/*
 * 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.
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 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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 * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */

using System;
using System.Collections.Generic;
using System.IO;
using System.IO.Compression;
using System.Reflection;
using System.Threading;
using System.Text;
using System.Xml;
using log4net;
using OpenMetaverse;
using OpenSim.Framework;
using OpenSim.Framework.Communications;
using OpenSim.Framework.Communications.Osp;
using OpenSim.Framework.Serialization;
using OpenSim.Framework.Serialization.External;
using OpenSim.Region.CoreModules.World.Archiver;
using OpenSim.Region.Framework.Scenes;
using OpenSim.Services.Interfaces;

namespace OpenSim.Region.CoreModules.Avatar.Inventory.Archiver
{
    public class InventoryArchiveReadRequest
    {
        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        /// <summary>
        /// The maximum major version of archive that we can read.  Minor versions shouldn't need a max number since version
        /// bumps here should be compatible.
        /// </summary>
        public static int MAX_MAJOR_VERSION = 0;
        
        protected TarArchiveReader archive;

        private UserAccount m_userInfo;
        private string m_invPath;

        /// <value>
        /// We only use this to request modules
        /// </value>
        protected Scene m_scene;

        /// <value>
        /// The stream from which the inventory archive will be loaded.
        /// </value>
        private Stream m_loadStream;

        public InventoryArchiveReadRequest(
            Scene scene, UserAccount userInfo, string invPath, string loadPath)
            : this(
                scene,
                userInfo,
                invPath,
                new GZipStream(ArchiveHelpers.GetStream(loadPath), CompressionMode.Decompress))
        {
        }

        public InventoryArchiveReadRequest(
            Scene scene, UserAccount userInfo, string invPath, Stream loadStream)
        {
            m_scene = scene;
            m_userInfo = userInfo;
            m_invPath = invPath;
            m_loadStream = loadStream;
        }

        /// <summary>
        /// Execute the request
        /// </summary>
        /// <returns>
        /// A list of the inventory nodes loaded.  If folders were loaded then only the root folders are
        /// returned
        /// </returns>
        public List<InventoryNodeBase> Execute()
        {
            string filePath = "ERROR";
            int successfulAssetRestores = 0;
            int failedAssetRestores = 0;
            int successfulItemRestores = 0;
            
            List<InventoryNodeBase> loadedNodes = new List<InventoryNodeBase>();
           
            List<InventoryFolderBase> folderCandidates
                = InventoryArchiveUtils.FindFolderByPath(
                    m_scene.InventoryService, m_userInfo.PrincipalID, m_invPath);

            if (folderCandidates.Count == 0)
            {
                // Possibly provide an option later on to automatically create this folder if it does not exist
                m_log.ErrorFormat("[INVENTORY ARCHIVER]: Inventory path {0} does not exist", m_invPath);

                return loadedNodes;
            }
            
            InventoryFolderBase rootDestinationFolder = folderCandidates[0];
            archive = new TarArchiveReader(m_loadStream);

            // In order to load identically named folders, we need to keep track of the folders that we have already
            // resolved
            Dictionary <string, InventoryFolderBase> resolvedFolders = new Dictionary<string, InventoryFolderBase>();

            byte[] data;
            TarArchiveReader.TarEntryType entryType;

            try
            {
                while ((data = archive.ReadEntry(out filePath, out entryType)) != null)
                {
                    if (filePath == ArchiveConstants.CONTROL_FILE_PATH)
                    {
                        LoadControlFile(filePath, data);
                    }                    
                    else if (filePath.StartsWith(ArchiveConstants.ASSETS_PATH))
                    {
                        if (LoadAsset(filePath, data))
                            successfulAssetRestores++;
                        else
                            failedAssetRestores++;
    
                        if ((successfulAssetRestores) % 50 == 0)
                            m_log.DebugFormat(
                                "[INVENTORY ARCHIVER]: Loaded {0} assets...", 
                                successfulAssetRestores);
                    }
                    else if (filePath.StartsWith(ArchiveConstants.INVENTORY_PATH))
                    {
                        filePath = filePath.Substring(ArchiveConstants.INVENTORY_PATH.Length);
                        
                        // Trim off the file portion if we aren't already dealing with a directory path
                        if (TarArchiveReader.TarEntryType.TYPE_DIRECTORY != entryType)
                            filePath = filePath.Remove(filePath.LastIndexOf("/") + 1);
                        
                        InventoryFolderBase foundFolder 
                            = ReplicateArchivePathToUserInventory(
                                filePath, rootDestinationFolder, resolvedFolders, loadedNodes);
    
                        if (TarArchiveReader.TarEntryType.TYPE_DIRECTORY != entryType)
                        {
                            InventoryItemBase item = LoadItem(data, foundFolder);
    
                            if (item != null)
                            {
                                successfulItemRestores++;
                                
                                // If we're loading an item directly into the given destination folder then we need to record
                                // it separately from any loaded root folders
                                if (rootDestinationFolder == foundFolder)
                                    loadedNodes.Add(item);
                            }
                        }
                    }
                }
            }
            finally
            {
                archive.Close();
            }

            m_log.DebugFormat(
                "[INVENTORY ARCHIVER]: Successfully loaded {0} assets with {1} failures", 
                successfulAssetRestores, failedAssetRestores);
            m_log.InfoFormat("[INVENTORY ARCHIVER]: Successfully loaded {0} items", successfulItemRestores);

            return loadedNodes;
        }

        public void Close()
        {
            if (m_loadStream != null)
                m_loadStream.Close();
        }

        /// <summary>
        /// Replicate the inventory paths in the archive to the user's inventory as necessary.
        /// </summary>
        /// <param name="iarPath">The item archive path to replicate</param>
        /// <param name="rootDestinationFolder">The root folder for the inventory load</param>
        /// <param name="resolvedFolders">
        /// The folders that we have resolved so far for a given archive path.  
        /// This method will add more folders if necessary
        /// </param>
        /// <param name="loadedNodes">
        /// Track the inventory nodes created.
        /// </param>
        /// <returns>The last user inventory folder created or found for the archive path</returns>
        public InventoryFolderBase ReplicateArchivePathToUserInventory(
            string iarPath, 
            InventoryFolderBase rootDestFolder, 
            Dictionary <string, InventoryFolderBase> resolvedFolders,
            List<InventoryNodeBase> loadedNodes)
        {
            string iarPathExisting = iarPath;

//            m_log.DebugFormat(
//                "[INVENTORY ARCHIVER]: Loading folder {0} {1}", rootDestFolder.Name, rootDestFolder.ID);
                        
            InventoryFolderBase destFolder = ResolveDestinationFolder(rootDestFolder, ref iarPathExisting, resolvedFolders);
            
//            m_log.DebugFormat(
//                "[INVENTORY ARCHIVER]: originalArchivePath [{0}], section already loaded [{1}]", 
//                iarPath, iarPathExisting);
            
            string iarPathToCreate = iarPath.Substring(iarPathExisting.Length);
            CreateFoldersForPath(destFolder, iarPathExisting, iarPathToCreate, resolvedFolders, loadedNodes);
            
            return destFolder;
        }

        /// <summary>
        /// Resolve a destination folder
        /// </summary>
        /// 
        /// We require here a root destination folder (usually the root of the user's inventory) and the archive
        /// path.  We also pass in a list of previously resolved folders in case we've found this one previously.
        /// 
        /// <param name="archivePath">
        /// The item archive path to resolve.  The portion of the path passed back is that
        /// which corresponds to the resolved desintation folder.
        /// <param name="rootDestinationFolder">
        /// The root folder for the inventory load
        /// </param>
        /// <param name="resolvedFolders">
        /// The folders that we have resolved so far for a given archive path.  
        /// </param>
        /// <returns>
        /// The folder in the user's inventory that matches best the archive path given.  If no such folder was found
        /// then the passed in root destination folder is returned.
        /// </returns>        
        protected InventoryFolderBase ResolveDestinationFolder(
            InventoryFolderBase rootDestFolder,                                                             
            ref string archivePath,             
            Dictionary <string, InventoryFolderBase> resolvedFolders)
        {                       
            string originalArchivePath = archivePath;

            InventoryFolderBase destFolder = null;

            if (archivePath.Length > 0)
            {
                while (null == destFolder && archivePath.Length > 0)
                {
//                    m_log.DebugFormat("[INVENTORY ARCHIVER]: Trying to resolve destination folder {0}", archivePath);
                    
                    if (resolvedFolders.ContainsKey(archivePath))
                    {
//                        m_log.DebugFormat(
//                            "[INVENTORY ARCHIVER]: Found previously created folder from archive path {0}", archivePath);
                        destFolder = resolvedFolders[archivePath];
                    }
                    else
                    {
                        // Don't include the last slash so find the penultimate one
                        int penultimateSlashIndex = archivePath.LastIndexOf("/", archivePath.Length - 2);

                        if (penultimateSlashIndex >= 0)
                        {
                            // Remove the last section of path so that we can see if we've already resolved the parent
                            archivePath = archivePath.Remove(penultimateSlashIndex + 1);
                        }
                        else
                        {
//                            m_log.DebugFormat(
//                                "[INVENTORY ARCHIVER]: Found no previously created folder for archive path {0}",
//                                originalArchivePath);
                            archivePath = string.Empty;
                            destFolder = rootDestFolder;
                        }
                    }
                }
            }
            
            if (null == destFolder)
                destFolder = rootDestFolder;
            
            return destFolder;
        }
        
        /// <summary>
        /// Create a set of folders for the given path.
        /// </summary>
        /// <param name="destFolder">
        /// The root folder from which the creation will take place.
        /// </param>
        /// <param name="iarPathExisting">
        /// the part of the iar path that already exists
        /// </param>
        /// <param name="iarPathToReplicate">
        /// The path to replicate in the user's inventory from iar
        /// </param>
        /// <param name="resolvedFolders">
        /// The folders that we have resolved so far for a given archive path.
        /// </param>
        /// <param name="loadedNodes">
        /// Track the inventory nodes created.
        /// </param>
        protected void CreateFoldersForPath(
            InventoryFolderBase destFolder, 
            string iarPathExisting,
            string iarPathToReplicate, 
            Dictionary <string, InventoryFolderBase> resolvedFolders, 
            List<InventoryNodeBase> loadedNodes)
        {
            string[] rawDirsToCreate = iarPathToReplicate.Split(new char[] { '/' }, StringSplitOptions.RemoveEmptyEntries);
            int i = 0;

            while (i < rawDirsToCreate.Length)
            {
//                m_log.DebugFormat("[INVENTORY ARCHIVER]: Creating folder {0} from IAR", rawDirsToCreate[i]);

                int identicalNameIdentifierIndex
                    = rawDirsToCreate[i].LastIndexOf(
                        ArchiveConstants.INVENTORY_NODE_NAME_COMPONENT_SEPARATOR);

                if (identicalNameIdentifierIndex < 0)
                {
                    i++;
                    continue;
                }
                string newFolderName = rawDirsToCreate[i].Remove(identicalNameIdentifierIndex);

                newFolderName = InventoryArchiveUtils.UnescapeArchivePath(newFolderName);
                UUID newFolderId = UUID.Random();

                // Asset type has to be Unknown here rather than Folder, otherwise the created folder can't be
                // deleted once the client has relogged.
                // The root folder appears to be labelled AssetType.Folder (shows up as "Category" in the client)
                // even though there is a AssetType.RootCategory
                destFolder 
                    = new InventoryFolderBase(
                        newFolderId, newFolderName, m_userInfo.PrincipalID, 
                        (short)AssetType.Unknown, destFolder.ID, 1);
                m_scene.InventoryService.AddFolder(destFolder);

                // Record that we have now created this folder
                iarPathExisting += rawDirsToCreate[i] + "/";
                m_log.DebugFormat("[INVENTORY ARCHIVER]: Created folder {0} from IAR", iarPathExisting);
                resolvedFolders[iarPathExisting] = destFolder;

                if (0 == i)
                    loadedNodes.Add(destFolder);

                i++;
            }            
        }
        
        /// <summary>
        /// Load an item from the archive
        /// </summary>
        /// <param name="filePath">The archive path for the item</param>
        /// <param name="data">The raw item data</param>
        /// <param name="rootDestinationFolder">The root destination folder for loaded items</param>
        /// <param name="nodesLoaded">All the inventory nodes (items and folders) loaded so far</param>
        protected InventoryItemBase LoadItem(byte[] data, InventoryFolderBase loadFolder)
        {
            InventoryItemBase item = UserInventoryItemSerializer.Deserialize(data);
            
            // Don't use the item ID that's in the file
            item.ID = UUID.Random();

            UUID ospResolvedId = OspResolver.ResolveOspa(item.CreatorId, m_scene.UserAccountService); 
            if (UUID.Zero != ospResolvedId)
            {
                item.CreatorIdAsUuid = ospResolvedId;

                // XXX: For now, don't preserve the OSPA in the creator id (which actually gets persisted to the
                // database).  Instead, replace with the UUID that we found.
                item.CreatorId = ospResolvedId.ToString();
            }
            else
            {
                item.CreatorIdAsUuid = m_userInfo.PrincipalID;
            }
            
            item.Owner = m_userInfo.PrincipalID;

            // Reset folder ID to the one in which we want to load it
            item.Folder = loadFolder.ID;

            //m_userInfo.AddItem(item);
            m_scene.InventoryService.AddItem(item);
        
            return item;
        }

        /// <summary>
        /// Load an asset
        /// </summary>
        /// <param name="assetFilename"></param>
        /// <param name="data"></param>
        /// <returns>true if asset was successfully loaded, false otherwise</returns>
        private bool LoadAsset(string assetPath, byte[] data)
        {
            //IRegionSerialiser serialiser = scene.RequestModuleInterface<IRegionSerialiser>();
            // Right now we're nastily obtaining the UUID from the filename
            string filename = assetPath.Remove(0, ArchiveConstants.ASSETS_PATH.Length);
            int i = filename.LastIndexOf(ArchiveConstants.ASSET_EXTENSION_SEPARATOR);

            if (i == -1)
            {
                m_log.ErrorFormat(
                   "[INVENTORY ARCHIVER]: Could not find extension information in asset path {0} since it's missing the separator {1}.  Skipping",
                    assetPath, ArchiveConstants.ASSET_EXTENSION_SEPARATOR);

                return false;
            }

            string extension = filename.Substring(i);
            string uuid = filename.Remove(filename.Length - extension.Length);

            if (ArchiveConstants.EXTENSION_TO_ASSET_TYPE.ContainsKey(extension))
            {
                sbyte assetType = ArchiveConstants.EXTENSION_TO_ASSET_TYPE[extension];

                if (assetType == (sbyte)AssetType.Unknown)
                    m_log.WarnFormat("[INVENTORY ARCHIVER]: Importing {0} byte asset {1} with unknown type", data.Length, uuid);

                //m_log.DebugFormat("[INVENTORY ARCHIVER]: Importing asset {0}, type {1}", uuid, assetType);

                AssetBase asset = new AssetBase(new UUID(uuid), "RandomName", assetType, UUID.Zero.ToString());
                asset.Data = data;

                m_scene.AssetService.Store(asset);

                return true;
            }
            else
            {
                m_log.ErrorFormat(
                   "[INVENTORY ARCHIVER]: Tried to dearchive data with path {0} with an unknown type extension {1}",
                    assetPath, extension);

                return false;
            }
        }

        /// <summary>
        /// Load control file
        /// </summary>
        /// <param name="path"></param>
        /// <param name="data"></param>
        protected void LoadControlFile(string path, byte[] data)
        {          
            int majorVersion = -1;
            int minorVersion = -1;
            string version = "ERROR";
            
            NameTable nt = new NameTable();
            XmlNamespaceManager nsmgr = new XmlNamespaceManager(nt);            
            XmlParserContext context = new XmlParserContext(null, nsmgr, null, XmlSpace.None);            
            XmlTextReader xtr = new XmlTextReader(Encoding.ASCII.GetString(data), XmlNodeType.Document, context);
            while (xtr.Read()) 
            {
                if (xtr.NodeType == XmlNodeType.Element) 
                {
                    if (xtr.Name.ToString() == "archive")
                    {
                        majorVersion = int.Parse(xtr["major_version"]);
                        minorVersion = int.Parse(xtr["minor_version"]);
                        version = string.Format("{0}.{1}", majorVersion, minorVersion);
                    }
                }
            }
                        
            if (majorVersion > MAX_MAJOR_VERSION)
            {
                throw new Exception(
                    string.Format(
                        "The IAR you are trying to load has major version number of {0} but this version of OpenSim can only load IARs with major version number {1} and below",
                        majorVersion, MAX_MAJOR_VERSION));
            }       
            
            m_log.InfoFormat("[INVENTORY ARCHIVER]: Loading IAR with version {0}", version);
        }
    }
}