/**
 * Strategy seam for the optional history + ledger + time-machine
 * service. Core imports `HistoryStrategy` type-only + `NO_HISTORY`
 * stub; real implementations of `saveHistory`, `LedgerStore`,
 * `VaultInstant`, `computePatch`, `diff` etc. are only reachable via
 * `withHistory()` in `./active.ts`.
 *
 * Applications that don't track per-record versioning, don't need the
 * hash-chained audit ledger, and don't restore to past instants ship
 * none of the ~1,880 LOC behind this seam.
 *
 * Strategy contract:
 *
 * - **saveHistory / pruneHistory / clearHistory** — no-ops under
 *   NO_HISTORY. Writes still succeed; no snapshot is captured.
 * - **getHistoryEntries / getVersionEnvelope / diff** — throw under
 *   NO_HISTORY. These are read APIs the consumer would only call
 *   after explicitly asking for history; the throw guides them to
 *   `@noy-db/hub/history`.
 * - **envelopePayloadHash / computePatch** — return empty / `[]`
 *   under NO_HISTORY. These are only used inside the
 *   `if (this.ledger)` branch, which is itself gated by
 *   `buildLedger()` returning null.
 * - **buildLedger** — returns `null` under NO_HISTORY. The Vault's
 *   public `vault.ledger()` accessor throws when null.
 * - **buildVaultInstant** — throws under NO_HISTORY. `vault.at()`
 *   propagates the throw.
 *
 * @internal
 */
import type { EncryptedEnvelope, NoydbStore, HistoryOptions, PruneOptions } from '../../kernel/types.js';
import type { LedgerStore } from './ledger/store.js';
import type { JsonPatch } from './ledger/patch.js';
import type { DiffEntry } from './diff.js';
import type { VaultInstant, VaultEngine } from './time-machine.js';
import type { EnclaveKey } from '../../kernel/enclave/index.js';
/**
 * Options accepted by `HistoryStrategy.buildLedger`. Mirrors the
 * `LedgerStore` constructor verbatim — kept in this file so `core`
 * code never imports the LedgerStore module at runtime.
 *
 * @internal
 */
export interface BuildLedgerOptions {
    adapter: NoydbStore;
    vault: string;
    encrypted: boolean;
    getDEK: (collectionName: string) => Promise<EnclaveKey>;
    actor: string;
}
/**
 * @internal
 */
export interface HistoryStrategy {
    /**
     * Persist a full encrypted envelope snapshot of the prior version
     * under `_history/{collection}:{id}:{paddedVersion}`. No-op under
     * `NO_HISTORY`.
     */
    saveHistory(adapter: NoydbStore, vault: string, collection: string, recordId: string, envelope: EncryptedEnvelope): Promise<void>;
    /**
     * List history envelopes for a record, newest first. Throws under
     * `NO_HISTORY` — callers reach this via `collection.history()` /
     * `collection.getVersion()` / `collection.diff()`, which only work
     * with the strategy enabled.
     */
    getHistoryEntries(adapter: NoydbStore, vault: string, collection: string, recordId: string, options?: HistoryOptions): Promise<EncryptedEnvelope[]>;
    /**
     * Fetch a specific version's envelope. Throws under `NO_HISTORY`.
     */
    getVersionEnvelope(adapter: NoydbStore, vault: string, collection: string, recordId: string, version: number): Promise<EncryptedEnvelope | null>;
    /**
     * Prune history entries by retention rule. Returns `0` under
     * `NO_HISTORY`.
     */
    pruneHistory(adapter: NoydbStore, vault: string, collection: string, recordId: string | undefined, options: PruneOptions): Promise<number>;
    /**
     * Clear all history for vault/collection/record. Returns `0` under
     * `NO_HISTORY`.
     */
    clearHistory(adapter: NoydbStore, vault: string, collection?: string, recordId?: string): Promise<number>;
    /**
     * Crypto-shred (overwrite-to-tombstone) every `_history` version of a
     * record for GDPR erasure. Returns the number of versions newly
     * tombstoned, or `0` under `NO_HISTORY` (no history = nothing to shred).
     */
    tombstoneHistory(adapter: NoydbStore, vault: string, collection: string, recordId: string, actor: string, encrypted: boolean): Promise<number>;
    /**
     * Re-key every `_history` snapshot of a record from `fromDek` to `toDek`
     * on a tier move (elevate/demote/putAtTier), mirroring the live-body
     * rewrap so prior versions are not left decryptable at rest under a tier
     * the record has moved away from. Optional `tier0Dek` enables the legacy
     * fallback for snapshots written before this rewrap existed (see
     * `history.ts` for the full contract). No-op under `NO_HISTORY` (no
     * history = nothing to rewrap).
     */
    rewrapHistory(adapter: NoydbStore, vault: string, collection: string, recordId: string, fromDek: EnclaveKey, toDek: EnclaveKey, tier0Dek?: EnclaveKey): Promise<void>;
    /**
     * Compute the SHA-256 hash of an envelope's encrypted payload, used
     * by `LedgerStore.append` to track tamper-evidence. Returns the
     * empty string under `NO_HISTORY` (the call site is gated by
     * `if (this.ledger)`, so the value is never observed).
     */
    envelopePayloadHash(envelope: EncryptedEnvelope | null): Promise<string>;
    /**
     * Compute the JSON patch from `from` → `to`. Returns `[]` under
     * `NO_HISTORY`.
     */
    computePatch(from: unknown, to: unknown): JsonPatch;
    /**
     * Compute the typed diff between two records. Throws under
     * `NO_HISTORY` — `collection.diff()` is a history-read API.
     */
    diff(recordA: unknown, recordB: unknown): DiffEntry[];
    /**
     * Construct (or return null) a `LedgerStore` for the vault. Returns
     * `null` under `NO_HISTORY`; the Vault treats null as "no ledger
     * attached" — collection write paths skip the append branch and the
     * public `vault.ledger()` accessor throws.
     */
    buildLedger(opts: BuildLedgerOptions): LedgerStore | null;
    /**
     * Construct a `VaultInstant` for time-machine reads. Throws under
     * `NO_HISTORY`.
     */
    buildVaultInstant(engine: VaultEngine, timestamp: string): VaultInstant;
}
/**
 * No-history stub. Snapshots and prune/clear are no-ops; reads and
 * time-machine throw with an actionable message; ledger construction
 * returns null so the write-path's `if (this.ledger)` branch is dead
 * code in the bundle.
 *
 * @internal
 */
export declare const NO_HISTORY: HistoryStrategy;