Rewrite CPT permalinks (alt way #2)

<?php

/*
 * Plugin Name: Hersteller/Dienstleistungen permalinks
 * Plugin URI: http://maciejbis.net
 * Description: A plugin that adjusts the functionality of this website
 * Version: 1.0
 * Author: Maciej Bis
 * Author URI: http://www.maciejbis.net
 * License: GPL2
*/

/**
 * Detect CPT permalinks
 */
function bis_detect_cpt_permalinks( $query ) {
    global $wpdb, $pm_query, $wp, $wp_rewrite, $orte_term;

    // 1. Extract the slugs
    preg_match( '/datenrettung-([^\/]+)\/(([^\/]*)(-[^-\/]+)?)(?:\/|$)/Ui', $wp->request, $parts );

    if ( ! empty( $parts[2] ) ) {
        $term_slug     = basename( $parts[1] );
        $post_slug     = basename( $parts[2] );
        $post_slug_alt = basename( $parts[3] );

        // 2A. Get all posts that have exact or similar slug extracted from URL
        $sql_query = sprintf( 'SELECT ID FROM %1$s WHERE 1=1 AND (
                (post_type = "dienstleistung" AND (post_name = "%2$s" OR post_name LIKE "%2$s-%%")) OR
                (post_type = "hersteller" AND (post_name = "%3$s" OR post_name LIKE "%3$s-%%" OR post_name = "%2$s" OR post_name LIKE "%2$s-%%"))
        )', $wpdb->posts, esc_sql( $post_slug ), esc_sql( $post_slug_alt ) );
        $url_posts = $wpdb->get_col( $sql_query );

        // Example (can be removed later)
        if ( $post_slug == 'permalink-manager' ) {
            $post_id = (int) reset( $url_posts );
            $post    = get_post( $post_id );

            $orte_term = get_term_by( 'slug', $term_slug, 'orte' );
        } else {
            // 2B. Get all posts that are assigned to a "ort" term extracted from URL
            $sql_query = sprintf( 'SELECT object_id FROM %s AS tr LEFT JOIN %s AS t ON tr.term_taxonomy_id = t.term_id WHERE t.slug = "%s"', $wpdb->term_relationships, $wpdb->terms, esc_sql( $term_slug ) );
            $ort_posts = $wpdb->get_col( $sql_query );

            // 2C. Check what posts are in both arrays (there should be only one post)
            if ( ! empty( $url_posts ) && ! empty( $ort_posts ) ) {
                $found_posts = array_intersect( $url_posts, $ort_posts );

                if ( ! empty( $found_posts ) ) {
                    $post_id = (int) reset( $found_posts );
                    $post    = get_post( $post_id );
                }
            }
        }
    } // If no post was found, check if the URL is used by a post without "orte" term
    else if ( ! empty( $query['name'] ) ) {

        $sql_query = sprintf( 'SELECT ID, post_title FROM %1$s p WHERE post_type IN ( "dienstleistung", "hersteller" ) AND (post_name = "%2$s" OR post_name LIKE "%2$s-%%") AND post_status = "publish" AND ID NOT IN (SELECT object_id FROM %3$s tr INNER JOIN %4$s tt ON tr.term_taxonomy_id = tt.term_taxonomy_id AND tt.taxonomy = "orte")', $wpdb->posts, basename( $query['name'] ), $wpdb->term_relationships, $wpdb->term_taxonomy );
        $post_id   = $wpdb->get_var( $sql_query );

        if ( ! empty( $post_id ) ) {
            $post = get_post( $post_id );
        }
    }

    // 3. Set the query parameters
    if ( ! empty( $post->post_name ) ) {
        $new_query = array(
            'post_type'       => $post->post_type,
            $post->post_type  => $post->post_name,
            'name'            => $post->post_name,
            'do_not_redirect' => 1,
        );
    }

    // 4. Debug the query parameters
    if ( isset( $_GET['debug_bis_query'] ) ) {
        $new_query = ( ! empty( $new_query ) ) ? $new_query : $query;
        var_dump( $parts );

        echo ( ! empty( $parts ) ) ? sprintf( '<h2>URL Parts:</h2><pre>%s</pre>', print_r( $parts, true ) ) : '';
        echo ( ! empty( $sql_query ) ) ? sprintf( '<h2>SQL query:</h2><pre>%s</pre>', print_r( $sql_query, true ) ) : '';
        echo ( ! empty( $query ) ) ? sprintf( '<h2>Old query value:</h2><pre>%s</pre>', print_r( $query, true ) ) : '';
        echo ( ! empty( $new_query ) ) ? sprintf( '<h2>New query value Parts:</h2><pre>%s</pre>', print_r( $new_query, true ) ) : '';
        echo ( ! empty( $term_slug ) ) ? sprintf( '<h2>Detected "orte" slug:</h2><pre>%s</pre>', print_r( $term_slug, true ) ) : '';

        die();
    }

    // 5. Overwrite the query object & disable canonical redirect
    if ( ! empty( $new_query ) ) {
        remove_action( 'template_redirect', 'wp_old_slug_redirect' );
        remove_action( 'template_redirect', 'redirect_canonical' );
        add_filter( 'wpml_is_redirected', '__return_false', 99, 2 );
        add_filter( 'pll_check_canonical_url', '__return_false', 99, 2 );

        $query = $new_query;
    }

    return $query;
}

add_filter( 'request', 'bis_detect_cpt_permalinks', 9999 );

/**
 * Rewrite permalinks
 */
function bis_filter_cpt_permalinks( $permalink, $post, $leavename, $sample ) {
    if ( empty( $post->post_type ) || $post->post_status !== 'publish' ) {
        return $permalink;
    }

    if ( in_array( $post->post_type, array(
        'hersteller',
        'dienstleistung'
    ) ) ) {
        // Get the slug of assigned 'orte' term
        $o_terms       = wp_get_object_terms( $post->ID, 'orte' );
        $o_lowest_term = ( ! is_wp_error( $o_terms ) && ! empty( $o_terms ) && is_object( $o_terms[0] ) ) ? bis_get_lowest_element( $o_terms[0], $o_terms ) : "";
        $o_slug        = ( ! empty( $o_lowest_term->slug ) ) ? $o_lowest_term->slug : '';

        // A. Hersteller
        if ( $post->post_type == 'hersteller' ) {

            // Get the slug of assigned 'herstellerkategorie' term
            $h_terms       = wp_get_object_terms( $post->ID, 'herstellerkategorie' );
            $h_lowest_term = ( ! is_wp_error( $h_terms ) && ! empty( $h_terms ) && is_object( $h_terms[0] ) ) ? bis_get_lowest_element( $h_terms[0], $h_terms ) : "";
            $h_slug        = ( ! empty( $h_lowest_term->slug ) ) ? $h_lowest_term->slug : '';

            // If some specific 'herstellerkategorie' terms are assigned, the term slug should not be appended to the end of URL
            // Permalink format: datenrettung-%orte_flat%/%hersteller%
            if ( in_array( $h_slug, array( 'raid' ) ) && ! empty ( $o_slug ) ) {
                $new_permalink = sprintf( '%s/datenrettung-%s', trim( get_option( 'home' ), '/' ), $o_slug );
                $new_slug      = sanitize_title( $post->post_title );
            } // Permalink format: datenrettung-%orte_flat%/%hersteller%-%herstellerkategorie%
            else if ( ! empty( $o_slug ) && ! empty ( $h_slug ) ) {
                $new_permalink = sprintf( '%s/datenrettung-%s', trim( get_option( 'home' ), '/' ), $o_slug );
                $new_slug      = sprintf( '%s-%s', sanitize_title( $post->post_title ), $h_slug );
            } // Permalink format: %hersteller%-%herstellerkategorie%
            else {
                $new_permalink = trim( get_option( 'home' ), '/' );
                $new_slug      = sanitize_title( $post->post_title );
            }
        }

        // B. Dienstleistung
        if ( $post->post_type == 'dienstleistung' ) {
            // Permalink format: datenrettung-%orte_flat%/%dienstleistung%
            if ( ! empty( $o_slug ) ) {
                $new_permalink = sprintf( '%s/datenrettung-%s', trim( get_option( 'home' ), '/' ), $o_slug );
                $new_slug      = sanitize_title( $post->post_title );
            } // Permalink format: %dienstleistung%
            else {
                $new_permalink = trim( get_option( 'home' ), '/' );
                $new_slug      = sanitize_title( $post->post_title );
            }
        }

        if ( ! empty( $sample ) ) {
            $new_permalink .= "/%{$post->post_type}%";
        } else if ( empty( $leavename ) ) {
            $new_permalink .= "/{$new_slug}";
        }

        $permalink = user_trailingslashit( $new_permalink );
    }

    return $permalink;
}

add_filter( 'post_type_link', 'bis_filter_cpt_permalinks', 1000, 4 );

/**
 * Register [orte] shortcode
 */
function bis_orte_shortcode($atts, $content) {
    global $orte_term;

    $atts = shortcode_atts( array(
        'before'   => 'in',
        'after'    => 'in',
        'no-orte'  => ''
    ), $atts, 'orte' );

    if ( !empty( $orte_term->slug ) ) {
        $orte = $orte_term->name;
    }

    // If 'orte' was found, use it
    if(!empty($orte)) {
        $html = (!empty($atts['before'])) ? $atts['before'] : '';
        $html .= $orte;
        $html .= (!empty($atts['after'])) ? $atts['after'] : '';
    }
    // If no 'orte' was found, use alternative text (if set in shortcode)
    else if(!empty($atts['no-orte'])) {
        $html = $atts['no-orte'];
    } else {
        $html = '';
    }

    return $html;
}
add_shortcode( 'orte', 'bis_orte_shortcode' );

/**
 * Allow shortcodes in the titles
 */
add_filter( 'the_title', 'do_shortcode' );

/**
 * Get the lowest-level term
 */
function bis_get_lowest_element( $first_element, $elements ) {
    if ( ! empty( $elements ) && ! empty( $first_element ) ) {
        // Get the ID of first element
        if ( ! empty( $first_element->term_id ) ) {
            $first_element_id = $first_element->term_id;
            $parent_key       = 'parent';
        } else if ( ! empty( $first_element->ID ) ) {
            $first_element_id = $first_element->ID;
            $parent_key       = 'post_parent';
        } else if ( is_numeric( $first_element ) ) {
            $first_element_id = $first_element;
            $parent_key       = 'post_parent';
        } else {
            return false;
        }

        $children = wp_filter_object_list( $elements, array(
            $parent_key => $first_element_id
        ) );
        if ( ! empty( $children ) ) {
            // Get the first term
            $child_term    = reset( $children );
            $first_element = bis_get_lowest_element( $child_term, $elements );
        }
    }

    return $first_element;
}