Track appointment bookings with Google Tag for Google analytics

functions.php

<?php 

function my_wappo_analytics_appointment_confirmed()
{

  echo '<script async src="https://www.googletagmanager.com/gtag/js?id=GA_MEASUREMENT_ID"></script>';
  echo "<script>
    window.dataLayer = window.dataLayer || [];
    function gtag(){window.dataLayer.push(arguments);}
    gtag('js', new Date());

    gtag('config', 'GA_MEASUREMENT_ID');
  </script>";
  
  echo '<script>';
  echo "document.addEventListener('wappo_confirmed', function (e) {
              
              gtag('event', 'wappointment', {'status': 'confirmed'});

        }, false);";
  echo '</script>';
}
add_action('wp_print_footer_scripts', 'my_wappo_analytics_appointment_confirmed');