/*
 * ***** BEGIN GPL LICENSE BLOCK *****
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License
 * as published by the Free Software Foundation; either version 2
 * of the License, or (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software Foundation,
 * Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.
 *
 * ***** END GPL LICENSE BLOCK *****
 */

#ifndef __SWEEPLINE_H__
#define __SWEEPLINE_H__

/** \file blender/freestyle/intern/geometry/SweepLine.h
 *  \ingroup freestyle
 *  \brief Class to define a Sweep Line
 *  \author Stephane Grabli
 *  \date 29/08/2002
 */

#include <list>
#include <vector>

#ifdef WITH_CXX_GUARDEDALLOC
#include "MEM_guardedalloc.h"
#endif

namespace Freestyle {

/*! Class to define the intersection berween two segments*/
template<class Edge>
class Intersection
{
public:
	template<class EdgeClass>
	Intersection(EdgeClass *eA, real ta, EdgeClass *eB, real tb)
	{
		EdgeA = eA;
		EdgeB = eB;
		tA = ta;
		tB = tb;
		userdata = 0;
	}

	Intersection(const Intersection& iBrother)
	{
		EdgeA = iBrother.EdgeA;
		EdgeB = iBrother.EdgeB;
		tA = iBrother.tA;
		tB = iBrother.tB;
		userdata = 0;
	}

	/*! returns the parameter giving the intersection, for the edge iEdge */
	real getParameter(Edge *iEdge)
	{
		if (iEdge == EdgeA)
			return tA;
		if (iEdge == EdgeB)
			return tB;
		return 0;
	}

public:
	void * userdata; // FIXME

	Edge *EdgeA; // first segment
	Edge *EdgeB; // second segment
	real tA; // parameter defining the intersection point with respect to the segment EdgeA.
	real tB; // parameter defining the intersection point with respect to the segment EdgeB.

#ifdef WITH_CXX_GUARDEDALLOC
	MEM_CXX_CLASS_ALLOC_FUNCS("Freestyle:Intersection")
#endif
};

#ifdef _MSC_VER
#pragma warning(push)
#pragma warning(disable: 4521) // disable warning C4521: multiple copy constructors specified
#endif

template<class T, class Point>
class Segment
{
public:
	Segment()
	{
	}

	Segment(T& s, const Point& iA, const Point& iB)
	{
		_edge = s;
		if (iA < iB) {
			A = iA;
			B = iB;
			_order = true;
		}
		else {
			A = iB;
			B = iA;
			_order = false;
		}
	}

	Segment(Segment<T, Point>& iBrother)
	{
		_edge = iBrother.edge();
		A = iBrother.A;
		B = iBrother.B;
		_Intersections = iBrother._Intersections;
		_order = iBrother._order;
	}

	Segment(const Segment<T, Point>& iBrother)
	{
		_edge = iBrother._edge;
		A = iBrother.A;
		B = iBrother.B;
		_Intersections = iBrother._Intersections;
		_order = iBrother._order;
	}

	~Segment()
	{
		_Intersections.clear();
	}

	inline Point operator[](const unsigned short int& i) const
	{
		return (i % 2 == 0) ? A : B;
	}

	inline bool operator==(const Segment<T, Point>& iBrother)
	{
		if (_edge == iBrother._edge)
			return true;
		return false;
	}

	/* Adds an intersection for this segment */
	inline void AddIntersection(Intersection<Segment<T, Point> > *i)
	{
		_Intersections.push_back(i);
	}

	/*! Checks for a common vertex with another edge */
	inline bool CommonVertex(const Segment<T, Point>& S, Point& CP)
	{
		if ((A == S[0]) || (A == S[1])) {
			CP = A;
			return true;
		}
		if ((B == S[0]) || (B == S[1])) {
			CP = B;
			return true;
		}
		return false;
	}

	inline vector<Intersection<Segment<T, Point> >*>& intersections()
	{
		return _Intersections;
	}

	inline bool order()
	{
		return _order;
	}

	inline T& edge()
	{
		return _edge;
	}

private:
	T _edge;
	Point A;
	Point B;
	std::vector<Intersection<Segment<T, Point> >*> _Intersections; // list of intersections parameters
	bool _order; // true if A and B are in the same order than _edge.A and _edge.B. false otherwise.

#ifdef WITH_CXX_GUARDEDALLOC
	MEM_CXX_CLASS_ALLOC_FUNCS("Freestyle:Segment")
#endif
};

#ifdef _MSC_VER
#pragma warning(pop)
#endif

/*! defines a binary function that can be overload by the user to specify at each condition the intersection
 *  between 2 edges must be computed
 */
template<class T1, class T2>
struct binary_rule
{
	binary_rule() {}
	template<class T3, class T4> binary_rule(const binary_rule<T3, T4>& brother) {}
	virtual ~binary_rule() {}

	virtual bool operator()(T1&, T2&)
	{
		return true;
	}
};


template<class T, class Point>
class SweepLine 
{
public:
	SweepLine() {}
	~SweepLine()
	{
		for (typename vector<Intersection<Segment<T, Point> >*>::iterator i = _Intersections.begin(),
		     iend = _Intersections.end();
		     i != iend;
		     i++)
		{
			delete (*i);
		}
	}

	inline void process(Point& p, vector<Segment<T, Point>*>& segments, 
#if 0
	                    binary_rule<Segment<T, Point>,Segment<T, Point> >& binrule = \
	                            binary_rule<Segment<T, Point>, Segment<T, Point> >(),
#else
	                    binary_rule<Segment<T, Point>, Segment<T, Point> >& binrule,
#endif
	                    real epsilon = M_EPSILON)
	{
		// first we remove the segments that need to be removed and then we add the segments to add
		vector<Segment<T, Point>*> toadd;
		typename vector<Segment<T, Point>*>::iterator s, send;
		for (s = segments.begin(), send = segments.end(); s != send; s++) {
			if (p == (*(*s))[0])
				toadd.push_back((*s));
			else
				remove((*s));
		}
		for (s = toadd.begin(), send = toadd.end(); s != send; s++) {
			add((*s), binrule, epsilon);
		}
	}

	inline void add(Segment<T, Point> *S,
#if 0
	                binary_rule<Segment<T, Point>, Segment<T, Point> >& binrule = \
	                        binary_rule<Segment<T, Point>, Segment<T, Point> >(),
#else
	                binary_rule<Segment<T, Point>, Segment<T, Point> >& binrule,
#endif
	                real epsilon)
	{
		real t, u;
		Point CP;
		Vec2r v0, v1, v2, v3;
		if (true == S->order()) {
			v0[0] = ((*S)[0])[0];
			v0[1] = ((*S)[0])[1];
			v1[0] = ((*S)[1])[0];
			v1[1] = ((*S)[1])[1];
		}
		else {
			v1[0] = ((*S)[0])[0];
			v1[1] = ((*S)[0])[1];
			v0[0] = ((*S)[1])[0];
			v0[1] = ((*S)[1])[1];
		}
		for (typename std::list<Segment<T, Point> *>::iterator s = _set.begin(), send = _set.end(); s != send; s++) {
			Segment<T, Point> *currentS = (*s);
			if (true != binrule(*S, *currentS))
				continue;

			if (true == currentS->order()) {
				v2[0] = ((*currentS)[0])[0];
				v2[1] = ((*currentS)[0])[1];
				v3[0] = ((*currentS)[1])[0];
				v3[1] = ((*currentS)[1])[1];
			}
			else {
				v3[0] = ((*currentS)[0])[0];
				v3[1] = ((*currentS)[0])[1];
				v2[0] = ((*currentS)[1])[0];
				v2[1] = ((*currentS)[1])[1];
			}
			if (S->CommonVertex(*currentS, CP))
				continue; // the two edges have a common vertex->no need to check

			if (GeomUtils::intersect2dSeg2dSegParametric(v0, v1, v2, v3, t, u, epsilon) == GeomUtils::DO_INTERSECT) {
				// create the intersection
				Intersection<Segment<T, Point> > *inter = new Intersection<Segment<T, Point> >(S, t, currentS, u);
				// add it to the intersections list
				_Intersections.push_back(inter);
				// add this intersection to the first edge intersections list
				S->AddIntersection(inter);
				// add this intersection to the second edge intersections list
				currentS->AddIntersection(inter);
			}
		}
		// add the added segment to the list of active segments
		_set.push_back(S);
	}

	inline void remove(Segment<T, Point> *s)
	{
		if (s->intersections().size() > 0)
			_IntersectedEdges.push_back(s);
		_set.remove(s);
	}

	vector<Segment<T, Point> *>& intersectedEdges()
	{
		return _IntersectedEdges;
	}

	vector<Intersection<Segment<T, Point> >*>& intersections()
	{
		return _Intersections;
	}

private:
	std::list<Segment<T, Point> *> _set; // set of active edges for a given position of the sweep line
	std::vector<Segment<T, Point> *> _IntersectedEdges; // the list of intersected edges
	std::vector<Intersection<Segment<T, Point> > *> _Intersections; // the list of all intersections.

#ifdef WITH_CXX_GUARDEDALLOC
	MEM_CXX_CLASS_ALLOC_FUNCS("Freestyle:SweepLine")
#endif
};

} /* namespace Freestyle */

#endif // __SWEEPLINE_H__
