/**
 * SQLite-backed CheckpointStorage adapter using bun:sqlite.
 *
 * Provides local file-based persistence with transaction support
 * and WAL mode for performance.
 */
import { Database } from 'bun:sqlite';
import type { CheckpointStorage, Checkpoint, CheckpointStatus } from './types';
/**
 * Configuration options for SqliteCheckpointStorage.
 */
export interface SqliteCheckpointStorageOptions {
    /**
     * Path to the SQLite database file.
     * Use ':memory:' for in-memory database (useful for tests).
     * @default 'fred.db'
     */
    path?: string;
    /**
     * Pre-configured Database instance for dependency injection (useful for testing).
     */
    db?: Database;
}
/**
 * SQLite-backed implementation of CheckpointStorage.
 *
 * Features:
 * - File-based or in-memory persistence
 * - Transaction support for atomic operations
 * - WAL mode for better concurrent read performance
 * - Best-effort recovery with warnings for corrupted rows
 */
export declare class SqliteCheckpointStorage implements CheckpointStorage {
    private db;
    private initialized;
    constructor(options?: SqliteCheckpointStorageOptions);
    /**
     * Ensure the database schema is initialized.
     * Enables foreign keys and WAL mode, then creates tables if needed.
     */
    private ensureInitialized;
    /**
     * Save a checkpoint (upsert by run_id + step).
     */
    save(checkpoint: Checkpoint): Promise<void>;
    /**
     * Get the latest checkpoint for a run (highest step number).
     * Returns null if no checkpoints exist for the run.
     */
    getLatest(runId: string): Promise<Checkpoint | null>;
    /**
     * Get a specific checkpoint by run_id and step.
     * Returns null if not found.
     */
    get(runId: string, step: number): Promise<Checkpoint | null>;
    /**
     * Update the status of a checkpoint.
     */
    updateStatus(runId: string, step: number, status: CheckpointStatus): Promise<void>;
    /**
     * Delete all checkpoints for a run.
     */
    deleteRun(runId: string): Promise<void>;
    /**
     * Delete expired checkpoints (where expires_at < current time).
     * Uses ISO 8601 string comparison since expires_at is stored as ISO string.
     * @returns The number of deleted checkpoints
     */
    deleteExpired(): Promise<number>;
    /**
     * List checkpoints by status (for querying pending pauses).
     * Excludes expired checkpoints (where expires_at < current time).
     */
    listByStatus(status: CheckpointStatus): Promise<Checkpoint[]>;
    /**
     * Get the latest checkpoint for a pipeline (highest step, timestamp tie-break).
     * Returns the checkpoint with the highest step number, using created_at as a tie-breaker.
     * Excludes expired checkpoints.
     */
    getLatestByPipelineId(pipelineId: string): Promise<Checkpoint | null>;
    /**
     * Close the database connection.
     */
    close(): Promise<void>;
    /**
     * Convert a database row to a Checkpoint object.
     */
    private rowToCheckpoint;
}
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