#! /usr/bin/env perl

use strict;
use warnings;

# Part of backupServer package. This module removes snapshots of the machine backup
# older than a certain number of days.
# This is the "cleanup" routine for version_zfs, which removes older versions
# Syntax: version_cleanup_zfs age rootDir client server
# rootDir, client and server are used to build the base directory
# age is the number of days to keep, so any snapshot older than that is suspect
# this assumes the snapshot name begins with @YYYYMMDD (everything after is ignored)

my $age = shift; # Number of days to keep
my $rootDir = shift;
my $client = shift;
my $server = shift;

sub getSnapshots {
   my $rootDirectory = shift;
   my @snapshots = map{ ($_) = split( "\t", $_) } `zfs list -H -t snapshot | grep $rootDirectory`;
   chomp @snapshots;
   return @snapshots;
}

sub getOldestToKeep {
   my $age = shift;
   my ($sec,$min,$hour,$mday,$mon,$year,$wday,$yday,$isdst)=localtime(time - ($age * 86400) );
   return sprintf ( "%04d%02d%02d", $year+1900,$mon+1,$mday);
}

$rootDir = "$rootDir/$client/$server";
die "Invalid Call, exiting" unless  ( $rootDir && $client && $server && $age);
die "Invalid Path for rolloff_version, exiting" unless -d $rootDir;
my $toKeep = &getOldestToKeep($age);

print "$toKeep\n";
# following command accepts path, and returns tab separated list, the first
# value being the zfs name mounted there
my $GETZFSFROMPATH = 'zfs list -H ';

($rootDir) = split( "\t", `$GETZFSFROMPATH $rootDir` );

print "$rootDir\n\n";


my @currentDirectories = sort &getSnapshots( "$client/$server" );
print join( "\n", @currentDirectories ) . "\n";

print "Removing old versions\n";
foreach my $snap ( @currentDirectories ) {
   $snap =~ m/\@(\d{8})/;
   my $timestamp = $1;
   if ( $timestamp < $toKeep ) {
      print "Removing snapshot $snap\n";
      `zfs destroy -r $snap`;
   }
}

1;