#!perl

my $cost = 2.50;

sub command :Tab(lasercutter) ($self, $cart, $command, @) {
    $command eq 'lasercutter' or return NEXT;

    return "How long did you use the machine? (h:mm)", \&time
}

sub time ($self, $cart, $time, @) {
    my ($h, $m) = $time =~ /^\s*([0-9]*)(?:[:.]([0-9]+))?\s*$/;

    $h ||= 0;
    $m ||= 0;

    $h or $m or return REJECT, "Invalid time.";

    print "Note: rounding up to next multiple of 0:15.\n" if $m % 15;
    my $q = $h * 4 + int($m / 15) + ($m % 15 ? 1 : 0);

    # reformat rounded time
    $time = int($q / 4) . ":" . sprintf("%02d", ($q % 4) * 15);

    $cart
        ->add(-$q * $cost, "Lasercutter usage ($time)")
        ->add_contra("+sales/lasercutter", $q * $cost, "\$you used lasercutter ($time)");

    return ACCEPT;
}