Send extra expiration warning emails with individual templates when using PMPro and the Extra Expiration Warning Emails add on.

my_add_extra_expiration_warning_templates.php

<?php
/**
 * Send extra expiration warning emails with individual templates.
 * Make sure the Extra Expiration Warning Emails Add On is also active.
 * https://www.paidmembershipspro.com/add-ons/extra-expiration-warning-emails-add-on/
 *
 * Then add this code into a custom plugin or code snippet.
 * https://www.paidmembershipspro.com/how-to-add-code-to-wordpress/ 
 */
// Tell the expiration warnings add on to use our templates.
function my_custom_pmproeewe_email_frequency_and_templates( $settings ) {
	$settings = array(
		10 => 'membership_expiring_1',
		20 => 'membership_expiring_2',
		60 => 'membership_expiring_3',
	);
	return $settings;
}
add_filter( 'pmproeewe_email_frequency_and_templates', 'my_custom_pmproeewe_email_frequency_and_templates', 10, 1 );

// Remove the hard-coded email subject so that the custom subject above is used.
function my_remove_pmproewee_email_subject( $translated_text, $text, $domain ) {
    if ( $domain === 'pmpro-extra-expiration-warning-emails' && $text === 'Your membership at %s will end soon' ) {
        return '';
    }

    return $translated_text;
}
add_filter( 'gettext', 'my_remove_pmproewee_email_subject', 10, 3 );

// Add the templates.
function my_add_extra_expiration_warning_templates( $templates ) {
	$templates['membership_expiring_1'] = array(
		'subject'     => "One Your membership at !!sitename!! will end soon.",
		'description' => "Membership Expiring 1",
		'body'		  => '<p>Replace This</p>',
		'help_text'   => "The first email sent members when their expiration date is approaching."
	);
	$templates['membership_expiring_2'] = array(
		'subject'     => "Two Your membership at !!sitename!! will end soon.",
		'description' => "Membership Expiring 2",
		'body'		  => '<p>Replace This</p>',
		'help_text'   => "The second email sent members when their expiration date is approaching."
	);
	$templates['membership_expiring_3'] = array(
		'subject'     => "Three Your membership at !!sitename!! will end soon.",
		'description' => "Membership Expiring 3",
		'body'		  => '<p>Replace This</p>',
		'help_text'   => "The third email sent members when their expiration date is approaching."
	);
	
	return $templates;
}
add_filter( 'pmproet_templates', 'my_add_extra_expiration_warning_templates' );