front-hub/src/utils/calcTariffPrices.ts

import { Discount, Tariff, findDiscountFactor } from "@frontend/kitui";
import { calcCart } from "./calcCart/calcCart";

export function calcIndividualTariffPrices(
  tariff: Tariff,
  discounts: Discount[],
  purchasesAmount: number,
  currentTariffs: Tariff[]
): {
  priceBeforeDiscounts: number;
  priceAfterDiscounts: number;
} {
  const priceBeforeDiscounts =
    tariff.price || tariff.privileges.reduce((sum, privilege) => sum + privilege.amount * privilege.price, 0);
  let priceAfterDiscounts = priceBeforeDiscounts;

  const cart = calcCart([...currentTariffs, tariff], discounts, purchasesAmount);

  cart.allAppliedDiscounts.forEach((discount) => {
    priceAfterDiscounts *= findDiscountFactor(discount);
  });

  return { priceBeforeDiscounts, priceAfterDiscounts };
}