import { type BaseGetConfigFromEnvOptions, type EnvSource, type ZodAdapter } from './types.js';
/**
 * Validates the delimiter option.
 * @param delimiter - The delimiter to validate
 * @throws Error if delimiter is empty
 */
export declare const validateDelimiter: (delimiter: string) => void;
/**
 * Creates a debug logger function.
 * @param debug - Whether debug mode is enabled
 * @returns Logger function that only logs when debug is true
 */
export declare const createLogger: (debug: boolean) => (message: string) => void;
/**
 * Applies environment variables to the config object based on schema paths.
 *
 * @param config - The config object to modify
 * @param schema - The Zod schema
 * @param adapter - The Zod adapter for version-specific operations
 * @param log - Logger function
 * @param delimiter - The delimiter used for nested paths in env var names
 * @param envSources - Ordered env-like sources to apply
 */
export declare const applyEnvVars: (config: Record<string, unknown>, schema: unknown, adapter: ZodAdapter, log: (message: string) => void, delimiter: string, envSources: readonly EnvSource[]) => void;
/**
 * Validates config against schema and handles debug logging for errors.
 *
 * @param schema - The Zod schema
 * @param config - The config object to validate
 * @param adapter - The Zod adapter for version-specific operations
 * @param log - Logger function
 * @param debug - Whether debug mode is enabled
 * @returns Validated config object
 */
export declare const validateConfig: <T>(schema: unknown, config: Record<string, unknown>, adapter: ZodAdapter, log: (message: string) => void, debug: boolean) => T;
/**
 * Core implementation of getConfigFromEnv that works with any Zod version.
 *
 * @param options - Configuration options
 * @param schema - The Zod schema
 * @param adapter - The Zod adapter for version-specific operations
 * @returns Validated configuration object
 */
export declare const getConfigFromEnvCore: <T>(options: BaseGetConfigFromEnvOptions, schema: unknown, adapter: ZodAdapter) => T;