export type PaymentPeriodType = 'day' | 'week' | 'month' | 'year';
export type PaymentDateInfo = {
    /** Zero-padded day of month, e.g. '06', '29' */
    day: string;
    /** Full month name, e.g. 'July', 'August' */
    month: string;
    dayNumber: number;
    /** 1-indexed month number, e.g. 5 for May, 1 for January */
    monthNumber: number;
    /** Underlying date, useful for locale-aware formatting by consumers. */
    date: Date;
};
export type PaymentStartCalculationParams = {
    /** Reference date the calculation starts from. Defaults to now. */
    dateNow?: Date;
    /** Subscription trial period length. */
    trialPeriod: number;
    trialPeriodType: PaymentPeriodType;
    /** Subscription billing period length. */
    period: number;
    periodType: PaymentPeriodType;
    /** Number of discounted recurring billing cycles. 0/undefined means none. */
    discountedRecurringBillingPeriod?: number;
};
export type PaymentStartCalculationResult = {
    /** Date the recurring billing starts (trial end). Null when there are no discounted cycles. */
    recurringBillingStartDate: PaymentDateInfo | null;
    /** Date the regular (non-discounted) payment starts. */
    paymentStartDate: PaymentDateInfo;
};
/**
 * Calculates the payment start date based on the trial period and, when present,
 * the discounted recurring billing cycles.
 *
 * Flow:
 * 1. Start from `dateNow` and add the trial period to get the initial payment start date.
 * 2. If `discountedRecurringBillingPeriod` is greater than 0, that date becomes the
 *    recurring billing start date, and the payment start date is pushed forward by
 *    `discountedRecurringBillingPeriod` billing periods — i.e. regular billing starts
 *    only after every discounted cycle has elapsed.
 */
export declare function calculatePaymentStartDate(params: PaymentStartCalculationParams): PaymentStartCalculationResult;