#!/usr/bin/perl

# Author: gilbertas matusevicius
# Kolmisoft, 2015

use strict;
use warnings;



use File::Basename;
use File::Path qw(remove_tree);
use File::Spec::Functions;
#use File::stat;

use Data::Dumper;

my $root_folder = "/var/log/m2/pcap";
my $config_file = "/etc/m2/system.conf";
my $DEFAULT_PCAP_HDD_RESERVED_SPACE=1000;

sub get_config {
    my $config_string = shift;
    my $value = 0;
    my $search_string = quotemeta "$config_string";
   
    open(my $fh, "<", $config_file) or die "cannot open $config_file: $!";
    
    while (my $row = <$fh>) {
       chomp $row;
       if ($row =~ m/$search_string\s*\=\s*(\d+)/g) {
           $value=$1;
           last;
       }
    }
    
    return $value;
       
}



sub get_dir_size {
    my $dir = shift;
    open my $dh, "du -sh -BM $dir |" || die "can't fork: $!";
    my $dh_output = <$dh>;
    chomp $dh_output;
    close $dh;
    my ($dir_size) = $dh_output =~ /(\d+)M/;  
    return $dir_size;
}

 





sub dirs_for_path {
    my $path = shift;
    
    my %directory_tree;
    opendir my $dfh, $path or die "Cannot open $path: $!";
    
    # get first level dirs: 20150701, 20150702, etc.
    my @directories = grep { -d } map { catfile($path, $_) }  readdir $dfh;
    close $dfh;

    
    for my $dir (@directories) {
        next if basename($dir) eq '.' or basename($dir) eq '..';
        
        #get only dirs whose name have two or more digits
        if (basename($dir) =~ /^\d\d+$/) {
            $directory_tree{$dir} = {};
        }
    }
    
    
    # get second level dirs: 11, 12, etc
    
    for my $monthly_dir (keys %directory_tree) {
      print "$monthly_dir\n";
      #next if $monthly_dir eq '.' or $monthly_dir eq '..';

      opendir my $dfh,  $monthly_dir or die "Cannot open $monthly_dir: $!";
      my @new_paths = grep { -d } map { catfile($monthly_dir, $_) } readdir $dfh;
      print "@new_paths\n";
      my %temp_hash;
        
      for my $hourly_dir (@new_paths) {
         next if basename($hourly_dir) eq '.' or basename($hourly_dir) eq '..';
         
          #get only dirs whose name have two or more digits
         if (basename($hourly_dir) =~ /^\d\d+$/) {
              $temp_hash{$hourly_dir} = get_dir_size $hourly_dir;
         }
        
      }
         
      $directory_tree{$monthly_dir} = \%temp_hash;
    }
    
    
    #print "@directories\n";
    
   
                 
    return \%directory_tree;


}


# MAIN logic

if (! -d $root_folder) {
    print "$root_folder does not exist or is not a directory. Exiting\n";
    exit 1;
}

my $max_size = get_config("pcap_hdd_reserved_space");
$max_size = $DEFAULT_PCAP_HDD_RESERVED_SPACE if $max_size < 1;

printf "Starting $0 script:\n";
printf "pcap_hdd_reserved_space = $max_size MB\n";

my $initial_size = get_dir_size $root_folder;

if ($initial_size < $max_size) {
     printf ("initial_size (%d MB) < max_size (%d MB), nothing to do!\n\nn", $initial_size, $max_size);
     exit 1;
}


my $directory_tree = dirs_for_path $root_folder;
#print Dumper($directory_tree);
    
printf ("initial_size (%d MB) > max_size (%d MB), will proceed to delete some dirs!\n", $initial_size, $max_size);

#TO DO delete empty monthly dirs

for my $monthly_dir ( sort {basename($a) <=> basename($b)} keys %$directory_tree ){
    last if ($initial_size < $max_size);
     
    for my $hourly_dir ( sort {basename($a) <=> basename($b) } keys %{$directory_tree->{$monthly_dir}}) {
        last if ($initial_size < $max_size);
        
        my $dir_size = $directory_tree->{$monthly_dir}{$hourly_dir};
        print("Proceeding to delete $hourly_dir\n");
        
        remove_tree( "$hourly_dir", {error => \my $err} );
        
        if (@$err) {
            for my $diag (@$err) {
                my ($file, $message) = %$diag;
                if ($file eq '') {
                    print "general error: $message\n";
                }
                else {
                    print "problem unlinking $file: $message\n";
                }
            }
        }
        else {
            print "No error encountered\n";
        }
        $initial_size = $initial_size - $dir_size;
        print "$hourly_dir deleted, $dir_size MB freed, current $root_folder size $initial_size MB, max allowed size $max_size MB\n\n";

    }
}