Custom WordPress Breadcrumbs

class.WP_Breadcrumbs.php

<?php

class PW_Breadcrumbs {

    // Declare variables
    private $home_link;
    private $home_text;
    private $link_before;
    private $link_after;
    private $link_attr;
    private $link;
    private $delimiter;
    private $before;
    private $after;
    private $page_addon;
    private $breadcrumb_trail;
    private $category_links;

    function __construct()
    {
        // Set variables
        $this->home_link        = site_url('/');
        $this->home_text        = __( 'Home' );
        $this->link_before      = '<li itemprop="itemListElement" itemscope itemtype="http://schema.org/ListItem">';
        $this->link_after       = '</li>';
        $this->link_attr        = ' itemscope itemtype="http://schema.org/Thing"
       itemprop="item"';
        $this->link             = $this->link_before . '<a' . $this->link_attr . ' href="%1$s"><span itemprop="name">%2$s</span></a>' . $this->link_after;
        $this->delimiter        = ' <li class="divider">&gt;</li> '; // Delimiter between crumbs
        $this->before           = '<li class="current" itemprop="itemListElement" itemscope
      itemtype="http://schema.org/ListItem"><span itemscope itemtype="http://schema.org/Thing"
       itemprop="item"><span itemprop="name">'; // Tag before the current crumb
        $this->after            = '</span></span></li>'; // Tag after the current crumb
        $this->page_addon       = ''; // Adds the page number if the query is paged
        $this->breadcrumb_trail = '';
        $this->category_links   = '';
    } // __construct()

    public function generate()
    {
        /**
         * Set our own $wp_the_query variable. Do not use the global variable version due to
         * reliability
         */
        $wp_the_query   = $GLOBALS['wp_the_query'];
        $queried_object = $wp_the_query->get_queried_object();

        // Handle single post requests which includes single pages, posts and attatchments
        if ( is_singular() )
        {
            /**
             * Set our own $post variable. Do not use the global variable version due to
             * reliability. We will set $post_object variable to $GLOBALS['wp_the_query']
             */
            $post_object = sanitize_post( $queried_object );

            // Set variables
            $title          = apply_filters( 'the_title', $post_object->post_title );
            $parent         = $post_object->post_parent;
            $post_type      = $post_object->post_type;
            $post_id        = $post_object->ID;
            $post_link      = $this->before . $title . $this->after;
            $parent_string  = '';
            $post_type_link = '';

            if ( 'post' === $post_type )
            {
                // Get the post categories
                $categories = get_the_category( $post_id );
                if ( $categories ) {
                    // Lets grab the first category
                    $category  = $categories[0];

                    $this->category_links = get_category_parents( $category, true, $this->delimiter );
                    $this->category_links = str_replace( '<a',   $this->link_before . '<a' . $this->link_attr, $this->category_links );
                    $this->category_links = str_replace( '</a>', '</a>' . $this->link_after, $this->category_links );
                }
            }

            if ( !in_array( $post_type, ['post', 'page', 'attachment'] ) )
            {
                $post_type_object = get_post_type_object( $post_type );
                $archive_link     = esc_url( get_post_type_archive_link( $post_type ) );

                $post_type_link   = sprintf( $this->link, $archive_link, $post_type_object->labels->singular_name );
            }

            // Get post parents if $parent !== 0
            if ( 0 !== $parent )
            {
                $parent_links = [];
                while ( $parent ) {
                    $post_parent = get_post( $parent );

                    $parent_links[] = sprintf( $this->link, esc_url( get_permalink( $post_parent->ID ) ), get_the_title( $post_parent->ID ) );

                    $parent = $post_parent->post_parent;
                }

                $parent_links = array_reverse( $parent_links );

                $parent_string = implode( $this->delimiter, $parent_links );
            }

            // Lets build the breadcrumb trail
            if ( $parent_string ) {
                $this->breadcrumb_trail = $parent_string . $this->delimiter . $post_link;
            } else {
                $this->breadcrumb_trail = $post_link;
            }

            if ( $post_type_link )
                $this->breadcrumb_trail = $post_type_link . $this->delimiter . $this->breadcrumb_trail;

            if ( $this->category_links )
                $this->breadcrumb_trail = $this->category_links . $this->breadcrumb_trail;
        }

        // Handle archives which includes category-, tag-, taxonomy-, date-, custom post type archives and author archives
        if( is_archive() )
        {
            if (    is_category()
                 || is_tag()
                 || is_tax()
            ) {
                // Set the variables for this section
                $term_object        = get_term( $queried_object );
                $taxonomy           = $term_object->taxonomy;
                $term_id            = $term_object->term_id;
                $term_name          = $term_object->name;
                $term_parent        = $term_object->parent;
                $taxonomy_object    = get_taxonomy( $taxonomy );
                $current_term_link  = $this->before . $taxonomy_object->labels->singular_name . ': ' . $term_name . $this->after;
                $parent_term_string = '';

                if ( 0 !== $term_parent )
                {
                    // Get all the current term ancestors
                    $parent_term_links = [];
                    while ( $term_parent ) {
                        $term = get_term( $term_parent, $taxonomy );

                        $parent_term_links[] = sprintf( $this->link, esc_url( get_term_link( $term ) ), $term->name );

                        $term_parent = $term->parent;
                    }

                    $parent_term_links  = array_reverse( $parent_term_links );
                    $parent_term_string = implode( $this->delimiter, $parent_term_links );
                }

                if ( $parent_term_string ) {
                    $this->breadcrumb_trail = $parent_term_string . $this->delimiter . $current_term_link;
                } else {
                    $this->breadcrumb_trail = $current_term_link;
                }

            } elseif ( is_author() ) {

                $this->breadcrumb_trail = __( 'Author archive for ') .  $this->before . $queried_object->data->display_name . $this->after;

            } elseif ( is_date() ) {
                // Set default variables
                $year     = $wp_the_query->query_vars['year'];
                $monthnum = $wp_the_query->query_vars['monthnum'];
                $day      = $wp_the_query->query_vars['day'];

                // Get the month name if $monthnum has a value
                if ( $monthnum ) {
                    $date_time  = DateTime::createFromFormat( '!m', $monthnum );
                    $month_name = $date_time->format( 'F' );
                }

                if ( is_year() ) {

                    $this->breadcrumb_trail = $this->before . $year . $this->after;

                } elseif( is_month() ) {

                    $year_link        = sprintf( $this->link, esc_url( get_year_link( $year ) ), $year );

                    $this->breadcrumb_trail = $year_link . $this->delimiter . $this->before . $month_name . $this->after;

                } elseif( is_day() ) {

                    $year_link        = sprintf( $this->link, esc_url( get_year_link( $year ) ),             $year       );
                    $month_link       = sprintf( $this->link, esc_url( get_month_link( $year, $monthnum ) ), $month_name );

                    $this->breadcrumb_trail = $year_link . $this->delimiter . $month_link . $this->delimiter . $this->before . $day . $this->after;
                }

            } elseif ( is_post_type_archive() ) {

                $post_type        = $wp_the_query->query_vars['post_type'];
                $post_type_object = get_post_type_object( $post_type );

                $this->breadcrumb_trail = $this->before . $post_type_object->labels->singular_name . $this->after;

            }
        }

        // Handle the search page
        if ( is_search() ) {
            $this->breadcrumb_trail = __( 'Search query for: ' ) . $this->before . get_search_query() . $this->after;
        }

        // Handle 404's
        if ( is_404() ) {
            $this->breadcrumb_trail = $this->before . __( 'Error 404' ) . $this->after;
        }

        // Handle paged pages
        if ( is_paged() ) {
            $current_page = get_query_var( 'paged' ) ? get_query_var( 'paged' ) : get_query_var( 'page' );
            $this->page_addon   = $this->before . sprintf( __( ' ( Page %s )' ), number_format_i18n( $current_page ) ) . $this->after;
        }

        $breadcrumb_output_link  = '';
        $breadcrumb_output_link .= '<ol class="awc-breadcrumbs" itemscope itemtype="http://schema.org/BreadcrumbList">';
        if ( is_home() || is_front_page()
        ) {
            // Do not show breadcrumbs on page one of home and frontpage
            if ( is_paged() || is_home() ) {
                $breadcrumb_output_link .= '<li itemprop="itemListElement" itemscope
      itemtype="http://schema.org/ListItem"><a href="' . $this->home_link . '" itemscope itemtype="http://schema.org/Thing"
       itemprop="item"><span itemprop="name">' . $this->home_text . '</span></a></li>';
                $breadcrumb_output_link .= $this->delimiter;

                if ( is_paged() ) {
                    $breadcrumb_output_link .= '<li itemprop="itemListElement" itemscope
      itemtype="http://schema.org/ListItem"><a href="' . site_url('/news/') . '" itemscope itemtype="http://schema.org/Thing"
       itemprop="item"><span itemprop="name">News</span></a></li>';
                    $breadcrumb_output_link .= $this->page_addon;
                } else {
                    $breadcrumb_output_link .= '<li class="current" itemprop="itemListElement" itemscope
      itemtype="http://schema.org/ListItem"><span itemscope itemtype="http://schema.org/Thing"
       itemprop="item"><span itemprop="name">News</span></span></li>';
                }
            }
        } else {
            $breadcrumb_output_link .= '<li itemprop="itemListElement" itemscope
      itemtype="http://schema.org/ListItem"><a href="' . $this->home_link . '" itemscope itemtype="http://schema.org/Thing"
       itemprop="item"><span itemprop="name">' . $this->home_text . '</span></a></li>';
            $breadcrumb_output_link .= $this->delimiter;
            $breadcrumb_output_link .= $this->breadcrumb_trail;
            $breadcrumb_output_link .= $this->page_addon;
        }
        $breadcrumb_output_link .= '</ol><!-- .breadcrumbs -->';

        return $breadcrumb_output_link;
    }

} // end PW_Breadcrumbs