//
//  EntityMotionState.h
//  libraries/entities/src
//
//  Created by Andrew Meadows on 2014.11.06
//  Copyright 2013 High Fidelity, Inc.
//
//  Distributed under the Apache License, Version 2.0.
//  See the accompanying file LICENSE or http://www.apache.org/licenses/LICENSE-2.0.html
//

#ifndef hifi_EntityMotionState_h
#define hifi_EntityMotionState_h

#include <AACube.h>

#include "ObjectMotionState.h"

class EntityItem;

// From the MotionState's perspective:
//      Inside = physics simulation
//      Outside = external agents (scripts, user interaction, other simulations)

class EntityMotionState : public ObjectMotionState {
public:

    EntityMotionState(btCollisionShape* shape, EntityItem* item);
    virtual ~EntityMotionState();

    void updateServerPhysicsVariables(uint32_t flags);
    virtual void handleEasyChanges(uint32_t flags);
    virtual void handleHardAndEasyChanges(uint32_t flags, PhysicsEngine* engine);

    /// \return MOTION_TYPE_DYNAMIC or MOTION_TYPE_STATIC based on params set in EntityItem
    virtual MotionType computeObjectMotionType() const;

    virtual bool isMoving() const;

    // this relays incoming position/rotation to the RigidBody
    virtual void getWorldTransform(btTransform& worldTrans) const;

    // this relays outgoing position/rotation to the EntityItem
    virtual void setWorldTransform(const btTransform& worldTrans);

    bool isCandidateForOwnership(const QUuid& sessionID) const;
    bool remoteSimulationOutOfSync(uint32_t simulationStep);
    bool shouldSendUpdate(uint32_t simulationStep, const QUuid& sessionID);
    void sendUpdate(OctreeEditPacketSender* packetSender, const QUuid& sessionID, uint32_t step);

    virtual uint32_t getAndClearIncomingDirtyFlags();

    void incrementAccelerationNearlyGravityCount() { _accelerationNearlyGravityCount++; }
    void resetAccelerationNearlyGravityCount() { _accelerationNearlyGravityCount = 0; }
    quint8 getAccelerationNearlyGravityCount() { return _accelerationNearlyGravityCount; }

    virtual float getObjectRestitution() const { return _entity->getRestitution(); }
    virtual float getObjectFriction() const { return _entity->getFriction(); }
    virtual float getObjectLinearDamping() const { return _entity->getDamping(); }
    virtual float getObjectAngularDamping() const { return _entity->getAngularDamping(); }

    virtual glm::vec3 getObjectPosition() const { return _entity->getPosition() - ObjectMotionState::getWorldOffset(); }
    virtual glm::quat getObjectRotation() const { return _entity->getRotation(); }
    virtual const glm::vec3& getObjectLinearVelocity() const { return _entity->getVelocity(); }
    virtual const glm::vec3& getObjectAngularVelocity() const { return _entity->getAngularVelocity(); }
    virtual const glm::vec3& getObjectGravity() const { return _entity->getGravity(); }

    virtual const QUuid& getObjectID() const { return _entity->getID(); }

    virtual QUuid getSimulatorID() const;
    virtual void bump();

    EntityItem* getEntity() const { return _entity; }

    void resetMeasuredBodyAcceleration();
    void measureBodyAcceleration();

    virtual QString getName();

    friend class PhysicalEntitySimulation;

protected:
    virtual btCollisionShape* computeNewShape();
    virtual void clearObjectBackPointer();
    virtual void setMotionType(MotionType motionType);

    EntityItem* _entity;

    bool _sentActive;   // true if body was active when we sent last update
    int _numNonMovingUpdates; // RELIABLE_SEND_HACK for "not so reliable" resends of packets for non-moving objects

    // these are for the prediction of the remote server's simple extrapolation
    uint32_t _lastStep; // last step of server extrapolation
    glm::vec3 _serverPosition;    // in simulation-frame (not world-frame)
    glm::quat _serverRotation;
    glm::vec3 _serverVelocity;
    glm::vec3 _serverAngularVelocity; // radians per second
    glm::vec3 _serverGravity;
    glm::vec3 _serverAcceleration;

    uint32_t _lastMeasureStep;
    glm::vec3 _lastVelocity;
    glm::vec3 _measuredAcceleration;

    quint8 _accelerationNearlyGravityCount;
    bool _candidateForOwnership;
    uint32_t _loopsSinceOwnershipBid;
    uint32_t _loopsWithoutOwner;
};

#endif // hifi_EntityMotionState_h