import type { NoydbPodStore } from '../../kernel/types.js';
import type { Vault } from '../../kernel/vault.js';
import type { SnapshotMeta, RetentionPolicy, SnapshotIndex } from './strategy.js';
export declare class SnapshotEngine {
    private readonly store;
    private readonly retention;
    constructor(store: NoydbPodStore, retention: RetentionPolicy);
    private indexKey;
    private snapKey;
    private autoKey;
    private readIndex;
    private writeIndex;
    snapshot(vault: Vault, by: string, opts?: {
        label?: string;
        note?: string;
    }): Promise<SnapshotMeta>;
    /**
     * Rolling auto-snapshot. Overwrites the single fixed `<vault>__auto` key and
     * stores its meta in `index.auto`, separate from the immutable `snapshots`
     * pool — retention never prunes it. Used by the cadence scheduler.
     */
    autoSnapshot(vault: Vault, by: string, opts?: {
        label?: string;
        note?: string;
    }): Promise<SnapshotMeta>;
    listSnapshots(vaultId: string): Promise<SnapshotMeta[]>;
    restoreSnapshot(vault: Vault, version: string): Promise<void>;
    /**
     * Applies the configured retention policy to `index`, mutating `index.snapshots`
     * in place and returning the blob keys that should be deleted from the store.
     * Called by `snapshot()` before the index is written.
     *
     * @internal — public for direct testing only
     */
    applyRetention(index: SnapshotIndex): string[];
}