Revise update account form feature

[remcotolsma]

To update payment details for a subscription we currently have this in place:

wp-pronamic-pay-memberpress/src/Gateways/Gateway.php

Lines 878 to 929 in 4218e02

	/**
	* Display update account form.
	*
	* @link https://github.com/wp-premium/memberpress/blob/1.9.21/app/controllers/MeprAccountCtrl.php#L438
	* @param string $sub_id Subscription ID.
	* @param string[] $errors Array with errors.
	* @param string $message Update message.
	* @return void
	*/
	public function display_update_account_form( $sub_id, $errors = [], $message = '' ) {
	$subscriptions = \get_pronamic_subscriptions_by_source( 'memberpress_subscription', $sub_id );
	$subscription = \reset( $subscriptions );
	$message = \__( 'The payment method for this subscription can not be updated manually.', 'pronamic_ideal' );
	if ( false !== $subscription ) {
	// Set URL to mandate selection URL.
	$url = $subscription->get_mandate_selection_url();
	// Maybe set URL to subscription renewal,
	// to catch up with last failed payment.
	$renewal_period = $subscription->get_renewal_period();
	if ( SubscriptionStatus::ACTIVE !== $subscription->get_status() && null !== $renewal_period ) {
	$url = $subscription->get_renewal_url();
	}
	$message = \sprintf(
	/* translators: %s: mandate selection URL anchor */
	\__( 'To update the payment method for this subscription, please visit the %s page.', 'pronamic_ideal' ),
	\sprintf(
	'<a href="%1$s" title="%2$s">%3$s</a>',
	\esc_url( $url ),
	\esc_attr( \__( 'payment method update', 'pronamic_ideal' ) ),
	\esc_html( \__( 'payment method update', 'pronamic_ideal' ) )
	)
	);
	}
	?>
	<h3>
	<?php echo \esc_html( __( 'Update payment method', 'pronamic_ideal' ) ); ?>
	</h3>
	<div>
	<?php echo \wp_kses_post( $message ); ?>
	</div>
	<?php
	}

It uses the mandate selection feature from https://github.com/pronamic/wp-pay-core.

If a payment method is chosen on the mandate change page from core for which no MemberPress gateway is active, a strange situation arises.

wp-pronamic-pay-memberpress/src/Extension.php

Lines 253 to 281 in 4218e02

	/**
	* If the payment method is changed we have to update the MemberPress
	* subscription.
	*
	* @link https://github.com/wp-pay-extensions/memberpress/commit/3631bcb24f376fb637c1317e15f540cb1f9136f4#diff-6f62438f6bf291e85f644dbdbb14b2a71a9a7ed205b01ce44290ed85abe2aa07L259-L290
	*/
	$memberpress_gateways = MeprOptions::fetch()->payment_methods();
	foreach ( $memberpress_gateways as $memberpress_gateway ) {
	if ( ! $memberpress_gateway instanceof Gateway ) {
	continue;
	}
	if ( $memberpress_gateway->get_payment_method() === $payment->get_payment_method() ) {
	$memberpress_subscription->gateway = $memberpress_gateway->id;
	}
	}
	/**
	* Payment method.
	*
	* @link https://github.com/wp-premium/memberpress/blob/1.9.21/app/models/MeprTransaction.php#L634-L637
	* @link https://github.com/wp-premium/memberpress/blob/1.9.21/app/models/MeprOptions.php#L798-L811
	*/
	$memberpress_gateway = $memberpress_subscription->payment_method();
	if ( ! $memberpress_gateway instanceof Gateway ) {
	return;
	}

We may need to limit updating information to, for example, credit card information. Within MemberPress itself, the options for switching payment methods are limited:

Switch from PayPal to Stripe or Vice Versa

Sometimes a customer may have used PayPal or Stripe when they originally signed up, or they used Stripe and want to switch to PayPal.

If the customer is using PayPal and just wants to change the payment method, they can do this from within their PayPal account and do not need to switch to Stripe. But sometimes a customer will not want to update their PayPal account (or won't be able to access it anymore) in which case they would need to switch to Stripe.

In these scenarios, you would need to cancel their current membership and have them sign up again. You can have them wait until their current term ends (recommended), or if you want them to sign up again right away you will have to create a coupon for them to use to give them a prorated price.

https://memberpress.com/docs/how-to-change-a-customers-payment-method/

CC @rvdsteege