#ifndef COLLISION_H_
#define COLLISION_H_

#include <stdarg.h>
#include <stdlib.h>
#include <stdio.h>

// Implementation details only, disregard as this is irrelevant to the implementation of the actual algorithm.

typedef struct {float x, y;} vec;
typedef struct {vec p0, dir;} ray;
typedef struct {vec p0, p1, dir;} seg;
typedef struct {int n; vec *vertices; seg *edges;} polygon; // Assumption: Simply connected => chain vertices together

polygon new_polygon(int nvertices, vec *vertices){
	seg *edges = (seg*)malloc(sizeof(seg)*(nvertices));
	for (int i = 0; i < nvertices-1; i++){
		vec dir = {vertices[i+1].x-vertices[i].x, vertices[i+1].y-vertices[i].y};seg cur = {vertices[i], vertices[i+1], dir};
		edges[i] = cur;
	}
	vec dir = {vertices[0].x-vertices[nvertices-1].x, vertices[0].y-vertices[nvertices-1].y};seg cur = {vertices[nvertices-1], vertices[0], dir};
	edges[nvertices-1] = cur;
	polygon shape = {nvertices, vertices, edges};
	return shape;
}

vec v(float x, float y){
	vec a = {x, y};
	return a;
}

polygon Polygon(int nvertices, ...){
	va_list args;
	va_start(args, nvertices);
	vec *vertices = (vec*)malloc(sizeof(vec)*nvertices);
	for (int i = 0; i < nvertices; i++){
		vertices[i] = va_arg(args, vec);
	}
	va_end(args);
	return new_polygon(nvertices, vertices);
}

#endif /* COLLISION_H_ */