EO: newsletter

function mz_create_event_excerpt($post_id){

    global $post;
    global $wpdb;

    $id = $post_id;

  // GET EVENT INFORMATION
    $event = $wpdb->get_row( $wpdb->prepare('SELECT * FROM wp_eo_events WHERE post_id = %d', $post_id ) );

  if( $event ) {

    $startdate  = date('d.m.Y', strtotime($event->StartDate));
    $endate     = date('d.m.Y', strtotime($event->EndDate));
    $starttime  = date('G:i', strtotime($event->StartTime));
    $endtime    = date('G:i', strtotime($event->FinishTime));

    $result  = "<span style='text-transform: uppercase; font-weight:bold;'>". $starttime . "</span>";

  }

  // GET POST INFORMATION (TITLE, CONTENT, ETC.)
    $post = $wpdb->get_row( $wpdb->prepare('SELECT * FROM wp_posts WHERE ID = %d', $post_id ) );

  $post_content = strip_tags($post->post_content);

  if( $event )
    $result .= " - <span style='text-transform: uppercase; font-weight:bold;'>".$post->post_title . "</span> <br>" . "<span style='color: #444444;'>".$post_content."</span>";
  else
    $result = "<span style='text-transform: uppercase; font-weight:bold;'>".$post->post_title . "</span> <br>" . "<span style='color: #444444;'>".$post_content."</span>";

  // GET EVENT VENUE ID TERM
  $event_terms = get_the_terms( $post_id, 'event-venue' );

  if( $event_terms ) {

    foreach ($event_terms as $term) {
      $venue_id = $term->term_id;
    }

    // GET EVENT VENUE ADDRESS INFO
    $address_details = eo_get_venue_address($venue_id);
    $result .= "<br><span style='color: #444444;'><b>ADRESA:</b> ".$address_details["city"].", ".$address_details["address"]." </span>";
  }

  // GET EVENT VENUE ID TERM
  $zdroj_terms = get_the_terms( $post_id, 'zdroj' );

  if( $zdroj_terms ) {

    foreach ($zdroj_terms as $zdroj_item) {
      $zdroj = $zdroj_item->description;
    }
    $result .= "<br><span style='color: #444444;'><b>ZDROJ:</b> ".$zdroj."</span>";
  }

    if ( ! wp_is_post_revision( $post_id ) ){

        // unhook this function so it doesn't loop infinitely
        remove_action('save_post', 'mz_create_event_excerpt', 999);

        // update the post, which calls save_post again
        wp_update_post(array('ID' => $post_id, 'post_excerpt' => $result));

        // re-hook this function
        add_action('save_post', 'mz_create_event_excerpt', 999);
    }
}
add_action('save_post', 'mz_create_event_excerpt', 999);