<?php
/**
 * Entity chain builder.
 *
 * Builds BreadcrumbList, Brand → Organization → Product entity chains,
 * and SameAs links for schema.org structured data.
 *
 * @package AICommerce\Schema
 */

declare(strict_types=1);

namespace AICommerce\Schema;

/**
 * Builds secondary schema entities that support the main Product schema.
 */
class EntityChain {

	/**
	 * Build BreadcrumbList schema from WooCommerce product category hierarchy.
	 *
	 * @param \WC_Product $product The WooCommerce product.
	 *
	 * @return array<string, mixed> BreadcrumbList schema or empty array.
	 */
	public function build_breadcrumb( \WC_Product $product ): array {
		$terms = $this->get_product_categories( $product );

		if ( empty( $terms ) ) {
			return array();
		}

		$items = array();
		$pos   = 1;

		// Home as first breadcrumb item.
		$items[] = array(
			'@type'    => 'ListItem',
			'position' => $pos++,
			'name'     => get_bloginfo( 'name' ),
			'item'     => home_url( '/' ),
		);

		// Shop page.
		$shop_page_id = wc_get_page_id( 'shop' );
		if ( $shop_page_id > 0 ) {
			$items[] = array(
				'@type'    => 'ListItem',
				'position' => $pos++,
				'name'     => get_the_title( $shop_page_id ),
				'item'     => get_permalink( $shop_page_id ),
			);
		}

		// Category hierarchy (deepest first in $terms, we want ancestors first).
		foreach ( $terms as $term ) {
			$items[] = array(
				'@type'    => 'ListItem',
				'position' => $pos++,
				'name'     => $term->name,
				'item'     => get_term_link( $term ),
			);
		}

		// Product itself as the final breadcrumb.
		$items[] = array(
			'@type'    => 'ListItem',
			'position' => $pos,
			'name'     => $product->get_name(),
			'item'     => get_permalink( $product->get_id() ),
		);

		$breadcrumb = array(
			'@context'        => 'https://schema.org',
			'@type'           => 'BreadcrumbList',
			'itemListElement' => $items,
		);

		/**
		 * Filters the BreadcrumbList schema.
		 *
		 * @param array<string, mixed> $breadcrumb The BreadcrumbList data.
		 * @param \WC_Product          $product    The WooCommerce product.
		 */
		return apply_filters( 'aicommerce_breadcrumb_schema', $breadcrumb, $product );
	}

	/**
	 * Build Brand → Organization entity chain.
	 *
	 * @param \WC_Product $product The WooCommerce product.
	 *
	 * @return array<string, mixed> Brand schema or empty array.
	 */
	public function build_brand( \WC_Product $product ): array {
		$brand_name = $product->get_meta( '_aicommerce_brand' );

		if ( empty( $brand_name ) ) {
			// Fall back to store name as brand.
			$brand_name = get_option( 'aicommerce_default_brand', '' );
		}

		if ( empty( $brand_name ) ) {
			return array();
		}

		$brand = array(
			'@type' => 'Brand',
			'name'  => $brand_name,
		);

		// If brand URL is available, add it.
		$brand_url = $product->get_meta( '_aicommerce_brand_url' );
		if ( ! empty( $brand_url ) ) {
			$brand['url'] = $brand_url;
		}

		return $brand;
	}

	/**
	 * Build Organization schema for the store.
	 *
	 * @return array<string, mixed> Organization schema.
	 */
	public function build_organization(): array {
		$org = array(
			'@context' => 'https://schema.org',
			'@type'    => 'Organization',
			'name'     => get_bloginfo( 'name' ),
			'url'      => home_url( '/' ),
		);

		// Logo.
		$logo_id = get_theme_mod( 'custom_logo' );
		if ( $logo_id ) {
			$logo_url = wp_get_attachment_url( $logo_id );
			if ( $logo_url ) {
				$org['logo'] = $logo_url;
			}
		}

		// SameAs links from plugin settings.
		$same_as = $this->get_same_as_links();
		if ( ! empty( $same_as ) ) {
			$org['sameAs'] = $same_as;
		}

		/**
		 * Filters the Organization schema.
		 *
		 * @param array<string, mixed> $org Organization schema data.
		 */
		return apply_filters( 'aicommerce_organization_schema', $org );
	}

	/**
	 * Get SameAs social/authority links from plugin settings.
	 *
	 * @return array<int, string> URLs for SameAs property.
	 */
	private function get_same_as_links(): array {
		$settings = get_option( 'aicommerce_same_as_links', array() );

		if ( ! is_array( $settings ) ) {
			return array();
		}

		// Filter out empty values and ensure URLs are valid.
		return array_values(
			array_filter(
				$settings,
				static function ( $url ): bool {
					return ! empty( $url ) && filter_var( $url, FILTER_VALIDATE_URL ) !== false;
				}
			)
		);
	}

	/**
	 * Get the deepest product category hierarchy for a product.
	 *
	 * Returns the category chain from root to the deepest assigned category,
	 * so the breadcrumb reflects the full taxonomy path.
	 *
	 * @param \WC_Product $product The product.
	 *
	 * @return array<int, \WP_Term> Ordered terms from root ancestor to deepest.
	 */
	private function get_product_categories( \WC_Product $product ): array {
		$terms = get_the_terms( $product->get_id(), 'product_cat' );

		if ( ! is_array( $terms ) || empty( $terms ) ) {
			return array();
		}

		// Find the deepest term (most ancestors).
		$deepest   = null;
		$max_depth = -1;

		foreach ( $terms as $term ) {
			$ancestors = get_ancestors( $term->term_id, 'product_cat', 'taxonomy' );
			$depth     = count( $ancestors );
			if ( $depth > $max_depth ) {
				$max_depth = $depth;
				$deepest   = $term;
			}
		}

		if ( null === $deepest ) {
			return array();
		}

		// Build the chain from root to deepest.
		$ancestors = get_ancestors( $deepest->term_id, 'product_cat', 'taxonomy' );
		$chain     = array();

		// Ancestors are returned deepest-first, reverse for root-first.
		$ancestors = array_reverse( $ancestors );

		foreach ( $ancestors as $ancestor_id ) {
			$ancestor_term = get_term( $ancestor_id, 'product_cat' );
			if ( $ancestor_term instanceof \WP_Term ) {
				$chain[] = $ancestor_term;
			}
		}

		// Add the deepest term itself.
		$chain[] = $deepest;

		return $chain;
	}
}