SEO Breadcrumbs Shortcode

<?php
if ( ! function_exists( 'scseed_breadcrumbs_shortcode_output' ) ) :
function scseed_breadcrumbs_shortcode_output( $atts ) {
    $atts = shortcode_atts(
        array(
            'separator' => ' &rsaquo; ',
            'home_text' => 'Home',
        ),
        $atts,
        'scseed_breadcrumbs'
    );
    $sep   = '<span class="scseed-bc-sep">' . esc_html( $atts['separator'] ) . '</span>';
    $parts = array();

    // Home crumb
    $parts[] = '<a href="' . esc_url( home_url( '/' ) ) . '">' . esc_html( $atts['home_text'] ) . '</a>';

    if ( is_singular() ) {
        $cats = get_the_category();
        if ( ! empty( $cats ) ) {
            $cat     = $cats[0];
            $parts[] = '<a href="' . esc_url( get_category_link( $cat->term_id ) ) . '">'
                       . esc_html( $cat->name ) . '</a>';
        }
        $parts[] = '<span class="scseed-bc-current">' . esc_html( get_the_title() ) . '</span>';
    } elseif ( is_category() ) {
        $parts[] = '<span class="scseed-bc-current">' . esc_html( single_cat_title( '', false ) ) . '</span>';
    } elseif ( is_tag() ) {
        $parts[] = '<span class="scseed-bc-current">' . esc_html( single_tag_title( '', false ) ) . '</span>';
    } elseif ( is_tax() ) {
        $term    = get_queried_object();
        $parts[] = '<span class="scseed-bc-current">' . esc_html( $term->name ) . '</span>';
    } elseif ( is_search() ) {
        $parts[] = '<span class="scseed-bc-current">Search: ' . esc_html( get_search_query() ) . '</span>';
    } elseif ( is_404() ) {
        $parts[] = '<span class="scseed-bc-current">Page Not Found</span>';
    }

    return '<nav class="scseed-breadcrumbs" aria-label="Breadcrumb">'
           . implode( $sep, $parts )
           . '</nav>';
}
add_shortcode( 'scseed_breadcrumbs', 'scseed_breadcrumbs_shortcode_output' );
endif;