Ready-Made Order Note Templates

$wpide_note_templates = array(
    'Dispatched today. Tracking details will follow by email.',
    'Waiting for stock from our supplier; expected within 5 working days.',
    'Customer contacted by phone about delivery.',
    'Address checked and confirmed with the customer.',
);

add_action( 'admin_footer', function () use ( $wpide_note_templates ) {
    $screen = get_current_screen();

    if ( ! $screen || ! function_exists( 'wc_get_page_screen_id' ) || wc_get_page_screen_id( 'shop-order' ) !== $screen->id ) {
        return;
    }
    ?>
    <script>
    ( function () {
        var box = document.getElementById( 'add_order_note' );
        if ( ! box ) { return; }
        var templates = <?php echo wp_json_encode( array_values( $wpide_note_templates ) ); ?>;
        var select = document.createElement( 'select' );
        select.setAttribute( 'aria-label', 'Insert a note template' );
        select.style.width = '100%';
        select.style.marginBottom = '6px';
        select.add( new Option( 'Insert a note template…', '' ) );
        templates.forEach( function ( text ) { select.add( new Option( text, text ) ); } );
        select.addEventListener( 'change', function () {
            if ( select.value ) { box.value = select.value; box.focus(); select.selectedIndex = 0; }
        } );
        box.parentNode.insertBefore( select, box );
    } )();
    </script>
    <?php
} );