<?php
/**
 * Class ValidationDataGarbageCollection.
 *
 * @package AmpProject\AmpWP
 */

namespace AmpProject\AmpWP\BackgroundTask;

use AMP_Validated_URL_Post_Type;
use AMP_Validation_Error_Taxonomy;

/**
 * Garbage collect validation data.
 *
 * This scheduled event removes validation data (amp_validated_url posts and amp_validation_error terms) which no longer
 * have any need to be retained. The batch size of 100 follows the lead of `_wp_batch_update_comment_type()` in
 * WordPress 5.5. Deleting data from posts older than 1 week follows the lead of `wp_delete_auto_drafts()`.
 *
 * @since 2.2
 * @see _wp_batch_update_comment_type()
 * @see wp_delete_auto_drafts()
 *
 * @link https://github.com/ampproject/amp-wp/issues/4779
 * @package AmpProject\AmpWP
 * @internal
 */
final class ValidationDataGarbageCollection extends RecurringBackgroundTask {

	/**
	 * Name of the event to schedule.
	 *
	 * @var string
	 */
	const EVENT_NAME = 'amp_validation_data_gc';

	/**
	 * Get the interval to use for the event.
	 *
	 * @return string An existing interval name.
	 */
	protected function get_interval() {
		return self::DEFAULT_INTERVAL_DAILY;
	}

	/**
	 * Get the event name.
	 *
	 * This is the "slug" of the event, not the display name.
	 *
	 * Note: the event name should be prefixed to prevent naming collisions.
	 *
	 * @return string Name of the event.
	 */
	protected function get_event_name() {
		return self::EVENT_NAME;
	}

	/**
	 * Process a single cron tick.
	 *
	 * @param mixed[] ...$args Unused callback arguments.
	 * @return void
	 */
	public function process( ...$args ) { // phpcs:ignore VariableAnalysis.CodeAnalysis.VariableAnalysis.UnusedVariable

		/**
		 * Filters the count of eligible validated URLs that should be garbage collected.
		 *
		 * If this is filtered to be zero or less, then garbage collection is disabled.
		 *
		 * @since 2.2
		 *
		 * @param int $count Validated URL count. Default 100.
		 */
		$count = apply_filters( 'amp_validation_data_gc_url_count', 100 );
		if ( $count <= 0 ) {
			return;
		}

		/**
		 * Filters the date before which validated URLs will be garbage collected.
		 *
		 * @since 2.2
		 *
		 * @param string|array $before Date before which to find amp_validated_url posts to delete. Default '1 week ago'.
		 *                             Accepts strtotime()-compatible string, or array of 'year', 'month', 'day' values.
		 */
		$before = apply_filters( 'amp_validation_data_gc_before', '1 week ago' );

		AMP_Validated_URL_Post_Type::garbage_collect_validated_urls( $count, $before );

		/**
		 * Filters whether to delete empty terms during validation garbage collection.
		 *
		 * @since 2.2
		 *
		 * @param bool $enabled Whether enabled. Default true.
		 */
		if ( apply_filters( 'amp_validation_data_gc_delete_empty_terms', true ) ) {
			// Finally, delete validation errors which may now be empty.
			AMP_Validation_Error_Taxonomy::delete_empty_terms();
		}
	}
}