import type { ID } from "./types.js";
import type { FeePolicy } from "./interfaces.js";
export declare function newId(): ID;
/**
 * Apply integer HALF_UP rounding to a floating-point intermediate result.
 * All final amounts must be integers in minor units; this helper is used
 * only when computing FX-converted amounts or fee percentages.
 */
export declare function roundHalfUp(value: number): number;
export declare function roundHalfDown(value: number): number;
export declare function roundFloor(value: number): number;
export declare function roundCeiling(value: number): number;
/**
 * Register custom currency decimal-place definitions.
 * Called by `createPayClient` when the `currencies` config option is provided.
 */
export declare function registerCurrencies(currencies: Array<{
    code: string;
    decimalPlaces: number;
}>): void;
/**
 * Return ISO 4217 minor unit exponent for a currency code.
 *
 * Checks the custom registry (populated via `registerCurrencies`) first,
 * then falls back to Intl.NumberFormat, then to 2.
 *
 * Examples:
 * - USD -> 2
 * - JPY -> 0
 * - KWD -> 3
 *
 * Falls back to 2 when unknown.
 */
export declare function getCurrencyExponent(currency: string): number;
export declare function minorToMajor(amountMinor: number, currency: string): number;
export declare function majorToMinor(amountMajor: number, currency: string, roundingMode?: string): number;
export declare function applyRounding(value: number, mode?: string): number;
/**
 * Convert an amount from one currency to another using a string rate.
 * Returns an integer in the target currency's minor units.
 *
 * Uses decimal.js for all intermediate arithmetic per §30 precision mandate.
 */
/**
 * Normalise incoming HTTP headers to lowercase keys with string values.
 * Multi-value headers (Express arrays) are joined with a comma.
 * Use this before passing headers to `verifyWebhook` or `verifyPayoutWebhook`.
 *
 * @example
 * const headers = normalizeHeaders(req.headers);
 * await adapter.verifyWebhook({ rawBody, headers, secret });
 */
export declare function normalizeHeaders(headers: Record<string, string | string[] | undefined>): Record<string, string>;
export declare function convertAmount(amountMinor: number, rate: string, roundingMode?: string, options?: {
    fromCurrency?: string;
    toCurrency?: string;
}): number;
export interface PayoutFeePolicyConfig {
    /**
     * Flat fee in minor units added to every withdrawal.
     * Use 0 to disable.
     */
    flat?: number;
    /**
     * Percentage fee as a plain number (e.g. `1.5` = 1.5%).
     * Computed from the withdrawal amount and added on top of the flat fee.
     * Use 0 to disable.
     */
    percent?: number;
    /**
     * Maximum total fee in minor units. When non-zero, the combined flat + percent
     * fee is capped at this value.
     * Use 0 for no cap.
     */
    cap?: number;
}
/**
 * Returns a `FeePolicy` that applies a flat fee, a percentage fee, or both,
 * with an optional cap. The policy only fires for `withdrawal` operations;
 * all other operation types receive `null` (no fee).
 *
 * @example
 * const pay = createPayClient({
 *   feePolicy: createPayoutFeePolicy({ flat: 0, percent: 1.5, cap: 50000 }),
 *   // ...
 * });
 */
export declare function createPayoutFeePolicy(config: PayoutFeePolicyConfig): FeePolicy;
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