#pragma once

class ParticleManager;

class ClothSystem
{
public:

	// Ctor
	ClothSystem(CKContext* iCtx);
	// Dtor
	~ClothSystem();

	///
	// Attributes accessor

	void	SetPointMass(const float iPointMass)
	{
		m_PointInverseMass = 1.0f / iPointMass;
	}
	
	void	SetDamping(const float iDamping)
	{
		m_DampingFactor = iDamping;
	}

	void	SetTightness(const float iTightness)
	{
		float tight2 = iTightness*iTightness;
		m_StrutLength2.x = m_StrutLength.x*m_StrutLength.x*tight2;
		m_StrutLength2.y = m_StrutLength.y*m_StrutLength.y*tight2;
		m_StrutLength2.z = m_StrutLength.z*m_StrutLength.z*tight2;
	}

	void	SetGravity(const VxVector& iGravity)
	{
		m_Gravity = iGravity;
	}

	void	SetIterations(int iIterations)
	{
		m_Iterations = iIterations;
	}

	// Update the cloth system
	void				Update(const float iDeltaTime);

	// Tesselate the cloth mesh
	void				Tesselate(const Vx2DVector& iResolution, const Vx2DVector& iSize, const Vx2DVector& iMapping, CKMaterial* iMaterial, CKMaterial* iBackMaterial);
	
	// Clear the hooks
	void				ClearHooks();

	// set a hook
	void				SetHook(CK3dEntity* iHook, const Vx2DVector& iPosition)
	{
		if (!iHook) return;

		int index = (int)(iPosition.x*(m_Width-1) + m_Width*(int)(iPosition.y*(m_Height-1)));

		m_Nodes[index].hook			= iHook;

	}

	// set the referential
	void				SetReferential(CK3dEntity* iReferential)
	{
		//if (m_Referential == iReferential)
		//	return;

		if ((iReferential != m_Referential) && m_Referential) {
			m_Referential->RemoveMesh(m_Mesh);
		}

		m_Referential = iReferential;
		if (m_Referential)
			m_Referential->SetCurrentMesh(m_Mesh);
	}


	void				SetMaterial(CKMaterial* iFrontMaterial);

protected:

	// Integrate
	void				_Integrate(const float iDeltaTime);

	// Constraint Solving
	void				_SatisfyConstraints(const float iDeltaTime);
	void				_SatisfyConstraintsSIMD(const float iDeltaTime);

	// Collision Response
	void				_SatisfyBoxDeflectors(const XObjectPointerArray& iBoxes);
	void				_SatisfySphereDeflectors(const XObjectPointerArray& iSpheres);
	void				_SatisfyInfinitePlaneDeflectors(const XObjectPointerArray& iPlanes);
	void				_SatisfyMeshDeflectors(const XObjectPointerArray& iMeshes);

	// The mesh
	CKMesh*				m_Mesh;
	
	// 3D Entity supporting the cloth
	CK3dEntity*			m_Referential;

	// Back material
	CKMaterial*			m_BackMaterial;

	// Particle Manager
	ParticleManager*	m_ParticleManager;

	// X Resolution
	int				m_Width;
	// Y Resolution
	int				m_Height;

	// 1/ Point Mass
	float			m_PointInverseMass;
	// Damping Factor
	float			m_DampingFactor;
	// gravity force
	VxVector		m_Gravity;
	// Solving iterations
	int				m_Iterations;

	// Strut length
	VxVector		m_StrutLength;
	VxVector		m_StrutLength2;

	struct Node {
		VxVector4	position;
		VxVector	oldPosition;
		CK3dEntity*	hook;
	};

	// System
	Node*			m_Nodes;

	// For Smoothing Purpose
	float			m_oldDeltaTime;
};