import type { Stats } from 'node:fs';
import type { LinkManifest } from './fan-out.manifest.js';
/** What a leftover scan found, and whether it could look at all. */
export interface LeftoverScan {
    /** Hidden folders beside the destination that an interrupted operation left. */
    folders: string[];
    /**
     * Set when the parent folder could not be listed. Round 24 (cross-model
     * review): returning an empty list then reports "could not look" as "nothing
     * is there", and the accepted residual's promise is that a displaced entry
     * gets reported.
     */
    unreadable?: string;
}
export declare const BACKUP_TAG = ".skillsmith-backup-";
export declare const STAGING_TAG = ".skillsmith-staging-";
export declare function escapeRegExp(s: string): string;
/** Hidden sibling name prefix for `dest`, e.g. `.foo.skillsmith-backup-`. */
export declare function siblingPrefix(dest: string, tag: string): string;
/** Exact match for a `mkdtemp` folder made from `siblingPrefix(dest, tag)` (6-char suffix). */
export declare function siblingPattern(dest: string, tag: string): RegExp;
export declare function lstatOrNull(p: string): Promise<Stats | null>;
/** Whether the link manifest records `dest` as a copy Skillsmith made. */
export declare function isRecordedCopy(dest: string, manifest: LinkManifest): boolean;
/**
 * Housekeeping under the destination lock, before any write:
 *  - remove an empty backup folder (a crash before anything was moved in);
 *  - restore a backup stranded by a crash between the rename-aside and the
 *    swap: the destination is missing, this is the only backup whose
 *    `original` is a real directory, and the manifest still records the
 *    destination as a copy. Backups are only ever made of recorded copies,
 *    so an unrecorded one has been uninstalled since, and restoring it would
 *    bring back a stale, untracked copy. With two or more, nothing says which
 *    is newest (a name can sort anywhere), so none is restored (round 9).
 *
 * Any other backup is left in place for `listLeftoverBackups` to report, and
 * so is a staging folder left by a crashed write: round 14 (cross-model
 * review) stopped deleting those here, since neither a folder's name nor its
 * contents proves who owns it now. Returns the backup folders restored from.
 */
export declare function recoverDestination(dest: string, manifest: LinkManifest): Promise<{
    restored: string[];
    unreadable?: string;
}>;
/**
 * Backup folders for `dest` that are still present: copies an interrupted
 * refresh left behind (after the swap, or unrestorable). Round 7: these are
 * reported to the user rather than kept silently or deleted. Round 8: an
 * empty one holds nothing to report and is removed. Round 9: on a volume
 * that ignores case, a backup made under another spelling of the name
 * (`.Foo.` for `foo`) belongs to this destination too, so it is reported;
 * it is never removed or restored, since on a case-sensitive volume the
 * same name belongs to a different destination. Round 14: a staging folder
 * left by a crashed write is reported the same way. Round 15: so is what a
 * crashed or failed removal left under a parked name. Call under the lock.
 */
export declare function listLeftoverBackups(dest: string): Promise<LeftoverScan>;
/** User-facing warning for a leftover backup, staging folder or parked entry. */
export declare function leftoverBackupWarning(folder: string): string;
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