#ifndef __GEOM_CROSSING_H

#define __GEOM_CROSSING_H

#include <vector>

#include <set>

#include "rect.h"

#include "sweep.h"

namespace Geom {

struct Crossing {

bool dir; //True: along a, a becomes outside.

double ta, tb; //time on a and b of crossing

unsigned a, b; //storage of indices

Crossing() : dir(false), ta(0), tb(1), a(0), b(1) {}

Crossing(double t_a, double t_b, bool direction) : dir(direction), ta(t_a), tb(t_b), a(0), b(1) {}

Crossing(double t_a, double t_b, unsigned ai, unsigned bi, bool direction) : dir(direction), ta(t_a), tb(t_b), a(ai), b(bi) {}

bool operator==(const Crossing & other) const { return a == other.a && b == other.b && dir == other.dir && ta == other.ta && tb == other.tb; }

bool operator!=(const Crossing & other) const { return !(*this == other); }

unsigned getOther(unsigned cur) const { return a == cur ? b : a; }

double getTime(unsigned cur) const { return a == cur ? ta : tb; }

double getOtherTime(unsigned cur) const { return a == cur ? tb : ta; }

bool onIx(unsigned ix) const { return a == ix || b == ix; }

};

struct CrossingOrder {

unsigned ix;

CrossingOrder(unsigned i) : ix(i) {}

bool operator()(Crossing a, Crossing b) {

return (ix == a.a ? a.ta : a.tb) <

(ix == b.a ? b.ta : b.tb);

}

};

typedef std::vector<Crossing> Crossings;

typedef std::vector<Crossings> CrossingSet;

template<typename C>

std::vector<Rect> bounds(C const &a) {

std::vector<Rect> rs;

for(unsigned i = 0; i < a.size(); i++) rs.push_back(a[i].boundsFast());

return rs;

}

inline void sort_crossings(Crossings &cr, unsigned ix) { std::sort(cr.begin(), cr.end(), CrossingOrder(ix)); }

template<typename T>

struct Crosser {

virtual ~Crosser() {}

virtual Crossings crossings(T const &a, T const &b) { return crossings(std::vector<T>(1,a), std::vector<T>(1,b))[0]; }

virtual CrossingSet crossings(std::vector<T> const &a, std::vector<T> const &b) {

CrossingSet results(a.size() + b.size(), Crossings());

std::vector<std::vector<unsigned> > cull = sweep_bounds(bounds(a), bounds(b));

for(unsigned i = 0; i < cull.size(); i++) {

for(unsigned jx = 0; jx < cull[i].size(); jx++) {

unsigned j = cull[i][jx];

unsigned jc = j + a.size();

Crossings cr = crossings(a[i], b[j]);

for(unsigned k = 0; k < cr.size(); k++) { cr[k].a = i; cr[k].b = jc; }

//Sort & add A-sorted crossings

sort_crossings(cr, i);

Crossings n(results[i].size() + cr.size());

std::merge(results[i].begin(), results[i].end(), cr.begin(), cr.end(), n.begin(), CrossingOrder(i));

results[i] = n;

//Sort & add B-sorted crossings

sort_crossings(cr, jc);

n.resize(results[jc].size() + cr.size());

std::merge(results[jc].begin(), results[jc].end(), cr.begin(), cr.end(), n.begin(), CrossingOrder(jc));

results[jc] = n;

}

}

return results;

}

};

void merge_crossings(Crossings &a, Crossings &b, unsigned i);

void offset_crossings(Crossings &cr, double a, double b);

Crossings reverse_ta(Crossings const &cr, std::vector<double> max);

Crossings reverse_tb(Crossings const &cr, unsigned split, std::vector<double> max);

CrossingSet reverse_ta(CrossingSet const &cr, unsigned split, std::vector<double> max);

CrossingSet reverse_tb(CrossingSet const &cr, unsigned split, std::vector<double> max);

void clean(Crossings &cr_a, Crossings &cr_b);

}

#endif