Cart normalizer

/* eslint-disable complexity */
import type { NormalizerContext } from "@/normalizers/types";
import type { ProductItem } from "@internal";
import { maybe } from "@/helpers";
import type { Basket, BasketAddress } from "@vsf-enterprise/sfcc-types";
import type { Maybe, SfAddress, SfCart, SfCartLineItem } from "@vue-storefront/unified-data-model";
import { defineNormalizer } from "../defineNormalizer";

/**
 * @link Reference: https://developer.salesforce.com/docs/commerce/commerce-api/references/shopper-baskets?meta=type:Basket
 */
export const normalizeCart = defineNormalizer.normalizeCart((context, basket) => {
  if (!basket.basketId || !basket.currency) {
    throw new Error("Basket must have an id, currency");
  }
  // In SAPCC basket currency is static and can't be changed.
  context.currency = basket.currency;
  const { normalizeCartCoupon, normalizeCartLineItem, normalizeMoney } = context.normalizers;
  const totalTax = getTotalTax(context, basket);
  const totalShippingPrice = basket.shippingTotal ? normalizeMoney(basket.shippingTotal) : null;
  const totalPrice = getTotalPrice(context, basket);
  const totalItems = getTotalItems(basket);
  const shippingAddress = getAddress(context, basket.shipments?.[0]?.shippingAddress);
  const billingAddress = getAddress(context, basket.billingAddress);
  const appliedCoupons = basket.couponItems?.map((coupon) => normalizeCartCoupon(coupon)) ?? [];
  const lineItems = basket.productItems?.map((item) => normalizeCartLineItem(item)) ?? [];
  const shippingMethod = getShippingMethod(context, basket);
  const totalCouponDiscounts = basket.productItems
    ? getTotalDiscounts(context, basket.productItems)
    : normalizeMoney(0);
  const subtotalRegularPrice = getSubtotalRegularPrice(context, lineItems);
  const subtotalDiscountedPrice = getSubtotalDiscountedPrice(context, basket.productItems);

  return {
    appliedCoupons,
    billingAddress,
    customerEmail: maybe(basket.customerInfo?.email || undefined),
    id: basket.basketId,
    lineItems,
    shippingAddress,
    shippingMethod,
    subtotalDiscountedPrice,
    subtotalRegularPrice,
    totalCouponDiscounts,
    totalItems,
    totalPrice,
    totalShippingPrice,
    totalTax,
  };
});

/**
 * taxTotal is undefined until the shipping method is selected, therefore we use adjustedMerchandizeTotalTax as a fallback.
 */
function getTotalTax(context: NormalizerContext, basket: Basket): SfCart["totalTax"] {
  const amount = basket.taxTotal ?? basket.adjustedMerchandizeTotalTax ?? 0;
  return context.normalizers.normalizeMoney(amount);
}

/**
 * orderTotal is undefined until the shipping method is selected, therefore we use productTotal as a fallback.
 */
function getTotalPrice(context: NormalizerContext, basket: Basket): SfCart["totalPrice"] {
  const shippingPrice = basket.shippingTotal ?? 0;
  const amount = basket.orderTotal || (basket.productTotal ?? 0) + shippingPrice;
  return context.normalizers.normalizeMoney(amount);
}

function getAddress(
  context: NormalizerContext,
  address: BasketAddress | undefined,
): Maybe<SfAddress> {
  return address ? context.normalizers.normalizeAddress(address) : null;
}

/**
 * SFCC always create one shipment which is available by default. Its id is "me". Although SFCC supports splitting product items into multiple shipments, we don't support it yet.
 * @link Reference: https://developer.salesforce.com/docs/commerce/commerce-api/references/shopper-baskets?meta=type:Shipment
 */
function getShippingMethod(context: NormalizerContext, basket: Basket): SfCart["shippingMethod"] {
  const unnormalizedShippingMethod = basket.shipments?.[0]?.shippingMethod;
  return unnormalizedShippingMethod
    ? context.normalizers.normalizeShippingMethod(unnormalizedShippingMethod)
    : null;
}

/**
 * ProductItem may include different types of discounts - coupons, promotions, manual discounts etc. All of them are sum up in priceAfterOrderDiscount.
 * To get discount components, you can iterate through priceAdjustments array.
 * @link Reference: https://developer.salesforce.com/docs/commerce/commerce-api/references/shopper-baskets?meta=type%3AProductItem
 */
function getTotalDiscounts(
  context: NormalizerContext,
  items: ProductItem[],
): SfCart["totalCouponDiscounts"] {
  const amount = items.reduce((acc, product) => {
    if (!product.price || !product.priceAfterOrderDiscount) return acc;

    const discount = product.price - product.priceAfterOrderDiscount;
    return acc + discount;
  }, 0);

  return context.normalizers.normalizeMoney(amount);
}

function getSubtotalRegularPrice(
  context: NormalizerContext,
  lineItems: SfCartLineItem[],
): SfCart["subtotalRegularPrice"] {
  const lineItemsAmount = lineItems.reduce(
    (acc, item) => acc + (item.unitPrice?.regularPrice.amount || 0) * item.quantity,
    0,
  );

  return context.normalizers.normalizeMoney(+lineItemsAmount.toFixed(2));
}

/**
 * Returns cumulated `productItem[].price` value, which is the price of the line item before applying any adjustments (e.g. coupons) or shipping charges.
 * Equals to purchasable price of the product - Sale pricebook value (if exists) or List pricebook value.
 * @link Reference: https://developer.salesforce.com/docs/commerce/commerce-api/references/shopper-baskets?meta=getBasket
 */
function getSubtotalDiscountedPrice(
  context: NormalizerContext,
  productItems: Basket["productItems"] = [],
): SfCart["subtotalDiscountedPrice"] {
  const amount = productItems.reduce((acc, item) => acc + (item.price || 0), 0);

  return context.normalizers.normalizeMoney(amount);
}

function getTotalItems(basket: Basket): SfCart["totalItems"] {
  return basket.productItems?.reduce((acc, curr) => acc + (curr.quantity || 0), 0) ?? 0;
}