/**
 * Postgres-backed ContextStorage adapter.
 *
 * Provides production-grade persistence using Postgres with safe transactions
 * and best-effort recovery for corrupted rows.
 */
import type { Pool } from 'pg';
import type { ContextStorage, ConversationContext, SessionSummary } from '../context';
/**
 * Configuration options for PostgresContextStorage.
 */
export interface PostgresContextStorageOptions {
    /**
     * Connection string for Postgres (e.g., postgres://user:pass@host:5432/db).
     * Either connectionString or pool must be provided.
     */
    connectionString?: string;
    /**
     * Pre-configured Pool instance for dependency injection (useful for testing).
     * Either connectionString or pool must be provided.
     */
    pool?: Pool;
}
/**
 * Postgres-backed implementation of ContextStorage.
 *
 * Features:
 * - Lazy schema initialization with CREATE TABLE IF NOT EXISTS
 * - Transactional writes for data integrity
 * - Best-effort recovery with warnings for corrupted rows
 * - Support for both connection string and injected pool (for testing)
 */
export declare class PostgresContextStorage implements ContextStorage {
    private pool;
    private initialized;
    private initPromise;
    constructor(options: PostgresContextStorageOptions);
    /**
     * Lazily initialize the database schema.
     * Safe to call multiple times; only executes once.
     */
    private ensureInitialized;
    private initializeSchema;
    /**
     * Get a conversation context by ID.
     * Returns null if the conversation doesn't exist.
     * Uses best-effort recovery, logging warnings for corrupted message rows.
     */
    get(id: string): Promise<ConversationContext | null>;
    /**
     * Store a conversation context.
     * Uses a transaction to ensure atomic writes:
     * 1. Upsert conversation metadata
     * 2. Delete existing messages
     * 3. Insert new messages with sequence numbers
     */
    set(id: string, context: ConversationContext): Promise<void>;
    /**
     * List session summaries ordered by updated_at DESC.
     */
    listSessions(): Promise<SessionSummary[]>;
    /**
     * Delete a conversation and all its messages.
     * Messages are automatically deleted via CASCADE.
     */
    delete(id: string): Promise<void>;
    /**
     * Clear all conversations and messages.
     */
    clear(): Promise<void>;
    /**
     * Close the connection pool.
     * Call this when shutting down to release resources.
     */
    close(): Promise<void>;
}
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