package Day11;

use strict;
use warnings;
use v5.32;

use Exporter qw( import );
our @EXPORT = qw( is_valid_password );

# create expression to match one increasing straight of at least three
# letters, like abc, bcd, cde, and so on, up to xyz.
my $number = ord( 'a' );
my $inc_straight = join "|", map { chr ( $number + $_ ) .
                                   chr ( $number + $_ + 1 ) .
                                   chr ( $number + $_ + 2 ) } ( 0 .. 23 );

sub is_valid_password {
    my $string = shift;
    return 0 if ( $string !~ m/$inc_straight/ ) ||
                ( $string =~ m/[iol]/ )         ||
                ( $string !~ m/(\w)\1.*(\w)\2/ );
    return 1;
}

1;