import { Log } from '@spinajs/log-common';
import { CronJob } from 'cron';
import { fs, IFsTempOptions } from './interfaces.js';
/**
 * Cleanup policy for temporary filesystems. Implement and register
 * to customize which files are considered stale and how they are removed,
 * then select it via `cleanupStrategy` option of fsTemp provider.
 *
 * Strategy also owns its schedule - scheduling mechanism ( interval, cron, ... )
 * is strategy specific and implemented in `start` / `stop`.
 *
 * Strategies hold scheduling state per temp filesystem, so implementations
 * must be registered with `@NewInstance()` - otherwise a single instance
 * would be shared between all temp filesystems.
 */
export declare abstract class TempCleanupStrategy {
    protected Logger: Log;
    /**
     * Performs single cleanup sweep on given filesystem.
     *
     * @param fs backend filesystem holding temp files
     * @param options temp fs configuration ( maxFileAge etc. )
     */
    abstract cleanup(fs: fs, options: IFsTempOptions): Promise<void>;
    /**
     * Starts scheduled cleanup - how sweeps are scheduled is up to the strategy.
     *
     * @param fs backend filesystem holding temp files
     * @param options temp fs configuration
     */
    abstract start(fs: fs, options: IFsTempOptions): void;
    /**
     * Stops scheduled cleanup. Safe to call multiple times.
     */
    abstract stop(): void;
    /**
     * Single sweep guarded against errors - remote backends can fail
     * ( network etc. ), scheduler tick must never crash.
     */
    protected safeCleanup(fs: fs, options: IFsTempOptions): Promise<void>;
}
/**
 * Default cleanup - deletes first level files older than `maxFileAge` seconds,
 * checked every `cleanupInterval` milliseconds.
 *
 * File age is taken from CreationTime when valid, otherwise from ModifiedTime -
 * remote backends often lack creation time ( s3 reports epoch, ftp reports none ).
 * Files with no usable timestamp are skipped. It does not check files recursively
 * in subdirectories.
 */
export declare class MaxAgeTempCleanupStrategy extends TempCleanupStrategy {
    /**
     * timer instance used by interval-based scheduling
     */
    protected cleanupTimer: NodeJS.Timeout | null;
    start(fs: fs, options: IFsTempOptions): void;
    stop(): void;
    cleanup(fs: fs, options: IFsTempOptions): Promise<void>;
}
/**
 * Same sweep as MaxAgeTempCleanupStrategy ( `maxFileAge` still applies ),
 * but scheduled by cron expression from `cleanupCronExpression` option
 * instead of fixed interval. Expression is required - creation fails without it.
 */
export declare class CronTempCleanupStrategy extends MaxAgeTempCleanupStrategy {
    protected cronJob: CronJob | null;
    start(fs: fs, options: IFsTempOptions): void;
    stop(): void;
}
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