/**
 * Secure logger for Schwab API client
 * Focuses on protecting authentication tokens and credentials
 */
export type LogLevel = 'debug' | 'info' | 'warn' | 'error';
export interface LoggerConfig {
    enabled: boolean;
    level: LogLevel;
}
export declare class SecureLogger {
    private config;
    constructor(config?: Partial<LoggerConfig>);
    /**
     * Check if a string looks like a token
     */
    private isLikelyToken;
    /**
     * Sanitize a value to remove sensitive information
     */
    private sanitizeValue;
    /**
     * Sanitize error objects
     */
    private sanitizeError;
    /**
     * Sanitize objects by checking field names
     */
    private sanitizeObject;
    /**
     * Format log arguments for output
     */
    private formatArgs;
    /**
     * Check if logging is allowed for the given level
     */
    private shouldLog;
    debug(...args: any[]): void;
    info(...args: any[]): void;
    warn(...args: any[]): void;
    error(...args: any[]): void;
    /**
     * Log an error with additional context
     * This method provides structured error logging
     */
    logError(message: string, error: unknown, context?: Record<string, any>): void;
}
/**
 * Create a logger instance for a specific module
 */
export declare function createLogger(moduleName: string): SecureLogger;
export declare const logger: SecureLogger;
/**
 * Sanitize a key for logging
 * Shows only the beginning and end of the key
 *
 * @param key The key to sanitize
 * @param options Sanitization options
 * @returns Sanitized key safe for logging
 */
export declare function sanitizeKeyForLog(key: string, options?: {
    maxLength?: number;
}): string;
/**
 * Sanitize an error object for safe logging
 * Removes sensitive data while preserving useful debugging information
 *
 * @param error The error to sanitize
 * @returns Sanitized error information
 */
export declare function sanitizeError(error: unknown): Record<string, any>;
/**
 * Sanitize a token for logging
 * Shows only the beginning of the token and optionally its length
 *
 * @param token The token to sanitize
 * @param options Sanitization options
 * @returns Sanitized token safe for logging
 */
export declare function sanitizeTokenForLog(token: string, options?: {
    showLength?: boolean;
}): string;