Umbra-Bookshelf/theme/inc/nav-menu.php

<?php
// Copyright 2026 Umbra Tools (umbratools.com)
// SPDX-License-Identifier: GPL-2.0-or-later

/**
 * Navigation Menu Hooks
 *
 * @package BD_Murphy
 */

if (!defined('ABSPATH')) {
    exit;
}

/**
 * Filter nav menu items to add dynamic submenus
 *
 * @param string $items Menu items HTML.
 * @param stdClass $args Menu arguments.
 * @return string
 */
function bdm_filter_nav_menu_items($items, $args) {
    if ($args->theme_location !== 'primary') {
        return $items;
    }

    // Get books for MyBooks submenu
    $books = bdm_get_books_for_menu();
    if (!empty($books)) {
        $books_submenu = bdm_build_book_submenu($books);
        
        // Find or create MyBooks menu item
        if (preg_match('/(<li[^>]*>.*?My\s*Books.*?<\/li>)/s', $items, $matches)) {
            $mybooks_item = $matches[1];
            // Add submenu class to the li
            $mybooks_item_with_sub = preg_replace(
                '/(<li[^>]*class=["\'])/',
                '$1menu-item-has-children ',
                $mybooks_item
            );
            // Close current li and add submenu
            $mybooks_item_with_sub = preg_replace(
                '/<\/li>\s*$/',
                $books_submenu . '</li>',
                $mybooks_item_with_sub
            );
            $items = str_replace($mybooks_item, $mybooks_item_with_sub, $items);
        }
    }

    // Get series for Series submenu
    $series = bdm_get_series_for_menu();
    if (!empty($series)) {
        $series_submenu = bdm_build_series_submenu($series);
        
        if (preg_match('/(<li[^>]*>.*?Series.*?<\/li>)/s', $items, $matches)) {
            $series_item = $matches[1];
            $series_item_with_sub = preg_replace(
                '/(<li[^>]*class=["\'])/',
                '$1menu-item-has-children ',
                $series_item
            );
            $series_item_with_sub = preg_replace(
                '/<\/li>\s*$/',
                $series_submenu . '</li>',
                $series_item_with_sub
            );
            $items = str_replace($series_item, $series_item_with_sub, $items);
        }
    }

    // Get books with reviews for Reviews submenu
    $review_books = bdm_get_books_with_reviews();
    if (!empty($review_books)) {
        $reviews_submenu = bdm_build_reviews_submenu($review_books);
        
        if (preg_match('/(<li[^>]*>.*?Reviews.*?<\/li>)/s', $items, $matches)) {
            $reviews_item = $matches[1];
            $reviews_item_with_sub = preg_replace(
                '/(<li[^>]*class=["\'])/',
                '$1menu-item-has-children ',
                $reviews_item
            );
            $reviews_item_with_sub = preg_replace(
                '/<\/li>\s*$/',
                $reviews_submenu . '</li>',
                $reviews_item_with_sub
            );
            $items = str_replace($reviews_item, $reviews_item_with_sub, $items);
        }
    }

    return $items;
}
add_filter('wp_nav_menu_items', 'bdm_filter_nav_menu_items', 10, 2);

/**
 * Get books for menu
 *
 * @return array
 */
function bdm_get_books_for_menu() {
    $books = get_posts(array(
        'post_type'      => 'book',
        'post_status'   => 'publish',
        'posts_per_page' => -1,
        'orderby'       => 'title',
        'order'         => 'ASC',
    ));
    
    return $books;
}

/**
 * Get series for menu
 *
 * @return array
 */
function bdm_get_series_for_menu() {
    if (!taxonomy_exists('series')) {
        return array();
    }
    
    $terms = get_terms(array(
        'taxonomy'   => 'series',
        'hide_empty' => true,
        'orderby'    => 'name',
        'order'      => 'ASC',
    ));
    
    return is_wp_error($terms) ? array() : $terms;
}

/**
 * Get books with reviews
 *
 * @return array
 */
function bdm_get_books_with_reviews() {
    $books = get_posts(array(
        'post_type'      => 'book',
        'post_status'   => 'publish',
        'posts_per_page' => -1,
        'orderby'       => 'title',
        'order'         => 'ASC',
    ));
    
    $review_books = array();
    foreach ($books as $book) {
        $goodreads = get_post_meta($book->ID, 'goodreads_url', true);
        $amazon = get_post_meta($book->ID, 'amazon_review_url', true);
        if (!empty($goodreads) || !empty($amazon)) {
            $review_books[] = $book;
        }
    }
    
    return $review_books;
}

/**
 * Build book submenu HTML
 *
 * @param array $books Books.
 * @return string
 */
function bdm_build_book_submenu($books) {
    if (empty($books)) {
        return '';
    }
    
    $submenu = "\n" . '<ul class="sub-menu">' . "\n";
    
    foreach ($books as $book) {
        $url = get_permalink($book->ID);
        $title = $book->post_title;
        $submenu .= '<li class="menu-item"><a href="' . esc_url($url) . '">' . esc_html($title) . '</a></li>' . "\n";
    }
    
    $submenu .= '</ul>';
    
    return $submenu;
}

/**
 * Build series submenu HTML
 *
 * @param array $series Series.
 * @return string
 */
function bdm_build_series_submenu($series) {
    if (empty($series)) {
        return '';
    }
    
    $submenu = "\n" . '<ul class="sub-menu">' . "\n";
    
    foreach ($series as $term) {
        $url = get_term_link($term);
        $submenu .= '<li class="menu-item"><a href="' . esc_url($url) . '">' . esc_html($term->name) . '</a></li>' . "\n";
    }
    
    $submenu .= '</ul>';
    
    return $submenu;
}

/**
 * Build reviews submenu HTML
 *
 * @param array $books Books with reviews.
 * @return string
 */
function bdm_build_reviews_submenu($books) {
    if (empty($books)) {
        return '';
    }
    
    $submenu = "\n" . '<ul class="sub-menu">' . "\n";
    
    foreach ($books as $book) {
        $title = $book->post_title;
        
        // Determine the review URL (prefer Goodreads if available)
        $goodreads = get_post_meta($book->ID, 'goodreads_url', true);
        $amazon = get_post_meta($book->ID, 'amazon_review_url', true);
        $url = !empty($goodreads) ? $goodreads : $amazon;
        
        if (!empty($url)) {
            $submenu .= '<li class="menu-item"><a href="' . esc_url($url) . '" target="_blank" rel="noopener noreferrer">' . esc_html($title) . '</a></li>' . "\n";
        }
    }
    
    $submenu .= '</ul>';
    
    return $submenu;
}

/**
 * Check if series exist
 *
 * @return bool
 */
function bdm_series_exist() {
    if (class_exists('BD_BookShelfHelper')) {
        $terms = get_terms(array(
            'taxonomy'   => 'series',
            'hide_empty' => true,
            'fields'     => 'count',
        ));
        return $terms > 0;
    }
    return false;
}

/**
 * Add series menu item class
 *
 * @param array $classes CSS classes.
 * @param WP_Post $item Menu item.
 * @param array $args Menu arguments.
 * @param int $depth Item depth.
 * @return array
 */
function bdm_nav_menu_css_class($classes, $item, $args, $depth) {
    if ($item->url && false !== strpos($item->url, '/series/')) {
        $classes[] = 'series-menu-item';
    }
    return $classes;
}
add_filter('nav_menu_css_class', 'bdm_nav_menu_css_class', 10, 4);