Woocommerce custom order status not triggering custom email - woocommerce

Question

I have a custom order status called Shipping Details which will be selected after the Order complete trigger is fired.
Code for the Order Status
function register_shipping_details_status() {
register_post_status( 'wc-shipping-details', array(
'label' => 'Send Shipping Details',
'public' => true,
'exclude_from_search' => false,
'show_in_admin_all_list' => true,
'show_in_admin_status_list' => true
//'label_count' => _n_noop( 'Shipping Details <span class="count">(%s)</span>', 'Shipping Details <span class="count">(%s)</span>' )
) );
}
add_action( 'init', 'register_shipping_details_status' );
// Add to list of WC Order statuses
function add_shipping_details_to_order_statuses( $order_statuses ) {
$new_order_statuses = array();
// add new order status after completed
foreach ( $order_statuses as $key => $status ) {
$new_order_statuses[ $key ] = $status;
if ( 'wc-completed' === $key ) {
$new_order_statuses['wc-shipping-details'] = 'Send Shipping Details';
}
}
return $new_order_statuses;
}
add_filter( 'wc_order_statuses', 'add_shipping_details_to_order_statuses' );
and my email trigger code is here.
if ( ! defined( 'ABSPATH' ) ) {
exit; // Exit if accessed directly
}
if ( ! class_exists( 'WC_Shipping_Details_Email' ) ) :
/**
* Customer Shipping Details Email
*/
class WC_Shipping_Details_Email extends WC_Email {
/**
* Constructor.
*/
public function __construct() {
$this->id = 'wc_shipping_details';
$this->customer_email = true;
$this->title = __( 'Shipping Details', 'woocommerce' );
$this->description = __( 'Shipping details emails are sent after the order has been marked completed .', 'woocommerce' );
$this->heading = __( 'Shipping Details for your order', 'woocommerce' );
$this->subject = __( 'Shipping details for your order from INAI', 'woocommerce' );
$this->template_html = 'emails/customer-shipping-details.php';
$this->template_plain = 'emails/plain/customer-shipping-details.php';
// Triggers for this email
add_action( 'woocommerce_order_status_shipping_details_notification', array( $this, 'trigger' ) );
// Call parent constuctor
parent::__construct();
}
/**
* Trigger.
*
* #param int $order_id
*/
public function trigger( $order_id ) {
if ( $order_id ) {
$this->object = wc_get_order( $order_id );
$this->recipient = $this->object->billing_email;
$this->find['order-date'] = '{order_date}';
$this->find['order-number'] = '{order_number}';
$this->replace['order-date'] = date_i18n( wc_date_format(), strtotime( $this->object->order_date ) );
$this->replace['order-number'] = $this->object->get_order_number();
}
if ( ! $this->is_enabled() || ! $this->get_recipient() ) {
return;
}
$this->send( $this->get_recipient(), $this->get_subject(), $this->get_content(), $this->get_headers(), $this->get_attachments() );
}
The action for registering the email
//custom hooks for custom woocommerce order email
function register_custom_order_status_action( $actions ){
$actions[] = 'woocommerce_order_status_shipping_details';
return $actions;
}
add_filter( 'woocommerce_email_actions', 'register_custom_order_status_action' );
For some reason the mail is not getting triggered. I have looked around a lot and even found a few others for whom the problem has been solved. WooCommerce - send custom email on custom order status change.
My code is almost exactly the same, still don't know what i'm missing. Please help.