<?php
/**
 * Deletes shopper photos, results and old request rows on schedule.
 *
 * @package Fitzaro
 */

namespace Fitzaro\Job;

use Fitzaro\Api\TryOnService;
use Fitzaro\Storage\FileStore;

defined( 'ABSPATH' ) || exit;

/**
 * Photos are personal data, so they are kept no longer than the feature needs them. Files are
 * found by modification time, which also catches photos no request ever used. Request rows hold
 * no images and are kept longer for spending totals and statistics.
 */
final class Cleanup {

	public const DEFAULTS = array(
		'uploads' => 86400,
		'results' => 604800,
		'rows'    => 7776000,
	);

	/**
	 * Results must outlive the image links handed out for them.
	 */
	public const MIN_RESULTS = 3600;

	/**
	 * Files deleted per kind and run, so one run stays short on a large backlog.
	 */
	public const BATCH = 500;

	/**
	 * Request storage.
	 *
	 * @var Requests
	 */
	private $requests;

	/**
	 * Private files.
	 *
	 * @var FileStore
	 */
	private $files;

	/**
	 * Seconds to keep each kind.
	 *
	 * @var array{uploads: int, results: int, rows: int}
	 */
	private $retention;

	/**
	 * Returns the current Unix time.
	 *
	 * @var callable
	 */
	private $clock;

	/**
	 * Creates the job.
	 *
	 * @param Requests                                     $requests  Request storage.
	 * @param FileStore                                    $files     Private files.
	 * @param array{uploads: int, results: int, rows: int} $retention From retention().
	 * @param callable                                     $clock     Returns the current Unix time.
	 */
	public function __construct( Requests $requests, FileStore $files, array $retention, callable $clock ) {
		$this->requests  = $requests;
		$this->files     = $files;
		$this->retention = $retention;
		$this->clock     = $clock;
	}

	/**
	 * Retention in seconds, with defaults and safe minimums.
	 *
	 * Photos must outlive their reference and any job using them; rows must outlive their results.
	 *
	 * @param mixed $retention Filtered settings.
	 * @return array{uploads: int, results: int, rows: int}
	 */
	public static function retention( $retention ): array {
		$retention = is_array( $retention ) ? $retention : array();

		$value = static function ( string $key ) use ( $retention ): int {
			$seconds = $retention[ $key ] ?? self::DEFAULTS[ $key ];

			return is_numeric( $seconds ) ? (int) $seconds : self::DEFAULTS[ $key ];
		};

		$results = max( self::MIN_RESULTS, $value( 'results' ) );

		return array(
			'uploads' => max( TryOnService::PHOTO_LIFETIME + LeasePolicy::MAX_AGE, $value( 'uploads' ) ),
			'results' => $results,
			'rows'    => max( $results, $value( 'rows' ) ),
		);
	}

	/**
	 * Runs one pass.
	 *
	 * @return array{uploads: int, results: int, expired: int, rows: int} What was removed.
	 */
	public function run(): array {
		$now = (int) ( $this->clock )();

		$expired = $this->requests->expire_results( gmdate( 'Y-m-d H:i:s', $now - $this->retention['results'] ) );
		$results = $this->delete( FileStore::RESULTS, $now - $this->retention['results'] );
		$uploads = $this->delete( FileStore::UPLOADS, $now - $this->retention['uploads'] );
		$rows    = $this->requests->delete_created_before( gmdate( 'Y-m-d H:i:s', $now - $this->retention['rows'] ) );

		return array(
			'uploads' => $uploads,
			'results' => $results,
			'expired' => $expired,
			'rows'    => $rows,
		);
	}

	/**
	 * Deletes files of a kind older than $before.
	 *
	 * @param string $kind   FileStore kind.
	 * @param int    $before Unix time.
	 */
	private function delete( string $kind, int $before ): int {
		$deleted = 0;
		foreach ( $this->files->stale( $kind, $before, self::BATCH ) as $path ) {
			if ( $this->files->delete( $path ) ) {
				++$deleted;
			}
		}

		return $deleted;
	}
}