#! /usr/local/env perl

use warnings;
use strict;


# Part of backupServer package. This module creates a copy of the current directory
# using cp -al (linked lists) in a dated copy
# allows multiple copies of a directory tree to exist without using a lot of disk space
# First two parameters are directories RELATIVE TO THE INSTALL DIRECTORY which we are working with
# Example call:
# version backup version /home/backups DailyData mal.dailydata.net
# First verifies the followind directories exist:
#    /home/backups/DailyData/mal.dailydata.net/
#    /home/backups/DailyData/mal.dailydata.net/backup
#    /home/backups/DailyData/mal.dailydata.net/version (creates if it does not exist)
# Then determines the current date. It then executes the command
# cp -al /home/backups/DailyData/mal.dailydata.net/backup /home/backups/DailyData/mal.dailydata.net/version/date
# which, on 1 Jan 2010 would copy /home/backups/DailyData/mal.dailydata.net/backup to
# /home/backups/DailyData/mal.dailydata.net/version/20100101, creating hard links
# between all files in the tree.
#
# NOTE: target and source MUST be on the same partition. Hard Links to not work across partitions

my $sourceDir = shift; # the directory which we copy from
my $targetDir = shift; # the directory under which we create the backup copy
my $rootDir = shift;
my $client = shift;
my $server = shift;
my $confDir = shift;

$sourceDir = "$rootDir/$client/$server/$sourceDir";
$targetDir = "$rootDir/$client/$server/$targetDir";
die "Invalid Call, exiting" unless  ( $rootDir && $client && $server && $confDir );
die "Invalid Path for version $sourceDir, exiting" unless -d "$sourceDir";
die "Source directory $sourceDir does not exist" unless -d $sourceDir;
print `mkdir -p $targetDir` unless -d $targetDir;
$targetDir .= '/' . `date +"%Y-%m-%d"`;
chomp $targetDir;

if ( -e $targetDir ) {
   print "Not creating [$targetDir], it already exists\n";
} else {
   print "Creating Linked Backup of source tree at " . `date`;
   print qx/cp -al $sourceDir $targetDir/;
   print "  Complete at " . `date`;
}
1;