Mepr Proration Tweaks

mepr_proration.php

<?php

add_filter('mepr-allow-multiple-upgrades-downgrades', function($allow, $user, $sub_in_group, $product) {
	return true;
}, 10, 4);

add_filter( 'mepr-proration', function ( $prorations, $old_amount, $new_amount, $old_period, $new_period, $old_days_left, $old_sub, $new_sub, $reset_period ) {
	//This only works for recurring to recurring upgrades during a prorate trial, 
	//so if that's not the case - just return the usual proration and skip all this.
	//NOTE: If the old sub had a trial that the proration was applied to - this won't work
	if ( isset( $old_sub ) && isset( $new_sub ) && $new_sub->is_upgrade() && $old_sub->prorated_trial && $old_sub->in_trial() ) {
		//We want to allow upgrade during proration period - so basically the only difference is that 
		//Instead of using the amount of the last trasaction - we need to the total of all previous transactions. 
		//My thinking: A - first subscription, B - first upgrade, C - this upgrade
		//The left over amount from A was applied when purchasing B, so the user did pay the full price of B
		//So if we use the full price for B when we upgrade C we *should* get the correct amount using the 
		//same math. 		
		$old_amount = $old_sub->price;
		$old_period = $old_sub->days_in_this_period(); //Resetting this just in case
		if ($old_days_left > $old_period) { //This is a fix to avoid weird prorations on if the upgrade on the same day.
			$old_days_left = $old_period;
		}
		
		// By default days left in the new sub are equal to the days left in the old
		$new_days_left = $old_days_left;

		if(is_numeric($old_period) && is_numeric($new_period) && $new_sub !== false && $old_amount > 0) {
		  // recurring to recurring
		  if($old_days_left > $new_period || $reset_period) {
			// What if the days left exceed the $new_period?
			// And the new outstanding amount is greater?
			// Days left should be reset to the new period
			$new_days_left = $new_period;
		  }

		  $old_per_day_amount = $old_amount / $old_period;
		  $new_per_day_amount = $new_amount / $new_period;

		  $old_outstanding_amount = $old_per_day_amount * $old_days_left;
		  $new_outstanding_amount = $new_per_day_amount * $new_days_left;

		  $proration = $new_outstanding_amount - $old_outstanding_amount;

		  $days = $new_days_left;
		  if($proration < 0) {
			$proration = 0;

			if($new_per_day_amount > 0 && $old_outstanding_amount > 0) {
			  $days = $old_outstanding_amount / $new_per_day_amount;
			}
			else {
			  $days = ($new_amount > 0 ? ((abs($proration)+$new_amount)/$new_amount)*$new_days_left : 0);
			}
		  }
		}
		elseif(is_numeric($old_period) && is_numeric($old_days_left) && ($new_period == 'lifetime' || $new_sub === false) && $old_amount > 0) {
		  // recurring to lifetime
		  // apply outstanding amount to lifetime purchase
		  // calculate amount of money left on old sub
		  $old_outstanding_amount = (($old_amount / $old_period) * $old_days_left);

		  $proration = max($new_amount - $old_outstanding_amount, 0.00);
		  $days = 0; // we just do this thing
		}
		elseif($old_period == 'lifetime' && is_numeric($new_period) && $old_amount > 0) {
		  // lifetime to recurring{
		  $proration = max($new_amount - $old_amount, 0.00);
		  $days = $new_period; //(is_numeric($old_days_left) && !$reset_period)?$old_days_left:$new_period;
		}
		elseif($old_period == 'lifetime' && $new_period == 'lifetime' && $old_amount > 0) {
		  // lifetime to lifetime
		  $proration = max(($new_amount - $old_amount), 0.00);
		  $days = 0; // We be lifetime brah
		}
		else {
		  // Default
		  $proration = 0;
		  $days = 0;
		}

		// Don't allow amounts that are less than a dollar but greater than zero
		$proration = (($proration > 0.00 && $proration < 1.00) ? 1.00 : $proration);
		$days = ceil($days);
		$proration = MeprUtils::format_float($proration);

		//Make sure we don't do more than 1 year on days
		if($days > 365) { $days = 365; }

		$prorations = (object)compact('proration', 'days');
	}
	
	return $prorations;
}, 10, 9 );