#!/usr/local/bin/perl

use strict;

# either pass a potential ABA number, or just invoke without passing
# invoking without a passed ABA number will validate the ABA routine i
+tself
# by reporting all 10 numbers in included test suite (they should all 
+be valid)

my $passed_aba = shift;

my @aba_nos;
if (length($passed_aba) gt 0 )
{
  push(@aba_nos,$passed_aba);
}
else
{
  # the following represents a test suite of the 10 possible configura
+tions
  @aba_nos = qw/ 221012181 231511232 091904513 063100264 051400125 071
+012166 063100277 067006238 063102149 263105250/;
}

my $aba;
for $aba ( @aba_nos )
{
  if ( aba($aba) )
  {
    print "\n", "$aba is valid";
  }
  else
  {
    print "\n", "$aba is not a valid ABA";
  }
}
exit;


sub aba
{
  my $EFTABA = shift;
  my $retval = 0;
  my $sum = 0;
  my ($lastpos, $checkdigit, $checksum);
  my @aba = split(//,$EFTABA);
  #  now do some math using weighing factor
  #  position  1 2 3 4 5 6 7 8
  #  weight    3 7 1 3 7 1 3 7
  $sum += ($aba[0] * 3);
  $sum += ($aba[1] * 7);
  $sum += ($aba[2] * 1);
  $sum += ($aba[3] * 3);
  $sum += ($aba[4] * 7);
  $sum += ($aba[5] * 1);
  $sum += ($aba[6] * 3);
  $sum += ($aba[7] * 7);
  # now the total gets subtracted from the next highest multiple of 10
  # (just subtract the last digit from 10....)
  # print "\nSum: $sum";
  $lastpos = length($sum);
  $checkdigit = substr($sum,($lastpos-1),1);
  # print "\nCheckdigit: $checkdigit";

  $checksum = ( 10 - $aba[8] );
  if ( $checksum eq 10 )        # 10 = 0
  {
    $checksum = 0;
  }
  if ( $checksum eq $checkdigit )
  {
    $retval = 1; #print "\n$EFTABA is a valid ABA number";
  }

  return $retval;
}
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