// Loaded from https://deno.land/x/segno@v1.1.0/lib/validations/isIP.ts


// @ts-ignore allowing typedoc to build
import { assertString } from '../helpers/assertString.ts';

/**
 * @ignore
 */
const ipv4Maybe = /^(([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])\.){3}([0-9]|[1-9][0-9]|1[0-9]{2}|2[0-4][0-9]|25[0-5])$/;

/**
 * @ignore
 */
const ipv6Block = /^[0-9A-F]{1,4}$/i;

export const isIP = (str: string, ipVersion?: string | number): boolean => {
  assertString(str);
  const version = ipVersion ? String(ipVersion) : '';

  if (!version) {
    return isIP(str, 4) || isIP(str, 6);
  } else if (version === '4') {
    if (!ipv4Maybe.test(str)) {
      return false;
    }

    const arr = str.split('.') as unknown;
    const parts = (arr as number[]).sort((a, b) => a - b);
    return (parts[3] <= 255) as boolean;
  } else if (version === '6') {
    let addressAndZone = [str];
    // ipv6 addresses could have scoped architecture
    // according to https://tools.ietf.org/html/rfc4007#section-11
    if (str.includes('%')) {
      addressAndZone = str.split('%');

      if (addressAndZone.length !== 2) {
        // it must be just two parts
        return false;
      }

      if (!addressAndZone[0].includes(':')) {
        // the first part must be the address
        return false;
      }

      if (addressAndZone[1] === '') {
        // the second part must not be empty
        return false;
      }
    }

    const blocks = addressAndZone[0].split(':');
    let foundOmissionBlock = false; // marker to indicate ::

    // At least some OS accept the last 32 bits of an IPv6 address
    // (i.e. 2 of the blocks) in IPv4 notation, and RFC 3493 says
    // that '::ffff:a.b.c.d' is valid for IPv4-mapped IPv6 addresses,
    // and '::a.b.c.d' is deprecated, but also valid.
    const foundIPv4TransitionBlock = isIP(blocks[blocks.length - 1], 4);
    const expectedNumberOfBlocks = foundIPv4TransitionBlock ? 7 : 8;

    if (blocks.length > expectedNumberOfBlocks) {
      return false;
    }
    // initial or final ::
    if (str === '::') {
      return true;
    } else if (str.substr(0, 2) === '::') {
      blocks.shift();
      blocks.shift();
      foundOmissionBlock = true;
    } else if (str.substr(str.length - 2) === '::') {
      blocks.pop();
      blocks.pop();
      foundOmissionBlock = true;
    }

    for (let i = 0; i < blocks.length; ++i) {
      // test for a :: which can not be at the string start/end
      // since those cases have been handled above
      if (blocks[i] === '' && i > 0 && i < blocks.length - 1) {
        if (foundOmissionBlock) {
          return false; // multiple :: in address
        }
        foundOmissionBlock = true;
      } else if (foundIPv4TransitionBlock && i === blocks.length - 1) {
        // it has been checked before that the last
        // block is a valid IPv4 address
      } else if (!ipv6Block.test(blocks[i])) {
        return false;
      }
    }

    if (foundOmissionBlock) {
      return blocks.length >= 1;
    }
    return blocks.length === expectedNumberOfBlocks;
  }
  return false;
};