#! /usr/bin/perl
use strict;
use Math::BigFloat;
Math::BigFloat->precision(0);

sub GetINDirFiles {
        my ($path) = @_;

        opendir DIR, $path or die $!;
        my @files = readdir DIR;
        my @files = grep {!/\_ACK_/} readdir DIR;
        closedir DIR;

        return(@files);
}

sub GetOUTDirFiles {
        my ($path) = @_;

        opendir DIR, $path or die $!;
        my @files = readdir DIR;
        my @files = grep {/\_ACK.xml$/} readdir DIR;
        closedir DIR;

        return(@files);
}

# Main
my $inpath = "/AAA/BBB/CCC/IN";
my $outpath = "/AAA/BBB/CCC/OUT";
my $outsuffix = "_ACK.xml";
my $insuffix = ".xml";                #    Added by me 
my $timethreshold = 900;       # set time threshold in seconds (900 seconds equal 15 minutes)
my @delindex;

my @infiles = &GetINDirFiles($inpath);
my @outfiles = &GetOUTDirFiles($outpath);

my $index = 0; # index used to get string position in array
foreach my $infile (@infiles) {
        $infile =~ s/(.*)$insuffix/$1/g;      # remove suffix to do comparation # Added by me
        foreach my $outfile (@outfiles) {
               $outfile =~ s/(.*)$outsuffix/$1/g;    # remove suffix to do comparation
               
               if ($outfile eq $infile){
                       push (@delindex, $index);      # get list of strings to be removed from array
               }              

        }
        $index += 1;
}

delete @infiles[@delindex];    # remove strings 

my $currenttime = time;        # get current time from system (epoch time)
foreach my $file (@infiles) {
        next unless (-f "$inpath/$file$insuffix");    # ignore directories   # INSERT SUFFIX AGAIN ($insuffix)
        my $mtime = (stat "$inpath/$file$insuffix" )[9];      # get mtime from file (epoch time)   # INSERT SUFFIX AGAIN ($insuffix)     
        my $diff = ($currenttime - $mtime);

        if ($diff > $timethreshold) {  
               print "\n - file " . $file . $insuffix . " in " . $inpath . " directory was created at more than "  . Math::BigFloat->new($diff / 60) . " minutes.";    # INSERT SUFFIX AGAIN ($insuffix)
               
               # PUT THE ACTION THAT YOU WANT DO HERE!!!

        } 
}