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


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

/**
 * @ignore
 */
const creditCard = /^(?:4[0-9]{12}(?:[0-9]{3,6})?|5[1-5][0-9]{14}|(222[1-9]|22[3-9][0-9]|2[3-6][0-9]{2}|27[01][0-9]|2720)[0-9]{12}|6(?:011|5[0-9][0-9])[0-9]{12,15}|3[47][0-9]{13}|3(?:0[0-5]|[68][0-9])[0-9]{11}|(?:2131|1800|35\d{3})\d{11}|6[27][0-9]{14})$/;

export const isCreditCard = (str: string) => {
  assertString(str);

  const sanitized = str.replace(/[- ]+/g, '');

  if (!creditCard.test(sanitized)) {
    return false;
  }

  let sum = 0;
  let digit;
  let tmpNum;
  let shouldDouble;

  for (let i = sanitized.length - 1; i >= 0; i--) {
    digit = sanitized.substring(i, i + 1);
    tmpNum = parseInt(digit, 10);
    if (shouldDouble) {
      tmpNum *= 2;
      if (tmpNum >= 10) {
        sum += (tmpNum % 10) + 1;
      } else {
        sum += tmpNum;
      }
    } else {
      sum += tmpNum;
    }
    shouldDouble = !shouldDouble;
  }
  return !!(sum % 10 === 0 ? sanitized : false);
};