package File::Session;

use 5.006000;
use strict;
use warnings;
use Cache::FileCache;
use CGI;
use Digest::SHA ('sha256_hex');


our @ISA = qw(Cache::FileCache CGI);
our $VERSION = '0.04';

sub new {
	my $class = shift;
	$class->SUPER::new(@_);	
}

sub retrieve_session {
	my ($self) = @_;
	my $session_id = $self->cookie('session_id');
	
	if ($session_id) {
		# Cookie vorhanden
                # Set the ID
		$self->id($session_id);
		return $session_id;
	}
	else {
		# kein Cookie vorhanden? Dann mach eines!
		my $cookie = $self->cookie(-name => 'session_id', 
                                           -value => $self->generate_id() );
		print $self->redirect(-cookie => $cookie, -uri => $self->self_url());
	}

}

sub generate_id {
	my ($self) = @_;
	
	my $len = 24;
	my @session_chars = ('A' .. 'Z', 'a' .. 'z', 0 .. 9, '.', '-');
	my $id;
	eval {
		open(RANDOM, "/dev/urandom") or die $!;
		read(RANDOM, $id, $len) == $len;
		close RANDOM;
		$id =~ s/(.)/$session_chars[ord($1) & 63]/esg;
		$id .= time() . $$;
		$id = sha256_hex($id);
		return $id;
	};
	if ($@) {
		# if random is not avaible, create the SID as in CGI::Session
		# thanks for the inspiration ;-)
		my $sha = Digest::SHA->new(256);
    		$sha->add($$ , time() , rand(time) );
    		$id = $sha->hexdigest();
	}
	return $id;
}

sub id {
	my ($self, $new_id) = @_;
	my $old_id = $self->{'id'};
	$self->{'id'} = $new_id if ($new_id);
	return $old_id;
}

sub get_data {
	my ($self) = @_;
	my $session_id = $self->id();
	my $data = $self->get($session_id);
	$self->set($session_id,$data);
        return $data;
}

1;

# Create File::Session Object
my $session = File::Session->new({'namespace'=>'sessions',
                                 'cache_root'=>"$DATADIR/cache",
                                 'default_expires_in' => '900s',
                                 'cache_depth' => '0'});
# Retrieve the session_id if there is still a session_cookie
# or if not create a cookie and redirect
my $session_id = $session->retrieve_session;
[...]
sub login {
# Wie gehabt. Nur muss der Login Status wie folgt gespeichert werden
# hier muss ich die set Funktion in jedem Fall noch überschreiben
$session->set($session_id, {"login" => "can_access"});
}
[...]
# Der Login Status wird wie folgt ausgelesen (zugleich wird die Zeit
# bis zum automatischen Logout durch die get_data Funktion hochgesetzt)
my $session_data = $session->get_data;
my $login = $session_data->{'login'} || undef;