Question

I have debugged this legacy code, and would like a sanity check on it.

The purpose of it is to allow someone to choose a delivery frequency for shipping a product. If someone wants their product Every Other Week, the system needs to determine if they should get an order next week, or two weeks from now. We call it A week, or B Week.

Keep in mind I did not write this, I am just trying to make sense of it and would like some help evaluating its accuracy:

if (date("l") == "Monday" ) {
            $start = 0;
        } else if (date("l") == "Tuesday" || date("l") == "Wednesday" || date("l") == "Thursday" || date("l") == "Friday" || date("l") == "Saturday"|| date("l") == "Sunday") {
        $start = -1;
    }

    // if changing to every other week set to next week's a/b-ness
    $a_week_tid = 34;
    $b_week_tid = 35;

    $every_other_week_frequency_id = 32;

    if ($delivery_frequency == $every_other_week_frequency_id) {
        $julian = (int) (strtotime('Monday +' . $start . ' week') / 86400);
        $julian_week = ($julian-4) / 7;
        if ($julian_week % 2) {
            $today_a_or_b = $b_week_tid;
            $next_week_a_or_b = $a_week_tid;
            $a_or_b_week_string = '(A Week)';
        } else {
            $today_a_or_b = $a_week_tid;
            $next_week_a_or_b = $b_week_tid;
            $a_or_b_week_string = '(B Week)';
        }
    } else {
        $next_week_a_or_b = NULL;
        $a_or_b_week_string = NULL;
    }

This code is not commented or documented. The part that confuses me is:

1. Why is 4 subtracted from Julian, then divided by 7?
2. If today is Monday, $julian_week is 2129, and 2129 % 2 evaluates TRUE. Is that correct?
3. Is this even how it should be done? Can’t I rewrite this using date(‘w’) a lot easier?

Answer 1

Yeah using date would totally be easier, plus it takes into account leap years, daylight saving time, all that extra stuff you don’t want to have to deal with.

if (date('W')%2==1)

That’s SOOOO much easier to maintain than the above.