import type { RatesConfig } from './RatesConfig';
/**
 * Loads and validates CalOohPay configuration from file system.
 *
 * This module handles loading the optional `.caloohpay.json` configuration file
 * from the project root. If no config file exists, it gracefully falls back to
 * default rates, ensuring the application works out-of-the-box.
 *
 * @category Configuration
 *
 * @remarks
 * Configuration loading follows this priority:
 * 1. `.caloohpay.json` in current working directory
 * 2. `.caloohpay.json` in user's home directory
 * 3. Default rates from Constants.ts
 *
 * @example
 * ```typescript
 * import { ConfigLoader } from './config/ConfigLoader';
 *
 * const loader = new ConfigLoader();
 * const rates = loader.loadRates();
 *
 * console.log(`Weekday rate: ${rates.weekdayRate}`);
 * console.log(`Weekend rate: ${rates.weekendRate}`);
 * ```
 */
export declare class ConfigLoader {
    /**
     * Configuration file name to search for.
     * @private
    
     */
    private static readonly CONFIG_FILENAME;
    /**
     * Loads compensation rates from config file or defaults.
     *
     * Attempts to load configuration from `.caloohpay.json` in the following locations:
     * 1. Current working directory (`process.cwd()`)
     * 2. User's home directory
     *
     * If no config file is found or parsing fails, returns default rates.
     *
     * @returns {RatesConfig} Validated compensation rates configuration
     *
     * @throws {Error} If config file exists but contains invalid rate values
     *
     * @remarks
     * Silent fallback behaviour:
     * - Missing config file → Use defaults (no error)
     * - Invalid JSON → Use defaults (logs warning)
     * - Invalid rate values → Throws error (business logic violation)
     *
     * @example
     * ```typescript
     * const loader = new ConfigLoader();
     * const rates = loader.loadRates();
     *
     * // Use rates in calculator
     * const calculator = new OnCallPaymentsCalculator(
     *   rates.weekdayRate,
     *   rates.weekendRate
     * );
     * ```
     */
    loadRates(): RatesConfig;
    /**
     * Attempts to load configuration from file system.
     *
     * Searches for `.caloohpay.json` in multiple locations and returns
     * the first valid configuration found.
     *
     * @private
     * @returns {CalOohPayConfig | null} Parsed configuration or null if not found
     *
     * @remarks
     * Search order:
     * 1. `process.cwd()/.caloohpay.json`
     * 2. `~/. caloohpay.json` (user home directory)
     *
     * JSON parsing errors are caught and logged, returning null to trigger
     * fallback to default rates.
     */
    private loadConfig;
    /**
     * Returns prioritized list of paths to search for config file.
     *
     * @private
     * @returns {string[]} Array of absolute file paths to check
     *
     * @remarks
     * Priority order:
     * 1. Current working directory (allows per-project customization)
     * 2. User home directory (allows user-wide defaults)
     */
    private getConfigSearchPaths;
    /**
     * Attempts to load and parse a single config file.
     *
     * @private
     * @param {string} filePath - Absolute path to config file
     * @returns {CalOohPayConfig | null} Parsed config or null if loading fails
     *
     * @remarks
     * Returns null in these cases:
     * - File doesn't exist
     * - File is not readable
     * - JSON parsing fails
     *
     * Errors are logged to console but don't throw, allowing graceful fallback.
     */
    private tryLoadConfigFile;
    /**
     * Validates and extracts rates from loaded configuration.
     *
     * Ensures that the configuration contains valid rate values and returns
     * a normalized RatesConfig object.
     *
     * @private
     * @param {CalOohPayConfig} config - Loaded configuration object
     * @returns {RatesConfig} Validated rates configuration
     *
     * @throws {Error} If rates are missing or invalid
     *
     * @remarks
     * Validation checks:
     * - `rates` object exists
     * - `weekdayRate` is a positive number
     * - `weekendRate` is a positive number
     * - `currency` is a non-empty string (if provided)
     *
     * Uses centralized InputValidator for consistency.
     */
    private validateAndExtractRates;
}
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