/*
 * Copyright (c) 2005 Erwin Coumans http://continuousphysics.com/Bullet/
 *
 * Permission to use, copy, modify, distribute and sell this software
 * and its documentation for any purpose is hereby granted without fee,
 * provided that the above copyright notice appear in all copies.
 * Erwin Coumans makes no representations about the suitability 
 * of this software for any purpose.  
 * It is provided "as is" without express or implied warranty.
*/

#include "BU_EdgeEdge.h"
#include "BU_Screwing.h"
#include <SimdPoint3.h>
#include <SimdPoint3.h>

//#include "BU_IntervalArithmeticPolynomialSolver.h"
#include "BU_AlgebraicPolynomialSolver.h"

#define USE_ALGEBRAIC
#ifdef USE_ALGEBRAIC	
#define BU_Polynomial BU_AlgebraicPolynomialSolver
#else	
#define BU_Polynomial BU_IntervalArithmeticPolynomialSolver
#endif

BU_EdgeEdge::BU_EdgeEdge()
{
}


bool BU_EdgeEdge::GetTimeOfImpact(
								  const BU_Screwing& screwAB,
								  const SimdPoint3& a,//edge in object A
								  const SimdVector3& u,
								  const SimdPoint3& c,//edge in object B
								  const SimdVector3& v,
								  SimdScalar &minTime,
								  SimdScalar &lambda1,
								  SimdScalar& mu1
								  
								  )
{
	bool hit=false;
	
	SimdScalar lambda;
	SimdScalar mu;
	
	const SimdScalar w=screwAB.GetW();
	const SimdScalar s=screwAB.GetS();
	
	if (SimdFuzzyZero(s) &&
		SimdFuzzyZero(w))
	{
		//no motion, no collision
		return false;
	}
	
	if (SimdFuzzyZero(w) )
	{
		//pure translation W=0, S <> 0
		//no trig, f(t)=t
		SimdScalar det = u.y()*v.x()-u.x()*v.y();
		if (!SimdFuzzyZero(det))
		{		
			lambda = (a.x()*v.y() - c.x() * v.y() - v.x() * a.y() + v.x() * c.y()) / det;
			mu = (u.y() * a.x() - u.y() * c.x() - u.x() * a.y() + u.x() * c.y()) / det;

			if (mu >=0 && mu <= 1 && lambda >= 0 && lambda <= 1)
			{
				// single potential collision is
				SimdScalar t = (c.z()-a.z()+mu*v.z()-lambda*u.z())/s;
				//if this is on the edge, and time t within [0..1] report hit
				if (t>=0 && t <= minTime)
				{
					hit = true;
					lambda1 = lambda;
					mu1 = mu;
					minTime=t;
				}
			}
			
		} else
		{
			//parallel case, not yet
		}
	} else
	{
		if (SimdFuzzyZero(s) )
		{
			if (SimdFuzzyZero(u.z()) )
			{
				if (SimdFuzzyZero(v.z()) )
				{
					//u.z()=0,v.z()=0
					if (SimdFuzzyZero(a.z()-c.z()))
					{
						//printf("NOT YET planar problem, 4 vertex=edge cases\n");
						
					} else
					{
						//printf("parallel but distinct planes, no collision\n");
						return false;
					}
					
				} else
				{
					SimdScalar mu = (a.z() - c.z())/v.z();
					if (0<=mu && mu <= 1)
					{
					//	printf("NOT YET//u.z()=0,v.z()<>0\n");
					} else
					{
						return false;
					}
					
				}
			} else
			{
				//u.z()<>0
				
				if (SimdFuzzyZero(v.z()) )
				{
					//printf("u.z()<>0,v.z()=0\n");
					lambda =  (c.z() - a.z())/u.z();
					if (0<=lambda && lambda <= 1)
					{
						//printf("u.z()<>0,v.z()=0\n");
						SimdPoint3 rotPt(a.x()+lambda * u.x(), a.y()+lambda * u.y(),0.f);
						SimdScalar r2 = rotPt.length2();//px*px + py*py;
						
						//either y=a*x+b, or x = a*x+b...
						//depends on whether value v.x() is zero or not
						SimdScalar aa;
						SimdScalar bb;
						
						if (SimdFuzzyZero(v.x()))
						{
							aa = v.x()/v.y();
							bb= c.x()+  (-c.y() /v.y()) *v.x();
						} else
						{
							//line is c+mu*v;
							//x = c.x()+mu*v.x();
							//mu = ((x-c.x())/v.x());
							//y = c.y()+((x-c.x())/v.x())*v.y();
							//y = c.y()+  (-c.x() /v.x()) *v.y() + (x /v.x())   *v.y();
							//y = a*x+b,where a = v.y()/v.x(), b= c.y()+  (-c.x() /v.x()) *v.y();
							aa = v.y()/v.x();
							bb= c.y()+  (-c.x() /v.x()) *v.y();
						}
						
						SimdScalar disc = aa*aa*r2 + r2 - bb*bb;
						if (disc <0)
						{
							//edge doesn't intersect the circle (motion of the vertex)
							return false;
						}
						SimdScalar rad = SimdSqrt(r2);
						
						if (SimdFuzzyZero(disc))
						{
							SimdPoint3 intersectPt;
							
							SimdScalar mu;
							//intersectionPoint edge with circle;
							if (SimdFuzzyZero(v.x()))
							{
								intersectPt.setY( (-2*aa*bb)/(2*(aa*aa+1)));
								intersectPt.setX( aa*intersectPt.y()+bb );
								mu = ((intersectPt.y()-c.y())/v.y());
							} else
							{
								intersectPt.setX((-2*aa*bb)/(2*(aa*aa+1)));
								intersectPt.setY(aa*intersectPt.x()+bb);
								mu = ((intersectPt.getX()-c.getX())/v.getX());
								
							}
							
							if (0 <= mu && mu <= 1)
							{
								hit = Calc2DRotationPointPoint(rotPt,rad,screwAB.GetW(),intersectPt,minTime);
							}
							//only one solution
						} else
						{
							//two points...
							//intersectionPoint edge with circle;
							SimdPoint3 intersectPt;
							//intersectionPoint edge with circle;
							if (SimdFuzzyZero(v.x()))
							{
								SimdScalar mu;
								
								intersectPt.setY((-2.f*aa*bb+2.f*SimdSqrt(disc))/(2.f*(aa*aa+1.f)));
								intersectPt.setX(aa*intersectPt.y()+bb);
								mu = ((intersectPt.getY()-c.getY())/v.getY());
								if (0.f <= mu && mu <= 1.f)
								{
									hit = Calc2DRotationPointPoint(rotPt,rad,screwAB.GetW(),intersectPt,minTime);
								}
								intersectPt.setY((-2.f*aa*bb-2.f*SimdSqrt(disc))/(2.f*(aa*aa+1.f)));
								intersectPt.setX(aa*intersectPt.y()+bb);
								mu = ((intersectPt.getY()-c.getY())/v.getY());
								if (0 <= mu && mu <= 1)
								{
									hit = hit || Calc2DRotationPointPoint(rotPt,rad,screwAB.GetW(),intersectPt,minTime);
								}
								
							} else
							{
								SimdScalar mu;
								
								intersectPt.setX((-2.f*aa*bb+2.f*SimdSqrt(disc))/(2*(aa*aa+1.f)));
								intersectPt.setY(aa*intersectPt.x()+bb);
								mu = ((intersectPt.getX()-c.getX())/v.getX());
								if (0 <= mu && mu <= 1)
								{
									hit = Calc2DRotationPointPoint(rotPt,rad,screwAB.GetW(),intersectPt,minTime);
								}
								intersectPt.setX((-2.f*aa*bb-2.f*SimdSqrt(disc))/(2.f*(aa*aa+1.f)));
								intersectPt.setY(aa*intersectPt.x()+bb);
								mu = ((intersectPt.getX()-c.getX())/v.getX());
								if (0.f <= mu && mu <= 1.f)
								{
									hit = hit || Calc2DRotationPointPoint(rotPt,rad,screwAB.GetW(),intersectPt,minTime);
								}
							}
						}
						
						
						
						int k=0;
						
					} else
					{
						return false;
					}
					
					
				} else
				{
					//u.z()<>0,v.z()<>0
					//printf("general case with s=0\n");
					hit = GetTimeOfImpactGeneralCase(screwAB,a,u,c,v,minTime,lambda,mu);
					if (hit)
					{
						lambda1 = lambda;
						mu1 = mu;
						
					}
				}
			}
			
		} else
		{
			//printf("general case, W<>0,S<>0\n");
			hit = GetTimeOfImpactGeneralCase(screwAB,a,u,c,v,minTime,lambda,mu);
			if (hit)
			{
				lambda1 = lambda;
				mu1 = mu;
			}
			
		}
		
		
		//W <> 0,pure rotation
	}
	
	return hit;
}


bool BU_EdgeEdge::GetTimeOfImpactGeneralCase(
											 const BU_Screwing& screwAB,
											 const SimdPoint3& a,//edge in object A
											 const SimdVector3& u,
											 const SimdPoint3& c,//edge in object B
											 const SimdVector3& v,
											 SimdScalar &minTime,
											 SimdScalar &lambda,
											 SimdScalar& mu
											 
											 )
{
	bool hit = false;
	
	SimdScalar coefs[4];
	BU_Polynomial polynomialSolver;
	int numroots = 0;
	
	SimdScalar eps=1e-15f;
	SimdScalar eps2=1e-20f;
	SimdScalar s=screwAB.GetS();
	SimdScalar w = screwAB.GetW();
	
	SimdScalar ax = a.x();
	SimdScalar ay = a.y();
	SimdScalar az = a.z();
	SimdScalar cx = c.x();
	SimdScalar cy = c.y();
	SimdScalar cz = c.z();
	SimdScalar vx = v.x();
	SimdScalar vy = v.y();
	SimdScalar vz = v.z();
	SimdScalar ux = u.x();
	SimdScalar uy = u.y();
	SimdScalar uz = u.z();
	
	
	if (!SimdFuzzyZero(v.z()))
	{
		
		//Maple Autogenerated C code
		SimdScalar t1,t2,t3,t4,t7,t8,t10;
		SimdScalar t13,t14,t15,t16,t17,t18,t19,t20;
		SimdScalar t21,t22,t23,t24,t25,t26,t27,t28,t29,t30;
		SimdScalar t31,t32,t33,t34,t35,t36,t39,t40;
		SimdScalar t41,t43,t48;
		SimdScalar t63;
		
		SimdScalar aa,bb,cc,dd;//the coefficients
		
		t1 = v.y()*s;      t2 = t1*u.x();
		t3 = v.x()*s;
		t4 = t3*u.y();
		t7 = SimdTan(w/2.0f);
		t8 = 1.0f/t7;
		t10 = 1.0f/v.z();
		aa = (t2-t4)*t8*t10;
		t13 = a.x()*t7;
		t14 = u.z()*v.y();
		t15 = t13*t14;
		t16 = u.x()*v.z();
		t17 = a.y()*t7;
		t18 = t16*t17;
		t19 = u.y()*v.z();
		t20 = t13*t19;
		t21 = v.y()*u.x();
		t22 = c.z()*t7;
		t23 = t21*t22;
		t24 = v.x()*a.z();
		t25 = t7*u.y();
		t26 = t24*t25;
		t27 = c.y()*t7;
		t28 = t16*t27;
		t29 = a.z()*t7;
		t30 = t21*t29;
		t31 = u.z()*v.x();
		t32 = t31*t27;
		t33 = t31*t17;
		t34 = c.x()*t7;
		t35 = t34*t19;
		t36 = t34*t14;
		t39 = v.x()*c.z();
		t40 = t39*t25;
		t41 = 2.0f*t1*u.y()-t15+t18-t20-t23-t26+t28+t30+t32+t33-t35-t36+2.0f*t3*u.x()+t40;
		bb = t41*t8*t10;
		t43 = t7*u.x();
		t48 = u.y()*v.y();
		cc = (-2.0f*t39*t43+2.0f*t24*t43+t4-2.0f*t48*t22+2.0f*t34*t16-2.0f*t31*t13-t2
			-2.0f*t17*t14+2.0f*t19*t27+2.0f*t48*t29)*t8*t10;
		t63 = -t36+t26+t32-t40+t23+t35-t20+t18-t28-t33+t15-t30;
		dd = t63*t8*t10;
		
		coefs[0]=aa;
		coefs[1]=bb;
		coefs[2]=cc;
		coefs[3]=dd;
		
	} else
	{
		
		SimdScalar t1,t2,t3,t4,t7,t8,t10;
		SimdScalar t13,t14,t15,t16,t17,t18,t19,t20;
		SimdScalar t21,t22,t23,t24,t25,t26,t27,t28,t29,t30;
		SimdScalar t31,t32,t33,t34,t35,t36,t37,t38,t57;
		SimdScalar p1,p2,p3,p4;

	  t1 = uy*s;
      t2 = t1*vx;
      t3 = ux*s;
      t4 = t3*vy;
      t7 = SimdTan(w/2.0f);
      t8 = 1/t7;
      t10 = 1/uz;
      t13 = ux*az;
      t14 = t7*vy;
      t15 = t13*t14;
      t16 = ax*t7;
      t17 = uy*vz;
      t18 = t16*t17;
      t19 = cx*t7;
      t20 = t19*t17;
      t21 = vy*uz;
      t22 = t19*t21;
      t23 = ay*t7;
      t24 = vx*uz;
      t25 = t23*t24;
      t26 = uy*cz;
      t27 = t7*vx;
      t28 = t26*t27;
      t29 = t16*t21;
      t30 = cy*t7;
      t31 = ux*vz;
      t32 = t30*t31;
      t33 = ux*cz;
      t34 = t33*t14;
      t35 = t23*t31;
      t36 = t30*t24;
      t37 = uy*az;
      t38 = t37*t27;

	  p4 = (-t2+t4)*t8*t10;
      p3 = 2.0f*t1*vy+t15-t18-t20-t22+t25+t28-t29+t32-t34+t35+t36-t38+2.0f*t3*vx;
      p2 = -2.0f*t33*t27-2.0f*t26*t14-2.0f*t23*t21+2.0f*t37*t14+2.0f*t30*t17+2.0f*t13
*t27+t2-t4+2.0f*t19*t31-2.0f*t16*t24;
      t57 = -t22+t29+t36-t25-t32+t34+t35-t28-t15+t20-t18+t38;
      p1 = t57*t8*t10;

	coefs[0] = p4;
	coefs[1] = p3;
	coefs[2] = p2;
	coefs[1] = p1;
		
	}
	
	numroots = polynomialSolver.Solve3Cubic(coefs[0],coefs[1],coefs[2],coefs[3]);
	
	for (int i=0;i<numroots;i++)
	{
		//SimdScalar tau = roots[i];//polynomialSolver.GetRoot(i);
		SimdScalar tau = polynomialSolver.GetRoot(i);
		
		//check whether mu and lambda are in range [0..1]
		
		if (!SimdFuzzyZero(v.z()))
		{
			SimdScalar A1=(ux-ux*tau*tau-2.f*tau*uy)-((1.f+tau*tau)*vx*uz/vz);
			SimdScalar B1=((1.f+tau*tau)*(cx*SimdTan(1.f/2.f*w)*vz+
				vx*az*SimdTan(1.f/2.f*w)-vx*cz*SimdTan(1.f/2.f*w)+
				vx*s*tau)/SimdTan(1.f/2.f*w)/vz)-(ax-ax*tau*tau-2.f*tau*ay);
			lambda = B1/A1;
			
			mu = (a.z()-c.z()+lambda*u.z()+(s*tau)/(SimdTan(w/2.f)))/v.z();
			
			
			//double check in original equation
			
			SimdScalar lhs = (a.x()+lambda*u.x())
				*((1.f-tau*tau)/(1.f+tau*tau))-
				(a.y()+lambda*u.y())*((2.f*tau)/(1.f+tau*tau));
			
			lhs = lambda*((ux-ux*tau*tau-2.f*tau*uy)-((1.f+tau*tau)*vx*uz/vz));
			
			SimdScalar rhs = c.x()+mu*v.x();
			
			rhs = ((1.f+tau*tau)*(cx*SimdTan(1.f/2.f*w)*vz+vx*az*SimdTan(1.f/2.f*w)-
				vx*cz*SimdTan(1.f/2.f*w)+vx*s*tau)/(SimdTan(1.f/2.f*w)*vz))-
				
				(ax-ax*tau*tau-2.f*tau*ay);
			
			SimdScalar res = coefs[0]*tau*tau*tau+
				coefs[1]*tau*tau+
				coefs[2]*tau+
				coefs[3];
			
			//lhs should be rhs !
			
			if (0.<= mu && mu <=1 && 0.<=lambda && lambda <= 1)
			{
				
			} else
			{
				//skip this solution, not really touching
				continue;				
			}
			
		}
		
		SimdScalar t = 2.f*SimdAtan(tau)/screwAB.GetW();
		//tau = tan (wt/2) so 2*atan (tau)/w
		if (t>=0.f && t<minTime)
		{
#ifdef STATS_EDGE_EDGE
			printf(" ax = %12.12f\n ay = %12.12f\n az = %12.12f\n",a.x(),a.y(),a.z());
			printf(" ux = %12.12f\n uy = %12.12f\n uz = %12.12f\n",u.x(),u.y(),u.z());
			printf(" cx = %12.12f\n cy = %12.12f\n cz = %12.12f\n",c.x(),c.y(),c.z());
			printf(" vx = %12.12f\n vy = %12.12f\n vz = %12.12f\n",v.x(),v.y(),v.z());
			printf(" s  = %12.12f\n w  = %12.12f\n",       s,     w);
			
			printf(" tau = %12.12f \n lambda = %12.12f \n mu = %f\n",tau,lambda,mu); 
			printf(" ---------------------------------------------\n"); 
			
#endif
			
			//	v,u,a,c,s,w
			
			//	BU_IntervalArithmeticPolynomialSolver iaSolver;
			//	int numroots2 = iaSolver.Solve3Cubic(coefs[0],coefs[1],coefs[2],coefs[3]);
			
			minTime = t;
			hit = true;
		}
	}
	
	return hit;
}


//C -S
//S C

bool BU_EdgeEdge::Calc2DRotationPointPoint(const SimdPoint3& rotPt, SimdScalar rotRadius, SimdScalar rotW,const SimdPoint3& intersectPt,SimdScalar& minTime)
{
	bool hit = false;
	
	// now calculate the planeEquation for the vertex motion,
	// and check if the intersectionpoint is at the positive side
	SimdPoint3 rotPt1(SimdCos(rotW)*rotPt.x()-SimdSin(rotW)*rotPt.y(),
	SimdSin(rotW)*rotPt.x()+SimdCos(rotW)*rotPt.y(),
	0.f);

	SimdVector3 rotVec = rotPt1-rotPt;
	
	SimdVector3 planeNormal( -rotVec.y() , rotVec.x() ,0.f);
	
	//SimdPoint3 pt(a.x(),a.y());//for sake of readability,could write dot directly
	SimdScalar planeD = planeNormal.dot(rotPt1);
	
	SimdScalar dist = (planeNormal.dot(intersectPt)-planeD);
	hit = (dist >= -0.001);
	
	//if (hit)
	{
		//		minTime = 0;
		//calculate the time of impact, using the fact of
		//toi = alpha / screwAB.getW();
		// cos (alpha) = adjacent/hypothenuse;
		//adjacent = dotproduct(ipedge,point);
		//hypothenuse = sqrt(r2);
		SimdScalar adjacent = intersectPt.dot(rotPt)/rotRadius;
		SimdScalar hypo = rotRadius;
		SimdScalar alpha = SimdAcos(adjacent/hypo);
		SimdScalar t = alpha / rotW;
		if (t >= 0 && t < minTime)
		{
			hit = true;
			minTime = t;
		} else
		{
			hit = false;
		}
		
	}
	return hit;
}

bool BU_EdgeEdge::GetTimeOfImpactVertexEdge(
											const BU_Screwing& screwAB,
											const SimdPoint3& a,//edge in object A
											const SimdVector3& u,
											const SimdPoint3& c,//edge in object B
											const SimdVector3& v,
											SimdScalar &minTime,
											SimdScalar &lamda,
											SimdScalar& mu
											
											)
{
	return false;
}