import type { Duration, RetryPolicy } from '../types.ts';
export declare function normalizeStorageTimestamp(timestamp: number, fieldName: string): number;
/**
 * Parse a human-readable duration string or number to milliseconds.
 *
 * @example
 * ```ts
 * import { parseDuration } from '@lostgradient/weft';
 *
 * console.log(parseDuration(5000));       // 5000
 * console.log(parseDuration('250ms'));    // 250
 * console.log(parseDuration('30s'));      // 30000
 * console.log(parseDuration('5 minutes')); // 300000
 * console.log(parseDuration('2h'));       // 7200000
 * console.log(parseDuration('1d'));       // 86400000
 * ```
 *
 * @throws Error when the string uses an invalid format or unknown unit.
 * @throws RangeError when the resulting duration is negative or non-finite.
 */
export declare function parseDuration(duration: Duration): number;
/**
 * Calculate exponential backoff delay for a given retry attempt.
 * `attempt` is 1-indexed: `calculateBackoff(1, policy)` returns
 * `initialBackoff` directly. Pass `0` only for non-retry probes; the result is
 * `initialBackoff / backoffMultiplier`.
 *
 * @example
 * ```ts
 * import { calculateBackoff, type RetryPolicy } from '@lostgradient/weft';
 *
 * const policy: RetryPolicy = {
 *   maxAttempts: 5,
 *   initialBackoff: '1s',
 *   backoffMultiplier: 2,
 *   maxBackoff: '30s',
 * };
 *
 * console.log(calculateBackoff(1, policy)); // 1000   (attempt 1: 1s)
 * console.log(calculateBackoff(2, policy)); // 2000   (attempt 2: 2s)
 * console.log(calculateBackoff(5, policy)); // 16000  (attempt 5: 16s, capped at 30s)
 * ```
 */
export declare function calculateBackoff(attempt: number, policy: RetryPolicy): number;