Add Invoice ID, Date, Total, and URL email variables to PMPro emails if they have a membership ID.

add-invoice-email-variables.php

<?php
/**
 * Add invoice_id, invoice_date, and invoice_total to PMPro email data.
 *
 * You can add this recipe to your site by creating a custom plugin
 * or using the Code Snippets plugin available for free in the WordPress repository.
 * Read this companion article for step-by-step directions on either method.
 * https://www.paidmembershipspro.com/create-a-plugin-for-pmpro-customizations/
 */
function my_pmpro_add_invoice_email_variables( $data, $email ) {

	// Let's only do this if required.
	if ( ( isset( $data['invoice_id'] ) && isset( $data['invoice_date'] ) && isset( $data['invoice_total'] ) && isset( $data['invoice_url'] ) ) || ! isset( $data['membership_id'] ) || empty( $data['membership_id'] ) ) {
		return $data;
	}

	// Get the user.
	$user = get_user_by( 'email', $email->email );

	// Get the membership level.
	$membership_level = $data['membership_id'];

	// Get last order for level.
	$invoice = new MemberOrder();
	$invoice->getLastMemberOrder( $user->ID, 'success', $membership_level );

	// Add invoice_id, invoice_date, and invoice_total to email data
	$data['invoice_id']    = $invoice->code;
	$data['invoice_date']  = date_i18n( get_option( 'date_format' ), $invoice->timestamp );
	$data['invoice_total'] = pmpro_formatPrice( $invoice->total );
	$data['invoice_url']   = pmpro_login_url( pmpro_url( 'invoice', '?invoice=' . $invoice->code ) );

	return $data;
}
add_filter( 'pmpro_email_data', 'my_pmpro_add_invoice_email_variables', 10, 2 );