/*
 * 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.Linq;
using System.Reflection;
using log4net;
using Mono.Addins;
using Nini.Config;
using OpenMetaverse;
using OpenSim.Framework;
using OpenSim.Region.Framework.Interfaces;
using OpenSim.Region.Framework.Scenes;

namespace OpenSim.Region.OptionalModules
{
    /// <summary>
    /// Enables Prim limits for parcel.
    /// </summary>
    /// <remarks>
    /// This module selectivly enables parcel prim limits.
    /// </remarks>
    [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule", Id = "PrimLimitsModule")]
    public class PrimLimitsModule : INonSharedRegionModule
    {
        protected IDialogModule m_dialogModule;
        private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
        private bool m_enabled;

        public string Name { get { return "PrimLimitsModule"; } }        
        
        public Type ReplaceableInterface { get { return null; } }
        
        public void Initialise(IConfigSource config)
        {
            string permissionModules = Util.GetConfigVarFromSections<string>(config, "permissionmodules",
                new string[] { "Startup", "Permissions" }, "DefaultPermissionsModule"); 

            List<string> modules = new List<string>(permissionModules.Split(',').Select(m => m.Trim()));

            if(!modules.Contains("PrimLimitsModule"))
                return;

            m_log.DebugFormat("[PRIM LIMITS]: Initialized module");
            m_enabled = true;
        }
        
        public void Close()
        {
        }
        
        public void AddRegion(Scene scene)
        {
            if (!m_enabled)
            {
                return;
            }
            scene.Permissions.OnRezObject += CanRezObject;
            scene.Permissions.OnObjectEntry += CanObjectEnter;
            scene.Permissions.OnDuplicateObject += CanDuplicateObject;

            m_log.DebugFormat("[PRIM LIMITS]: Region {0} added", scene.RegionInfo.RegionName);
        }
        
        public void RemoveRegion(Scene scene)
        {
            if (m_enabled)
            {
                return;
            }

            scene.Permissions.OnRezObject -= CanRezObject;
            scene.Permissions.OnObjectEntry -= CanObjectEnter;
            scene.Permissions.OnDuplicateObject -= CanDuplicateObject;
        }        
        
        public void RegionLoaded(Scene scene)
        {
            m_dialogModule = scene.RequestModuleInterface<IDialogModule>();
        }                

        private bool CanRezObject(int objectCount, UUID owner, Vector3 objectPosition, Scene scene)
        {
            ILandObject lo = scene.LandChannel.GetLandObject(objectPosition.X, objectPosition.Y);
            int usedPrims = lo.PrimCounts.Total;
            int simulatorCapacity = lo.GetSimulatorMaxPrimCount();

            if (objectCount + usedPrims > simulatorCapacity)
            {
                m_dialogModule.SendAlertToUser(owner, "Unable to rez object because the parcel is too full");
                return false;
            }

            return true;
        }

        private bool CanObjectEnter(UUID objectID, bool enteringRegion, Vector3 newPoint, Scene scene)
        {
            SceneObjectPart obj = scene.GetSceneObjectPart(objectID);
            Vector3 oldPoint = obj.GroupPosition;
            int objectCount = obj.ParentGroup.PrimCount;
            ILandObject oldParcel = scene.LandChannel.GetLandObject(oldPoint.X, oldPoint.Y);
            ILandObject newParcel = scene.LandChannel.GetLandObject(newPoint.X, newPoint.Y);

            // newParcel will be null only if it outside of our current region.  If this is the case, then the 
            // receiving permissions will perform the check.
            if (newParcel == null)
                return true;

            int usedPrims = newParcel.PrimCounts.Total;
            int simulatorCapacity = newParcel.GetSimulatorMaxPrimCount();
            
            // The prim hasn't crossed a region boundry so we don't need to worry
            // about prim counts here
            if(oldParcel.Equals(newParcel))
            {
                return true;
            }

            // Prim counts are determined by the location of the root prim.  if we're
            // moving a child prim, just let it pass
            if(!obj.IsRoot)
            {
                return true;
            }

            // TODO: Add Special Case here for temporary prims
            
            if(objectCount + usedPrims > simulatorCapacity)
            {
                m_dialogModule.SendAlertToUser(obj.OwnerID, "Unable to move object because the destination parcel  is too full");
                return false;
            }

            return true;
        }

        //OnDuplicateObject
        private bool CanDuplicateObject(int objectCount, UUID objectID, UUID owner, Scene scene, Vector3 objectPosition)
        {
            ILandObject lo = scene.LandChannel.GetLandObject(objectPosition.X, objectPosition.Y);
            int usedPrims = lo.PrimCounts.Total;
            int simulatorCapacity = lo.GetSimulatorMaxPrimCount();

            if(objectCount + usedPrims > simulatorCapacity)
            {
                m_dialogModule.SendAlertToUser(owner, "Unable to duplicate object because the parcel is too full");
                return false;
            }

            return true;
        }
    }
}