<?php
/**
 * Page-cache purging for writes that cache plugins cannot see.
 *
 * Page caches (LiteSpeed, WP Rocket, W3 Total Cache, ...) serve saved HTML to
 * visitors and purge it on the WordPress events an edit in wp-admin fires:
 * save_post, comment changes, menu saves. A write that goes straight to post
 * meta or to table rows fires none of them, so visitors keep the old page
 * until the cache expires, while the tool that made the change reports
 * success. Callers that make such a write ask this class to purge.
 *
 * Every engine is called through its own public API, guarded by a check that
 * it is loaded, and a failure in one never stops the others or turns a
 * successful edit into a failed call.
 *
 * @package GripMCP
 */

declare( strict_types=1 );

namespace GripMCP\Support;

defined( 'ABSPATH' ) || exit;

final class Page_Cache {

	/**
	 * Purge the cached pages of one post: its own URL and, on most engines,
	 * the front page and the archives it appears on.
	 *
	 * @param int $post_id Post id.
	 * @return array<int, string> The engines that were asked to purge.
	 */
	public static function purge_post( int $post_id ): array {
		$done = array();
		$url  = (string) get_permalink( $post_id );

		self::attempt(
			$done,
			'litespeed',
			defined( 'LSCWP_V' ),
			static function () use ( $post_id ): void {
				do_action( 'litespeed_purge_post', $post_id ); // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- LiteSpeed Cache's own purge hook.
			}
		);

		self::attempt(
			$done,
			'wp_rocket',
			function_exists( 'rocket_clean_post' ),
			static function () use ( $post_id ): void {
				rocket_clean_post( $post_id );
			}
		);

		self::attempt(
			$done,
			'w3_total_cache',
			function_exists( 'w3tc_flush_post' ),
			static function () use ( $post_id ): void {
				w3tc_flush_post( $post_id );
			}
		);

		self::attempt(
			$done,
			'wp_super_cache',
			function_exists( 'wp_cache_post_change' ),
			static function () use ( $post_id ): void {
				wp_cache_post_change( $post_id );
			}
		);

		self::attempt(
			$done,
			'sg_optimizer',
			function_exists( 'sg_cachepress_purge_cache' ) && '' !== $url,
			static function () use ( $url ): void {
				sg_cachepress_purge_cache( $url );
			}
		);

		self::attempt(
			$done,
			'wp_fastest_cache',
			class_exists( 'WpFastestCache' ),
			static function () use ( $post_id ): void {
				do_action( 'wpfc_clear_post_cache_by_id', false, $post_id ); // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- WP Fastest Cache's own purge hook.
			}
		);

		/**
		 * Fires after GripMCP changed a post in a way cache plugins cannot
		 * see, so a host or a cache plugin not covered here can purge it.
		 *
		 * @param int $post_id Post id.
		 */
		do_action( 'gripmcp/purge_post', $post_id );

		return $done;
	}

	/**
	 * Purge every cached page. Only for changes that reach across the site,
	 * such as a live search and replace: a full purge makes every visitor's
	 * next request rebuild a page.
	 *
	 * @return array<int, string> The engines that were asked to purge.
	 */
	public static function purge_all(): array {
		$done = array();

		self::attempt(
			$done,
			'litespeed',
			defined( 'LSCWP_V' ),
			static function (): void {
				do_action( 'litespeed_purge_all' ); // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- LiteSpeed Cache's own purge hook.
			}
		);

		self::attempt(
			$done,
			'wp_rocket',
			function_exists( 'rocket_clean_domain' ),
			static function (): void {
				rocket_clean_domain();
			}
		);

		self::attempt(
			$done,
			'w3_total_cache',
			function_exists( 'w3tc_flush_all' ),
			static function (): void {
				w3tc_flush_all();
			}
		);

		self::attempt(
			$done,
			'wp_super_cache',
			function_exists( 'wp_cache_clear_cache' ),
			static function (): void {
				wp_cache_clear_cache();
			}
		);

		self::attempt(
			$done,
			'sg_optimizer',
			function_exists( 'sg_cachepress_purge_cache' ),
			static function (): void {
				sg_cachepress_purge_cache();
			}
		);

		self::attempt(
			$done,
			'wp_fastest_cache',
			class_exists( 'WpFastestCache' ),
			static function (): void {
				do_action( 'wpfc_clear_all_cache' ); // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- WP Fastest Cache's own purge hook.
			}
		);

		self::attempt(
			$done,
			'breeze',
			defined( 'BREEZE_VERSION' ),
			static function (): void {
				do_action( 'breeze_clear_all_cache' ); // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- Breeze's own purge hook.
			}
		);

		self::attempt(
			$done,
			'wp_optimize',
			class_exists( 'WPO_Page_Cache' ) && method_exists( 'WPO_Page_Cache', 'instance' ),
			static function (): void {
				$cache = \WPO_Page_Cache::instance();

				if ( is_object( $cache ) && method_exists( $cache, 'purge' ) ) {
					$cache->purge();
				}
			}
		);

		self::attempt(
			$done,
			'nginx_helper',
			defined( 'NGINX_HELPER_BASENAME' ),
			static function (): void {
				do_action( 'rt_nginx_helper_purge_all' ); // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- Nginx Helper's own purge hook.
			}
		);

		/**
		 * Fires after GripMCP made a site-wide change cache plugins cannot
		 * see, so a host or a cache plugin not covered here can purge.
		 */
		do_action( 'gripmcp/purge_all' );

		return $done;
	}

	/**
	 * Run one engine's purge if it is present, recording it by name.
	 *
	 * @param array<int, string> $done    Engines purged so far, by reference.
	 * @param string             $name    Engine name for the report.
	 * @param bool               $present Whether the engine is loaded.
	 * @param callable           $purge   The purge call.
	 */
	private static function attempt( array &$done, string $name, bool $present, callable $purge ): void {
		if ( ! $present ) {
			return;
		}

		try {
			$purge();
			$done[] = $name;
		} catch ( \Throwable $e ) {
			// A stale page fixes itself when the cache expires; one engine's
			// failure must not stop the others or fail the caller's edit.
			unset( $e );
		}
	}
}