/**
 * NeuroLink Unified Logger Utility
 *
 * Centralized logging for the entire NeuroLink ecosystem.
 * Provides structured logging with different severity levels and consistent formatting.
 * Supports both CLI --debug flag and NEUROLINK_DEBUG environment variable.
 * Maintains compatibility with MCP logging while providing enhanced features.
 *
 * Features:
 * - Multiple log levels (debug, info, warn, error)
 * - Log history retention with configurable limits
 * - Conditional logging based on environment settings
 * - Structured data support for complex objects
 * - Tabular data display
 */
import type { LogEntry, LogLevel } from "../types/index.js";
declare class NeuroLinkLogger {
    private logLevel;
    private logs;
    private maxLogs;
    private isDebugMode;
    private eventEmitter?;
    constructor();
    /**
     * Sets the event emitter that will receive log events.
     * When set, all log operations will emit a "log-event" event.
     *
     * @param emitter - The event emitter instance
     */
    setEventEmitter(emitter: {
        emit: (event: string, ...args: unknown[]) => boolean;
    }): void;
    /**
     * Clears the event emitter reference.
     * Should be called when a NeuroLink instance is disposed to prevent memory leaks.
     */
    clearEventEmitter(): void;
    /**
     * Sets the minimum log level that will be processed and output.
     * Log messages with a level lower than this will be ignored.
     *
     * @param level - The minimum log level to process ("debug", "info", "warn", or "error")
     */
    setLogLevel(level: LogLevel): void;
    /**
     * Determines whether a message with the given log level should be processed.
     * This method considers both the configured log level and the current debug mode.
     *
     * Logic:
     * 1. If not in debug mode, only error messages are allowed
     * 2. If in debug mode, messages at or above the configured log level are allowed
     *
     * @param level - The log level to check
     * @returns True if a message with this level should be logged, false otherwise
     */
    shouldLog(level: LogLevel): boolean;
    /**
     * Generates a standardized prefix for log messages.
     * The prefix includes a timestamp and the log level in a consistent format.
     *
     * @param timestamp - ISO string representation of the log timestamp
     * @param level - The log level for this message
     * @returns Formatted prefix string like "[2025-08-18T13:45:30.123Z] [NEUROLINK:ERROR]"
     */
    private getLogPrefix;
    /**
     * Extracts current OTel trace context (trace_id, span_id) if available.
     * Returns empty object if OTel is not initialized or no active span exists.
     */
    private getTraceContext;
    /**
     * Safely serialize data to fully expanded JSON string.
     * Handles circular references and non-serializable values.
     * Zero truncation — all nested objects and arrays are fully expanded.
     */
    private serializeData;
    /**
     * Outputs a log entry to the console based on the log level.
     * Data is fully serialized to JSON — no [Object] or [Array] truncation.
     *
     * @param level - The log level (debug, info, warn, error).
     * @param prefix - The formatted log prefix.
     * @param message - The log message.
     * @param data - Optional additional data to log.
     */
    private outputToConsole;
    /**
     * Core internal logging method that handles:
     * 1. Creating log entries with consistent format
     * 2. Storing entries in the log history
     * 3. Managing log rotation to prevent memory issues
     * 4. Outputting formatted logs to the console
     * 5. Emitting log events if an event emitter is configured
     *
     * This is the central method called by all specific logging methods (debug, info, etc.)
     *
     * @param level - The severity level for this log entry
     * @param message - The message text to log
     * @param data - Optional additional context data to include
     */
    private log;
    /**
     * Logs a message at the debug level.
     * Used for detailed troubleshooting information.
     *
     * @param message - The message to log
     * @param data - Optional additional context data
     */
    debug(message: string, data?: unknown): void;
    /**
     * Logs a message at the info level.
     * Used for general information about system operation.
     *
     * @param message - The message to log
     * @param data - Optional additional context data
     */
    info(message: string, data?: unknown): void;
    /**
     * Logs a message at the warn level.
     * Used for potentially problematic situations that don't prevent operation.
     *
     * @param message - The message to log
     * @param data - Optional additional context data
     */
    warn(message: string, data?: unknown): void;
    /**
     * Logs a message at the error level.
     * Used for critical issues that may cause failures.
     *
     * @param message - The message to log
     * @param data - Optional additional context data
     */
    error(message: string, data?: unknown): void;
    /**
     * Retrieves stored log entries, optionally filtered by log level.
     * Returns a copy of the log entries to prevent external modification.
     *
     * @param level - Optional log level to filter by
     * @returns Array of log entries, either all or filtered by level
     */
    getLogs(level?: LogLevel): LogEntry[];
    /**
     * Removes all stored log entries.
     * Useful for testing or when log history is no longer needed.
     */
    clearLogs(): void;
    /**
     * Logs messages unconditionally using `console.log`.
     *
     * This method is part of a legacy simple logger interface for backward compatibility.
     * It bypasses the structured logging mechanism and should only be used when
     * unstructured, unconditional logging is required.
     *
     * Use with caution in production environments as it outputs to the console
     * regardless of the current log level or debug mode settings.
     *
     * Use cases:
     * - Critical system information that must always be visible
     * - Status messages during initialization before logging is fully configured
     * - Debugging in environments where normal logging might be suppressed
     *
     * @param args - The arguments to log. These are passed directly to `console.log`.
     */
    always(...args: unknown[]): void;
    /**
     * Displays tabular data unconditionally using `console.table`.
     *
     * Similar to the `always` method, this bypasses log level checks and
     * will display data regardless of current logging settings.
     *
     * Important differences from other logging methods:
     * - Does NOT store entries in the log history
     * - Does NOT use the structured logging format with timestamps and prefixes
     * - Outputs directly to console without additional formatting
     *
     * Particularly useful for:
     * - Displaying structured data in a readable format during debugging
     * - Showing configuration options and their current values
     * - Presenting comparison data between different system states
     * - Performance metrics and timing data
     *
     * @param data - The data to display in table format. Can be an array of objects or an object with key-value pairs.
     */
    table(data: unknown): void;
}
/**
 * Main unified logger export that provides a simplified API for logging.
 * This is the primary interface that should be used by application code.
 *
 * Features:
 * - Convenient logging methods (debug, info, warn, error)
 * - Unconditional logging (always, table)
 * - Log level control and configuration
 * - Log history management
 * - Event emission for all log operations (when emitter is configured)
 */
export declare const logger: {
    debug: (...args: unknown[]) => void;
    info: (...args: unknown[]) => void;
    warn: (...args: unknown[]) => void;
    error: (...args: unknown[]) => void;
    always: (...args: unknown[]) => void;
    table: (data: unknown) => void;
    shouldLog: (level: LogLevel) => boolean;
    setLogLevel: (level: LogLevel) => void;
    getLogs: (level?: LogLevel) => LogEntry[];
    clearLogs: () => void;
    setEventEmitter: (emitter: {
        emit: (event: string, ...args: unknown[]) => boolean;
    }) => void;
    clearEventEmitter: () => void;
};
/**
 * MCP compatibility exports - all use the same unified logger instance.
 * These exports maintain backward compatibility with code that expects
 * separate loggers for different MCP components, while actually using
 * the same underlying logger instance.
 */
export declare const mcpLogger: NeuroLinkLogger;
export declare const autoDiscoveryLogger: NeuroLinkLogger;
export declare const registryLogger: NeuroLinkLogger;
export declare const unifiedRegistryLogger: NeuroLinkLogger;
/**
 * Sets the global log level for all MCP-related logging.
 * This function provides a convenient way to adjust logging verbosity
 * for all MCP components at once.
 *
 * @param level - The log level to set ("debug", "info", "warn", or "error")
 */
export declare function setGlobalMCPLogLevel(level: LogLevel): void;
/**
 * Export LogLevel enum for runtime use.
 * Provides type-safe log level constants for use in application code.
 *
 * Example usage:
 * ```
 * import { logger, LogLevels } from './logger';  // Import from your project's path
 *
 * // Using the LogLevels constants (recommended for type safety):
 * logger.setLogLevel(LogLevels.debug);
 *
 * // Or directly using string values:
 * logger.setLogLevel('debug');
 * ```
 */
export declare const LogLevels: {
    readonly debug: "debug";
    readonly info: "info";
    readonly warn: "warn";
    readonly error: "error";
};
export {};