Send alert when new tag beta

function send_alert_when_new_tag( $data, $postarr ) {
    global $post_id;
    $post_title   = get_the_title( $post_id ); // retrive the post tile
    $post_url     = get_permalink( $post_id ); // retrive the post url
    $author       = get_post( $post_id );      // gets author from post
    $author_id    = $author->post_author;      // gets author id for the post
    $author_name  = get_the_author_meta( 'display_name', $author_id ); // retrive display name
    $current_user = wp_get_current_user();     // retrive current user
    $tag_url      = get_bloginfo( 'url' ).'/wp-admin/edit-tags.php?taxonomy=article_tags&post_type=article'; // tag url
    $subject      = 'Alerta de tag creado por: '.$current_user->display_name;

    $taxonomy_array = array( 'post_tag', 'article_tags', 'special_edition_tag', 'topic_tags' );

    $args = array(
        'hide_empty' => 0
    );

    $global_tags       = get_terms( $taxonomy_array, $args );
    $global_tags_array = array();

    foreach ( $global_tags as $value ) {
        array_push( $global_tags_array, $value->slug );
    }

    //$term = get_the_terms( $post_id, 'article_tags' );
    //$term = wp_get_post_terms( $post_id, 'article_tags', array( "fields" => "all" ) );
    $term   = wp_get_object_terms( $post_id, 'article_tags' );
    $term_array = array();

    if( $term ) {
        foreach ( $term as $value ) {
            /*if ( !in_array( $value->slug , $global_tags_array) ) {
                array_push( $term_array, $value->slug );
            }*/
            if ( !has_term( $value->slug, 'article_tags' ) ){
                array_push( $term_array, $value->slug );
            }
        }
    }

    // if tag exists
    //if( !empty( $term_array ) ) {

        $tags = implode(",", $term_array);
        //$tags = implode(",", $postarr['tags_input'] );

        $message      = 'Tag creado:'. $tags ."\n\n";
        $message     .= 'Título del artículo: '.$post_title."\n\n";
        $message     .= 'Usuario: '.$current_user->display_name."\n\n";
        $message     .= 'Author: '.$author_name."\n\n";
        $message     .= 'Url del artículo: '.$post_url."\n\n";
        $message     .= 'Url de tags: ' . $tag_url;

        // Send test email
        //wp_mail( '[email protected]', $subject, $message );
    //}

    return $data;
}

add_filter( 'wp_insert_post_data', 'send_alert_when_new_tag', '99', 2 );
//add_action( 'save_post', 'send_alert_when_new_tag' );