renewal-reminders.php

<?php
/**
 * Plugin Name: Renewal Reminder
 * Plugin URI: http://www.sethetter.com
 * Description: Sends email reminders for members to renew memberships 30 days in advanced and when it has expired.
 * Version: 0.0.0
 * Author: Seth Etter
 * Author URI: http://www.sethetter.com
 * License: GPL2
 */

register_activation_hook(__FILE__, 'rr_activate_reminders');
register_deactivation_hook(__FILE__, 'rr_deactivate_reminders');

add_action('check_for_renewal_reminders', 'rr_perform_renewal_reminder_check');
add_action('plugins_loaded', 'rr_perform_renewal_reminder_check');

/**
 * Function that checks for email reminders to be sent
 */
function rr_perform_renewal_reminder_check() {

  $users = get_users('orderby=username');

  foreach ($users as $user) {
    // get user name, email and EOT date

    $email = $user->user_email;
    $headers = 'From: [email protected]';
    $renewal_timestamp = get_user_meta($user->ID, 'wpag_s2member_auto_eot_time', true);

    if (!$renewal_timestamp) continue;

    $now_timestamp = time();
    $days_to_expiration = floor(($now_timestamp - $renewal_timestamp) / (60 * 60 * 24));

    if ($days_to_expiration == -30) {
      // If 30 days from renewal date, send 30 days reminder email
      $subject = 'Your membership expires in 30 days!';
      $message = 'Just so you know, your G.A.N.G. membership expires in 30 days. You might want to renew it soon!';

      wp_mail($email, $subject, $message, $headers);
    }

    if ($days_to_expiration == 0) {
      // If on renewal date, send membership expired email
      $subject = 'Your membership has expired!';
      $message = 'Your G.A.N.G. membership has expired! You will need to renew to gain access to member features.';

      wp_mail($email, $subject, $message, $headers);
    }
    
  }

}

function rr_activate_reminders() {
  wp_schedule_event(time(), 'daily', 'check_for_renewal_reminders');
}

function rr_deactivate_reminders() {
  wp_clear_scheduled_hook('check_for_renewal_reminders');
}