<?php
/**
 * Page caches: a change made in ProdTabs can reach many product pages at once (a shared tab, the settings of the
 * WooCommerce tabs, a bulk action, an import, the copy of a list to the translations of a product), while cache plugins
 * only purge the page of the post being saved. The pages concerned are purged at the end of the request.
 *
 * @package Prodtabs
 */

namespace Prodtabs;

defined( 'ABSPATH' ) || exit;

/**
 * Purge of the product pages whose tabs changed.
 */
final class Cache_Purge {

	/** Above this number of products, the whole cache is purged instead, in one call. */
	const MAX_PRODUCTS = 100;

	/**
	 * Products to purge, as keys.
	 *
	 * @var true[]
	 */
	private static $products = array();

	/** Whether every page is to be purged. */
	private static $all = false;

	/**
	 * Shared tabs whose products were already collected, as keys.
	 *
	 * @var true[]
	 */
	private static $shared_tabs = array();

	/** Hooks. */
	public static function init(): void {
		add_action( 'added_post_meta', array( __CLASS__, 'meta_changed' ), 10, 4 );
		add_action( 'updated_post_meta', array( __CLASS__, 'meta_changed' ), 10, 4 );
		add_action( 'deleted_post_meta', array( __CLASS__, 'meta_changed' ), 10, 4 );
		add_action( 'post_updated', array( __CLASS__, 'post_updated' ), 10, 3 );
		add_action( 'future_to_publish', array( __CLASS__, 'scheduled' ) );
		add_action( 'add_option_' . Settings::OPTION, array( __CLASS__, 'everything' ) );
		add_action( 'update_option_' . Settings::OPTION, array( __CLASS__, 'everything' ) );
		add_action( 'shutdown', array( __CLASS__, 'flush' ) );
	}

	/**
	 * A meta of ProdTabs changed: the tabs of a product, or a shared tab.
	 *
	 * @param mixed  $meta_id    Meta id (ids when deleted).
	 * @param int    $object_id  Post id.
	 * @param string $meta_key   Meta key.
	 * @param mixed  $meta_value Meta value.
	 */
	public static function meta_changed( $meta_id, $object_id, $meta_key, $meta_value = null ): void {
		$meta_key = (string) $meta_key;
		if ( Tabs::META_LAYOUT === $meta_key || Tabs::META_TEXTS === $meta_key ) {
			if ( 'product' === get_post_type( (int) $object_id ) ) {
				// The translations of a source show its list and its texts where they have none of their own.
				self::products( Multilingual::source_product( (int) $object_id ) ? array( (int) $object_id ) : Multilingual::translation_ids( (int) $object_id, 'product' ) );
			}
			return;
		}
		if ( 0 !== strpos( $meta_key, '_prodtabs' ) || Library::POST_TYPE !== get_post_type( (int) $object_id ) ) {
			return;
		}
		if ( 'added_post_meta' === current_action() && empty( $meta_value ) ) {
			return; // A setting saved empty for the first time: nothing shows differently.
		}
		// The "Show on" setting, or a setting added by an extension (targeting): where it applied before is unknown.
		self::shared_tab( (int) $object_id, Library::META_SHOP_TITLE !== $meta_key );
	}

	/**
	 * A shared tab was saved, published, unpublished or trashed.
	 *
	 * @param int      $post_id Post id.
	 * @param \WP_Post $after   Post after the update.
	 * @param \WP_Post $before  Post before the update.
	 */
	public static function post_updated( $post_id, $after, $before ): void {
		if ( ! $after instanceof \WP_Post || Library::POST_TYPE !== $after->post_type ) {
			return;
		}
		$was_shown = $before instanceof \WP_Post && 'publish' === $before->post_status;
		if ( 'publish' !== $after->post_status && ! $was_shown ) {
			return; // A draft that stays a draft.
		}
		self::shared_tab( (int) $post_id, false );
	}

	/**
	 * A shared tab scheduled for later went live: WordPress publishes it without the hooks of an update.
	 *
	 * @param \WP_Post $post Post published.
	 */
	public static function scheduled( $post ): void {
		if ( $post instanceof \WP_Post && Library::POST_TYPE === $post->post_type ) {
			self::shared_tab( (int) $post->ID, false );
		}
	}

	/**
	 * Pages showing a shared tab: every product when the tab shows on its own, the products it is added to otherwise.
	 *
	 * @param int  $id        Shared tab.
	 * @param bool $all_pages Purge everything whatever the setting.
	 */
	private static function shared_tab( int $id, bool $all_pages ): void {
		if ( self::$all ) {
			return;
		}
		if ( $all_pages || '' !== (string) get_post_meta( $id, Library::META_SCOPE, true ) ) {
			self::everything();
			return;
		}
		if ( isset( self::$shared_tabs[ $id ] ) ) {
			return; // Already looked up: a save changes the post and its metas.
		}
		self::$shared_tabs[ $id ] = true;
		$ids                      = Library::products_using( $id, self::MAX_PRODUCTS + 1 );
		if ( count( $ids ) > self::MAX_PRODUCTS ) {
			self::everything();
			return;
		}
		self::products( $ids );
	}

	/**
	 * Products to purge at the end of the request.
	 *
	 * @param int[] $ids Product ids.
	 */
	private static function products( array $ids ): void {
		foreach ( $ids as $id ) {
			self::$products[ (int) $id ] = true;
		}
	}

	/** Every page to purge at the end of the request (the WooCommerce tabs of every product changed). */
	public static function everything(): void {
		self::$all = true;
	}

	/** End of the request: purges the pages collected. */
	public static function flush(): void {
		$all      = self::$all;
		$products = array_keys( self::$products );

		self::$all         = false;
		self::$products    = array();
		self::$shared_tabs = array();

		$ids = array();
		if ( ! $all ) {
			foreach ( $products as $id ) {
				if ( 'publish' === get_post_status( $id ) ) {
					$ids[] = $id;
				}
			}
			if ( ! $ids ) {
				return;
			}
			$all = count( $ids ) > self::MAX_PRODUCTS;
		}

		if ( $all ) {
			do_action( 'litespeed_purge_all' ); // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- LiteSpeed Cache hook.
			if ( function_exists( 'rocket_clean_domain' ) ) {
				rocket_clean_domain();
			}
			if ( function_exists( 'w3tc_flush_all' ) ) {
				w3tc_flush_all();
			}
			if ( function_exists( 'wp_cache_clear_cache' ) ) {
				wp_cache_clear_cache();
			}
			if ( function_exists( 'wpfc_clear_all_cache' ) ) {
				wpfc_clear_all_cache();
			}
			$ids = array();
		} else {
			foreach ( $ids as $id ) {
				do_action( 'litespeed_purge_post', $id ); // phpcs:ignore WordPress.NamingConventions.PrefixAllGlobals.NonPrefixedHooknameFound -- LiteSpeed Cache hook.
				if ( function_exists( 'rocket_clean_post' ) ) {
					rocket_clean_post( $id );
				}
				if ( function_exists( 'w3tc_flush_post' ) ) {
					w3tc_flush_post( $id );
				}
				if ( function_exists( 'wpsc_delete_post_cache' ) ) {
					wpsc_delete_post_cache( $id );
				}
				if ( function_exists( 'wpfc_clear_post_cache_by_id' ) ) {
					wpfc_clear_post_cache_by_id( $id );
				}
			}
		}

		/**
		 * Product pages whose tabs changed, once the cache plugins ProdTabs knows have been asked to purge them. For a
		 * host cache or another cache plugin.
		 *
		 * @param int[] $ids Product ids; empty when every page is concerned.
		 */
		do_action( 'prodtabs_purge_cache', $ids );
	}
}