uct->get_id();
		$global_identifier_values = get_post_meta( $product_id, 'wpseo_global_identifier_values', true );

		if ( ! is_array( $global_identifier_values ) || $global_identifier_values === [] ) {
			return false;
		}

		foreach ( $global_identifier_values as $type => $value ) {
			if ( empty( $value ) ) {
				continue;
			}
			$this->data[ $type ] = $value;
			if ( $type === 'isbn' ) {
				if ( ! isset( $this->data['@type'] ) ) {
					$this->data['@type'] = 'Product';
				}
				if ( ! is_array( $this->data['@type'] ) ) {
					$this->data['@type'] = [ $this->data['@type'] ];
				}
				$this->data['@type'] = array_merge( [ 'Book' ], $this->data['@type'] );
			}
		}

		return true;
	}

	/**
	 * Update the seller attribute to reference the Organization, when it is set.
	 *
	 * @param array<string,string|int|array<string,string|int>> $data Schema Product data.
	 *
	 * @return array<string,string|int|array<string,string|int>> Schema Product data.
	 */
	protected function change_seller_in_offers( $data ) {
		$company_or_person = WPSEO_Options::get( 'company_or_person', false );
		$company_name      = WPSEO_Options::get( 'company_name' );

		if ( $company_or_person !== 'company' || empty( $company_name ) ) {
			return $data;
		}

		if ( ! empty( $data['offers'] ) ) {
			foreach ( $data['offers'] as $key => $offer ) {
				$data['offers'][ $key ]['seller'] = [
					'@id' => trailingslashit( YoastSEO()->meta->for_current_page()->site_url ) . Schema_IDs::ORGANIZATION_HASH,
				];
			}
		}

		return $data;
	}

	/**
	 * Add brand to our output.
	 *
	 * @param WC_Product $product Product object.
	 *
	 * @return void
	 */
	private function add_brand( $product ) {
		$schema_brand = WPSEO_Options::get( 'woo_schema_brand' );
		if ( ! empty( $schema_brand ) ) {
			$this->add_attribute_as( 'brand', $product, $schema_brand, 'Brand' );
		}
	}

	/**
	 * Add manufacturer to our output.
	 *
	 * @param WC_Product $product Product object.
	 *
	 * @return void
	 */
	private function add_manufacturer( $product ) {
		$schema_manufacturer = WPSEO_Options::get( 'woo_schema_manufacturer' );
		if ( ! empty( $schema_manufacturer ) ) {
			$this->add_attribute_as( 'manufacturer', $product, $schema_manufacturer );
		}
	}

	/**
	 * Adds an attribute to our Product data array with the value from a taxonomy, as an Organization,
	 *
	 * @param string     $attribute The attribute we're adding to Product.
	 * @param WC_Product $product   The WooCommerce product we're working with.
	 * @param string     $taxonomy  The taxonomy to get the attribute's value from.
	 * @param string     $type      The Schema type to use.
	 *
	 * @return void
	 */
	private function add_attribute_as( $attribute, $product, $taxonomy, $type = 'Organization' ) {
		$term = $this->get_primary_term_or_first_term( $taxonomy, $product->get_id() );

		if ( $term !== null ) {
			$this->data[ $attribute ] = [
				'@type' => $type,
				'name'  => wp_strip_all_tags( $term->name ),
			];
		}
	}

	/**
	 * Adds image schema.
	 *
	 * @return void
	 */
	private function add_image() {
		/**
		 * WooCommerce will set the image to false if none is available. This is incorrect schema and we should fix it
		 * for our users for now.
		 *
		 * See https://github.com/woocommerce/woocommerce/issues/24188.
		 */
		if ( isset( $this->data['image'] ) && $this->data['image'] === false ) {
			unset( $this->data['image'] );
		}

		if ( has_post_thumbnail() ) {
			$this->data['image'] = [
				'@id' => YoastSEO()->meta->for_current_page()->canonical . Schema_IDs::PRIMARY_IMAGE_HASH,
			];

			return;
		}

		// Fallback to WooCommerce placeholder image.
		if ( function_exists( 'wc_placeholder_img_src' ) ) {
			$image_schema_id     = YoastSEO()->meta->for_current_page()->canonical . '#woocommerceimageplaceholder';
			$placeholder_img_src = wc_placeholder_img_src();
			$this->data['image'] = YoastSEO()->helpers->schema->image->generate_from_url( $image_schema_id, $placeholder_img_src, '', false, false );
		}
	}

	/**
	 * Adds image schema for product variations to main node.
	 *
	 * @return void
	 */
	private function add_variation_images() {
		$image_list = [];
		if ( is_array( $this->variation_images ) && count( $this->variation_images ) !== 0 ) {
			$image_list[] = $this->data['image'];
			foreach ( $this->variation_images as $image ) {
				$image_list[] = $image;
			}
			$this->data['image'] = $image_list;
		}
	}

	/**
	 * Add a custom schema property to the Schema output.
	 *
	 * @param WC_Product $product     The product object.
	 * @param string     $option_name The option name.
	 * @param string     $schema_id   The schema identifier to use.
	 *
	 * @return void
	 */
	private function add_custom_schema_property( $product, $option_name, $schema_id ) {
		$schema_data = WPSEO_Options::get( $option_name );

		if ( ! empty( $schema_data ) ) {
			$terms = get_the_terms( $product->get_id(), $schema_data );

			if ( is_array( $terms ) ) {
				// Variable products can have more than one color.
				$is_variable_product = false;
				if ( isset( $this->data['offers'] ) ) {
					foreach ( $this->data['offers'] as $offer ) {
						if ( $offer['@type'] === 'AggregateOffer' ) {
							$is_variable_product = true;
						}
					}
				}

				if ( count( $terms ) === 1 ) {
					$term                     = reset( $terms );
					$this->data[ $schema_id ] = strtolower( $term->name );
				}
				elseif ( $is_variable_product ) {
					$schema_data_content = [];
					foreach ( $terms as $term ) {
						$schema_data_content[] = strtolower( $term->name );
					}

					$this->data[ $schema_id ] = $schema_data_content;
				}
			}
		}
	}

	/**
	 * Adds the product color property to the Schema output.
	 *
	 * @param WC_Product $product The product object.
	 *
	 * @return void
	 */
	private function add_color( $product ) {
		$this->add_custom_schema_property( $product, 'woo_schema_color', 'color' );
	}

	/**
	 * Adds the product pattern property to the Schema output.
	 *
	 * @param WC_Product $product The product object.
	 *
	 * @return void
	 */
	private function add_pattern( $product ) {
		$this->add_custom_schema_property( $product, 'woo_schema_pattern', 'pattern' );
	}

	/**
	 * Adds the product material property to the Schema output.
	 *
	 * @param WC_Product $product The product object.
	 *
	 * @return void
	 */
	private function add_material( $product ) {
		$this->add_custom_schema_property( $product, 'woo_schema_material', 'material' );
	}

	/**
	 * Tries to get the primary term, then the first term, null if none found.
	 *
	 * @param string $taxonomy_name Taxonomy name for the term.
	 * @param int    $post_id       Post ID for the term.
	 *
	 * @return WP_Term|null The primary term, the first term or null.
	 */
	protected function get_primary_term_or_first_term( $taxonomy_name, $post_id ) {
		$primary_term    = new WPSEO_Primary_Term( $taxonomy_name, $post_id );
		$primary_term_id = $primary_term->get_primary_term();

		if ( $primary_term_id !== false ) {
			$primary_term = get_term( $primary_term_id );
			if ( $primary_term instanceof WP_Term ) {
				return $primary_term;
			}
		}

		$terms = get_the_terms( $post_id, $taxonomy_name );

		if ( is_array( $terms ) && count( $terms ) > 0 ) {
			return $terms[0];
		}

		return null;
	}

	/**
	 * Adds the individual product variants as variants of the offer.
	 *
	 * @param WC_Product                          $product   The WooCommerce Product we're working with.
	 * @param array<string|int|array<string|int>> $variation The WooCommerce variation we're working with.
	 * @param int                                 $key       The nth product variation.
	 *
	 * @return array<string|int|array<string|int>> Schema Offers data.
	 */
	protected function add_individual_offer( $product, $variation, $key ) {

		$currency           = get_woocommerce_currency();
		$tax_enabled        = wc_tax_enabled();
		$prices_include_tax = WPSEO_WooCommerce_Utils::prices_have_tax_included();
		$decimals           = wc_get_price_decimals();
		$product_id         = $product->get_id();
		$product_name       = $product->get_name();
		$variation_name     = implode( ' / ', $variation['attributes'] );

		$offer = [
			'@type'              => 'Offer',
			'@id'                => YoastSEO()->meta->for_current_page()->site_url . '#/schema/offer/' . $product_id . '-' . $key,
			'name'               => $product_name . ' - ' . $variation_name,
			'url'                => get_permalink( $variation['variation_id'] ),
			'priceSpecification' => [
				'@type'         => 'PriceSpecification',
				'price'         => wc_format_decimal( $variation['display_price'], $decimals ),
				'priceCurrency' => $currency,
			],
		];

		if ( $tax_enabled ) {
			$offer['priceSpecification']['valueAddedTaxIncluded'] = $prices_include_tax;
		}

		if ( ! $product->is_on_sale() || ! $product->get_date_on_sale_to() ) {
			unset( $offer['priceValidUntil'] );
		}

		if ( $product->is_on_backorder() ) {
			$offer['availability'] = 'https://schema.org/PreOrder';
		}

		/**
		 * Filter: 'wpseo_schema_offer' - Allow changing the offer schema.
		 *
		 * @param array<string|int|array<string|int>> $offer     The schema offer data.
		 * @param WC_Product_Variation                $variation The WooCommerce product variation we're working with.
		 * @param WC_Product                          $product   The WooCommerce product we're working with.
		 */
		$data = apply_filters( 'wpseo_schema_offer', $offer, $variation, $product );

		if ( is_array( $data ) ) {
			return $data;
		}

		return $offer;
	}

	/**
	 * Adds the individual product variants.
	 *
	 * @param WC_Product           $product   The WooCommerce product we're working with.
	 * @param array<string,string> $variation The variation data.
	 * @param int                  $key       The nth product variation data.
	 *
	 * @return array<string,string|int|array<string,string|int>> Schema Product data.
	 */
	protected function add_individual_product_variation( $product, $variation, $key ) {
		$product_id         = $product->get_id();
		$product_name       = $product->get_name();
		$product_global_ids = get_post_meta( $product_id, 'wpseo_global_identifier_values', true );

		$variation_name = implode( ' / ', $variation['attributes'] );

		$product_schema = [
			'@type' => 'Product',
			'@id'   => YoastSEO()->meta->for_current_page()->site_url . '#/product/' . $product_id . '-' . $key,
			'name'  => $product_name . ' - ' . $variation_name,
			'url'   => get_permalink( $variation['variation_id'] ),
			'image' => $this->add_variation_image( $variation ),

		];

		if ( ! empty( $variation['sku'] ) ) {
			$product_schema['sku'] = $variation['sku'];
		}

		if ( $variation['variation_description'] !== '' ) {
			$product_schema['description'] = YoastSEO()->helpers->string->strip_all_tags( stripslashes( $variation['variation_description'] ) );
		}
		// Adds variation's global identifiers to the $offer array.
		$variation_global_ids    = get_post_meta( $variation['variation_id'], 'wpseo_variation_global_identifiers_values', true );
		$global_identifier_types = [
			'gtin8',
			'gtin12',
			'gtin13',
			'gtin14',
			'mpn',
		];

		foreach ( $global_identifier_types as $global_identifier_type ) {
			if ( isset( $variation_global_ids[ $global_identifier_type ] ) && ! empty( $variation_global_ids[ $global_identifier_type ] ) ) {
				$product_schema[ $global_identifier_type ] = $variation_global_ids[ $global_identifier_type ];
			}
			elseif ( isset( $product_global_ids[ $global_identifier_type ] ) && ! empty( $product_global_ids[ $global_identifier_type ] ) ) {
				$product_schema[ $global_identifier_type ] = $product_global_ids[ $global_identifier_type ];
			}
		}

		$product_schema['offers'] = $this->add_individual_offer( $product, $variation, $key );

		return $product_schema;
	}

	/**
	 * Adds image schema for a product variation.
	 *
	 * @param array<string,string> $variation_data The variation data.
	 *
	 * @return array<string,string> The imageObject schema.
	 */
	private function add_variation_image( $variation_data ) {
		$image_schema_id = YoastSEO()->meta->for_current_page()->canonical . '#' . $variation_data['image']['title'];

		return YoastSEO()->helpers->schema->image->generate_from_url( $image_schema_id, $variation_data['image']['url'], $variation_data['image']['caption'] );
	}

	/**
	 * Enhances the review data output by WooCommerce.
	 *
	 * @param array<string,string|int|array<string,string|int>> $data    Review Schema data.
	 * @param WC_Product                                        $product The WooCommerce product we're working with.
	 *
	 * @return array<string,string|int|array<string,string|int>> Review Schema data.
	 */
	protected function filter_reviews( $data, $product ) {
		if ( ! isset( $data['review'] ) || $data['review'] === [] ) {
			return $data;
		}

		$product_id   = $product->get_id();
		$product_name = $product->get_name();

		foreach ( $data['review'] as $key => $review ) {
			$data['review'][ $key ]['@id']  = YoastSEO()->meta->for_current_page()->site_url . '#/schema/review/' . $product_id . '-' . $key;
			$data['review'][ $key ]['name'] = $product_name;
		}

		return $data;
	}
}