#ifndef RECT2_H
#define RECT2_H

#include "Vector2.h"

#include <cmath>

namespace godot {

typedef Vector2 Size2;
typedef Vector2 Point2;

class Transform2D;

#ifndef MAX
#define MAX(a, b) (a > b ? a : b)
#endif

#ifndef MIN
#define MIN(a, b) (a < b ? a : b)
#endif

struct Rect2 {

	Point2 pos;
	Size2 size;

	const Vector2& get_pos() const { return pos; }
	void set_pos(const Vector2& p_pos) { pos=p_pos; }
	const Vector2& get_size() const { return size; }
	void set_size(const Vector2& p_size) { size=p_size; }

	real_t get_area() const { return size.width*size.height; }

	inline bool intersects(const Rect2& p_rect) const {
		if ( pos.x >= (p_rect.pos.x + p_rect.size.width) )
			return false;
		if ( (pos.x+size.width) <= p_rect.pos.x  )
			return false;
		if ( pos.y >= (p_rect.pos.y + p_rect.size.height) )
			return false;
		if ( (pos.y+size.height) <= p_rect.pos.y  )
			return false;

		return true;
	}

	inline real_t distance_to(const Vector2& p_point) const {

		real_t dist = 1e20;

		if (p_point.x < pos.x) {
			dist=MIN(dist,pos.x-p_point.x);
		}
		if (p_point.y < pos.y) {
			dist=MIN(dist,pos.y-p_point.y);
		}
		if (p_point.x >= (pos.x+size.x) ) {
			dist=MIN(p_point.x-(pos.x+size.x),dist);
		}
		if (p_point.y >= (pos.y+size.y) ) {
			dist=MIN(p_point.y-(pos.y+size.y),dist);
		}

		if (dist==1e20)
			return 0;
		else
			return dist;
	}

	bool intersects_transformed(const Transform2D& p_xform, const Rect2& p_rect) const;

	bool intersects_segment(const Point2& p_from, const Point2& p_to, Point2* r_pos=NULL, Point2* r_normal=NULL) const;

	inline bool encloses(const Rect2& p_rect) const {

		return 	(p_rect.pos.x>=pos.x) && (p_rect.pos.y>=pos.y) &&
			((p_rect.pos.x+p_rect.size.x)<(pos.x+size.x)) &&
			((p_rect.pos.y+p_rect.size.y)<(pos.y+size.y));

	}

	inline bool has_no_area() const {

		return (size.x<=0 || size.y<=0);

	}
	inline Rect2 clip(const Rect2& p_rect) const { /// return a clipped rect

		Rect2 new_rect=p_rect;

		if (!intersects( new_rect ))
			return Rect2();

		new_rect.pos.x = MAX( p_rect.pos.x , pos.x );
		new_rect.pos.y = MAX( p_rect.pos.y , pos.y );

		Point2 p_rect_end=p_rect.pos+p_rect.size;
		Point2 end=pos+size;

		new_rect.size.x=MIN(p_rect_end.x,end.x) - new_rect.pos.x;
		new_rect.size.y=MIN(p_rect_end.y,end.y) - new_rect.pos.y;

		return new_rect;
	}

	inline Rect2 merge(const Rect2& p_rect) const { ///< return a merged rect

		Rect2 new_rect;

		new_rect.pos.x=MIN( p_rect.pos.x , pos.x );
		new_rect.pos.y=MIN( p_rect.pos.y , pos.y );


		new_rect.size.x = MAX( p_rect.pos.x+p_rect.size.x , pos.x+size.x );
		new_rect.size.y = MAX( p_rect.pos.y+p_rect.size.y , pos.y+size.y );

		new_rect.size = new_rect.size - new_rect.pos; //make relative again

		return new_rect;
	}
	inline bool has_point(const Point2& p_point) const {
		if (p_point.x < pos.x)
			return false;
		if (p_point.y < pos.y)
			return false;

		if (p_point.x >= (pos.x+size.x) )
			return false;
		if (p_point.y >= (pos.y+size.y) )
			return false;

		return true;
	}

	inline bool no_area() const { return (size.width<=0 || size.height<=0 ); }

	bool operator==(const Rect2& p_rect) const { return pos==p_rect.pos && size==p_rect.size; }
	bool operator!=(const Rect2& p_rect) const { return pos!=p_rect.pos || size!=p_rect.size; }

	inline Rect2 grow(real_t p_by) const {

		Rect2 g=*this;
		g.pos.x-=p_by;
		g.pos.y-=p_by;
		g.size.width+=p_by*2;
		g.size.height+=p_by*2;
		return g;
	}

	inline Rect2 expand(const Vector2& p_vector) const {

		Rect2 r = *this;
		r.expand_to(p_vector);
		return r;
	}

	inline void expand_to(const Vector2& p_vector) { //in place function for speed

		Vector2 begin=pos;
		Vector2 end=pos+size;

		if (p_vector.x<begin.x)
			begin.x=p_vector.x;
		if (p_vector.y<begin.y)
			begin.y=p_vector.y;

		if (p_vector.x>end.x)
			end.x=p_vector.x;
		if (p_vector.y>end.y)
			end.y=p_vector.y;

		pos=begin;
		size=end-begin;
	}


	operator String() const { return String(pos)+", "+String(size); }

	Rect2() {}
	Rect2( real_t p_x, real_t p_y, real_t p_width, real_t p_height) { pos=Point2(p_x,p_y); size=Size2( p_width, p_height ); }
	Rect2( const Point2& p_pos, const Size2& p_size ) { pos=p_pos; size=p_size; }
};


bool Rect2::intersects_segment(const Point2& p_from, const Point2& p_to, Point2* r_pos,Point2* r_normal) const {

	real_t min=0,max=1;
	int axis=0;
	real_t sign=0;

	for(int i=0;i<2;i++) {
		real_t seg_from=p_from[i];
		real_t seg_to=p_to[i];
		real_t box_begin=pos[i];
		real_t box_end=box_begin+size[i];
		real_t cmin,cmax;
		real_t csign;

		if (seg_from < seg_to) {

			if (seg_from > box_end || seg_to < box_begin)
				return false;
			real_t length=seg_to-seg_from;
			cmin = (seg_from < box_begin)?((box_begin - seg_from)/length):0;
			cmax = (seg_to > box_end)?((box_end - seg_from)/length):1;
			csign=-1.0;

		} else {

			if (seg_to > box_end || seg_from < box_begin)
				return false;
			real_t length=seg_to-seg_from;
			cmin = (seg_from > box_end)?(box_end - seg_from)/length:0;
			cmax = (seg_to < box_begin)?(box_begin - seg_from)/length:1;
			csign=1.0;
		}

		if (cmin > min) {
			min = cmin;
			axis=i;
			sign=csign;
		}
		if (cmax < max)
			max = cmax;
		if (max < min)
			return false;
	}


	Vector2 rel=p_to-p_from;

	if (r_normal) {
		Vector2 normal;
		normal[axis]=sign;
		*r_normal=normal;
	}

	if (r_pos)
		*r_pos=p_from+rel*min;

	return true;
}

}

#include "Transform2D.h"

namespace godot {

bool Rect2::intersects_transformed(const Transform2D& p_xform, const Rect2& p_rect) const {

	//SAT intersection between local and transformed rect2

	Vector2 xf_points[4]={
		p_xform.xform(p_rect.pos),
		p_xform.xform(Vector2(p_rect.pos.x+p_rect.size.x,p_rect.pos.y)),
		p_xform.xform(Vector2(p_rect.pos.x,p_rect.pos.y+p_rect.size.y)),
		p_xform.xform(Vector2(p_rect.pos.x+p_rect.size.x,p_rect.pos.y+p_rect.size.y)),
	};

	real_t low_limit;

	//base rect2 first (faster)

	if (xf_points[0].y>pos.y)
		goto next1;
	if (xf_points[1].y>pos.y)
		goto next1;
	if (xf_points[2].y>pos.y)
		goto next1;
	if (xf_points[3].y>pos.y)
		goto next1;

	return false;

	next1:

	low_limit=pos.y+size.y;

	if (xf_points[0].y<low_limit)
		goto next2;
	if (xf_points[1].y<low_limit)
		goto next2;
	if (xf_points[2].y<low_limit)
		goto next2;
	if (xf_points[3].y<low_limit)
		goto next2;

	return false;

	next2:

	if (xf_points[0].x>pos.x)
		goto next3;
	if (xf_points[1].x>pos.x)
		goto next3;
	if (xf_points[2].x>pos.x)
		goto next3;
	if (xf_points[3].x>pos.x)
		goto next3;

	return false;

	next3:

	low_limit=pos.x+size.x;

	if (xf_points[0].x<low_limit)
		goto next4;
	if (xf_points[1].x<low_limit)
		goto next4;
	if (xf_points[2].x<low_limit)
		goto next4;
	if (xf_points[3].x<low_limit)
		goto next4;

	return false;

	next4:

	Vector2 xf_points2[4]={
		pos,
		Vector2(pos.x+size.x,pos.y),
		Vector2(pos.x,pos.y+size.y),
		Vector2(pos.x+size.x,pos.y+size.y),
	};

	real_t maxa=p_xform.elements[0].dot(xf_points2[0]);
	real_t mina=maxa;

	real_t dp = p_xform.elements[0].dot(xf_points2[1]);
	maxa=MAX(dp,maxa);
	mina=MIN(dp,mina);

	dp = p_xform.elements[0].dot(xf_points2[2]);
	maxa=MAX(dp,maxa);
	mina=MIN(dp,mina);

	dp = p_xform.elements[0].dot(xf_points2[3]);
	maxa=MAX(dp,maxa);
	mina=MIN(dp,mina);

	real_t maxb=p_xform.elements[0].dot(xf_points[0]);
	real_t minb=maxb;

	dp = p_xform.elements[0].dot(xf_points[1]);
	maxb=MAX(dp,maxb);
	minb=MIN(dp,minb);

	dp = p_xform.elements[0].dot(xf_points[2]);
	maxb=MAX(dp,maxb);
	minb=MIN(dp,minb);

	dp = p_xform.elements[0].dot(xf_points[3]);
	maxb=MAX(dp,maxb);
	minb=MIN(dp,minb);


	if ( mina > maxb )
		return false;
	if ( minb > maxa  )
		return false;

	maxa=p_xform.elements[1].dot(xf_points2[0]);
	mina=maxa;

	dp = p_xform.elements[1].dot(xf_points2[1]);
	maxa=MAX(dp,maxa);
	mina=MIN(dp,mina);

	dp = p_xform.elements[1].dot(xf_points2[2]);
	maxa=MAX(dp,maxa);
	mina=MIN(dp,mina);

	dp = p_xform.elements[1].dot(xf_points2[3]);
	maxa=MAX(dp,maxa);
	mina=MIN(dp,mina);

	maxb=p_xform.elements[1].dot(xf_points[0]);
	minb=maxb;

	dp = p_xform.elements[1].dot(xf_points[1]);
	maxb=MAX(dp,maxb);
	minb=MIN(dp,minb);

	dp = p_xform.elements[1].dot(xf_points[2]);
	maxb=MAX(dp,maxb);
	minb=MIN(dp,minb);

	dp = p_xform.elements[1].dot(xf_points[3]);
	maxb=MAX(dp,maxb);
	minb=MIN(dp,minb);


	if ( mina > maxb )
		return false;
	if ( minb > maxa  )
		return false;


	return true;

}

}

#endif // RECT2_H