import { Collision } from '../model/data/collision';

import { Circle } from '../math/circle';
import { Collidable } from '../math/collision';
import { LineSegment, Movement } from '../math/line';
import { Point } from '../math/point';

import { vec2 } from 'gl-matrix';

export function mkCollision(collision: Collision[]): Collidable[] {
	const ret: Collidable[] = [];

	for (const c of collision) {
		switch (c.type) {
		case 'polygon':
			if (!c.vertices.length)
				continue;

			let prev = c.vertices[c.vertices.length - 1];

			for (const v of c.vertices) {
				ret.push(LineSegment.fromPoints(vec2.clone(prev), vec2.clone(v)));
				prev = v;
			}

			for (const v of c.vertices) {
				ret.push(new Point(vec2.clone(v)));
				prev = v;
			}
			break;

		case 'circle':
			ret.push(new Circle(vec2.clone(c.center), c.radius));
			break;
		}
	}

	return ret;
}

export interface CollidableGroup {
	getTranslation(): vec2|null;
	getCollidables(): Collidable[];
}

export function collide(collision: CollidableGroup, out: vec2, move: Movement, radius: number): boolean {
	const t = collision.getTranslation();
	if (t)
		move = move.translate(vec2.negate(vec2.create(), t));

	for (const c of collision.getCollidables()) {
		if (!c.collide(out, move, radius))
			continue;

		if (vec2.squaredDistance(move.src, out) >= vec2.squaredDistance(move.src, move.dest))
			continue;

		if (t)
			vec2.add(out, out, t);

		return true;
	}

	return false;
}