const fmt = new Intl.DateTimeFormat("en", { month: "short", day: "numeric", year: "numeric", timeZone: "UTC" });

export const date = (iso: string | null) => (iso ? fmt.format(new Date(`${iso}T00:00:00Z`)) : "");

export const plural = (n: number, word: string) => `${n} ${word}${n === 1 ? "" : "s"}`;

// Spread the 17 disciplines around the colour wheel (golden-angle steps).
const hues = new Map<string, number>();
export function hue(discipline: string, order: string[]): number {
	let h = hues.get(discipline);
	if (h === undefined) {
		const i = Math.max(0, order.indexOf(discipline));
		h = Math.round((i * 137.508 + 225) % 360);
		hues.set(discipline, h);
	}
	return h;
}