独立站 B2B 产品结构化数据优化黄金实践：基于 WordPress 原生架构的轻量化 SEO 蜕变

add_action('wp_head', 'funion_b2b_standard_products_schema');
function funion_b2b_standard_products_schema() {
    // 双重保险：确保绝对不在后台运行，且不影响 AJAX 请求
    if ( is_admin() || (defined('DOING_AJAX') && DOING_AJAX) ) {
        return;
    }

    // ==========================================
    // 1. 针对“原生分类列表页” (自动递归支持指定的父分类及其所有子分类)
    // ==========================================
    $is_product_cat = false;
    if ( is_category() ) {
        $current_cat = get_queried_object();
        if ( $current_cat ) {
            // 请将 'products' 替换为你网站实际的产品分类 Slug
            $target_cat = get_term_by('slug', 'products', 'category');
            if ( $target_cat ) {
                // 判断当前分类是否是指定分类本身，或者属于它的子分类
                if ( $current_cat->term_id == $target_cat->term_id || cat_is_ancestor_of($target_cat->term_id, $current_cat->term_id) ) {
                    $is_product_cat = true;
                }
            }
        }
    }

    if ( $is_product_cat ) {
        $cat_name = $current_cat->name;
        $cat_url  = get_category_link($current_cat->term_id);
        
        // 深度清洗分类描述，防止换行符或特殊符号导致 JSON 解析失败
        $raw_desc = category_description($current_cat->term_id) ?: "Browse our range of high-quality products.";
        $cat_desc = esc_attr( trim( preg_replace( '/\s+/', ' ', wp_strip_all_tags( strip_shortcodes( $raw_desc ) ) ) ) );

        $schema = [
            "@context" => "https://schema.org",
            "@type" => "ItemList",
            "name" => $cat_name,
            "description" => $cat_desc,
            "url" => $cat_url,
            "itemListElement" => []
        ];

        // 核心优化：直接通过全局数组提取数据，完全不触动前端 Loop 指针，100% 避免排版冲突
        global $wp_query;
        if ( ! empty( $wp_query->posts ) ) {
            $position = 1;
            foreach ( $wp_query->posts as $p ) {
                $schema['itemListElement'][] = [
                    "@type" => "ListItem",
                    "position" => $position,
                    "url" => get_permalink( $p->ID ),
                    "name" => get_the_title( $p->ID )
                ];
                $position++;
            }
        }

        if ( ! empty($schema['itemListElement']) ) {
            $schema['numberOfItems'] = count($schema['itemListElement']);
            echo "\n" . '<!-- B2B Category ItemList Schema -->' . "\n";
            echo '<script type="application/ld+json">' . json_encode($schema, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT) . '</script>' . "\n";
        }
    }

    // ==========================================
    // 2. 针对“原生文章详情页” (完美兼容所有多级子分类产品)
    // ==========================================
    if ( is_single() ) {
        global $post;
        if ( ! $post ) return;
        
        // 核心递归检查：请将 'products' 替换为你网站实际的产品分类 Slug
        $is_product_single = false;
        $target_cat = get_term_by('slug', 'products', 'category');
        if ( $target_cat ) {
            $post_categories = wp_get_post_categories($post->ID);
            foreach ( $post_categories as $c_id ) {
                if ( $c_id == $target_cat->term_id || cat_is_ancestor_of($target_cat->term_id, $c_id) ) {
                    $is_product_single = true;
                    break;
                }
            }
        }
        
        if ( $is_product_single ) {
            // 零手工维护兜底：若未来加了 ACF 字段则自动调用，否则利用文章 ID 自动生成全网唯一的货号密文
            $sku = function_exists('get_field') && get_field('product_sku') ? get_field('product_sku') : 'SKU-' . $post->ID;
            $mpn = function_exists('get_field') && get_field('product_mpn') ? get_field('product_mpn') : 'MPN-' . $post->ID;
            $img = get_the_post_thumbnail_url($post->ID, 'full') ?: '';
            
            // 深度清洗文章摘要与正文内容
            $raw_excerpt = $post->post_excerpt ? $post->post_excerpt : wp_trim_words($post->post_content, 35, '...');
            $excerpt     = esc_attr( trim( preg_replace( '/\s+/', ' ', wp_strip_all_tags( strip_shortcodes( $raw_excerpt ) ) ) ) );

            // =======================================================
            // 配置区：配置下方的大写占位符，即可完美适配任意 B2B 独立站
            // =======================================================
            $schema = [
                "@context" => "https://schema.org",
                "@type" => "Product",
                "name" => get_the_title($post->ID),
                "description" => $excerpt,
                "sku" => $sku,
                "mpn" => $mpn,
                "brand" => [
                    "@type" => "Brand",
                    "name" => "YOUR_BRAND_NAME" // 替换为你的产品品牌名
                ],
                "manufacturer" => [
                    "@type" => "Organization",
                    "name" => "YOUR_COMPANY_LEGAL_NAME", // 替换为你的公司法定主体名称
                    "url" => home_url('/')
                ],
                "offers" => [
                    "@type" => "AggregateOffer",
                    "priceCurrency" => "USD",
                    "lowPrice" => "1.00",   // B2B 预期低价区间
                    "highPrice" => "50.00", // B2B 预期高价区间
                    "offerCount" => "1",
                    "priceValidUntil" => "2027-12-31",
                    "availability" => "https://schema.org/InStock",
                    "itemCondition" => "https://schema.org/NewCondition",
                    "url" => get_permalink($post->ID),
                    "seller" => [
                        "@type" => "Organization",
                        "name" => "YOUR_COMPANY_LEGAL_NAME" // 替换为你的销售方公司名称
                    ],
                    // B2B 核心扩展：面向批发/起订量的隐形价格规范，完美通过谷歌富媒体测试
                    "priceSpecification" => [
                        "@type" => "PriceSpecification",
                        "valueAddedTaxIncluded" => "false",
                        "description" => "Wholesale business pricing based on order quantity / MOQ."
                    ]
                ]
            ];

            if ( $img ) {
                $schema['image'] = [ $img ];
            }

            echo "\n" . '<!-- B2B Product Single Schema -->' . "\n";
            echo '<script type="application/ld+json">' . json_encode($schema, JSON_UNESCAPED_SLASHES | JSON_UNESCAPED_UNICODE | JSON_PRETTY_PRINT) . '</script>' . "\n";
        }
    }
}