/**
 * Extracts /48, /56, and /64 prefixes from an IPv6 address
 * @param {string} ipv6 - The IPv6 address in standard or compressed format
 * @returns {Object} Object containing the /48, /56, and /64 prefixes
 */
function extractIPv6Prefixes(ipv6) {
  // Expand the compressed IPv6 address
  let expandedIPv6 = expandIPv6(ipv6);
  
  // Split the address into groups
  const groups = expandedIPv6.split(':');
  
  // Extract prefixes
  const prefix48 = groups.slice(0, 3).join(':');
  const prefix56 = groups.slice(0, 3).join(':') + ':' + groups[3].substring(0, 1);
  const prefix64 = groups.slice(0, 4).join(':');
  
  return {
    prefix48: prefix48,
    prefix56: prefix56,
    prefix64: prefix64,
    expanded: expandedIPv6
  };
}

/**
 * Expands a compressed IPv6 address to its full form
 * @param {string} ipv6 - The IPv6 address, possibly in compressed format
 * @returns {string} The expanded IPv6 address
 */
function expandIPv6(ipv6) {
  // Handle double colon expansion
  if (ipv6.includes('::')) {
    const parts = ipv6.split('::');
    const left = parts[0] ? parts[0].split(':') : [];
    const right = parts[1] ? parts[1].split(':') : [];
    const missing = 8 - left.length - right.length;
    
    // Create the expanded middle section
    const middle = Array(missing).fill('0000');
    
    // Join all parts together
    const full = [...left, ...middle, ...right];
    
    // Ensure each part is properly padded
    return full.map(part => part.padStart(4, '0')).join(':');
  }
  
  // If no compression, just ensure each part is padded
  return ipv6.split(':').map(part => part.padStart(4, '0')).join(':');
}