#!/usr/bin/perl

#program to generate 6 Million unique codes, Oct 15, 2011.

use strict;
use warnings;

my $codes_filename  = shift || "codesSixMil2.txt";
my $desiredQuantity = shift || 6_000_001;
my $code_length     = shift || 10;
my @code_set        = ('a'..'z', 3,4,6,7,9);


sub generate_random_string {
  my $stringsize = shift;
  return join '', map { $code_set[rand@code_set] } (1..$stringsize);
}


my %unique_codes;
while ( scalar keys %unique_codes < $desiredQuantity ) {
  $unique_codes{ generate_random_string( $code_length ) }++;
}


my $unique_codes_count = scalar keys %unique_codes;

die "Mismatch: Codes generated: $unique_codes_count, but wanted $desiredQuantity!"
  if $unique_codes_count != $desiredQuantity;


open( MYOUTFILE, '>', $codes_filename ) or die "cannot open $codes_filename - $!";
for my $code ( keys %unique_codes ) {
    print MYOUTFILE $code, "\r\n";
}
close(MYOUTFILE);


print "Unique codes (size=$code_length) written to '$codes_filename': $unique_codes_count\n";