/*
 * 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
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 * 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 Nini.Config;
using Mono.Addins;
using OpenMetaverse;
using OpenSim.Framework;
using OpenSim.Region.PhysicsModules.SharedBase;
using OpenSim.Region.Framework.Scenes;
using OpenSim.Region.Framework.Interfaces;

namespace OpenSim.Region.PhysicsModule.BasicPhysics
{
    /// <summary>
    /// This is an incomplete extremely basic physics implementation
    /// </summary>
    /// <remarks>
    /// Not useful for anything at the moment apart from some regression testing in other components where some form
    /// of physics plugin is needed.
    /// </remarks>
    [Extension(Path = "/OpenSim/RegionModules", NodeName = "RegionModule", Id = "BasicPhysicsScene")]
    public class BasicScene : PhysicsScene, INonSharedRegionModule
    {
        private List<BasicActor> _actors = new List<BasicActor>();
        private List<BasicPhysicsPrim> _prims = new List<BasicPhysicsPrim>();
        private float[] _heightMap;
        private Vector3 m_regionExtent;

        private bool m_Enabled = false;

        //protected internal string sceneIdentifier;
        #region INonSharedRegionModule
        public string Name
        {
            get { return "basicphysics"; }
        }

        public string Version
        {
            get { return "1.0"; }
        }

        public Type ReplaceableInterface
        {
            get { return null; }
        }

        public void Initialise(IConfigSource source)
        {
            // TODO: Move this out of Startup
            IConfig config = source.Configs["Startup"];
            if (config != null)
            {
                string physics = config.GetString("physics", string.Empty);
                if (physics == Name)
                    m_Enabled = true;
            }

        }

        public void Close()
        {
        }

        public void AddRegion(Scene scene)
        {
            if (!m_Enabled)
                return;

            EngineType = Name;
            PhysicsSceneName = EngineType + "/" + scene.RegionInfo.RegionName;
            EngineName = Name + " " + Version;

            scene.RegisterModuleInterface<PhysicsScene>(this);
            m_regionExtent = new Vector3(scene.RegionInfo.RegionSizeX, scene.RegionInfo.RegionSizeY, scene.RegionInfo.RegionSizeZ);
            base.Initialise(scene.PhysicsRequestAsset,
                (scene.Heightmap != null ? scene.Heightmap.GetFloatsSerialised() : new float[scene.RegionInfo.RegionSizeX * scene.RegionInfo.RegionSizeY]),
                (float)scene.RegionInfo.RegionSettings.WaterHeight);

        }

        public void RemoveRegion(Scene scene)
        {
            if (!m_Enabled)
                return;
        }

        public void RegionLoaded(Scene scene)
        {
            if (!m_Enabled)
                return;
        }
        #endregion

        public override void Dispose() {}

        public override PhysicsActor AddPrimShape(string primName, PrimitiveBaseShape pbs, Vector3 position,
                                                  Vector3 size, Quaternion rotation, bool isPhysical, uint localid)
        {
            BasicPhysicsPrim prim = new BasicPhysicsPrim(primName, localid, position, size, rotation, pbs);
            prim.IsPhysical = isPhysical;

            _prims.Add(prim);

            return prim;
        }

        public override PhysicsActor AddAvatar(string avName, Vector3 position, Vector3 velocity, Vector3 size, bool isFlying)
        {
            BasicActor act = new BasicActor(size);
            act.Position = position;
            act.Velocity = velocity;
            act.Flying = isFlying;
            _actors.Add(act);
            return act;
        }

        public override void RemovePrim(PhysicsActor actor)
        {
            BasicPhysicsPrim prim = (BasicPhysicsPrim)actor;
            if (_prims.Contains(prim))
                _prims.Remove(prim);
        }

        public override void RemoveAvatar(PhysicsActor actor)
        {
            BasicActor act = (BasicActor)actor;
            if (_actors.Contains(act))
                _actors.Remove(act);
        }

        public override void AddPhysicsActorTaint(PhysicsActor prim)
        {
        }

        public override float Simulate(float timeStep)
        {
//            Console.WriteLine("Simulating");

            float fps = 1.0f / timeStep;
            for (int i = 0; i < _actors.Count; ++i)
            {
                BasicActor actor = _actors[i];
                Vector3 actorPosition = actor.Position;
                Vector3 actorVelocity = actor.Velocity;

                //Console.WriteLine(
                //    "Processing actor {0}, starting pos {1}, starting vel {2}", i, actorPosition, actorVelocity);

                actorPosition.X += actor.Velocity.X * timeStep;
                actorPosition.Y += actor.Velocity.Y * timeStep;

                if (actor.Position.Y < 0)
                {
                    actorPosition.Y = 0.1F;
                }
                else if (actor.Position.Y >= m_regionExtent.Y)
                {
                    actorPosition.Y = (m_regionExtent.Y - 0.1f);
                }

                if (actor.Position.X < 0)
                {
                    actorPosition.X = 0.1F;
                }
                else if (actor.Position.X >= m_regionExtent.X)
                {
                    actorPosition.X = (m_regionExtent.X - 0.1f);
                }

                float terrainHeight = 0;
                if (_heightMap != null)
                    terrainHeight = _heightMap[(int)actor.Position.Y * (int)m_regionExtent.Y + (int)actor.Position.X];

                float height = terrainHeight + actor.Size.Z;
//                Console.WriteLine("height {0}, actorPosition {1}", height, actorPosition);

                if (actor.Flying)
                {
                    if (actor.Position.Z + (actor.Velocity.Z * timeStep) < terrainHeight + 2)
                    {
                        actorPosition.Z = height;
                        actorVelocity.Z = 0;
                        actor.IsColliding = true;
                    }
                    else
                    {
                        actorPosition.Z += actor.Velocity.Z * timeStep;
                        actor.IsColliding = false;
                    }
                }
                else
                {
                    actorPosition.Z = height;
                    actorVelocity.Z = 0;
                    actor.IsColliding = true;
                }

                actor.Position = actorPosition;
                actor.Velocity = actorVelocity;
            }

            return fps;
        }

        public override void GetResults()
        {
        }

        public override bool IsThreaded
        {
            get { return (false); // for now we won't be multithreaded
            }
        }

        public override void SetTerrain(float[] heightMap)
        {
            _heightMap = heightMap;
        }

        public override void DeleteTerrain()
        {
        }

        public override void SetWaterLevel(float baseheight)
        {
        }

        public override Dictionary<uint, float> GetTopColliders()
        {
            Dictionary<uint, float> returncolliders = new Dictionary<uint, float>();
            return returncolliders;
        }

    }
}