#!/usr/bin/perl

# our needed packages
use strict "vars";
use Getopt::Std;

# Global Variables
my $VERBOSE = 0;
my $DEBUG = 0;


# Add support for the config file
my $opt_string = "vdhsc:";
getopts( "$opt_string", \my %opt ) or usage() and exit(1);

$VERBOSE = 1 if $opt{'v'};
$DEBUG = 1 if $opt{'d'};
if ( $opt{'h'} ) {
    usage();
    exit 0;
}

my $SIMULATE = $opt{s};

my $CONFIG = $opt{c};

my $ITERATIONS = 3;

usage() and die("You need to supply a config file please. \n") unless $CONFIG;


# debug ("Checking if the remote host is up and the folder is present \n");
# die("The remote host could not verify the directory $DIR or is down. Exiting.\n") unless verify_host($HOST,$DIR,$USER);

####################################################
# Main part

# for all hosts: ( Also for every line )
open(CONF,"$CONFIG") or die("Unable to open config $CONFIG: $!\n");
while( my $line = <CONF> ) {
    my $HOST;
    my $LIST;
    if ( $line =~ /(\S+):(.*)/ ) {
	$HOST = $1;
	$LIST = $2;
	debug("Read line with host: '$HOST' and dirs: '$LIST' \n");
    } else {
	next;
    }

    my $LOCAL = $HOST;
# remove the oldest if number equals $ITERATIONS
    if ( stat($LOCAL . "." . $ITERATIONS) ) {
    run_command("rm -rf " . $LOCAL . "." . $ITERATIONS);
    }

# rotate the folders from 1 until the end backwards
    for ( my $i = ( $ITERATIONS -1); $i >= 1; $i--){
	if (stat($LOCAL . "." . $i)) { 
	    run_command("mv " . $LOCAL . "." . $i . " " . $LOCAL . "." . ( $i + 1));
	}
    }

# copy with hard links base folder to .1
    run_command("cp -al " . $LOCAL . " " . $LOCAL . ".1"); 

# execute rsync
# for every folder
    my @FOLDERS = split /,/,$LIST;
    foreach my $DIR ( @FOLDERS ) {
	run_command("rsync -av --delete -e ssh $HOST:$DIR $LOCAL");
    }
}

debug("script is finished,exiting...\n");
  exit 0;

#####################################################
# subroutines


sub usage {
    
    print "Usage:\n";
    print "-h for help\n";
    print "-v for verbose (more output ) \n";
    print "-d for debug (even more output)\n";
    print "-s Simulate only, no command will be executed! \n";
    print "----\n";
    print "-c <config> in order to supply the backup configuration file \n";
}


sub verbose {
    print "VERBOSE: " . $_[0] if ( $VERBOSE or $DEBUG );
}


sub debug {
    print "DEBUG: " . $_[0] if ( $DEBUG );
}


sub verify_host {
   my $host = $_[0];
   my $dir = $_[1];
   my $user = $_[2];
    
    $host = $user . "@" . $host if $user;
    open(SSH,"ssh $host stat $dir |");
    while ( my $line = <SSH> ) {
        if ( $line =~ /Modify: / ) {
	    close(SSH);
	    return 1;
    }
 }
    close(SSH);
    return 0;
    
}


sub run_command {
    my $command = $_[0];
    debug("EXEC: " .$command . "\n");
    system($command) unless $SIMULATE;
}