueCollection
            {
                { "RequestMethod", "GetScenes" },
                { "NameQuery", name },
                { "Enabled", "1" }
            };
            if (maxNumber > 0)
                requestArgs["MaxNumber"] = maxNumber.ToString();

            OSDMap response = WebUtil.PostToService(m_serverUrl, requestArgs);
            if (response["Success"].AsBoolean())
            {
                OSDArray array = response["Scenes"] as OSDArray;
                if (array != null)
                {
                    for (int i = 0; i < array.Count; i++)
                    {
                        GridRegion region = ResponseToGridRegion(array[i] as OSDMap);
                        if (region != null)
                            foundRegions.Add(region);
                    }
                }
            }

            return foundRegions;
        }

        public List<GridRegion> GetRegionRange(UUID scopeID, int xmin, int xmax, int ymin, int ymax)
        {
            List<GridRegion> foundRegions = new List<GridRegion>();

            Vector3d minPosition = new Vector3d(xmin, ymin, 0.0);
            Vector3d maxPosition = new Vector3d(xmax, ymax, 4096.0);

            NameValueCollection requestArgs = new NameValueCollection
            {
                { "RequestMethod", "GetScenes" },
                { "MinPosition", minPosition.ToString() },
                { "MaxPosition", maxPosition.ToString() },
                { "Enabled", "1" }
            };

            OSDMap response = WebUtil.PostToService(m_serverUrl, requestArgs);
            if (response["Success"].AsBoolean())
            {
                OSDArray array = response["Scenes"] as OSDArray;
                if (array != null)
                {
                    for (int i = 0; i < array.Count; i++)
                    {
                        GridRegion region = ResponseToGridRegion(array[i] as OSDMap);
                        if (region != null)
                            foundRegions.Add(region);
                    }
                }
            }

            return foundRegions;
        }

        public List<GridRegion> GetDefaultRegions(UUID scopeID)
        {
            // TODO: Allow specifying the default grid location
            const int DEFAULT_X = 1000 * 256;
            const int DEFAULT_Y = 1000 * 256;

            GridRegion defRegion = GetNearestRegion(new Vector3d(DEFAULT_X, DEFAULT_Y, 0.0), true);
            if (defRegion != null)
                return new List<GridRegion>(1) { defRegion };
            else
                return new List<GridRegion>(0);
        }

        public List<GridRegion> GetFallbackRegions(UUID scopeID, int x, int y)
        {
            GridRegion defRegion = GetNearestRegion(new Vector3d(x, y, 0.0), true);
            if (defRegion != null)
                return new List<GridRegion>(1) { defRegion };
            else
                return new List<GridRegion>(0);
        }

        public int GetRegionFlags(UUID scopeID, UUID regionID)
        {
            const int REGION_ONLINE = 4;

            NameValueCollection requestArgs = new NameValueCollection
            {
                { "RequestMethod", "GetScene" },
                { "SceneID", regionID.ToString() }
            };

            OSDMap response = WebUtil.PostToService(m_serverUrl, requestArgs);
            if (response["Success"].AsBoolean())
            {
                return response["Enabled"].AsBoolean() ? REGION_ONLINE : 0;
            }
            else
            {
                m_log.Warn("[SIMIAN GRID CONNECTOR]: Grid service did not find a match for region " + regionID + " during region flags check");
                return -1;
            }
        }

        #endregion IGridService

        private void UploadMapTile(IScene scene)
        {
            string errorMessage = null;

            // Create a PNG map tile and upload it to the AddMapTile API
            byte[] pngData = Utils.EmptyBytes;
            IMapImageGenerator tileGenerator = scene.RequestModuleInterface<IMapImageGenerator>();
            if (tileGenerator == null)
            {
                m_log.Warn("[SIMIAN GRID CONNECTOR]: Cannot upload PNG map tile without an IMapImageGenerator");
                return;
            }

            using (Image mapTile = tileGenerator.CreateMapTile("defaultstripe.png"))
            {
                using (MemoryStream stream = new MemoryStream())
                {
                    mapTile.Save(stream, ImageFormat.Png);
                    pngData = stream.ToArray();
                }
            }

            List<MultipartForm.Element> postParameters = new List<MultipartForm.Element>()
            {
                new MultipartForm.Parameter("X", scene.RegionInfo.RegionLocX.ToString()),
                new MultipartForm.Parameter("Y", scene.RegionInfo.RegionLocY.ToString()),
                new MultipartForm.File("Tile", "tile.png", "image/png", pngData)
            };

            // Make the remote storage request
            try
            {
                HttpWebRequest request = (HttpWebRequest)HttpWebRequest.Create(m_serverUrl);

                HttpWebResponse response = MultipartForm.Post(request, postParameters);
                using (Stream responseStream = response.GetResponseStream())
                {
                    string responseStr = null;

                    try
                    {
                        responseStr = responseStream.GetStreamString();
                        OSD responseOSD = OSDParser.Deserialize(responseStr);
                        if (responseOSD.Type == OSDType.Map)
                        {
                            OSDMap responseMap = (OSDMap)responseOSD;
                            if (responseMap["Success"].AsBoolean())
                                m_log.Info("[SIMIAN GRID CONNECTOR]: Uploaded " + pngData.Length + " byte PNG map tile to AddMapTile");
                            else
                                errorMessage = "Upload failed: " + responseMap["Message"].AsString();
                        }
                        else
                        {
                            errorMessage = "Response format was invalid:\n" + responseStr;
                        }
                    }
                    catch (Exception ex)
                    {
                        if (!String.IsNullOrEmpty(responseStr))
                            errorMessage = "Failed to parse the response:\n" + responseStr;
                        else
                            errorMessage = "Failed to retrieve the response: " + ex.Message;
                    }
                }
            }
            catch (WebException ex)
            {
                errorMessage = ex.Message;
            }

            if (!String.IsNullOrEmpty(errorMessage))
            {
                m_log.WarnFormat("[SIMIAN GRID CONNECTOR]: Failed to store {0} byte PNG map tile for {1}: {2}",
                    pngData.Length, scene.RegionInfo.RegionName, errorMessage);
            }
        }

        private GridRegion GetNearestRegion(Vector3d position, bool onlyEnabled)
        {
            NameValueCollection requestArgs = new NameValueCollection
            {
                { "RequestMethod", "GetScene" },
                { "Position", position.ToString() },
                { "FindClosest", "1" }
            };
            if (onlyEnabled)
                requestArgs["Enabled"] = "1";

            OSDMap response = WebUtil.PostToService(m_serverUrl, requestArgs);
            if (response["Success"].AsBoolean())
            {
                return ResponseToGridRegion(response);
            }
            else
            {
                m_log.Warn("[SIMIAN GRID CONNECTOR]: Grid service did not find a match for region at " + position);
                return null;
            }
        }

        private GridRegion ResponseToGridRegion(OSDMap response)
        {
            if (response == null)
                return null;

            OSDMap extraData = response["ExtraData"] as OSDMap;
            if (extraData == null)
                return null;

            GridRegion region = new GridRegion();

            region.RegionID = response["SceneID"].AsUUID();
            region.RegionName = response["Name"].AsString();

            Vector3d minPosition = response["MinPosition"].AsVector3d();
            region.RegionLocX = (int)minPosition.X;
            region.RegionLocY = (int)minPosition.Y;

            Uri httpAddress = response["Address"].AsUri();
            region.ExternalHostName = httpAddress.Host;
            region.HttpPort = (uint)httpAddress.Port;

            region.ServerURI = extraData["ServerURI"].AsString();

            IPAddress internalAddress;
            IPAddress.TryParse(extraData["InternalAddress"].AsString(), out internalAddress);
            if (internalAddress == null)
                internalAddress = IPAddress.Any;

            region.InternalEndPoint = new IPEndPoint(internalAddress, extraData["InternalPort"].AsInteger());
            region.TerrainImage = extraData["MapTexture"].AsUUID();
            region.Access = (byte)extraData["Access"].AsInteger();
            region.RegionSecret = extraData["RegionSecret"].AsString();
            region.EstateOwner = extraData["EstateOwner"].AsUUID();
            region.Token = extraData["Token"].AsString();

            return region;
        }
    }
}