Woocommerce Subscriptions update next payment date from functions.php - function

Question

I would like to change the next payment date of active subscriptions after the Initial (first) Subscription payment is completed after the trial period.
<?php global $woocommerce;
$all_meta_for_user = get_user_meta( 53 );
$order = new WC_Order(4843);
$order_id=4846;//PUT YOUR ORDER ID HERE
$subscription = wcs_get_subscription( 4846 );
add_action('woocommerce_subscription_payment_complete', 'nextpaymentdatechange', 10, 1);
function nextpaymentdatechange($order_id){
if (WC_Subscriptions_Order::order_contains_subscription($order_id)) {
$nextdate = get_post_meta( $order_id, '_schedule_next_payment', true );
$threedays_ago = date('Y-m-d H:i:s', strtotime('-15 days', strtotime($nextdate)));
update_post_meta($order_id , '_schedule_next_payment', $threedays_ago);
}
} ?>

Answer 1

I got a solution for the subscription-related question which posted. It may help others.
function pro_subscription($subscription){
$sid = $subscription->id;
$uid = $subscription->customer_user;
$subscription = wcs_get_subscription( $sid );
$items = $subscription->get_items();
foreach ( $items as $item ) {
$product_id = $item->get_product_id();
$order_id = $subscription->get_parent_id();
}
$subscription_key = WC_Subscriptions_Manager::get_subscription_key( $order_id, $product_id);
$td = new DateTime($subscription->get_date( 'trial_end_date' ));
$try_date = $td->format('Y-m-d');
$sd = new DateTime($subscription->get_date( 'next_payment_date' ));
$pay_date = $sd->format('Y-m-d');
$sdt = new DateTime($subscription->get_date( 'start_date' ));
$sst = $sd->format('Y-m-d H:i:s');
$tst = $td->format('Y-m-d H:i:s');
$date1=date_create($tst);
$date2=date_create($sst);
$diff=date_diff($date1,$date2);
$df = 30 - $diff->format("%a");
$next_pay = date('Y-m-d H:i:s', strtotime($ts. ' + ' . $df . ' days'));
if($try_date == $pay_date){
WC_Subscriptions_Manager::set_next_payment_date( $subscription_key, $uid, $next_pay );
}
}