Email Inactive Users

email_inactive_users.php

add_action( 'init', 'register_daily_email_inactive_members_email');
 
// Function which will register the event
function register_daily_email_inactive_members_email()
{
	// Make sure this event hasn't been scheduled
	if( !wp_next_scheduled( 'email_inactive_members' ) ) {
		// Schedule the event
		wp_schedule_event( time(), 'daily', 'email_inactive_members' );
	}
}

add_action('email_inactive_members', 'my_email_inactive_members');

function my_email_inactive_members()
{
	//get the inactive members
	
	$max_inactive_time = 30*24*60*60; //30 days in seconds
	//$max_inactive_time = 3600; //one hour for testing purposes
	
	$args = array(
	'meta_query' => array(
		'relation' => 'AND',
		array(
			'key'     => 'last_login',
			'value'   =>  current_time('timestamp') - $max_inactive_time,
			'compare' => '<'
		),
		array(
			'key'     => 'last_login_reminder_sent',
			'value'   => 1,
			'compare' => '<'
		),
	));

	
	$inactive_user_query = new WP_User_Query($args);
	$inactive_members = $inactive_user_query->get_results();

	foreach($inactive_members as $inactive_member)
	{
		wp_mail($inactive_member->data->user_email, "Come back!", "Please come back and visit us! ");
		
		//make sure we don't keep sending them emails!
		update_user_meta($inactive_member->ID, 'last_login_reminder_sent', 1);
	}
}

//associating a function to login hook
add_action('wp_login', 'set_last_login');

//function for setting the last login
function set_last_login($login)
{
	$user = get_user_by('login', $login);

	//add or update the last login value for logged in user
	update_user_meta( $user->ID, 'last_login', current_time('timestamp'));
	
	//if they login, reset the reminder
	update_user_meta($user->ID, 'last_login_reminder_sent', 0);
}