/*
 * 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 System;
using System.Collections.Generic;
using System.Reflection;
using System.Threading;
using OpenMetaverse;
using log4net;
using OpenSim.Framework;
using OpenSim.Framework.Communications.Cache;
using OpenSim.Region.Environment.Interfaces;

namespace OpenSim.Region.Environment.Scenes
{
    public abstract class SceneBase : IScene
    {
        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);

        #region Events

        public event restart OnRestart;

        #endregion

        #region Fields

        /// <summary>
        /// The last allocated local prim id.  When a new local id is requested, the next number in the sequence is
        /// dispensed.
        /// </summary>
        protected uint m_lastAllocatedLocalId = 720000;

        private readonly Mutex _primAllocateMutex = new Mutex(false);
        
        private readonly ClientManager m_clientManager = new ClientManager();

        public ClientManager ClientManager
        {
            get { return m_clientManager; }
        }

        protected ulong m_regionHandle;
        protected string m_regionName;
        protected RegionInfo m_regInfo;

        //public TerrainEngine Terrain;
        public ITerrainChannel Heightmap;

        /// <value>
        /// Allows retrieval of land information for this scene.
        /// </value>
        public ILandChannel LandChannel;

        /// <value>
        /// Manage events that occur in this scene (avatar movement, script rez, etc.).  Commonly used by region modules
        /// to subscribe to scene events.
        /// </value>
        public EventManager EventManager
        {
            get { return m_eventManager; }
        }
        protected EventManager m_eventManager;

        protected ScenePermissions m_permissions;
        public ScenePermissions Permissions
        {
            get { return m_permissions; }
        }

        protected string m_datastore;

        private AssetCache m_assetCache;

        public AssetCache AssetCache
        {
            get { return m_assetCache; }
            set { m_assetCache = value; }
        }

        protected RegionStatus m_regStatus;

        public RegionStatus Region_Status
        {
            get { return m_regStatus; }
            set { m_regStatus = value; }
        }

        #endregion

        #region Update Methods

        /// <summary>
        /// Normally called once every frame/tick to let the world preform anything required (like running the physics simulation)
        /// </summary>
        public abstract void Update();

        #endregion

        #region Terrain Methods

        /// <summary>
        /// Loads the World heightmap
        /// </summary>
        public abstract void LoadWorldMap();

        /// <summary>
        /// Send the region heightmap to the client
        /// </summary>
        /// <param name="RemoteClient">Client to send to</param>
        public virtual void SendLayerData(IClientAPI RemoteClient)
        {
            RemoteClient.SendLayerData(Heightmap.GetFloatsSerialised());
        }

        #endregion

        #region Add/Remove Agent/Avatar

        /// <summary>
        /// Register the new client with the scene.  The client starts off as a child agent - the later agent crossing
        /// will promote it to a root agent during login.
        /// </summary>
        /// <param name="client"></param
        public abstract void AddNewClient(IClientAPI client);

        /// <summary>
        /// Remove a client from the scene
        /// </summary>
        /// <param name="agentID"></param>
        public abstract void RemoveClient(UUID agentID);

        public abstract void CloseAllAgents(uint circuitcode);

        #endregion

        /// <summary>
        ///
        /// </summary>
        /// <returns></returns>
        public virtual RegionInfo RegionInfo
        {
            get { return m_regInfo; }
        }

        #region admin stuff

        /// <summary>
        /// Region Restart - Seconds till restart.
        /// </summary>
        /// <param name="seconds"></param>
        public virtual void Restart(int seconds)
        {
            m_log.Error("[REGION]: passing Restart Message up the namespace");
            restart handlerPhysicsCrash = OnRestart;
            if (handlerPhysicsCrash != null)
                handlerPhysicsCrash(RegionInfo);
        }

        public virtual bool PresenceChildStatus(UUID avatarID)
        {
            return false;
        }
        
        public abstract bool OtherRegionUp(RegionInfo thisRegion);

        public virtual string GetSimulatorVersion()
        {
            return "OpenSimulator Server";
        }

        #endregion

        #region Shutdown

        /// <summary>
        /// Tidy before shutdown
        /// </summary>
        public virtual void Close()
        {
            try
            {
                EventManager.TriggerShutdown();
            }
            catch (Exception e)
            {
                m_log.Error("[SCENE]: SceneBase.cs: Close() - Failed with exception " + e.ToString());
            }
        }

        #endregion

        /// <summary>
        /// XXX These two methods are very temporary
        /// </summary>
        protected Dictionary<UUID, string> capsPaths = new Dictionary<UUID, string>();
        public string GetCapsPath(UUID agentId)
        {
            if (capsPaths.ContainsKey(agentId))
            {
                return capsPaths[agentId];
            }

            return null;
        }
        
        /// <summary>
        /// Returns a new unallocated local ID
        /// </summary>
        /// <returns>A brand new local ID</returns>
        protected internal uint AllocateLocalId()
        {
            uint myID;

            _primAllocateMutex.WaitOne();
            myID = ++m_lastAllocatedLocalId;
            _primAllocateMutex.ReleaseMutex();

            return myID;
        }        

        public virtual T RequestModuleInterface<T>()
        {
            return default(T);
        }

        public virtual T[] RequestModuleInterfaces<T>()
        {
            return new T[] { default(T) };
        }
    }
}