/*
 * 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;
 * 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.Reflection;
using System.Collections.Generic;
using OpenSim.Framework;
using OpenSim.Services.Interfaces;
using OpenMetaverse;
using log4net;

namespace OpenSim.Region.CoreModules.ServiceConnectorsOut.UserAccounts
{
    public class UserAccountCache : IUserAccountCacheModule
    {
        private const double CACHE_ALIEN_EXPIRATION_SECONDS = 172800; // 48 hours
        private const double CACHE_EXPIRATION_SECONDS = 3600.0; // 1 hour!
        private const double CACHE_NULL_EXPIRATION_SECONDS = 600; // 10minutes

//        private static readonly ILog m_log =
//                LogManager.GetLogger(
//                MethodBase.GetCurrentMethod().DeclaringType);

        private ExpiringCache<UUID, UserAccount> m_UUIDCache;
        private ExpiringCache<string, UUID> m_NameCache;
        private object accessLock = new object();

        public UserAccountCache()
        {
            m_UUIDCache = new ExpiringCache<UUID, UserAccount>();
            m_NameCache = new ExpiringCache<string, UUID>();
        }

        public void Cache(UUID userID, UserAccount account)
        {
            // Cache even null accounts
            lock(accessLock)
            {
                if (account == null)
                    m_UUIDCache.AddOrUpdate(userID, null, CACHE_NULL_EXPIRATION_SECONDS);
                else if(account.LocalToGrid)
                {
                    m_UUIDCache.AddOrUpdate(userID, account, CACHE_EXPIRATION_SECONDS);
                    m_NameCache.AddOrUpdate(account.Name, account.PrincipalID, CACHE_EXPIRATION_SECONDS);
                }
                else
                {
                    m_UUIDCache.AddOrUpdate(userID, account, CACHE_ALIEN_EXPIRATION_SECONDS);
                    m_NameCache.AddOrUpdate(account.Name, account.PrincipalID, CACHE_ALIEN_EXPIRATION_SECONDS);
                }
            //m_log.DebugFormat("[USER CACHE]: cached user {0}", userID);
            }
        }


        public UserAccount Get(UUID userID, out bool inCache)
        {
            UserAccount account = null;
            inCache = false;
            lock(accessLock)
            {
                if (m_UUIDCache.TryGetValue(userID, out account))
                {
                    //m_log.DebugFormat("[USER CACHE]: Account {0} {1} found in cache", account.FirstName, account.LastName);
                    inCache = true;
                    return account;
                }
            }
            return null;
        }

        public UserAccount Get(string name, out bool inCache)
        {
            inCache = false;
            lock(accessLock)
            {
                if (!m_NameCache.Contains(name))
                    return null;

                UserAccount account = null;
                UUID uuid = UUID.Zero;
                if (m_NameCache.TryGetValue(name, out uuid))
                {
                    if (m_UUIDCache.TryGetValue(uuid, out account))
                    {
                        inCache = true;
                        return account;
                    }
                }
            }
            return null;
        }

        public void Invalidate(UUID userID)
        {
                m_UUIDCache.Remove(userID);
        }

        public void Remove(UUID id)
        {
            lock(accessLock)
            {
                if (!m_UUIDCache.Contains(id))
                    return;

                UserAccount account = null;
                if (m_UUIDCache.TryGetValue(id, out account) && account != null)
                    m_NameCache.Remove(account.Name);
                m_UUIDCache.Remove(id);
            }
        }

        public void Remove(string name)
        {
            lock(accessLock)
            {
                if (!m_NameCache.Contains(name))
                    return;

                UUID uuid = UUID.Zero;
                if (m_NameCache.TryGetValue(name, out uuid))
                {
                    m_NameCache.Remove(name);
                    m_UUIDCache.Remove(uuid);
                }
            }
        }
    }
}