/**
 * DatabaseService - Centralized database connection and SQL execution service
 * Handles connection pooling, retry logic, and SQL execution with transaction management
 */
import { EventEmitter } from 'node:events';
import pg from 'pg';
import type { CLIConfig, MigrationError } from '../types.js';
export interface DatabaseServiceConfig {
    connectionString: string;
    connectionTimeoutMillis?: number;
    maxConnections?: number;
    idleTimeoutMillis?: number;
    maxUses?: number;
    maxRetries?: number;
    retryDelayMs?: number;
    wrapInTransaction?: boolean;
}
export interface ConnectionStats {
    total: number;
    idle: number;
    active: number;
}
export declare enum DatabaseErrorType {
    CONNECTION_ERROR = "CONNECTION_ERROR",
    SYNTAX_ERROR = "SYNTAX_ERROR",
    CONSTRAINT_VIOLATION = "CONSTRAINT_VIOLATION",
    TIMEOUT_ERROR = "TIMEOUT_ERROR",
    TRANSACTION_ERROR = "TRANSACTION_ERROR",
    POOL_EXHAUSTED = "POOL_EXHAUSTED",
    UNKNOWN_ERROR = "UNKNOWN_ERROR"
}
export interface DatabaseError {
    type: DatabaseErrorType;
    message: string;
    originalError?: Error;
    code?: string;
    detail?: string;
    hint?: string;
}
export interface SqlExecutionResult {
    success: boolean;
    error?: string;
    databaseError?: DatabaseError;
    rows?: unknown[];
    rowCount?: number;
    data?: unknown;
}
export interface ExecutionConfig {
    templateName?: string;
    useTransaction?: boolean;
    silent?: boolean;
    parameters?: unknown[];
    isolationLevel?: 'READ UNCOMMITTED' | 'READ COMMITTED' | 'REPEATABLE READ' | 'SERIALIZABLE';
}
export declare class DatabaseService extends EventEmitter {
    private config;
    private pool;
    private connectionAttempts;
    private disposed;
    constructor(config: DatabaseServiceConfig);
    /**
     * Categorize database errors for better error handling
     */
    private categorizeError;
    /**
     * Create and configure database connection pool
     */
    private createPool;
    /**
     * Establish database connection with retry logic
     */
    private retryConnection;
    /**
     * Get a database connection with retry logic
     */
    connect(params?: {
        silent?: boolean;
    }): Promise<pg.PoolClient>;
    /**
     * Test database connectivity
     */
    testConnection(): Promise<boolean>;
    /**
     * Execute SQL with optional transaction wrapping and parameterized queries
     * Core method for running template content or any SQL
     */
    executeSQL(sql: string, config?: ExecutionConfig): Promise<SqlExecutionResult>;
    /**
     * Execute SQL and return migration-compatible result
     * Used by migration/template application logic
     */
    executeMigration(content: string, templateName: string, silent?: boolean): Promise<true | MigrationError>;
    /**
     * Get connection pool statistics
     */
    getConnectionStats(): ConnectionStats | null;
    /**
     * Gracefully close all database connections
     */
    dispose(): Promise<void>;
    /**
     * Create DatabaseService from CLI config
     */
    static fromConfig(config: CLIConfig): DatabaseService;
}