Registration using ajax in pay per view

There is custom login function in pay per view using ajax

add_action('wp_ajax_nopriv_ppw_ajax_login', array($this, 'ajax_login'));

function ajax_login( ) {

header("Content-type: application/json");
$user = wp_signon( );

if ( !is_wp_error($user) ) {
$reveal = 0;
if ( get_user_meta( $user->ID, "ppw_subscribe", true) != '' OR $this->is_authorised() )
$reveal = 1;

die(json_encode(array(
"status" => 1,
"user_id"=>$user->ID,
"reveal"=>$reveal
)));
}
die(json_encode(array(
"status" => 0,
"error" => $user->get_error_message()
)));
}

How can I create Registration function in same manner similarly using ajax