export function formatResetCountdown(resetAtSeconds: number): string {
  const nowSeconds = Math.floor(Date.now() / 1000);
  const diffSeconds = resetAtSeconds - nowSeconds;

  if (diffSeconds <= 0) return "resetting now";
  if (diffSeconds < 60) return "resets in <1m";

  const totalHours = Math.floor(diffSeconds / 3600);
  const minutes = Math.floor((diffSeconds % 3600) / 60);

  if (totalHours >= 24) {
    const days = Math.floor(totalHours / 24);
    const hours = totalHours % 24;
    if (hours > 0) return `resets in ${days}d ${hours}h`;
    return `resets in ${days}d`;
  }
  if (totalHours > 0 && minutes > 0) return `resets in ${totalHours}h ${minutes}m`;
  if (totalHours > 0) return `resets in ${totalHours}h`;
  return `resets in ${minutes}m`;
}

export function parseTimeInput(
  value: string
): { hour: number; minute: number } | null {
  const match = value.trim().match(/^(\d{1,2}):(\d{2})$/);
  if (!match) return null;

  const hour = Number.parseInt(match[1], 10);
  const minute = Number.parseInt(match[2], 10);
  if (hour > 23 || minute > 59) return null;

  return { hour, minute };
}

export function formatTime(hour: number, minute: number): string {
  return `${String(hour).padStart(2, "0")}:${String(minute).padStart(2, "0")}`;
}

export function formatLastUpdated(timestamp: number, now = Date.now()): string {
  const elapsedSeconds = Math.max(0, Math.floor((now - timestamp) / 1000));
  if (elapsedSeconds < 60) return "Updated just now";

  const minutes = Math.floor(elapsedSeconds / 60);
  if (minutes < 60) return `Updated ${minutes} min ago`;

  const hours = Math.floor(minutes / 60);
  if (hours < 24) return `Updated ${hours} hr${hours === 1 ? "" : "s"} ago`;

  const days = Math.floor(hours / 24);
  return `Updated ${days} day${days === 1 ? "" : "s"} ago`;
}

export function formatResetCountdownISO(isoString: string): string {
  const resetAtSeconds = Math.floor(new Date(isoString).getTime() / 1000);
  return formatResetCountdown(resetAtSeconds);
}

export function windowLabel(limitWindowSeconds: number): string {
  const hours = limitWindowSeconds / 3600;
  if (hours < 24) return `${Math.round(hours)}h`;
  const days = hours / 24;
  const wholeDays = Math.floor(days);
  const remainderHours = Math.round(hours - wholeDays * 24);
  if (remainderHours === 0) return `${wholeDays}d`;
  return `${wholeDays}d ${remainderHours}h`;
}