Create groovy script to generate Luhn Algorithm

Hi Sanj,

I am looking to create the data, rather than validate it. There really are not a lot of resources specific to creation that I've found. One of my coworkers had created a Google app script to generate the data so that it can be used in Sheets, and I've extracted the script, but am having one heck of a time converting it to Groovy. 

function RanSin () {
  for (;;){
    var n=9, sum=0, rn, ranSin, nextDigit, total=0;
    var evenDigit = false;
    while (n>0){
      rn = Math.floor(Math.random()*(9-1))+1;   
      sum+=rn;
      if ( n == 1){
        break;
      }
      sum*=10;
      n-=1;
    }
    ranSin=sum;
    while ( ranSin > 0 ) {
      nextDigit = ranSin %10;
      ranSin = Math.floor(ranSin / 10);
      if (evenDigit) {
        nextDigit = 2* nextDigit;
        nextDigit = Math.floor(nextDigit / 10) + (nextDigit % 10); 
      }
      total += nextDigit;
      evenDigit = !evenDigit;
    } 
    if ( 0 == (total%10)){
      return sum; 
      break;
    }
  }
}