Redirect to Invoice After Estimate Approval

functions.php

<?php // don't include this line since your functions.php file should already have this.

function si_redirect_after_estimate_approval() {
	if ( 'estimate' !== si_get_doc_context() ) {
			return;
	}
	?>
		<script type="text/javascript">
			jQuery(document).on('status_updated', function(e) {
				window.location = window.location.pathname + '?redirect_after_status=1';
			});
		</script>
	<?php
}
add_action( 'si_footer', 'si_redirect_after_estimate_approval' );


function si_maybe_redirect_after_estimate_approval() {
	if ( 'estimate' !== si_get_doc_context() ) {
		return;
	}
	if ( ! isset( $_GET['redirect_after_status'] ) && $_GET['redirect_after_status'] ) {
		return;
	}
	$estimate = si_get_doc_object();
	$status = $estimate->get_status();
	// Check if approved
	if ( SI_Estimate::STATUS_APPROVED !== $status ) {
		return;
	}
	$invoice_id = $estimate->get_invoice_id();
	if ( ! $invoice_id ) {
		return;
	}
	wp_redirect( get_permalink( $invoice_id ) );
	exit();
}
add_action( 'pre_si_estimate_view', 'si_maybe_redirect_after_estimate_approval' );

If we initially create an Estimate and send it then do we create an invoice to be lying in wait for the client to approve the estimate for this to work?