//
// Lol Engine
//
// Copyright: (c) 2010-2012 Sam Hocevar <sam@hocevar.net>
//            (c) 2009-2012 Benjamin Huet <huet.benjamin@gmail.com>
//   This program is free software; you can redistribute it and/or
//   modify it under the terms of the Do What The Fuck You Want To
//   Public License, Version 2, as published by Sam Hocevar. See
//   http://sam.zoy.org/projects/COPYING.WTFPL for more details.
//

//
// The EasyPhysic class
// ------------------
//

#if !defined __EASYPHYSICS_EASYPHYSICS_H__
#define __EASYPHYSICS_EASYPHYSICS_H__

#ifdef HAVE_PHYS_USE_BULLET
#include "core.h"
#include <bullet/btBulletDynamicsCommon.h>
#include <bullet/btBulletCollisionCommon.h>
#include <bullet/BulletCollision/CollisionDispatch/btGhostObject.h>
#include <BulletDynamics/Character/btKinematicCharacterController.h>
#endif

namespace lol
{

namespace phys
{

class EasyPhysic
{

	friend class EasyConstraint;

#ifdef HAVE_PHYS_USE_BULLET

public:
	EasyPhysic();
	~EasyPhysic();

	virtual void SetShapeToBox(lol::vec3& box_size);
	virtual void SetShapeToSphere(float radius);
	virtual void SetShapeToCone(float radius, float height);
	virtual void SetShapeToCylinder(lol::vec3& cyl_size);
	virtual void SetShapeToCapsule(float radius, float height);

	virtual bool CanChangeCollisionChannel() { return (m_rigid_body == NULL); }
	virtual void SetTransform(const lol::vec3& base_location, const lol::quat& base_rotation=lol::quat(lol::mat4(1.0f)));
	virtual void SetMass(float mass);
	virtual void InitBodyToRigid(bool ZeroMassIsKinematic=false);
	virtual void InitBodyToGhost();
	virtual void AddToSimulation(class Simulation* current_simulation);
	virtual void RemoveFromSimulation(class Simulation* current_simulation);
	virtual mat4 GetTransform();

protected:
	virtual void SetLocalInertia(float mass);
	virtual void SetShapeTo(btCollisionShape* collision_shape);

	virtual btGhostObject* GetGhostObject();

	btCollisionObject*							m_collision_object;

	btGhostObject*								m_ghost_object;

	btRigidBody*								m_rigid_body;
	btVector3									m_local_inertia;

	btCollisionShape*							m_collision_shape;
	btConvexShape*								m_convex_shape;
	btMotionState*								m_motion_state;

#else  // NO PHYSIC IMPLEMENTATION

public:
	EasyPhysic() { }

	virtual void SetShapeToBox(lol::vec3& BoxSize) { }
	virtual void SetShapeToSphere(float radius) { }
	virtual void SetShapeToCone(float radius, float height) { }
	virtual void SetShapeToCylinder(lol::vec3& cyl_size) { }
	virtual void SetShapeToCapsule(float radius, float height) { }

	virtual bool CanChangeCollisionChannel() { return true; }
	virtual void SetTransform(const lol::vec3& base_location, const lol::quat& base_rotation=lol::quat(lol::mat4(1.0f))) { }
	virtual void SetMass(float mass) { }
	virtual void InitBodyToRigid() { }
	virtual void InitBodyToGhost() { }
	virtual void AddToSimulation(class Simulation* current_simulation) { }
	virtual void RemoveFromSimulation(class Simulation* current_simulation) { }
	virtual mat4 GetTransform() { return mat4(1.0f); }

	virtual void InitBodyToGhost() { }

#endif // PHYSIC IMPLEMENTATION

public:
	//Sets the collision Group & Mask.
	//Mask can change at runtime, not group !
	virtual bool SetCollisionChannel(int NewGroup, int NewMask)
	{
		if (CanChangeCollisionChannel())
		{
			m_collision_group = (1<<NewGroup);
			m_collision_mask = NewMask;
			return true;
		}
		return false;
	}
	int GetCollisionGroup() { return m_collision_group; }
	int GetCollisionMask()	{ return m_collision_mask; }

protected:
	lol::mat4									m_local_to_world;
	float										m_mass;
	int											m_collision_group;
	int											m_collision_mask;
};

class EasyCharacterController : public EasyPhysic
{

#ifdef HAVE_PHYS_USE_BULLET

public:
	EasyCharacterController() :
		EasyPhysic(),
		m_character(NULL)
	{
		m_up_axis = 1;
	}
	~EasyCharacterController()
	{
		delete m_character;
	}

	virtual void InitBodyToRigid(bool ZeroMassIsKinematic=false);
	virtual void InitBodyToGhost();
	virtual void AddToSimulation(class Simulation* current_simulation);
	virtual void RemoveFromSimulation(class Simulation* current_simulation);
	virtual void SetMovementForFrame(vec3 const &MoveQuantity);

protected:

	virtual btGhostObject* GetGhostObject();

	btPairCachingGhostObject*		m_pair_caching_object;
	btKinematicCharacterController*	m_character;

	float							m_step_height;
	int								m_up_axis;

#else  // NO PHYSIC IMPLEMENTATION

	virtual void InitBodyToRigid(bool ZeroMassIsKinematic=false) { }
	virtual void InitBodyToGhost() { }
	virtual void AddToSimulation(class Simulation* current_simulation) { }
	virtual void RemoveFromSimulation(class Simulation* current_simulation) { }
	virtual void SetMovementForFrame(vec3 const &MoveQuantity) { }

#endif // PHYSIC IMPLEMENTATION

};

class EasyConstraint
{
#ifdef HAVE_PHYS_USE_BULLET

public:
	EasyConstraint() :
		m_typed_constraint(NULL),
		m_p2p_constraint(NULL),
		m_hinge_constraint(NULL),
		m_slider_constraint(NULL),
		m_cone_twist_constraint(NULL),
		m_6dof_constraint(NULL),
		m_a_physobj(NULL),
		m_b_physobj(NULL),
		m_a_transform(lol::mat4(1.f)),
		m_b_transform(lol::mat4(1.f)),
		m_using_ref_a(false),
		m_disable_a2b_collision(false)

	{
	}
	~EasyConstraint()
	{
		delete m_typed_constraint;
		m_p2p_constraint = NULL;
		m_hinge_constraint = NULL;
		m_slider_constraint = NULL;
		m_cone_twist_constraint = NULL;
		m_6dof_constraint = NULL;
	}

	void AddToSimulation(class Simulation* current_simulation);
	void RemoveFromSimulation(class Simulation* current_simulation);

private:

	//check if Init can be done
	bool CanProceedWithInit()
	{
		if (!m_a_physobj || !m_b_physobj)
			return false;

		if (!m_a_physobj->m_rigid_body || !m_b_physobj->m_rigid_body)
			return false;

		return true;
	}

	//-------------------------------------------------------------------------
	//Init constraint functions
	//--
	void CustomInitConstraintToPoint2Point()
	{
		m_p2p_constraint = new btPoint2PointConstraint(*m_a_physobj->m_rigid_body, *m_b_physobj->m_rigid_body,
														LOL2BT_VEC3(m_a_transform.v3.xyz * LOL2BT_UNIT), LOL2BT_VEC3(m_b_transform.v3.xyz * LOL2BT_UNIT));
		m_typed_constraint = m_p2p_constraint;
	}

	void CustomInitConstraintToHinge()
	{
		m_hinge_constraint = new btHingeConstraint(*m_a_physobj->m_rigid_body, *m_b_physobj->m_rigid_body,
														btTransform(LOL2BT_QUAT(quat(m_a_transform)), LOL2BT_VEC3(m_a_transform.v3.xyz * LOL2BT_UNIT)),
														btTransform(LOL2BT_QUAT(quat(m_b_transform)), LOL2BT_VEC3(m_b_transform.v3.xyz * LOL2BT_UNIT)),
														m_using_ref_a);
		m_typed_constraint = m_hinge_constraint;
	}

	void CustomInitConstraintToSlider()
	{
		m_slider_constraint = new btSliderConstraint(*m_a_physobj->m_rigid_body, *m_b_physobj->m_rigid_body,
														btTransform(LOL2BT_QUAT(quat(m_a_transform)), LOL2BT_VEC3(m_a_transform.v3.xyz * LOL2BT_UNIT)),
														btTransform(LOL2BT_QUAT(quat(m_b_transform)), LOL2BT_VEC3(m_b_transform.v3.xyz * LOL2BT_UNIT)),
														m_using_ref_a);
		m_typed_constraint = m_slider_constraint;
	}

	void CustomInitConstraintToConeTwist()
	{
		m_cone_twist_constraint = new btConeTwistConstraint(*m_a_physobj->m_rigid_body, *m_b_physobj->m_rigid_body,
														btTransform(LOL2BT_QUAT(quat(m_a_transform)), LOL2BT_VEC3(m_a_transform.v3.xyz * LOL2BT_UNIT)),
														btTransform(LOL2BT_QUAT(quat(m_b_transform)), LOL2BT_VEC3(m_b_transform.v3.xyz * LOL2BT_UNIT)));
		m_typed_constraint = m_cone_twist_constraint;
	}

	void CustomInitConstraintTo6Dof()
	{
		m_6dof_constraint = new btGeneric6DofConstraint(*m_a_physobj->m_rigid_body, *m_b_physobj->m_rigid_body,
														btTransform(LOL2BT_QUAT(quat(m_a_transform)), LOL2BT_VEC3(m_a_transform.v3.xyz * LOL2BT_UNIT)),
														btTransform(LOL2BT_QUAT(quat(m_b_transform)), LOL2BT_VEC3(m_b_transform.v3.xyz * LOL2BT_UNIT)),
														m_using_ref_a);
		m_typed_constraint = m_6dof_constraint;
	}

	btTypedConstraint*			m_typed_constraint;
	btPoint2PointConstraint*	m_p2p_constraint;
	btHingeConstraint*			m_hinge_constraint;
	btSliderConstraint*			m_slider_constraint;
	btConeTwistConstraint*		m_cone_twist_constraint;
	btGeneric6DofConstraint*	m_6dof_constraint;

#else  // NO PHYSIC IMPLEMENTATION

public:
	EasyConstraint() :
		m_a_physobj(NULL),
		m_b_physobj(NULL),
		m_a_transform(lol::mat4(1.f)),
		m_b_transform(lol::mat4(1.f)),
		m_using_ref_a(false),
		m_disable_a2b_collision(false)
	{
	}

private:

	void AddToSimulation(class Simulation* current_simulation) { }
	void RemoveFromSimulation(class Simulation* current_simulation) { }

	//check if Init can be done
	bool CanProceedWithInit() { return false; }
	void CustomInitConstraintToPoint2Point() { }
	void CustomInitConstraintToHinge() { }
	void CustomInitConstraintToSlider() { }
	void CustomInitConstraintToConeTwist() { }
	void CustomInitConstraintTo6Dof() { }

#endif // PHYSIC IMPLEMENTATION

public:
	void InitConstraintToPoint2Point()	{ if (CanProceedWithInit()) CustomInitConstraintToPoint2Point(); }
	void InitConstraintToHinge()		{ if (CanProceedWithInit()) CustomInitConstraintToHinge(); }
	void InitConstraintToSlider()		{ if (CanProceedWithInit()) CustomInitConstraintToSlider(); }
	void InitConstraintToConeTwist()	{ if (CanProceedWithInit()) CustomInitConstraintToConeTwist(); }
	void InitConstraintTo6Dof()			{ if (CanProceedWithInit()) CustomInitConstraintTo6Dof(); }

	//Set given physic object to the proper slot.
	void SetPhysObjA(EasyPhysic* NewPhysObj, lol::mat4 NewTransform) { SetPhysObj(false, NewPhysObj, NewTransform); }
	void SetPhysObjB(EasyPhysic* NewPhysObj, lol::mat4 NewTransform) { SetPhysObj(true, NewPhysObj, NewTransform); }
	void SetPhysObj(bool SetToB, EasyPhysic* NewPhysObj, lol::mat4 NewTransform)
	{
		if (SetToB)
		{
			m_b_physobj = NewPhysObj;
			m_b_transform = NewTransform;
		}
		else
		{
			m_a_physobj = NewPhysObj;
			m_a_transform = NewTransform;
		}
	}

	//Set whether or not the physic engine should use the A object as the reference (most constraint transform are local).
	void SetRefAsA(bool NewUseRefA)
	{
		m_using_ref_a = NewUseRefA;
	}

	//Set whether or not to disable the collision between the bodies
	void DisableCollisionBetweenObjs(bool DisableCollision)
	{
		m_disable_a2b_collision = DisableCollision;
	}

private:
	EasyPhysic*					m_a_physobj;
	EasyPhysic*					m_b_physobj;
	lol::mat4					m_a_transform;
	lol::mat4					m_b_transform;
	bool						m_using_ref_a;
	bool						m_disable_a2b_collision;

};

} /* namespace phys */

} /* namespace lol */

#endif /* __EASYPHYSICS_EASYPHYSICS_H__ */