/**
Axis-Aligned Bounding Box.

Copyright:
Copyright (c) 2007-2018 Juan Linietsky, Ariel Manzur.  
Copyright (c) 2014-2018 Godot Engine contributors (cf. AUTHORS.md)  
Copyright (c) 2017-2018 Godot-D contributors  

License: $(LINK2 https://opensource.org/licenses/MIT, MIT License)


*/
module godot.core.aabb;

import godot.core.defs;
import godot.core.vector3;
import godot.core.plane;

import std.algorithm.mutation : swap;

/**
AABB consists of a position, a size, and several utility functions. It is typically used for fast overlap tests.
*/
struct AABB
{
	@nogc nothrow:
	
	Vector3 pos;
	Vector3 size;
	
	bool hasNoArea() const
	{
		return (size.x<=CMP_EPSILON || size.y<=CMP_EPSILON  || size.z<=CMP_EPSILON);
	}

	bool hasNoSurface() const
	{
		return (size.x<=CMP_EPSILON && size.y<=CMP_EPSILON  && size.z<=CMP_EPSILON);
	}
	
	bool intersects(in AABB p_aabb) const
	{
		if ( pos.x >= (p_aabb.pos.x + p_aabb.size.x) )
			return false;
		if ( (pos.x+size.x) <= p_aabb.pos.x  )
			return false;
		if ( pos.y >= (p_aabb.pos.y + p_aabb.size.y) )
			return false;
		if ( (pos.y+size.y) <= p_aabb.pos.y  )
			return false;
		if ( pos.z >= (p_aabb.pos.z + p_aabb.size.z) )
			return false;
		if ( (pos.z+size.z) <= p_aabb.pos.z  )
			return false;
		return true;
	}
	
	bool intersectsInclusive(in AABB p_aabb) const
	{
		if ( pos.x > (p_aabb.pos.x + p_aabb.size.x) )
			return false;
		if ( (pos.x+size.x) < p_aabb.pos.x  )
			return false;
		if ( pos.y > (p_aabb.pos.y + p_aabb.size.y) )
			return false;
		if ( (pos.y+size.y) < p_aabb.pos.y  )
			return false;
		if ( pos.z > (p_aabb.pos.z + p_aabb.size.z) )
			return false;
		if ( (pos.z+size.z) < p_aabb.pos.z  )
			return false;
		return true;
	}
	
	bool encloses(in AABB p_aabb) const
	{
		Vector3 src_min=pos;
		Vector3 src_max=pos+size;
		Vector3 dst_min=p_aabb.pos;
		Vector3 dst_max=p_aabb.pos+p_aabb.size;
	
		return  (
			(src_min.x <= dst_min.x) &&
			(src_max.x > dst_max.x) &&
			(src_min.y <= dst_min.y) &&
			(src_max.y > dst_max.y) &&
			(src_min.z <= dst_min.z) &&
			(src_max.z > dst_max.z) );
	
	}
	
	Vector3 getSupport(in Vector3 p_normal) const
	{
		Vector3 half_extents = size * 0.5;
		Vector3 ofs = pos + half_extents;
		
		return Vector3(
			(p_normal.x>0) ? -half_extents.x : half_extents.x,
			(p_normal.y>0) ? -half_extents.y : half_extents.y,
			(p_normal.z>0) ? -half_extents.z : half_extents.z
		)+ofs;
	}
	
	
	Vector3 getEndpoint(int p_point) const
	{
		switch(p_point)
		{
			case 0: return Vector3( pos.x, pos.y, pos.z);
			case 1: return Vector3( pos.x, pos.y, pos.z+size.z);
			case 2: return Vector3( pos.x, pos.y+size.y, pos.z);
			case 3: return Vector3( pos.x, pos.y+size.y, pos.z+size.z);
			case 4: return Vector3( pos.x+size.x, pos.y, pos.z);
			case 5: return Vector3( pos.x+size.x, pos.y, pos.z+size.z);
			case 6: return Vector3( pos.x+size.x, pos.y+size.y, pos.z);
			case 7: return Vector3( pos.x+size.x, pos.y+size.y, pos.z+size.z);
			default: assert(0); ///ERR_FAIL_V(Vector3())
		}
	}
	
	bool intersectsConvexShape(in Plane[] p_planes) const
	{
		Vector3 half_extents = size * 0.5;
		Vector3 ofs = pos + half_extents;
	
		foreach(const ref p; p_planes)
		{
			Vector3 point = Vector3(
				(p.normal.x>0) ? -half_extents.x : half_extents.x,
				(p.normal.y>0) ? -half_extents.y : half_extents.y,
				(p.normal.z>0) ? -half_extents.z : half_extents.z
			);
			point+=ofs;
			if (p.isPointOver(point))
				return false;
		}
	
		return true;
	}
	
	bool hasPoint(in Vector3 p_point) const
	{
		if (p_point.x<pos.x)
			return false;
		if (p_point.y<pos.y)
			return false;
		if (p_point.z<pos.z)
			return false;
		if (p_point.x>pos.x+size.x)
			return false;
		if (p_point.y>pos.y+size.y)
			return false;
		if (p_point.z>pos.z+size.z)
			return false;
		
		return true;
	}
	
	
	void expandTo(in Vector3 p_vector)
	{
		Vector3 begin=pos;
		Vector3 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.z<begin.z)
			begin.z=p_vector.z;
		
		if (p_vector.x>end.x)
			end.x=p_vector.x;
		if (p_vector.y>end.y)
			end.y=p_vector.y;
		if (p_vector.z>end.z)
			end.z=p_vector.z;
		
		pos=begin;
		size=end-begin;
	}
	
	void projectRangeInPlane(in Plane p_plane, out real_t r_min, out real_t r_max) const
	{
		Vector3 half_extents = Vector3( size.x * 0.5, size.y * 0.5, size.z * 0.5 );
		Vector3 center = Vector3( pos.x + half_extents.x, pos.y + half_extents.y, pos.z + half_extents.z );
	
		real_t length = p_plane.normal.abs().dot(half_extents);
		real_t distance = p_plane.distanceTo( center );
		r_min = distance - length;
		r_max = distance + length;
	}
	
	real_t getLongestAxisSize() const
	{
		real_t max_size=size.x;
		
		if (size.y > max_size ) {
			max_size=size.y;
		}
		
		if (size.z > max_size ) {
			max_size=size.z;
		}
		
		return max_size;
	}
	
	real_t getShortestAxisSize() const
	{
		real_t max_size=size.x;
		
		if (size.y < max_size ) {
			max_size=size.y;
		}
		
		if (size.z < max_size ) {
			max_size=size.z;
		}
		
		return max_size;
	}
	
	bool smitsIntersectRay(in Vector3 from, in Vector3 dir, real_t t0, real_t t1) const
	{
		real_t divx=1.0/dir.x;
		real_t divy=1.0/dir.y;
		real_t divz=1.0/dir.z;
		
		Vector3 upbound=pos+size;
		real_t tmin, tmax, tymin, tymax, tzmin, tzmax;
		if (dir.x >= 0) {
			tmin = (pos.x - from.x) * divx;
			tmax = (upbound.x - from.x) * divx;
		}
		else {
			tmin = (upbound.x - from.x) * divx;
			tmax = (pos.x - from.x) * divx;
		}
		if (dir.y >= 0) {
			tymin = (pos.y - from.y) * divy;
			tymax = (upbound.y - from.y) * divy;
		}
		else {
			tymin = (upbound.y - from.y) * divy;
			tymax = (pos.y - from.y) * divy;
		}
		if ( (tmin > tymax) || (tymin > tmax) )
			return false;
		if (tymin > tmin)
				tmin = tymin;
		if (tymax < tmax)
			tmax = tymax;
		if (dir.z >= 0) {
			tzmin = (pos.z - from.z) * divz;
			tzmax = (upbound.z - from.z) * divz;
		}
		else {
			tzmin = (upbound.z - from.z) * divz;
			tzmax = (pos.z - from.z) * divz;
		}
		if ( (tmin > tzmax) || (tzmin > tmax) )
			return false;
		if (tzmin > tmin)
			tmin = tzmin;
		if (tzmax < tmax)
			tmax = tzmax;
		return ( (tmin < t1) && (tmax > t0) );
	}
	
	void growBy(real_t p_amount)
	{
		pos.x-=p_amount;
		pos.y-=p_amount;
		pos.z-=p_amount;
		size.x+=2.0*p_amount;
		size.y+=2.0*p_amount;
		size.z+=2.0*p_amount;
	}
	
	
	real_t getArea() const
	{
		return size.x*size.y*size.z;
	}
	
	void mergeWith(in AABB p_aabb)
	{
		Vector3 beg_1,beg_2;
		Vector3 end_1,end_2;
		Vector3 min,max;
		
		beg_1=pos;
		beg_2=p_aabb.pos;
		end_1=Vector3(size.x,size.y,size.z)+beg_1;
		end_2=Vector3(p_aabb.size.x,p_aabb.size.y,p_aabb.size.z)+beg_2;
		
		min.x=(beg_1.x<beg_2.x)?beg_1.x:beg_2.x;
		min.y=(beg_1.y<beg_2.y)?beg_1.y:beg_2.y;
		min.z=(beg_1.z<beg_2.z)?beg_1.z:beg_2.z;
		
		max.x=(end_1.x>end_2.x)?end_1.x:end_2.x;
		max.y=(end_1.y>end_2.y)?end_1.y:end_2.y;
		max.z=(end_1.z>end_2.z)?end_1.z:end_2.z;
		
		pos=min;
		size=max-min;
	}
	
	AABB intersection(in AABB p_aabb) const
	{
		Vector3 src_min=pos;
		Vector3 src_max=pos+size;
		Vector3 dst_min=p_aabb.pos;
		Vector3 dst_max=p_aabb.pos+p_aabb.size;
		
		Vector3 min,max;
		
		if (src_min.x > dst_max.x || src_max.x < dst_min.x )
			return AABB();
		else
		{
			min.x= ( src_min.x > dst_min.x ) ? src_min.x :dst_min.x;
			max.x= ( src_max.x < dst_max.x ) ? src_max.x :dst_max.x;
		}
		
		if (src_min.y > dst_max.y || src_max.y < dst_min.y )
			return AABB();
		else
		{
			min.y= ( src_min.y > dst_min.y ) ? src_min.y :dst_min.y;
			max.y= ( src_max.y < dst_max.y ) ? src_max.y :dst_max.y;
		}
		
		if (src_min.z > dst_max.z || src_max.z < dst_min.z )
			return AABB();
		else
		{
			min.z= ( src_min.z > dst_min.z ) ? src_min.z :dst_min.z;
			max.z= ( src_max.z < dst_max.z ) ? src_max.z :dst_max.z;
		}
		
		
		return AABB( min, max-min );
	}
	
	bool intersectsRay(in Vector3 p_from, in Vector3 p_dir, Vector3* r_clip = null, Vector3* r_normal = null) const
	{
		Vector3 c1, c2;
		Vector3 end = pos+size;
		real_t near=-1e20;
		real_t far=1e20;
		int axis=0;
	
		for (int i=0;i<3;i++)
		{
			if (p_dir[i] == 0)
			{
				if ((p_from[i] < pos[i]) || (p_from[i] > end[i]))
				{
					return false;
				}
			} else { // ray not parallel to planes in this direction
				c1[i] = (pos[i] - p_from[i]) / p_dir[i];
				c2[i] = (end[i] - p_from[i]) / p_dir[i];
	
				if(c1[i] > c2[i]){
					swap(c1,c2);
				}
				if (c1[i] > near){
					near = c1[i];
					axis=i;
				}
				if (c2[i] < far){
					far = c2[i];
				}
				if( (near > far) || (far < 0) ){
					return false;
				}
			}
		}
		if (r_clip)
			*r_clip=c1;
		if (r_normal)
		{
			*r_normal=Vector3();
			(*r_normal)[axis]=p_dir[axis]?-1:1;
		}
		return true;
	}
	
	bool intersectsSegment(in Vector3 p_from, in Vector3 p_to, Vector3* r_clip = null, Vector3* r_normal = null) const
	{
		real_t min=0,max=1;
		int axis=0;
		real_t sign=0;
		
		for(int i=0;i<3;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;
		}
		
		Vector3 rel=p_to-p_from;
		
		if (r_normal)
		{
			Vector3 normal;
			normal[axis]=sign;
			*r_normal=normal;
		}
		
		if (r_clip)
			*r_clip=p_from+rel*min;
		
		return true;
	}
	
	
	bool intersectsPlane(in Plane p_plane) const
	{
		Vector3[8] points = [
			Vector3( pos.x, pos.y, pos.z),
			Vector3( pos.x, pos.y, pos.z+size.z),
			Vector3( pos.x, pos.y+size.y, pos.z),
			Vector3( pos.x, pos.y+size.y, pos.z+size.z),
			Vector3( pos.x+size.x, pos.y, pos.z),
			Vector3( pos.x+size.x, pos.y, pos.z+size.z),
			Vector3( pos.x+size.x, pos.y+size.y, pos.z),
			Vector3( pos.x+size.x, pos.y+size.y, pos.z+size.z),
		];
		
		bool over=false;
		bool under=false;
		
		for (int i=0;i<8;i++)
		{
			if (p_plane.distanceTo(points[i])>0)
				over=true;
			else
				under=true;
		}
		return under && over;
	}
	
	Vector3 getLongestAxis() const
	{
		Vector3 axis = Vector3(1,0,0);
		real_t max_size=size.x;
		
		if (size.y > max_size )
		{
			axis=Vector3(0,1,0);
			max_size=size.y;
		}
		
		if (size.z > max_size )
		{
			axis=Vector3(0,0,1);
			max_size=size.z;
		}
		
		return axis;
	}
	int getLongestAxisIndex() const
	{
		int axis=0;
		real_t max_size=size.x;
		
		if (size.y > max_size )
		{
			axis=1;
			max_size=size.y;
		}
		
		if (size.z > max_size )
		{
			axis=2;
			max_size=size.z;
		}
		
		return axis;
	}
	
	Vector3 getShortestAxis() const
	{
		Vector3 axis = Vector3(1,0,0);
		real_t max_size=size.x;
		
		if (size.y < max_size )
		{
			axis=Vector3(0,1,0);
			max_size=size.y;
		}
		
		if (size.z < max_size )
		{
			axis=Vector3(0,0,1);
			max_size=size.z;
		}
		
		return axis;
	}
	int getShortestAxisIndex() const
	{
		int axis=0;
		real_t max_size=size.x;
		
		if (size.y < max_size )
		{
			axis=1;
			max_size=size.y;
		}
		
		if (size.z < max_size )
		{
			axis=2;
			max_size=size.z;
		}
		
		return axis;
	}
	
	AABB merge(in AABB p_with) const
	{
		AABB aabb=this;
		aabb.mergeWith(p_with);
		return aabb;
	}
	AABB expand(in Vector3 p_vector) const
	{
		AABB aabb=this;
		aabb.expandTo(p_vector);
		return aabb;
	
	}
	AABB grow(real_t p_by) const
	{
		AABB aabb=this;
		aabb.growBy(p_by);
		return aabb;
	}
	
	void getEdge(int p_edge, out Vector3 r_from, out Vector3 r_to) const
	{
		///ERR_FAIL_INDEX(p_edge,12);
		switch(p_edge)
		{
			case 0:{
				r_from=Vector3( pos.x+size.x	, pos.y		, pos.z		);
				r_to=Vector3( pos.x	, pos.y		, pos.z		);
			} break;
			case 1:{
				r_from=Vector3( pos.x+size.x	, pos.y		, pos.z+size.z	);
				r_to=Vector3( pos.x+size.x	, pos.y		, pos.z		);
			} break;
			case 2:{
				r_from=Vector3( pos.x	, pos.y		, pos.z+size.z	);
				r_to=Vector3( pos.x+size.x	, pos.y		, pos.z+size.z	);
			} break;
			case 3:{
				r_from=Vector3( pos.x	, pos.y		, pos.z		);
				r_to=Vector3( pos.x	, pos.y		, pos.z+size.z	);
			} break;
			case 4:{
				r_from=Vector3( pos.x	, pos.y+size.y		, pos.z		);
				r_to=Vector3( pos.x+size.x	, pos.y+size.y		, pos.z		);
			} break;
			case 5:{
				r_from=Vector3( pos.x+size.x	, pos.y+size.y		, pos.z		);
				r_to=Vector3( pos.x+size.x	, pos.y+size.y		, pos.z+size.z	);
			} break;
			case 6:{
				r_from=Vector3( pos.x+size.x	, pos.y+size.y		, pos.z+size.z	);
				r_to=Vector3( pos.x	, pos.y+size.y		, pos.z+size.z	);
			} break;
			case 7:{
				r_from=Vector3( pos.x	, pos.y+size.y		, pos.z+size.z	);
				r_to=Vector3( pos.x	, pos.y+size.y		, pos.z		);
			} break;
			case 8:{
				r_from=Vector3( pos.x	, pos.y		, pos.z+size.z	);
				r_to=Vector3( pos.x	, pos.y+size.y		, pos.z+size.z	);
			} break;
			case 9:{
				r_from=Vector3( pos.x	, pos.y		, pos.z		);
				r_to=Vector3( pos.x	, pos.y+size.y	, pos.z		);
			} break;
			case 10:{
				r_from=Vector3( pos.x+size.x	, pos.y		, pos.z		);
				r_to=Vector3( pos.x+size.x	, pos.y+size.y	, pos.z		);
			} break;
			case 11:{
				r_from=Vector3( pos.x+size.x	, pos.y		, pos.z+size.z		);
				r_to=Vector3( pos.x+size.x	, pos.y+size.y	, pos.z+size.z		);
			} break;
			default: assert(0);
		}
	}
}