interface LogContext {
    [key: string]: any;
}
/**
 * Backend interface for pluggable logger implementations.
 * Consumers can provide pino, winston, or any logger that satisfies this shape.
 */
export interface LoggerBackend {
    debug(message: string, context?: Record<string, unknown>): void;
    info(message: string, context?: Record<string, unknown>): void;
    warn(message: string, context?: Record<string, unknown>): void;
    error(message: string, context?: Record<string, unknown>): void;
}
/**
 * Factory that creates a LoggerBackend for a given context name.
 * Use this to integrate structured loggers like pino:
 *
 * @example
 * ```ts
 * import pino from 'pino';
 * const root = pino();
 * setLoggerBackend((context) => root.child({ context }));
 * ```
 */
export type LoggerBackendFactory = (context: string) => LoggerBackend;
/**
 * Set a custom logger backend factory.
 * All existing and future loggers created via createLogger() will use this backend.
 * Pass `null` to reset to the default console-based logger.
 */
export declare function setLoggerBackend(factory: LoggerBackendFactory | null): void;
/**
 * Sanitization utilities for secure logging
 */
/**
 * Sanitize tokens by returning only a hash prefix
 * Prevents token exposure while maintaining debuggability
 */
export declare function sanitizeToken(token: string | undefined | null): string;
/**
 * Sanitize email addresses
 * Shows first 2 chars of local part + domain
 */
export declare function sanitizeEmail(email: string | undefined | null): string;
/**
 * Sanitize user IDs
 * Shows only first 8 characters with prefix
 */
export declare function sanitizeUserId(userId: string | undefined | null): string;
/**
 * Sanitize objects by redacting sensitive fields
 * Automatically redacts fields containing: token, password, secret, key, authorization
 */
export declare function sanitizeObject(obj: any): any;
declare class Logger {
    private context;
    constructor(context: string);
    private getBackend;
    private log;
    debug(message: string, data?: LogContext): void;
    info(message: string, data?: LogContext): void;
    warn(message: string, data?: LogContext): void;
    error(message: string, error?: Error | any, data?: LogContext): void;
}
export declare function createLogger(context: string): Logger;
export declare const authLogger: Logger;
export declare const apiLogger: Logger;
export declare const dbLogger: Logger;
export declare const chatLogger: Logger;
export {};
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