/*
 * Copyright (c) Contributors, http://opensimulator.org/
 * See CONTRIBUTORS.TXT for a full list of copyright holders.
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 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
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 *       notice, this list of conditions and the following disclaimer.
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 *       notice, this list of conditions and the following disclaimer in the
 *       documentation and/or other materials provided with the distribution.
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 *       names of its contributors may be used to endorse or promote products
 *       derived from this software without specific prior written permission.
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 * THIS SOFTWARE IS PROVIDED BY THE DEVELOPERS ``AS IS'' AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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 */
using System;
using System.Collections.Generic;
using System.Reflection;
using log4net;
using OMV = OpenMetaverse;
using OpenSim.Framework;
using OpenSim.Region.Physics.Manager;

namespace OpenSim.Region.Physics.BulletSPlugin
{
public class BSCharacter : BSPhysObject
{
    private static readonly ILog m_log = LogManager.GetLogger(MethodBase.GetCurrentMethod().DeclaringType);
    private static readonly string LogHeader = "[BULLETS CHAR]";

    private String _avName;
    // private bool _stopped;
    private OMV.Vector3 _size;
    private OMV.Vector3 _scale;
    private PrimitiveBaseShape _pbs;
    private uint _localID = 0;
    private bool _grabbed;
    private bool _selected;
    private OMV.Vector3 _position;
    private float _mass;
    public float _density;
    public float _avatarVolume;
    private OMV.Vector3 _force;
    private OMV.Vector3 _velocity;
    private OMV.Vector3 _torque;
    private float _collisionScore;
    private OMV.Vector3 _acceleration;
    private OMV.Quaternion _orientation;
    private int _physicsActorType;
    private bool _isPhysical;
    private bool _flying;
    private bool _setAlwaysRun;
    private bool _throttleUpdates;
    private bool _isColliding;
    private long _collidingStep;
    private bool _collidingGround;
    private long _collidingGroundStep;
    private bool _collidingObj;
    private bool _floatOnWater;
    private OMV.Vector3 _rotationalVelocity;
    private bool _kinematic;
    private float _buoyancy;

    private int _subscribedEventsMs = 0;
    private int _nextCollisionOkTime = 0;

    private OMV.Vector3 _PIDTarget;
    private bool _usePID;
    private float _PIDTau;
    private bool _useHoverPID;
    private float _PIDHoverHeight;
    private PIDHoverType _PIDHoverType;
    private float _PIDHoverTao;

    public BSCharacter(uint localID, String avName, BSScene parent_scene, OMV.Vector3 pos, OMV.Vector3 size, bool isFlying)
    {
        base.BaseInitialize(parent_scene);
        _localID = localID;
        _avName = avName;
        _physicsActorType = (int)ActorTypes.Agent;
        _position = pos;
        _size = size;
        _flying = isFlying;
        _orientation = OMV.Quaternion.Identity;
        _velocity = OMV.Vector3.Zero;
        _buoyancy = ComputeBuoyancyFromFlying(isFlying);
        // The dimensions of the avatar capsule are kept in the scale.
        // Physics creates a unit capsule which is scaled by the physics engine.
        _scale = new OMV.Vector3(PhysicsScene.Params.avatarCapsuleRadius, PhysicsScene.Params.avatarCapsuleRadius, size.Z);
        _density = PhysicsScene.Params.avatarDensity;
        ComputeAvatarVolumeAndMass();   // set _avatarVolume and _mass based on capsule size, _density and _scale

        ShapeData shapeData = new ShapeData();
        shapeData.ID = _localID;
        shapeData.Type = ShapeData.PhysicsShapeType.SHAPE_AVATAR;
        shapeData.Position = _position;
        shapeData.Rotation = _orientation;
        shapeData.Velocity = _velocity;
        shapeData.Scale = _scale;
        shapeData.Mass = _mass;
        shapeData.Buoyancy = _buoyancy;
        shapeData.Static = ShapeData.numericFalse;
        shapeData.Friction = PhysicsScene.Params.avatarFriction;
        shapeData.Restitution = PhysicsScene.Params.avatarRestitution;

        // do actual create at taint time
        PhysicsScene.TaintedObject("BSCharacter.create", delegate()
        {
            DetailLog("{0},BSCharacter.create", _localID);
            BulletSimAPI.CreateObject(PhysicsScene.WorldID, shapeData);

            // Set the buoyancy for flying. This will be refactored when all the settings happen in C#
            BulletSimAPI.SetObjectBuoyancy(PhysicsScene.WorldID, LocalID, _buoyancy);

            BSBody = new BulletBody(LocalID, BulletSimAPI.GetBodyHandle2(PhysicsScene.World.Ptr, LocalID));
        });
            
        return;
    }

    // called when this character is being destroyed and the resources should be released
    public override void Destroy()
    {
        DetailLog("{0},BSCharacter.Destroy", LocalID);
        PhysicsScene.TaintedObject("BSCharacter.destroy", delegate()
        {
            BulletSimAPI.DestroyObject(PhysicsScene.WorldID, _localID);
        });
    }

    public override void RequestPhysicsterseUpdate()
    {
        base.RequestPhysicsterseUpdate();
    }
    // No one calls this method so I don't know what it could possibly mean
    public override bool Stopped { 
        get { return false; } 
    }
    public override OMV.Vector3 Size {
        get
        {
            // Avatar capsule size is kept in the scale parameter.
            return new OMV.Vector3(_scale.X * 2, _scale.Y * 2, _scale.Z);
        }

        set { 
            // When an avatar's size is set, only the height is changed
            //    and that really only depends on the radius.
            _size = value;
            _scale.Z = (_size.Z * 1.15f) - (_scale.X + _scale.Y);

            // TODO: something has to be done with the avatar's vertical position

            ComputeAvatarVolumeAndMass();

            PhysicsScene.TaintedObject("BSCharacter.setSize", delegate()
            {
                BulletSimAPI.SetObjectScaleMass(PhysicsScene.WorldID, LocalID, _scale, _mass, true);
            });

        } 
    }
    public override PrimitiveBaseShape Shape { 
        set { _pbs = value; 
        } 
    }
    public override uint LocalID { 
        set { _localID = value; 
        }
        get { return _localID; }
    }
    public override bool Grabbed { 
        set { _grabbed = value; 
        } 
    }
    public override bool Selected { 
        set { _selected = value; 
        } 
    }
    public override void CrossingFailure() { return; }
    public override void link(PhysicsActor obj) { return; }
    public override void delink() { return; }

    // Set motion values to zero.
    // Do it to the properties so the values get set in the physics engine.
    // Push the setting of the values to the viewer.
    // Called at taint time!
    public override void ZeroMotion()
    {
        _velocity = OMV.Vector3.Zero;
        _acceleration = OMV.Vector3.Zero;
        _rotationalVelocity = OMV.Vector3.Zero;

        // Zero some other properties directly into the physics engine
        BulletSimAPI.SetLinearVelocity2(BSBody.Ptr, OMV.Vector3.Zero);
        BulletSimAPI.SetAngularVelocity2(BSBody.Ptr, OMV.Vector3.Zero);
        BulletSimAPI.SetInterpolationVelocity2(BSBody.Ptr, OMV.Vector3.Zero, OMV.Vector3.Zero);
        BulletSimAPI.ClearForces2(BSBody.Ptr);
    }

    public override void LockAngularMotion(OMV.Vector3 axis) { return; }

    public override OMV.Vector3 Position { 
        get {
            // _position = BulletSimAPI.GetObjectPosition(Scene.WorldID, _localID);
            return _position; 
        } 
        set {
            _position = value;
            PositionSanityCheck();

            PhysicsScene.TaintedObject("BSCharacter.setPosition", delegate()
            {
                DetailLog("{0},BSCharacter.SetPosition,taint,pos={1},orient={2}", LocalID, _position, _orientation);
                BulletSimAPI.SetObjectTranslation(PhysicsScene.WorldID, _localID, _position, _orientation);
            });
        } 
    }

    // Check that the current position is sane and, if not, modify the position to make it so.
    // Check for being below terrain and being out of bounds.
    // Returns 'true' of the position was made sane by some action.
    private bool PositionSanityCheck()
    {
        bool ret = false;
        
        // If below the ground, move the avatar up
        float terrainHeight = PhysicsScene.TerrainManager.GetTerrainHeightAtXYZ(_position);
        if (Position.Z < terrainHeight)
        {
            DetailLog("{0},BSCharacter.PositionAdjustUnderGround,call,pos={1},terrain={2}", LocalID, _position, terrainHeight);
            _position.Z = terrainHeight + 2.0f;
            ret = true;
        }

        // TODO: check for out of bounds
        return ret;
    }

    // A version of the sanity check that also makes sure a new position value is
    //    pushed back to the physics engine. This routine would be used by anyone
    //    who is not already pushing the value.
    private bool PositionSanityCheck2()
    {
        bool ret = false;
        if (PositionSanityCheck())
        {
            // The new position value must be pushed into the physics engine but we can't
            //    just assign to "Position" because of potential call loops.
            PhysicsScene.TaintedObject("BSCharacter.PositionSanityCheck", delegate()
            {
                DetailLog("{0},BSCharacter.PositionSanityCheck,taint,pos={1},orient={2}", LocalID, _position, _orientation);
                BulletSimAPI.SetObjectTranslation(PhysicsScene.WorldID, _localID, _position, _orientation);
            });
            ret = true;
        }
        return ret;
    }

    public override float Mass { 
        get { 
            return _mass; 
        } 
    }

    // used when we only want this prim's mass and not the linkset thing
    public override float MassRaw { get {return _mass; } }

    public override OMV.Vector3 Force { 
        get { return _force; } 
        set {
            _force = value;
            // m_log.DebugFormat("{0}: Force = {1}", LogHeader, _force);
            PhysicsScene.TaintedObject("BSCharacter.SetForce", delegate()
            {
                DetailLog("{0},BSCharacter.setForce,taint,force={1}", LocalID, _force);
                BulletSimAPI.SetObjectForce(PhysicsScene.WorldID, LocalID, _force);
            });
        } 
    }

    public override int VehicleType { 
        get { return 0; } 
        set { return; } 
    }
    public override void VehicleFloatParam(int param, float value) { }
    public override void VehicleVectorParam(int param, OMV.Vector3 value) {}
    public override void VehicleRotationParam(int param, OMV.Quaternion rotation) { }
    public override void VehicleFlags(int param, bool remove) { }

    // Allows the detection of collisions with inherently non-physical prims. see llVolumeDetect for more
    public override void SetVolumeDetect(int param) { return; }

    public override OMV.Vector3 GeometricCenter { get { return OMV.Vector3.Zero; } }
    public override OMV.Vector3 CenterOfMass { get { return OMV.Vector3.Zero; } }
    public override OMV.Vector3 Velocity { 
        get { return _velocity; } 
        set {
            _velocity = value;
            // m_log.DebugFormat("{0}: set velocity = {1}", LogHeader, _velocity);
            PhysicsScene.TaintedObject("BSCharacter.setVelocity", delegate()
            {
                DetailLog("{0},BSCharacter.setVelocity,taint,vel={1}", LocalID, _velocity);
                BulletSimAPI.SetObjectVelocity(PhysicsScene.WorldID, _localID, _velocity);
            });
        } 
    }
    public override OMV.Vector3 Torque { 
        get { return _torque; } 
        set { _torque = value; 
        } 
    }
    public override float CollisionScore { 
        get { return _collisionScore; } 
        set { _collisionScore = value; 
        } 
    }
    public override OMV.Vector3 Acceleration { 
        get { return _acceleration; }
        set { _acceleration = value; }
    }
    public override OMV.Quaternion Orientation { 
        get { return _orientation; } 
        set {
            _orientation = value;
            // m_log.DebugFormat("{0}: set orientation to {1}", LogHeader, _orientation);
            PhysicsScene.TaintedObject("BSCharacter.setOrientation", delegate()
            {
                // _position = BulletSimAPI.GetObjectPosition(Scene.WorldID, _localID);
                BulletSimAPI.SetObjectTranslation(PhysicsScene.WorldID, _localID, _position, _orientation);
            });
        } 
    }
    public override int PhysicsActorType { 
        get { return _physicsActorType; } 
        set { _physicsActorType = value; 
        } 
    }
    public override bool IsPhysical { 
        get { return _isPhysical; } 
        set { _isPhysical = value;
        } 
    }
    public override bool Flying { 
        get { return _flying; } 
        set {
            _flying = value;
            // simulate flying by changing the effect of gravity
            this.Buoyancy = ComputeBuoyancyFromFlying(_flying);
        } 
    }
    // Flying is implimented by changing the avatar's buoyancy.
    // Would this be done better with a vehicle type?
    private float ComputeBuoyancyFromFlying(bool ifFlying) {
        return ifFlying ? 1f : 0f;
    }
    public override bool 
        SetAlwaysRun { 
        get { return _setAlwaysRun; } 
        set { _setAlwaysRun = value; } 
    }
    public override bool ThrottleUpdates { 
        get { return _throttleUpdates; } 
        set { _throttleUpdates = value; } 
    }
    public override bool IsColliding {
        get { return (_collidingStep == PhysicsScene.SimulationStep); } 
        set { _isColliding = value; } 
    }
    public override bool CollidingGround {
        get { return (_collidingGroundStep == PhysicsScene.SimulationStep); } 
        set { _collidingGround = value; } 
    }
    public override bool CollidingObj { 
        get { return _collidingObj; } 
        set { _collidingObj = value; } 
    }
    public override bool FloatOnWater { 
        set { _floatOnWater = value; } 
    }
    public override OMV.Vector3 RotationalVelocity { 
        get { return _rotationalVelocity; } 
        set { _rotationalVelocity = value; } 
    }
    public override bool Kinematic { 
        get { return _kinematic; } 
        set { _kinematic = value; } 
    }
    // neg=fall quickly, 0=1g, 1=0g, pos=float up
    public override float Buoyancy { 
        get { return _buoyancy; } 
        set { _buoyancy = value; 
            PhysicsScene.TaintedObject("BSCharacter.setBuoyancy", delegate()
            {
                DetailLog("{0},BSCharacter.setBuoyancy,taint,buoy={1}", LocalID, _buoyancy);
                BulletSimAPI.SetObjectBuoyancy(PhysicsScene.WorldID, LocalID, _buoyancy);
            });
        } 
    }

    // Used for MoveTo
    public override OMV.Vector3 PIDTarget { 
        set { _PIDTarget = value; } 
    }
    public override bool PIDActive { 
        set { _usePID = value; } 
    }
    public override float PIDTau { 
        set { _PIDTau = value; } 
    }

    // Used for llSetHoverHeight and maybe vehicle height
    // Hover Height will override MoveTo target's Z
    public override bool PIDHoverActive { 
        set { _useHoverPID = value; }
    }
    public override float PIDHoverHeight { 
        set { _PIDHoverHeight = value; }
    }
    public override PIDHoverType PIDHoverType { 
        set { _PIDHoverType = value; }
    }
    public override float PIDHoverTau { 
        set { _PIDHoverTao = value; }
    }

    // For RotLookAt
    public override OMV.Quaternion APIDTarget { set { return; } }
    public override bool APIDActive { set { return; } }
    public override float APIDStrength { set { return; } }
    public override float APIDDamping { set { return; } }

    public override void AddForce(OMV.Vector3 force, bool pushforce) { 
        if (force.IsFinite())
        {
            _force.X += force.X;
            _force.Y += force.Y;
            _force.Z += force.Z;
            // m_log.DebugFormat("{0}: AddForce. adding={1}, newForce={2}", LogHeader, force, _force);
            PhysicsScene.TaintedObject("BSCharacter.AddForce", delegate()
            {
                DetailLog("{0},BSCharacter.setAddForce,taint,addedForce={1}", LocalID, _force);
                BulletSimAPI.SetObjectForce2(BSBody.Ptr, _force);
            });
        }
        else
        {
            m_log.ErrorFormat("{0}: Got a NaN force applied to a Character", LogHeader);
        }
        //m_lastUpdateSent = false;
    }

    public override void AddAngularForce(OMV.Vector3 force, bool pushforce) { 
    }
    public override void SetMomentum(OMV.Vector3 momentum) { 
    }

    // set _avatarVolume and _mass based on capsule size, _density and _scale
    private void ComputeAvatarVolumeAndMass()
    {
        _avatarVolume = (float)(
                        Math.PI
                        * _scale.X
                        * _scale.Y  // the area of capsule cylinder
                        * _scale.Z  // times height of capsule cylinder
                      + 1.33333333f
                        * Math.PI
                        * _scale.X
                        * Math.Min(_scale.X, _scale.Y)
                        * _scale.Y  // plus the volume of the capsule end caps
                        );
        _mass = _density * _avatarVolume;
    }

    // The physics engine says that properties have updated. Update same and inform
    // the world that things have changed.
    public override void UpdateProperties(EntityProperties entprop)
    {
        _position = entprop.Position;
        _orientation = entprop.Rotation;
        _velocity = entprop.Velocity;
        _acceleration = entprop.Acceleration;
        _rotationalVelocity = entprop.RotationalVelocity;
        // Avatars don't report their changes the usual way. Changes are checked for in the heartbeat loop.
        // base.RequestPhysicsterseUpdate();

        // Do some sanity checking for the avatar. Make sure it's above ground and inbounds.
        PositionSanityCheck2();

        float heightHere = PhysicsScene.TerrainManager.GetTerrainHeightAtXYZ(_position);   // only for debug
        DetailLog("{0},BSCharacter.UpdateProperties,call,pos={1},orient={2},vel={3},accel={4},rotVel={5},terrain={6}",
                LocalID, _position, _orientation, _velocity, _acceleration, _rotationalVelocity, heightHere);
    }

    // Invoke the detailed logger and output something if it's enabled.
    private void DetailLog(string msg, params Object[] args)
    {
        PhysicsScene.PhysicsLogging.Write(msg, args);
    }
}
}