/**
 * Compares a given range to the value, returning the relative position.
 *
 * If the returned value is 1, the value sits AFTER the range.
 * If the returned value is 0, the value sits WITHIN the range.
 * If the returned value is -1, the value sits BEFORE the range.
 * The range given is considered to be inclusive (e.g. 6 sits WITHIN 6-10).
 *
 * @param value The value.
 * @param range The range, two positive numbers split by a single dash.
 * @returns {number} The relative position of the value to the range as -1, 0 or 1.
 */
function compareASN(value: number, range: string): number {
  const [start, end] = range.split("-", 2) as [string, string];
  if (value < parseInt(start)) return -1;
  if (value > parseInt(end)) return 1;
  return 0;
}

/**
 * Find the range in which a given ASN exists via binary search. If not found, -1 is used.
 */
export function findASN(asn: number, ranges: string[]) {
  let start = 0;
  let end = ranges.length - 1;

  while (start <= end) {
    const mid = Math.floor((start + end) / 2);
    const comparison = compareASN(asn, ranges[mid] as string);
    if (comparison == 0) return mid; // Success case
    if (comparison == -1) end = mid - 1;
    else start = mid + 1;
  }
  return -1; // Failure case
}