Setting default booking status to pending confirmation

function.php

<?php

/**
 * Change default booking status to confirmed when order is placed.
 *
 * @param string $status Status of Booking.
 */
function bkap_booking_status_on_create_order( $status ) {
	return 'pending-confirmation';
}
add_filter( 'bkap_booking_status_on_create_order', 'bkap_booking_status_on_create_order', 10, 1 );

function bkap_booking_pending_to_confirmed( $order_id, $old_status, $new_status ) {

	if ( 'failed' !== $old_status && in_array( $new_status, array( 'processing' ), true ) ) {

		$order       = wc_get_order( $order_id );
		$order_items = $order->get_items();
		foreach ( $order_items as $item_key => $item_value ) {
			$booking_status = wc_get_order_item_meta( $item_key, '_wapbk_booking_status' );
			if ( isset( $booking_status ) && 'pending-confirmation' === $booking_status ) {
				$status = 'confirmed';
				wc_update_order_item_meta( $item_key, '_wapbk_booking_status', $status );
				$booking_id = bkap_common::get_booking_id( $item_key );
				if ( $booking_id ) {
					$new_booking = bkap_checkout::get_bkap_booking( $booking_id );
					$new_booking->update_status( $status );
					$product_id = $item_value->get_product_id();
					bkap_insert_event_to_gcal( $order, $product_id, $item_key );
				}
			}
		}
	}
}
add_action( 'woocommerce_order_status_changed', 'bkap_booking_pending_to_confirmed', 8, 3 );