/*
 * 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
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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.Reflection;
using System.Xml;

using Nini.Config;
using log4net;
using OpenMetaverse;

using OpenSim.Framework;
using OpenSim.Framework.Serialization.External;
using OpenSim.Server.Base;
using OpenSim.Services.Interfaces;
using OpenSim.Services.AssetService;

namespace OpenSim.Services.HypergridService
{
    /// <summary>
    /// Hypergrid asset service. It serves the IAssetService interface,
    /// but implements it in ways that are appropriate for inter-grid
    /// asset exchanges.
    /// </summary>
    public class HGAssetService : OpenSim.Services.AssetService.AssetService, IAssetService
    {
        private static readonly ILog m_log =
            LogManager.GetLogger(
            MethodBase.GetCurrentMethod().DeclaringType);

        private string m_HomeURL;
        private IUserAccountService m_UserAccountService;

        private UserAccountCache m_Cache;

        private bool[] m_DisallowGET, m_DisallowPOST;
        private string[] m_AssetTypeNames;

        public HGAssetService(IConfigSource config, string configName) : base(config, configName)
        {
            m_log.Debug("[HGAsset Service]: Starting");
            IConfig assetConfig = config.Configs[configName];
            if (assetConfig == null)
                throw new Exception("No HGAssetService configuration");

            string userAccountsDll = assetConfig.GetString("UserAccountsService", string.Empty);
            if (userAccountsDll == string.Empty)
                throw new Exception("Please specify UserAccountsService in HGAssetService configuration");

            Object[] args = new Object[] { config };
            m_UserAccountService = ServerUtils.LoadPlugin<IUserAccountService>(userAccountsDll, args);
            if (m_UserAccountService == null)
                throw new Exception(String.Format("Unable to create UserAccountService from {0}", userAccountsDll));

            // legacy configuration [obsolete]
            m_HomeURL = assetConfig.GetString("ProfileServerURI", string.Empty);
            // Preferred
            m_HomeURL = assetConfig.GetString("HomeURI", m_HomeURL);

            m_Cache = UserAccountCache.CreateUserAccountCache(m_UserAccountService);

            // Permissions
            Type enumType = typeof(AssetType);
            m_AssetTypeNames = Enum.GetNames(enumType);
            for (int i = 0; i < m_AssetTypeNames.Length; i++)
                m_AssetTypeNames[i] = m_AssetTypeNames[i].ToLower();
            int n = Enum.GetValues(enumType).Length;
            m_DisallowGET = new bool[n];
            m_DisallowPOST = new bool[n];

            LoadPermsFromConfig(assetConfig, "DisallowGET", m_DisallowGET);
            LoadPermsFromConfig(assetConfig, "DisallowPOST", m_DisallowPOST);

        }

        private void LoadPermsFromConfig(IConfig assetConfig, string variable, bool[] bitArray)
        {
            string perms = assetConfig.GetString(variable, String.Empty);
            string[] parts = perms.Split(new char[] {','}, StringSplitOptions.RemoveEmptyEntries);
            foreach (string s in parts)
            {
                int index = Array.IndexOf(m_AssetTypeNames, s.Trim().ToLower());
                if (index >= 0)
                    bitArray[index] = true;
                else
                    m_log.WarnFormat("[HGAsset Service]: Invalid AssetType {0}", s);
            }

        }

        #region IAssetService overrides
        public override AssetBase Get(string id)
        {
            AssetBase asset = base.Get(id);

            if (asset == null)
                return null;

            if (!AllowedGet(asset.Type))
                return null;

            if (asset.Metadata.Type == (sbyte)AssetType.Object)
                asset.Data = AdjustIdentifiers(asset.Data); ;

            AdjustIdentifiers(asset.Metadata);

            return asset;
        }

        public override AssetMetadata GetMetadata(string id)
        {
            AssetMetadata meta = base.GetMetadata(id);

            if (meta == null)
                return null;

            AdjustIdentifiers(meta);

            return meta;
        }

        public override byte[] GetData(string id)
        {
            AssetBase asset = Get(id);

            if (asset == null)
                return null;

            if (!AllowedGet(asset.Type))
                return null;

            return asset.Data;
        }

        //public virtual bool Get(string id, Object sender, AssetRetrieved handler)

        public override string Store(AssetBase asset)
        {
            if (!AllowedPost(asset.Type))
                return UUID.Zero.ToString();

            return base.Store(asset);
        }

        public override bool Delete(string id)
        {
            // NOGO
            return false;
        }

        #endregion 

        protected bool AllowedGet(sbyte type)
        {
            string assetTypeName = ((AssetType)type).ToString();

            int index = Array.IndexOf(m_AssetTypeNames, assetTypeName.ToLower());
            if (index >= 0 && m_DisallowGET[index])
            {
                m_log.DebugFormat("[HGAsset Service]: GET denied: service does not allow export of AssetType {0}", assetTypeName);
                return false;
            }

            return true;
        }

        protected bool AllowedPost(sbyte type)
        {
            string assetTypeName = ((AssetType)type).ToString();

            int index = Array.IndexOf(m_AssetTypeNames, assetTypeName.ToLower());
            if (index >= 0 && m_DisallowPOST[index])
            {
                m_log.DebugFormat("[HGAsset Service]: POST denied: service does not allow import of AssetType {0}", assetTypeName);
                return false;
            }

            return true;
        }

        protected void AdjustIdentifiers(AssetMetadata meta)
        {
            if (meta == null || m_Cache == null)
                return;

            UserAccount creator = m_Cache.GetUser(meta.CreatorID);
            if (creator != null)
                meta.CreatorID = meta.CreatorID + ";" + m_HomeURL + "/" + creator.FirstName + " " + creator.LastName;
        }

        protected byte[] AdjustIdentifiers(byte[] data)
        {
            string xml = Utils.BytesToString(data);
            return Utils.StringToBytes(ExternalRepresentationUtils.RewriteSOP(xml, m_HomeURL, m_Cache, UUID.Zero));
        }

    }

}