#!/usr/bin/perl
use strict;
use warnings;
use CGI qw( :standard );
use File::Spec::Functions;
use Cwd;


my $cgi = CGI->new();

my $index = $cgi->param('index');


my @files = find_files_by_index( $index );


print "index: $index\n@files", $/;


sub find_files_by_index {
        my $idx   = shift;
        my $dir   = cwd();
        my @files = ();

        opendir my $dh, $dir or die "$dir: $!\n";

        while ( my $file = readdir $dh ) {
                my $fullpath = catfile( $dir, $file );
                if ( !-d $fullpath and $file =~ m/_${idx}.[^.]+\z/ ) {
                        push @files, $file;
                }
        }

        closedir $dh;

        return @files;
}