import type { EmbeddingCacheEntry, EmbeddingCacheStore } from '../types/embeddings.js';
import type { MigrationResult, SchemaMigration } from '../utils/schema-migrations.js';
import { type SqliteDatabaseLike, type SqliteLikeClient } from './client.js';
import type { SqliteMigrateOptions } from './migrations.js';
/** Options for the SQLite embedding cache. */
export interface SqliteEmbeddingCacheOptions {
    /** The table. Defaults to `nexus_embedding_cache`. */
    table?: string;
    /** Replaces the system clock, for tests. */
    now?: () => number;
}
/** The versioned schema, which `migrate()` applies. */
export declare function sqliteEmbeddingCacheMigrations(options?: {
    table?: string;
}): SchemaMigration[];
/**
 * Vectors in a SQLite table, for one machine's processes, or a team's through libSQL. A vector is
 * packed float32 in a blob, and a batch of keys is read in statements of 500.
 */
export declare class SqliteEmbeddingCache implements EmbeddingCacheStore {
    private readonly options;
    private readonly client;
    private readonly table;
    private readonly now;
    constructor(database: SqliteLikeClient | SqliteDatabaseLike, options?: SqliteEmbeddingCacheOptions);
    /** Applies the table's pending migrations. Never runs implicitly. */
    migrate(options?: SqliteMigrateOptions): Promise<MigrationResult>;
    /** The vectors under these keys, in order, with `undefined` for each miss or expired entry. */
    getMany(keys: readonly string[]): Promise<Array<number[] | undefined>>;
    /** Stores vectors, each for `ttlSeconds` when given. */
    setMany(entries: readonly EmbeddingCacheEntry[], ttlSeconds?: number): Promise<void>;
    /** Deletes expired vectors, returning how many went. */
    purgeExpired(): Promise<number>;
}