$drive = Coles_Backup_Drive->new( \$disk, SPACE_THRESHOLD );

##</code><code>##


package Backup_Drive;
use strict;

use constant LAST_MODIFIED => 0;
use constant FILE_SIZE => 1;
use constant TRANSACTION_LOG => 'trn';
use constant FULL_BACKUP => 'bak';

# make database backups private
my %_last_full_backups = ();
my @_full_backup_files = [];
my %_trn_backups =();
my $_space_threshold;

sub new{
	my ( $class, @arg ) = @_;
	my $self = bless $arg[0], $class;
	$_space_threshold = $arg[1];
	return $self;
}

sub add_file{
### THIS IS THE PROBLEM WHEN PASSING DETAIL FROM THIS METHOD TO add_full_backup ###

	# add the file to the relevant file type data
	my( $self, $database_name, $file ) = @_;
	
	if( lc( $file->Extension ) eq FULL_BACKUP ){
		add_full_backup( $self, $database_name, $file );
	} else {
		add_trn_log( $self, $database_name, $file );
	}
	print "wait\n";
}

sub add_full_backup{
	my( $self, $database_name, $file ) = @_;
	
	# capture the last backup details
	if( exists $_last_full_backups{ $database_name } ){
		# record the file size only if the database backup is more recent the the one recorded
		if( $_last_full_backups{ $database_name }->[ LAST_MODIFIED ] < $file->LastModified ){
			# one file I found returned an undefined value for its size. So I defaulted the size to zero.
			$_last_full_backups{ $database_name } = [ $file->LastModified, defined $file->FileSize ? $file->FileSize : 0 ];
		}
	} else {
		# add new details
		$_last_full_backups{ $database_name } = [ $file->LastModified, defined $file->FileSize ? $file->FileSize : 0 ];
	}
	
	# add file to file list
	push ( @_full_backup_files, $file );
	print "test\n";
}

sub add_trn_log{
	my( $self, $database_name, $file ) = @_;
	
	if( exists $_trn_backups{ $database_name } ){
		$_trn_backups{ $database_name } = [ \$file ];
	} else {
		push( @{ $_trn_backups{ $database_name } }, \$file );
	}
}

sub get_last_backup_modified{
	# return the last modified date for the passed in database
	my( $self, $database_name ) = @_;
	$_last_full_backups{ $database_name }->[ LAST_MODIFIED ];
}

sub get_last_backup_file_size{
	# return the last modified date for the passed in database
	my( $self, $database_name ) = @_;
	$_last_full_backups{ $database_name }->[ FILE_SIZE ];
}

sub need_drive_space{
	# return whether the drive needs space to keep it above the space warning threshold.
	my $self = shift;
	if( _database_space_required() > $$self->FreeSpace ){
		return 1;
	}
	
	return 0;
}

sub _database_space_required{
	my $self = shift;
	my $total = 0;
	my $key;
	
	for $key ( keys %_last_full_backups ){
		$total += get_last_backup_file_size( $key );
	}
	
	$total += $_space_threshold;	# keep above threshold warning size
	return $total;
}


#__END__

1;