/**
 * Configuration Helper Utilities for Photon
 *
 * Provides utility functions for validating and accessing environment variables
 * with clear, actionable error messages.
 */
/**
 * Require an environment variable, throwing a clear error if not set
 *
 * @param name Environment variable name
 * @param description Optional description of what this variable is used for
 * @returns The environment variable value
 * @throws Error if environment variable is not set
 *
 * @example
 * const apiKey = requireEnv('OPENAI_API_KEY', 'Required for OpenAI API access');
 */
export declare function requireEnv(name: string, description?: string): string;
/**
 * Get an optional environment variable with a default value
 *
 * @param name Environment variable name
 * @param defaultValue Default value if not set
 * @returns The environment variable value or default
 *
 * @example
 * const region = optionalEnv('AWS_REGION', 'us-east-1');
 * const port = optionalEnv('PORT', '3000');
 */
export declare function optionalEnv(name: string, defaultValue?: string): string | undefined;
/**
 * Validate multiple environment variables at once
 *
 * @param schema Object mapping env var names to config
 * @returns Object mapping env var names to values
 * @throws Error if any required variable is missing
 *
 * @example
 * const config = validateConfig({
 *   OPENAI_API_KEY: { required: true, description: 'OpenAI API key' },
 *   OPENAI_ORG_ID: { required: false, default: 'personal' },
 *   AWS_REGION: { required: false, default: 'us-east-1' }
 * });
 * // Returns: { OPENAI_API_KEY: 'sk-...', OPENAI_ORG_ID: 'personal', AWS_REGION: 'us-east-1' }
 */
export declare function validateConfig(schema: Record<string, {
    required?: boolean;
    default?: string;
    description?: string;
}>): Record<string, string | undefined>;
/**
 * Check if an environment variable is set
 *
 * @param name Environment variable name
 * @returns True if set and non-empty
 *
 * @example
 * if (hasEnv('OPENAI_API_KEY')) {
 *   // Use OpenAI
 * } else {
 *   // Fall back to other provider
 * }
 */
export declare function hasEnv(name: string): boolean;
/**
 * Get environment variable or throw with custom error message
 *
 * @param name Environment variable name
 * @param errorMessage Custom error message
 * @returns The environment variable value
 * @throws Error with custom message if not set
 *
 * @example
 * const token = requireEnvOr(
 *   'GITHUB_TOKEN',
 *   'GitHub token required. Get one at https://github.com/settings/tokens'
 * );
 */
export declare function requireEnvOr(name: string, errorMessage: string): string;
/**
 * Validate environment variable matches a pattern
 *
 * @param name Environment variable name
 * @param pattern Regular expression pattern
 * @param description Description of expected format
 * @returns The environment variable value
 * @throws Error if not set or doesn't match pattern
 *
 * @example
 * const apiKey = validateEnvPattern(
 *   'OPENAI_API_KEY',
 *   /^sk-[a-zA-Z0-9]{40,}$/,
 *   'OpenAI API key format: sk-...'
 * );
 */
export declare function validateEnvPattern(name: string, pattern: RegExp, description?: string): string;
/**
 * Parse environment variable as integer
 *
 * @param name Environment variable name
 * @param defaultValue Default value if not set or invalid
 * @returns Parsed integer value
 *
 * @example
 * const port = envInt('PORT', 3000);
 * const timeout = envInt('TIMEOUT', 30);
 */
export declare function envInt(name: string, defaultValue: number): number;
/**
 * Parse environment variable as boolean
 *
 * Treats 'true', '1', 'yes', 'on' as true (case-insensitive)
 * Treats 'false', '0', 'no', 'off' as false (case-insensitive)
 *
 * @param name Environment variable name
 * @param defaultValue Default value if not set or invalid
 * @returns Boolean value
 *
 * @example
 * const debug = envBool('DEBUG', false);
 * const secure = envBool('SMTP_SECURE', true);
 */
export declare function envBool(name: string, defaultValue: boolean): boolean;
/**
 * Parse environment variable as JSON
 *
 * @param name Environment variable name
 * @param defaultValue Default value if not set or invalid
 * @returns Parsed JSON value
 *
 * @example
 * const gcpCreds = envJSON('GCP_CREDENTIALS', {});
 * const config = envJSON('APP_CONFIG', { timeout: 30 });
 */
export declare function envJSON<T = any>(name: string, defaultValue: T): T;
/**
 * Build connection string from environment variables
 *
 * @param template Template string with {{VAR}} placeholders
 * @param required Array of required variable names
 * @returns Connection string with variables replaced
 * @throws Error if any required variable is missing
 *
 * @example
 * const dbUrl = buildConnectionString(
 *   'postgresql://{{DB_USER}}:{{DB_PASS}}@{{DB_HOST}}:{{DB_PORT}}/{{DB_NAME}}',
 *   ['DB_USER', 'DB_PASS', 'DB_HOST', 'DB_PORT', 'DB_NAME']
 * );
 */
export declare function buildConnectionString(template: string, required: string[]): string;
//# sourceMappingURL=config-helpers.d.ts.map