An ID or a WP_Post object.
		 * @param  array        $taxonomies          An array of taxonomy names.
		 * @param  false        $skipUnselectedTerms Allow unselected terms to be filtered out from the crumbs.
		 * @return array                             An array of the taxonomy name + a term hierarchy.
		 */
		public function getPostTaxTermHierarchy( $post, $taxonomies = [], $skipUnselectedTerms = false ) {
			// Get all taxonomies attached to the post.
			if ( empty( $taxonomies ) ) {
				$taxonomies = get_object_taxonomies( get_post_type( $post ), 'objects' );
				$taxonomies = wp_filter_object_list( $taxonomies, [ 'public' => true ], 'and', 'name' );
			}

			foreach ( $taxonomies as $taxonomy ) {
				$primaryTerm = aioseo()->standalone->primaryTerm->getPrimaryTerm( $post->ID, $taxonomy );
				$terms       = wp_get_object_terms( $post->ID, $taxonomy );
				// Use the first taxonomy with terms.
				if ( empty( $terms ) || is_wp_error( $terms ) ) {
					continue;
				}

				// Determines the lengthier term hierarchy.
				$termHierarchy = [];
				foreach ( $terms as $term ) {
					// Gets our filtered ancestors.
					$ancestors = $this->getFilteredTermHierarchy( $term->term_id, $term->taxonomy, $skipUnselectedTerms ? $terms : [] );

					// Merge the current term to be used in the breadcrumbs.
					$ancestors = array_merge( $ancestors, [ $term->term_id ] );

					// If the current term is the primary term, use it.
					if ( is_a( $primaryTerm, 'WP_Term' ) && $primaryTerm->term_id === $term->term_id ) {
						$termHierarchy = $ancestors;
						break;
					}

					$termHierarchy = ( count( $termHierarchy ) < count( $ancestors ) ) ? $ancestors : $termHierarchy;
				}

				// Return a top to bottom hierarchy.
				return [
					'taxonomy' => $taxonomy,
					'terms'    => $termHierarchy
				];
			}

			return [];
		}

		/**
		 * Filters a term's parent hierarchy against other terms.
		 *
		 * @since 4.1.1
		 *
		 * @param  int    $termId               A term id.
		 * @param  string $taxonomy             The taxonomy name.
		 * @param  array  $termsToFilterAgainst Terms to filter out of the hierarchy.
		 * @return array                        The term's parent hierarchy.
		 */
		public function getFilteredTermHierarchy( $termId, $taxonomy, $termsToFilterAgainst = [] ) {
			$ancestors = $this->getTermHierarchy( $termId, $taxonomy );

			// Keep only selected terms in the hierarchy.
			if ( ! empty( $termsToFilterAgainst ) ) {
				// If it's a WP_Term array make it a term_id array.
				if ( is_a( current( $termsToFilterAgainst ), 'WP_Term' ) ) {
					$termsToFilterAgainst = wp_list_pluck( $termsToFilterAgainst, 'term_id' );
				}

				$ancestors = array_intersect( $ancestors, $termsToFilterAgainst );
			}

			return $ancestors;
		}

		/**
		 * Gets a term's parent hierarchy.
		 *
		 * @since 4.1.1
		 *
		 * @param  int    $termId   A term id.
		 * @param  string $taxonomy A taxonomy name.
		 * @return array            The term parent hierarchy.
		 */
		public function getTermHierarchy( $termId, $taxonomy ) {
			// Return a top to bottom hierarchy.
			return array_reverse( get_ancestors( $termId, $taxonomy, 'taxonomy' ) );
		}

		/**
		 * Gets a post's parent hierarchy.
		 *
		 * @since 4.1.1
		 *
		 * @param  int|\WP_Post $post An ID or a WP_Post object.
		 * @return array              The post parent hierarchy.
		 */
		public function getPostHierarchy( $post ) {
			$postId = ! empty( $post->ID ) ? $post->ID : $post;

			// Return a top to bottom hierarchy.
			return array_reverse( get_ancestors( $postId, '', 'post_type' ) );
		}

		/**
		 * Register our breadcrumb widget.
		 *
		 * @since 4.1.1
		 *
		 * @return void
		 */
		public function registerWidget() {
			if ( aioseo()->helpers->canRegisterLegacyWidget( 'aioseo-breadcrumb-widget' ) ) {
				register_widget( 'AIOSEO\Plugin\Common\Breadcrumbs\Widget' );
			}
		}
	}
}

namespace {
	// Exit if accessed directly.
	if ( ! defined( 'ABSPATH' ) ) {
		exit;
	}

	if ( ! function_exists( 'aioseo_breadcrumbs' ) ) {
		/**
		 * Global function for breadcrumbs output.
		 *
		 * @since 4.1.1
		 *
		 * @param  boolean     $echo Echo or return the output.
		 * @return string|void       The output.
		 */
		function aioseo_breadcrumbs( $echo = true ) {
			return aioseo()->breadcrumbs->frontend->display( $echo );
		}
	}
}