headplane/app/utils/time.ts

/**
 * Formats the time delta since a given date into a human-readable string.
 * - Under 1 hour: "X minutes ago"
 * - Under 1 day: "X hours, Y minutes ago"
 * - Under 1 month: "X days, Y hours ago"
 * - Over 1 month: "X months, Y days ago"
 */
export function formatTimeDelta(date: Date): string {
	const now = new Date();
	const diffMs = now.getTime() - date.getTime();

	const minutes = Math.floor(diffMs / (1000 * 60));
	const hours = Math.floor(diffMs / (1000 * 60 * 60));
	const days = Math.floor(diffMs / (1000 * 60 * 60 * 24));
	const months = Math.floor(days / 30);

	if (minutes < 60) {
		return `${minutes} minute${minutes !== 1 ? 's' : ''} ago`;
	}

	if (hours < 24) {
		const remainingMinutes = minutes % 60;
		if (remainingMinutes === 0) {
			return `${hours} hour${hours !== 1 ? 's' : ''} ago`;
		}
		return `${hours} hour${hours !== 1 ? 's' : ''}, ${remainingMinutes} minute${remainingMinutes !== 1 ? 's' : ''} ago`;
	}

	if (days < 30) {
		const remainingHours = hours % 24;
		if (remainingHours === 0) {
			return `${days} day${days !== 1 ? 's' : ''} ago`;
		}
		return `${days} day${days !== 1 ? 's' : ''}, ${remainingHours} hour${remainingHours !== 1 ? 's' : ''} ago`;
	}

	const remainingDays = days % 30;
	if (remainingDays === 0) {
		return `${months} month${months !== 1 ? 's' : ''} ago`;
	}
	return `${months} month${months !== 1 ? 's' : ''}, ${remainingDays} day${remainingDays !== 1 ? 's' : ''} ago`;
}