package CentralOffice;

my %events;
my %names;
my $counter = 0;

sub subscribe {
    my $self = shift;
    my ($event, $callback, $name) = @_;
    $event = lc $event;
    $name ||= sprintf( "subscription_%04d", $counter++ );
    $name = lc $name;

    $events{$event} ||= {};

    # This is the subscribe step
    $events{$event}{$name} = $callback;

    return $name;
}

sub unsubscribe {
    my $self = shift;
    my ($event, $name) = @_;
    $event = lc $event;
    $name = lc $name;

    # This is the unsubscribe step
    return delete $events{$event}{$name};
}

sub publish {
    my $self = shift;
    my ($event, @args) = @_;

    return unless %{$events{$event}};

    # This is the publish step.
    $_->(@args) for values %{$events{$event}};

    return 1;
}