/*
 * 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;
 * 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 OpenSim.Framework;
using OpenSim.Framework.Communications.Cache;
using OpenSim.Region.Environment.Interfaces;
using OpenSim.Region.Environment.Modules.World.Serialiser;
using OpenSim.Region.Environment.Scenes;
using System.Collections.Generic;
using System.Reflection;
using libsecondlife;
using log4net;
using Nini.Config;

namespace OpenSim.Region.Environment
{       
    /// <summary>
    /// Method called when all the necessary assets for an archive request have been received.
    /// </summary>
    public delegate void AssetsRequestCallback(IDictionary<LLUUID, AssetBase> assets);
    
    /// <summary>
    /// Handles an individual archive request
    /// </summary>
    public class ArchiveRequest
    {        
        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
        
        private Scene m_scene;
        private string m_savePath;
        
        public ArchiveRequest(Scene scene, string savePath)
        {
            m_scene = scene;
            m_savePath = savePath;
            
            ArchiveRegion();
        }
        
        protected void ArchiveRegion()
        {
            m_log.Warn("[ARCHIVER]: Archive region not yet implemented");

            Dictionary<LLUUID, int> textureUuids = new Dictionary<LLUUID, int>(); 

            List<EntityBase> entities = m_scene.GetEntities();

            foreach (EntityBase entity in entities)
            {
                if (entity is SceneObjectGroup)
                {
                    SceneObjectGroup sceneObject = (SceneObjectGroup)entity;
                    
                    foreach (SceneObjectPart part in sceneObject.GetParts())
                    {
                        LLUUID texture = new LLUUID(part.Shape.TextureEntry, 0);
                        textureUuids[texture] = 1;
                    }
                }                
            }          

            string serEntities = SerializeObjects(entities);

            if (serEntities != null && serEntities.Length > 0)
            {
                m_log.DebugFormat("[ARCHIVER]: Successfully got serialization for {0} entities", entities.Count);
                m_log.DebugFormat("[ARCHIVER]: Requiring save of {0} textures", textureUuids.Count);
                
                // Asynchronously request all the assets required to perform this archive operation
                new AssetsRequest(ReceivedAllAssets, m_scene.AssetCache, textureUuids.Keys);
            }
        }
        
        protected internal void ReceivedAllAssets(IDictionary<LLUUID, AssetBase> assets)
        {
            m_log.DebugFormat("[ARCHIVER]: Received all {0} textures required", assets.Count);
        }
                
        /// <summary>
        /// Get an xml representation of the given scene objects.
        /// </summary>
        /// <param name="scene"></param>
        /// <returns></returns>
        protected static string SerializeObjects(List<EntityBase> entities)
        {
            string serialization = "<scene>";

            List<string> serObjects = new List<string>();

            foreach (EntityBase ent in entities)
            {
                if (ent is SceneObjectGroup)
                {
                    serObjects.Add(((SceneObjectGroup) ent).ToXmlString2());
                }
            }

            foreach (string serObject in serObjects)
                serialization += serObject;

            serialization += "</scene>";

            return serialization;
        }
    }

    /// <summary>
    /// Encapsulate the asynchronous requests for the assets required for an archive operation
    /// </summary>
    class AssetsRequest
    {
        /// <summary>
        /// Callback used when all the assets requested have been received.
        /// </summary>
        protected AssetsRequestCallback m_assetsRequestCallback;
        
        /// <summary>
        /// Assets retrieved in this request
        /// </summary>
        protected Dictionary<LLUUID, AssetBase> m_assets = new Dictionary<LLUUID, AssetBase>();
        
        /// <summary>
        /// Record the number of asset replies required so we know when we've finished
        /// </summary>
        private int m_repliesRequired;
        
        /// <summary>
        /// Asset cache used to request the assets
        /// </summary>
        protected AssetCache m_assetCache;                
        
        protected internal AssetsRequest(AssetsRequestCallback assetsRequestCallback, AssetCache assetCache, ICollection<LLUUID> uuids) 
        {            
            m_assetsRequestCallback = assetsRequestCallback;           
            m_assetCache = assetCache;
            m_repliesRequired = uuids.Count;
            
            // We can stop here if there are no assets to fetch
            if (m_repliesRequired == 0)
                m_assetsRequestCallback(m_assets);                       
            
            foreach (LLUUID uuid in uuids)
            {
                m_assetCache.GetAsset(uuid, AssetRequestCallback, true);                
            }
        }
        
        /// <summary>
        /// Called back by the asset cache when it has the asset
        /// </summary>
        /// <param name="assetID"></param>
        /// <param name="asset"></param>
        public void AssetRequestCallback(LLUUID assetID, AssetBase asset)
        {
            m_assets[assetID] = asset;
            
            if (m_assets.Count == m_repliesRequired)
            {
                m_assetsRequestCallback(m_assets);
            }
        }
    }
}