// Finished in earlier steps — reuse, don't rewrite.
export type Vec = { x: number; y: number };
export const vec = (x: number, y: number): Vec => ({ x, y });

export type AABB = { x: number; y: number; w: number; h: number };
export type Span = { entry: number; exit: number };

/** Step 05, finished. */
export function sweepInterval(
	p: number,
	v: number,
	min: number,
	max: number,
): Span | null {
	if (v === 0) {
		return min <= p && p <= max ? { entry: -Infinity, exit: Infinity } : null;
	}

	let t1 = (min - p) / v;
	let t2 = (max - p) / v;
	if (t1 > t2) {
		[t1, t2] = [t2, t1];
	}

	return { entry: t1, exit: t2 };
}