/* 
 * Copyright (c) 2008 Intel Corporation
 * All rights reserved.
 * 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 Intel Corporation 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 COPYRIGHT HOLDERS AND CONTRIBUTORS
 * ``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 INTEL OR ITS
 * 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.Generic;
using System.Net;
using System.Data;
using System.Xml;
using MySql.Data.MySqlClient;
using CookComputing.XmlRpc;
using OpenDHTLib;
using ExtensionLoader;
using ExtensionLoader.Config;
using OpenMetaverse;
using OpenMetaverse.StructuredData;

namespace AssetServer.Extensions
{
    public static class DBConnString
    {
        public const string OLD_CONFIG_FILE = "AssetServer_Config.xml";

        private static string connectionString;

        /// <summary>
        /// Parses the MySQL connection string out of either the asset server
        /// .ini or a OpenSim-style .xml file and caches the result for future
        /// requests
        /// </summary>
        public static string GetConnectionString(IniConfigSource configFile)
        {
            if (connectionString == null)
            {
                // Try parsing from the ini file first
                try
                {
                    // Load the extension list (and ordering) from our config file
                    IConfig extensionConfig = configFile.Configs["MySQL"];
                    connectionString = extensionConfig.GetString("database_connect", null);
                }
                catch (Exception) { }

                if (connectionString == null)
                {
                    try
                    {
                        // Parse the connection string out of the OpenSim asset server config file
                        XmlTextReader reader = new XmlTextReader(OLD_CONFIG_FILE);

                        if (reader.ReadToFollowing("Config"))
                        {
                            connectionString = reader.GetAttribute("database_connect");

                            // Force connection pooling on
                            MySqlConnectionStringBuilder builder = new MySqlConnectionStringBuilder(connectionString);
                            builder.Pooling = true;
                            connectionString = builder.ToString();
                        }
                        else
                        {
                            connectionString = String.Empty;
                            Logger.Log(String.Format(
                                "Cannot find MySQL configuration in {0}, make sure this file is in the same " +
                                "directory as the asset server and the database_connect attribute is correct",
                                OLD_CONFIG_FILE), Helpers.LogLevel.Error);
                        }

                        reader.Close();
                    }
                    catch (Exception)
                    {
                        connectionString = String.Empty;
                    }
                }
            }

            return connectionString;
        }
    }

    class DistributedStorage : IExtension<AssetServer>, IMetadataProvider, IDataProvider, ICreateAssetProvider
    {
        AssetServer server;

        public DistributedStorage()
        {
        }

        public void Start(AssetServer server)
        {
            this.server = server;

            using (MySqlConnection dbConnection = new MySqlConnection(DBConnString.GetConnectionString(server.ConfigFile)))
            {
                try
                {
                    dbConnection.Open();
                    Logger.Log("Connected to MySQL backend: " + dbConnection.ServerVersion, Helpers.LogLevel.Info);
                }
                catch (MySqlException ex)
                {
                    Logger.Log("Connection to MySQL backend failed: " + ex.Message, Helpers.LogLevel.Error);
                }
            }
        }

        public void Stop()
        {
        }

        public bool TryFetchMetadata(UUID assetID, out Metadata metadata)
        {
            metadata = null;
            byte[] data = null;

            try
            {
                IOpenDHT proxy = (IOpenDHT)XmlRpcProxyGen.Create(typeof(IOpenDHT));
                (proxy as XmlRpcClientProtocol).UseIndentation = false;
                object[] objs = proxy.Get(assetID.GetBytes(), 1, new byte[0], "AssetServer.DistributedStorage");
                if (objs != null && objs.Length == 2)
                    data = (byte[])((object[])objs[0])[0];
                else
                    Logger.Log(String.Format("Metadata for asset {0} not found in OpenDHT", assetID), Helpers.LogLevel.Warning);
            }
            catch (Exception ex)
            {
                Logger.Log("OpenDHT metadata lookup failed: " + ex.Message, Helpers.LogLevel.Warning);
                return false;
            }

            if (data != null)
            {
                metadata = new Metadata();
                OSDMap map = (OSDMap)OSDParser.DeserializeLLSDXml(data);

                metadata.AssetURL = map["asset_url"].AsString();
                metadata.CreationDate = map["creation_date"].AsDate();
                metadata.Description = map["description"].AsString();
                if (map.ContainsKey("extra_data"))
                    metadata.ExtraData = (OSDMap)map["extra_data"];
                metadata.ID = assetID;
                metadata.Name = map["name"].AsString();
                metadata.SHA1 = map["sha1"].AsBinary();
                metadata.Temporary = map["temporary"].AsBoolean();
                OpenMetaverse.Utils.EnumTryParse<AssetType>(map["type"].AsString(), out metadata.Type);

                return true;
            }
            else
            {
                return false;
            }
        }

        public void ForEach(Action<Metadata> action)
        {
            Logger.Log("ForEach() called on DistributedStorage which does not support enumeration",
                Helpers.LogLevel.Warning);
        }

        public bool TryFetchData(UUID assetID, out byte[] assetData)
        {
            assetData = null;

            using (MySqlConnection dbConnection = new MySqlConnection(DBConnString.GetConnectionString(server.ConfigFile)))
            {
                try { dbConnection.Open(); }
                catch (MySqlException ex)
                {
                    Logger.Log("Connection to MySQL backend failed: " + ex.Message, Helpers.LogLevel.Error);
                    return false;
                }

                IDbCommand command = dbConnection.CreateCommand();
                command.CommandText = String.Format("SELECT data FROM assets WHERE id='{0}'", assetID.ToString());
                IDataReader reader = command.ExecuteReader();

                if (reader.Read())
                {
                    assetData = (byte[])reader.GetValue(0);
                    return true;
                }
                else
                {
                    return false;
                }
            }
        }

        public bool TryCreateAsset(Metadata metadata, byte[] assetData, out UUID assetID)
        {
            assetID = metadata.ID = UUID.Random();
            return TryCreateAsset(metadata, assetData);
        }

        public bool TryCreateAsset(Metadata metadata, byte[] assetData)
        {
            // Generate the asset URL
            metadata.AssetURL = String.Format("http://{0}:{1}/{2}/data", Dns.GetHostName(), server.HttpPort, metadata.ID);

            using (MySqlConnection dbConnection = new MySqlConnection(DBConnString.GetConnectionString(server.ConfigFile)))
            {
                try { dbConnection.Open(); }
                catch (MySqlException ex)
                {
                    Logger.Log("Connection to MySQL backend failed: " + ex.Message, Helpers.LogLevel.Error);
                    return false;
                }

                MySqlCommand command = new MySqlCommand(
                    "REPLACE INTO assets (name,description,assetType,local,temporary,data,id) VALUES " +
                    "(?name,?description,?assetType,?local,?temporary,?data,?id)",
                    dbConnection);

                command.Parameters.AddWithValue("?name", metadata.Name);
                command.Parameters.AddWithValue("?description", metadata.Description);
                command.Parameters.AddWithValue("?assetType", (int)metadata.Type);
                command.Parameters.AddWithValue("?local", 0);
                command.Parameters.AddWithValue("?temporary", metadata.Temporary);
                command.Parameters.AddWithValue("?data", assetData);
                command.Parameters.AddWithValue("?id", metadata.ID.ToString());

                int result = command.ExecuteNonQuery();
                dbConnection.Close();

                if (result == 1)
                {
                    // Database insertion succeeded, insert the metadata into OpenDHT
                    OSDMap osdata = new OSDMap();
                    osdata["id"] = OSD.FromUUID(metadata.ID);
                    osdata["name"] = OSD.FromString(metadata.Name);
                    osdata["description"] = OSD.FromString(metadata.Description);
                    osdata["creation_date"] = OSD.FromDate(metadata.CreationDate);
                    osdata["type"] = OSD.FromString(metadata.Type.ToString());
                    osdata["sha1"] = OSD.FromBinary(metadata.SHA1);
                    osdata["temporary"] = OSD.FromBoolean(metadata.Temporary);
                    osdata["asset_url"] = OSD.FromString(metadata.AssetURL);
                    if (metadata.ExtraData != null)
                        osdata["extra_data"] = metadata.ExtraData;

                    byte[] serializedData = OSDParser.SerializeLLSDXmlBytes(osdata);

                    try
                    {
                        IOpenDHT proxy = (IOpenDHT)XmlRpcProxyGen.Create(typeof(IOpenDHT));
                        (proxy as XmlRpcClientProtocol).UseIndentation = false;
                        // 86,400 seconds == one day
                        result = proxy.Put(metadata.ID.GetBytes(), serializedData, 86400, "AssetServer.DistributedStorage");

                        switch (result)
                        {
                            case 0:
                                Logger.DebugLog("Metadata successfully inserted into OpenDHT");
                                return true;
                            case 1:
                                Logger.Log("Metadata was too large to fit in OpenDHT", Helpers.LogLevel.Error);
                                break;
                            case 2:
                                Logger.Log("OpenDHT had a temporary failure preventing the metadata from being uploaded",
                                    Helpers.LogLevel.Error);
                                break;
                            default:
                                Logger.Log("Unknown OpenDHT error", Helpers.LogLevel.Error);
                                break;
                        }
                    }
                    catch (WebException ex)
                    {
                        Logger.Log("Failed to connect to OpenDHT: " + ex.Message, Helpers.LogLevel.Warning);
                    }

                    // Something went wrong, delete the asset from the database
                    try { dbConnection.Open(); }
                    catch (MySqlException mex)
                    {
                        Logger.Log("Connection to MySQL backend failed: " + mex.Message, Helpers.LogLevel.Error);
                        return false;
                    }

                    command = new MySqlCommand(String.Format("DELETE FROM assets WHERE id='{0}'", metadata.ID), dbConnection);
                    result = command.ExecuteNonQuery();

                    if (result == 1)
                        Logger.DebugLog("Asset removed from the database");
                    else
                        Logger.Log("Failed to remove the asset from the database", Helpers.LogLevel.Error);

                    return false;
                }
            }

            return false;
        }
    }
}