I need to rotate 3 options based on the current week number; ie:
if($weekNumber == 42 || $weekNumber == 43){
$thisID = 1;
}
else if($weekNumber == 44 || $weekNumber == 45){
$thisID = 3;
}
else if($weekNumber == 46 || $weekNumber == 47){
$thisID = 2;
}
else if($weekNumber == 48 || $weekNumber == 49){
$thisID = 1;
}
I'd obviously prefer this to be less manual! I've considered placing the 3 ID's in an array and selecting based on the number of weeks that have passed since date X but I'm not sure how to implement that.
And additionally... the rollover needs to be at Midday on a Friday. I considered simply incrementing the week number in the above plan too, with additional adjustments for when we're rolling from week 52 to week 1, but there must be a more sensible approach!
Thanks
Why don't you take the rounded half of the week number? Then you only need a catalog holding 26 IDs and you can implement a direct lookup:
$catalog=[1,2,3,4,5,6,3,4,2,5,6,7,4,4,7,9,5,8,8,9,2,4,5,7,6,8,9];
$thisID = $catalog[floor($weekNumber/2)];
This should work:
$options = array(1,2,3);
$offset = 129600;
$twoWeeks = 1209600;
$idx = floor((time()-$offset)/$twoWeeks) % count($options);
$chosenOption = $options[$idx];
Some explanation:
time()-$offset we shift the time to set Friday at midday as the zero point of our time calculation.