<?php
/**
 * Basic AI readiness checks for the store and its products.
 *
 * @package AgentAisle
 */

defined( 'ABSPATH' ) || exit;

class AgentAisle_Readiness {

	const PRODUCT_LIMIT = 25;

	/**
	 * Store-level checks.
	 *
	 * @return array[] Each: label, pass, help.
	 */
	public static function store_checks() {
		$checks = array();

		$checks[] = array(
			'label' => __( 'Search engines allowed to index the site', 'agentaisle' ),
			'pass'  => (bool) get_option( 'blog_public' ),
			'help'  => __( 'Settings > Reading: untick "Discourage search engines".', 'agentaisle' ),
		);
		$checks[] = array(
			'label' => __( 'Readable permalinks', 'agentaisle' ),
			'pass'  => '' !== (string) get_option( 'permalink_structure' ),
			'help'  => __( 'Settings > Permalinks: choose any option except "Plain".', 'agentaisle' ),
		);
		$checks[] = array(
			'label' => __( 'llms.txt is published', 'agentaisle' ),
			'pass'  => ! empty( agentaisle_settings()['llms_enabled'] ),
			'help'  => __( 'Turn it on in the llms.txt tab.', 'agentaisle' ),
		);
		$checks[] = array(
			'label' => __( 'WooCommerce product structured data is active', 'agentaisle' ),
			'pass'  => self::wc_schema_active(),
			'help'  => __( 'Another plugin or your theme may have removed it. Check your SEO plugin settings.', 'agentaisle' ),
		);
		$checks[] = array(
			'label' => __( 'Terms and conditions page set', 'agentaisle' ),
			'pass'  => function_exists( 'wc_terms_and_conditions_page_id' ) && wc_terms_and_conditions_page_id() > 0,
			'help'  => __( 'WooCommerce > Settings > Advanced > Page setup.', 'agentaisle' ),
		);
		$checks[] = array(
			'label' => __( 'Shipping information page published', 'agentaisle' ),
			'pass'  => self::page_exists( array( 'shipping', 'delivery' ) ),
			'help'  => __( 'Publish a page with "Shipping" or "Delivery" in the title.', 'agentaisle' ),
		);
		$checks[] = array(
			'label' => __( 'Returns or refund policy page published', 'agentaisle' ),
			'pass'  => self::page_exists( array( 'return', 'refund' ) ),
			'help'  => __( 'Publish a page with "Returns" or "Refund" in the title.', 'agentaisle' ),
		);

		return $checks;
	}

	/**
	 * Score up to PRODUCT_LIMIT products.
	 *
	 * @return array[] Each: id, name, edit, score, missing[].
	 */
	public static function product_report() {
		if ( ! function_exists( 'wc_get_products' ) ) {
			return array();
		}
		$products = wc_get_products(
			array(
				'status'  => 'publish',
				'limit'   => self::limit(),
				'orderby' => 'date',
				'order'   => 'DESC',
			)
		);
		$rows = array();
		foreach ( $products as $product ) {
			$rows[] = self::score_product( $product );
		}
		usort(
			$rows,
			function ( $a, $b ) {
				return $a['score'] <=> $b['score'];
			}
		);
		return $rows;
	}

	/**
	 * Number of products the readiness report covers.
	 *
	 * @return int
	 */
	public static function limit() {
		return max( 1, (int) apply_filters( 'agentaisle_readiness_product_limit', self::PRODUCT_LIMIT ) );
	}

	/**
	 * Score one product.
	 *
	 * @param WC_Product $product Product.
	 * @return array
	 */
	public static function score_product( $product ) {
		$checks = array(
			__( 'Price', 'agentaisle' )             => '' !== (string) $product->get_price(),
			__( 'Stock status', 'agentaisle' )      => '' !== (string) $product->get_stock_status(),
			__( 'Image', 'agentaisle' )             => (bool) $product->get_image_id(),
			__( 'Short description', 'agentaisle' ) => '' !== trim( wp_strip_all_tags( $product->get_short_description() ) ),
			__( 'Description (50+ words)', 'agentaisle' ) => str_word_count( wp_strip_all_tags( $product->get_description() ) ) >= 50,
			__( 'SKU', 'agentaisle' )               => '' !== (string) $product->get_sku(),
			__( 'GTIN / EAN / UPC', 'agentaisle' )  => self::has_gtin( $product ),
			__( 'Brand', 'agentaisle' )             => self::has_brand( $product ),
			__( 'Category', 'agentaisle' )          => (bool) array_diff( $product->get_category_ids(), array( (int) get_option( 'default_product_cat' ) ) ),
		);

		$missing = array();
		foreach ( $checks as $label => $pass ) {
			if ( ! $pass ) {
				$missing[] = $label;
			}
		}

		return array(
			'id'      => $product->get_id(),
			'name'    => $product->get_name(),
			'edit'    => get_edit_post_link( $product->get_id(), 'raw' ),
			'score'   => (int) round( 100 * ( count( $checks ) - count( $missing ) ) / count( $checks ) ),
			'missing' => $missing,
		);
	}

	/**
	 * Average of product scores.
	 *
	 * @param array $rows Product report rows.
	 * @return int|null
	 */
	public static function average( $rows ) {
		if ( ! $rows ) {
			return null;
		}
		return (int) round( array_sum( wp_list_pluck( $rows, 'score' ) ) / count( $rows ) );
	}

	/**
	 * GTIN check: core field (WC 9.2+) or common meta keys.
	 *
	 * @param WC_Product $product Product.
	 * @return bool
	 */
	public static function has_gtin( $product ) {
		if ( method_exists( $product, 'get_global_unique_id' ) && '' !== (string) $product->get_global_unique_id() ) {
			return true;
		}
		foreach ( array( '_gtin', '_ean', '_upc', '_barcode', 'gtin', 'ean' ) as $key ) {
			if ( '' !== (string) $product->get_meta( $key ) ) {
				return true;
			}
		}
		return false;
	}

	/**
	 * Brand check: core brands taxonomy (WC 9.6+) or a brand attribute.
	 *
	 * @param WC_Product $product Product.
	 * @return bool
	 */
	public static function has_brand( $product ) {
		if ( taxonomy_exists( 'product_brand' ) ) {
			$terms = wp_get_post_terms( $product->get_id(), 'product_brand', array( 'fields' => 'ids' ) );
			if ( ! is_wp_error( $terms ) && $terms ) {
				return true;
			}
		}
		foreach ( array( 'pa_brand', 'brand' ) as $attr ) {
			if ( '' !== (string) $product->get_attribute( $attr ) ) {
				return true;
			}
		}
		return false;
	}

	/**
	 * Whether WooCommerce's product structured data output is still hooked.
	 *
	 * @return bool
	 */
	private static function wc_schema_active() {
		if ( ! function_exists( 'WC' ) || ! isset( WC()->structured_data ) ) {
			return false;
		}
		return false !== has_action( 'woocommerce_single_product_summary', array( WC()->structured_data, 'generate_product_data' ) );
	}

	/**
	 * Whether a published page title contains any of the terms.
	 *
	 * @param string[] $terms Terms.
	 * @return bool
	 */
	private static function page_exists( $terms ) {
		foreach ( $terms as $term ) {
			$found = get_posts(
				array(
					'post_type'      => 'page',
					'post_status'    => 'publish',
					's'              => $term,
					'search_columns' => array( 'post_title' ),
					'posts_per_page' => 1,
					'fields'         => 'ids',
				)
			);
			if ( $found ) {
				return true;
			}
		}
		return false;
	}
}