<?php
/**
 * Content analyzer class.
 *
 * @package AIIL
 */

// Exit if accessed directly.
if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

/**
 * Content analyzer.
 */
class AIIL_Content_Analyzer {

	/**
	 * Get available links for internal linking.
	 *
	 * @param int $exclude_post_id Post ID to exclude.
	 * @return array
	 */
	public function get_available_links( $exclude_post_id = 0 ) {
		$cache_key = 'aiil_available_links_' . $exclude_post_id;
		$links     = get_transient( $cache_key );

		if ( false !== $links ) {
			return $links;
		}

		$post_types = AIIL_Core::get_linking_post_types();

		$args = array(
			'post_type'      => $post_types,
			'post_status'    => 'publish',
			'posts_per_page' => 500, // Limit for performance.
			'orderby'        => 'modified',
			'order'          => 'DESC',
			'no_found_rows'  => true,
			'fields'         => 'ids',
		);

		/**
		 * Filter query args for available links.
		 *
		 * @since 1.0.0
		 * @param array $args         Query args.
		 * @param int   $exclude_post_id Excluded post ID.
		 */
		$args = apply_filters( 'aiil_available_links_args', $args, $exclude_post_id );

		$query = new WP_Query( $args );
		$links = array();

		if ( $query->have_posts() ) {
			foreach ( $query->posts as $post_id ) {
				// Filter out excluded post manually to avoid post__not_in performance issues.
				if ( $exclude_post_id && absint( $post_id ) === absint( $exclude_post_id ) ) {
					continue;
				}

				$links[] = array(
					'id'    => $post_id,
					'title' => get_the_title( $post_id ),
					'url'   => get_permalink( $post_id ),
					'type'  => get_post_type( $post_id ),
				);
			}
		}

		// Cache for 1 hour.
		set_transient( $cache_key, $links, HOUR_IN_SECONDS );

		return $links;
	}

	/**
	 * Clear available links cache.
	 *
	 * @param int $post_id Post ID.
	 */
	public static function clear_cache( $post_id = 0 ) {
		global $wpdb;

		if ( $post_id ) {
			delete_transient( 'aiil_available_links_' . $post_id );
		} else {
			// Clear all cached links.
			// Check cache first to avoid unnecessary DB query.
			$cache_key = 'aiil_transient_cleanup_' . gmdate( 'Y-m-d-H' );
			$cached    = wp_cache_get( $cache_key, 'aiil_cache' );

			if ( false === $cached ) {
				// phpcs:ignore WordPress.DB.DirectDatabaseQuery.DirectQuery, WordPress.DB.DirectDatabaseQuery.NoCaching -- Cache cleared intentionally, query runs max once per hour.
				$wpdb->query(
					$wpdb->prepare(
						"DELETE FROM {$wpdb->options} WHERE option_name LIKE %s",
						$wpdb->esc_like( '_transient_aiil_available_links_' ) . '%'
					)
				);
				// Cache this cleanup action for 1 hour to prevent repeated queries.
				wp_cache_set( $cache_key, true, 'aiil_cache', HOUR_IN_SECONDS );
			}
		}
	}
}

// Clear cache when posts are updated.
add_action( 'save_post', array( 'AIIL_Content_Analyzer', 'clear_cache' ) );
add_action( 'deleted_post', array( 'AIIL_Content_Analyzer', 'clear_cache' ) );