/**
 * Layered Configuration System - Hierarchical configuration management
 *
 * This module implements a layered configuration system with:
 * - Global defaults
 * - User-specific settings
 * - Runtime overrides
 * - Environment-specific configurations
 */
import { Logger } from "../types.js";
export interface ConfigLayer {
    name: string;
    priority: number;
    source: string;
    config: Record<string, unknown>;
    loaded: boolean;
    lastModified?: Date;
}
export interface LayeredConfigOptions {
    configDir?: string;
    enableEnvironmentOverrides?: boolean;
    enableRuntimeOverrides?: boolean;
    configFileName?: string;
    userConfigFileName?: string;
    environmentConfigFileName?: string;
}
export declare class LayeredConfigManager {
    private layers;
    private logger;
    private options;
    private mergedConfig;
    private configWatchers;
    constructor(logger: Logger, options?: LayeredConfigOptions);
    /**
     * Load all configuration layers
     */
    loadAllLayers(): Promise<Record<string, unknown>>;
    /**
     * Get merged configuration
     */
    getConfig(): Record<string, unknown>;
    /**
     * Get configuration value with dot notation
     */
    getValue<T>(path: string): T | undefined;
    /**
     * Set configuration value with dot notation
     */
    setValue(path: string, value: unknown): void;
    /**
     * Override configuration at runtime
     */
    setRuntimeOverride(path: string, value: unknown): void;
    /**
     * Clear runtime overrides
     */
    clearRuntimeOverrides(): void;
    /**
     * Reload a specific layer
     */
    reloadLayer(layerName: string): Promise<void>;
    /**
     * Enable file watching for a layer
     */
    enableFileWatching(layerName: string): void;
    /**
     * Get layer information
     */
    getLayerInfo(): Array<{
        name: string;
        priority: number;
        source: string;
        loaded: boolean;
        lastModified?: Date;
        configKeys: string[];
    }>;
    /**
     * Initialize configuration layers
     */
    private initializeLayers;
    /**
     * Load a specific configuration layer
     */
    private loadLayer;
    /**
     * Load configuration from file
     */
    private loadConfigFromFile;
    /**
     * Load environment variables
     */
    private loadEnvironmentVariables;
    /**
     * Parse environment variable value
     */
    private parseEnvironmentValue;
    /**
     * Merge all configuration layers
     */
    private mergeLayers;
    /**
     * Deep merge objects
     */
    private deepMerge;
    /**
     * Set nested value using dot notation
     */
    private setNestedValue;
    /**
     * Watch configuration file for changes
     */
    private watchConfigFile;
    /**
     * Get default configuration directory
     */
    private getDefaultConfigDir;
    /**
     * Get default configuration
     */
    private getDefaultConfiguration;
    /**
     * Cleanup resources
     */
    destroy(): void;
}
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